Patent Grant
7910326
The contents of the text file submitted electronically are incorporated herein by reference in their entirety: A computer readable format copy of the Sequence Listing (filename: ARBG—001—06US_SubSeqList_ST25.txt, date recorded: Aug. 28, 2009, file size 451 kilobytes).
This invention relates to polynucleotides, including partial and extended sequences as well as probes and primers, constructs comprising the polynucleotides, biological materials (including plants, microorganisms and multicellular organisms) incorporating the polynucleotides, polypeptides encoded by the polynucleotides, and methods for using the polynucleotides and polypeptides. The invention relates, more particularly, to the modification of lignin content and composition in biological materials including plants, to polypeptides involved in the lignin biosynthetic pathway, and to polynucleotides encoding such enzymes.
Lignin is an insoluble polymer that is primarily responsible for the rigidity of plant stems. Specifically, lignin serves as a matrix around the polysaccharide components of some plant cell walls. The higher the lignin content, the more rigid the plant. For example, tree species synthesize large quantities of lignin, with lignin constituting between 20% to 30% of the dry weight of wood. In addition to providing rigidity, lignin aids in water transport within plants by rendering cell walls hydrophobic and water impermeable. Lignin also plays a role in disease resistance of plants by impeding the penetration and propagation of pathogenic agents.
The high concentration of lignin in trees presents a significant problem in the paper industry wherein considerable resources must be employed to separate lignin from the cellulose fiber needed for the production of paper. Methods typically employed for the removal of lignin are highly energy- and chemical-intensive, resulting in increased costs and increased levels of undesirable waste products. In the U.S. alone, about 20 million tons of lignin are removed from wood per year.
Lignin is largely responsible for the digestibility, or lack thereof, of forage crops, with small increases in plant lignin content resulting in relatively high decreases in digestibility. For example, crops with reduced lignin content provide more efficient forage for cattle, with the yield of milk and meat being higher relative to the amount of forage crop consumed. During normal plant growth, the increase in dry matter content is accompanied by a corresponding decrease in digestibility. When deciding on the optimum time to harvest forage crops, farmers must therefore chose between a high yield of less digestible material and a lower yield of more digestible material.
For some applications, an increase in lignin content is desirable since increasing the lignin content of a plant would lead to increased mechanical strength of wood, changes in its color and increased resistance to rot. Mycorrhizal species composition and abundance may also be favorably manipulated by modifying lignin content and structural composition.
As discussed in detail below, lignin is formed by polymerization of at least three different monolignols that are synthesized in a multistep pathway, each step in the pathway being catalyzed by a different enzyme. It has been shown that manipulation of the number of copies of genes encoding certain enzymes, such as cinnamyl alcohol dehydrogenase (CAD) and caffeic acid 3-O-methyltransferase (COMT) results in modification of the amount of lignin produced; see, for example, U.S. Pat. No. 5,451,514 and PCT Publication No. WO 94/23044. Furthermore, it has been shown that antisense expression of sequences encoding CAD in poplar leads to the production of lignin having a modified composition (Grand C et al., Planta (Berl.) 163:232-237, 1985).
While polynucleotides encoding some of the enzymes involved in the lignin biosynthetic pathway have been isolated for certain species of plants, genes encoding many of the enzymes in a wide range of plant species have not yet been identified. Thus there remains a need in the art for materials useful in the modification of lignin content and composition in plants and for methods for their use.
Briefly, the present invention provides isolated polynucleotides identified in the attached Sequence Listing as SEQ ID NO: 1-266, 350-375, 404 and 406, variants of those sequences, genetic constructs comprising such sequences, extended sequences comprising the sequences of SEQ ID NO: 1-266, 350-375, 404 and 406, and their variants, probes and primers corresponding to the sequences set out in SEQ ID NO: 1-266, 350-375, 404, 406 and their variants, and polynucleotides comprising at least a specified number of contiguous residues of any of the polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406 (x-mers), all of which are referred to herein, collectively, as “polynucleotides of the present invention.” Polynucleotides of the present invention are preferably obtainable from eucalyptus and pine species, and preferably comprise open reading frames or partial open reading frames encoding enzymes, or functional portions of enzymes, involved in the lignin biosynthetic pathway. Genetic constructs incorporating such polynucleotides, methods for using such polynucleotides and genetic constructs, and biological materials, including plant cells and plants having an altered genomic and/or lignin content and composition are provided. The present invention also provides isolated polypeptide sequences identified in the attached Sequence Listing as SEQ ID NO: 267-349, 376-401, 405 and 407; polypeptide variants of those sequences; and polypeptides comprising the inventive polypeptide sequences and variants of those sequences.
In one aspect, the present invention provides isolated polynucleotides encoding the following enzymes, or portions of the following enzymes: cinnamate 4-hydroxylase (C4H), coumarate 3-hydroxylase (C3H), phenolase (PNL), O-methyl transferase (OMT), cinnamyl alcohol dehydrogenase (CAD), cinnamoyl-CoA reductase (CCR), phenylalanine ammonia-lyase (PAL), 4-coumarate: CoA ligase (4CL), coniferol glucosyl transferase (CGT), coniferin beta-glucosidase (CBG), laccase (LAC), peroxidase (POX), ferulate-5-hydroxylase (F5H), alpha amylase, caffeic acid methyl transferase, caffeoyl CoA methyl transferase, coumerate 6A ligase, cytochrome P450 LXX1A, diphenol oxidase, flavonol glucosyl transferase, flavonoid hydroxylase, and isoflavone reductase.
In one embodiment, polynucleotides of the present invention encompass polynucleotides comprising a nucleotide sequence selected from the group consisting of: (a) polynucleotides recited in SEQ ID NO: 1-266, 350-375, 404 and 406; (b) complements of the polynucleotides recited in SEQ ID NO: 1-266, 350-375, 404 and 406; (c) reverse complements of the sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406; (d) reverse sequences of the sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406; and (e) variants of the polynucleotides recited in SEQ ID NO: 1-266, 350-375, 404 and 406. In another embodiment of the present invention, the inventive polynucleotides comprise at least a specified number of contiguous residues (x-mers) of any of the polynucleotides of SEQ ID NO: 1-266, 350-375, 404 and 406. In yet another aspect, the inventive polynucleotides comprise probes and primers corresponding to any of the polynucleotides of SEQ ID NO: 1-266, 350-375, 404 and 406.
In a further aspect, the present invention provides genetic constructs comprising a polynucleotide of the present invention, either alone or in combination with one or more of the inventive sequences, or in combination with one or more known polynucleotides; together with host cells and transgenic cells comprising such constructs.
In a related aspect, the present invention provides genetic constructs comprising, in the 5′-3′ direction, a gene promoter sequence; an open reading frame coding for at least a functional portion of an enzyme encoded by a polynucleotide of the present invention; and a gene termination sequence. An open reading frame may be orientated in either a sense or antisense direction. Genetic constructs comprising a non-coding region of a gene coding for an enzyme encoded by the above polynucleotides or a polynucleotide complementary to a non-coding region, together with a gene promoter sequence and a gene termination sequence, are also provided. Preferably, the gene promoter and termination sequences are functional in a host cell, such as a plant cell. Most preferably, the gene promoter and termination sequences are those of the original enzyme genes but others generally used in the art, such as the Cauliflower Mosaic Virus (CMV) promoter, with or without enhancers, such as the Kozak sequence or Omega enhancer, and Agrobacterium tumefaciens nopalin synthase terminator may be usefully employed in the present invention. Tissue-specific promoters may be employed in order to target expression to one or more desired tissues. In a preferred embodiment, the gene promoter sequence provides for transcription in xylem. The construct may further include a marker for the identification of transformed cells.
In a further aspect, transgenic cells, such as transgenic plant cells, comprising the genetic constructs of the present invention are provided, together with plants comprising such transgenic cells, and fruits and seeds of such plants.
In yet another aspect, methods for modulating the lignin content and composition of a target organism such as a plant are provided, such methods including stably incorporating into the genome of the target plant a genetic construct comprising a polynucleotide of the present invention. In a preferred embodiment, the target plant is a woody plant, preferably selected from the group consisting of eucalyptus and pine species, most preferably from the group consisting of Eucalyptus grandis and Pinus radiata. In a related aspect, a method for producing a plant having altered lignin content is provided, the method comprising transforming a plant cell with a genetic construct comprising a polynucleotide of the present invention to provide a transgenic cell, and cultivating the transgenic cell under conditions conducive to regeneration and mature plant growth.
In yet a further aspect, the present invention provides methods for modifying the activity of an enzyme in a target organism such as a plant, comprising stably incorporating into the genome of the target organism a genetic construct of the present invention. In a preferred embodiment, the target plant is a woody plant, preferably selected from the group consisting of eucalyptus and pine species, most preferably from the group consisting of Eucalyptus grandis and Pinus radiata.
The present invention also provides polypeptides encoded by the inventive polynucleotides. In certain specific embodiments, such polypeptides comprise a sequence selected from the group consisting of: SEQ ID NO: 267-349, 376-401, 405 and 407, and variants of those sequences.
The above-mentioned and additional features of the present invention and the manner of obtaining them will become apparent, and the invention will be best understood by reference to the following more detailed description, read in conjunction with the accompanying drawing.
Lignin is formed by polymerization of at least three different monolignols, primarily para-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. While these three types of lignin subunits are well known, it is possible that slightly different variants of these subunits may be involved in the lignin biosynthetic pathway in various plants. The relative concentration of these residues in lignin varies among different plant species and within species. In addition, the composition of lignin may also vary among different tissues within a specific plant. The three monolignols are derived from phenylalanine in a multistep process and are believed to be polymerized into lignin by a free radical mechanism.
The formation of sinapyl alcohol involves an additional enzyme, ferulate-5-hydroxylase (F5H). For a more detailed review of the lignin biosynthetic pathway, see Whetton R and Sederoff R, The Plant Cell, 7:1001-1013, 1995.
Quantitative and qualitative modifications in plant lignin content are known to be induced by external factors such as light stimulation, low calcium levels and mechanical stress. Synthesis of new types of lignins, sometimes in tissues not normally lignified, can also be induced by infection with pathogens. In addition to lignin, several other classes of plant products are derived from phenylalanine, including flavonoids, coumarins, stilbenes and benzoic acid derivatives, with the initial steps in the synthesis of all these compounds being the same. Thus modification of the action of PAL, C4H, 4CL and other enzymes involved in the lignin biosynthetic pathway may affect the synthesis of other plant products in addition to lignin.
Using the methods and materials of the present invention, the lignin content of a plant may be modulated by modulating expression of polynucleotides of the present invention, or by modifying the polypeptides encoded by polynucleotides or the polynucleotides. The lignin content of a target organism, such as a plant, may be modified, for example, by incorporating additional copies of genes encoding enzymes involved in the lignin biosynthetic pathway into the genome of the target plant. Similarly, a modified lignin content can be obtained by transforming the target plant with antisense copies of such genes. In addition, the number of copies of genes encoding for different enzymes in the lignin biosynthetic pathway can be manipulated to modify the relative amount of each monolignol synthesized, thereby leading to the formation of lignin having altered composition. The alteration of lignin composition would be advantageous, for example, in applications of wood processing for paper, and may also be effective in altering the palatability of wood materials to rotting fungi.
In a first aspect, the present invention provides isolated polynucleotide sequences identified in the attached Sequence Listing as SEQ ID NO: 1-266, 350-375, 404 and 406, variants of those sequences, extended sequences comprising the sequences set out in SEQ ID NO: 1-266, 350-375, 404 and 406, and their variants, probes and primers corresponding to the sequences set out in SEQ ID NO: 1-266, 350-375, 404 and 406, and their variants, polynucleotides comprising at least a specified number of contiguous residues of any of the polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406 (x -mers), and extended sequences comprising portions of the sequences set out in SEQ ID NO: 1-266, 350-375, 404 and 406, all of which are referred to herein, collectively, as “polynucleotides of the present invention.” The present invention also provides isolated polypeptide sequences identified in the attached Sequence Listing as SEQ ID NO: 267-349, 376-401, 405 and 407, polypeptide variants of those sequences, and polypeptides comprising the isolated polypeptide sequences and variants of those sequences.
The polynucleotides disclosed herein were derived from forestry plant sources, namely from Eucalyptus grandis and Pinus radiata. Some of the polynucleotides of the present invention are “partial” sequences, in that they do not represent a full length gene encoding a full length polypeptide. Such partial sequences may be extended by analyzing and sequencing various DNA libraries using primers and/or probes and well known hybridization and/or PCR techniques. Partial sequences may be extended until an open reading frame encoding a polypeptide, a full length polynucleotide and/or gene capable of expressing a polypeptide, or another useful portion of the genome is identified. Such extended sequences, including full length polynucleotides and genes, are described as “corresponding to” a sequence identified as one of the sequences of SEQ ID NO: 1-266, 350-375, 404 and 406, or a variant thereof, or a portion of one of the sequences of SEQ ID NO: 1-266, 350-375, 404 and 406, or a variant thereof, when the extended polynucleotide comprises an identified sequence or its variant, or an identified contiguous portion (x-mer) of one of the sequences of SEQ ID NO: 1-266, 350-375, 404 and 406, or a variant thereof. Similarly, RNA sequences, reverse sequences, complementary sequences, antisense sequences, and the like, corresponding to the polynucleotides of the present invention, may be routinely ascertained and obtained using the cDNA sequences identified as SEQ ID NO: 1-266, 350-375, 404 and 406.
The polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406 contain open reading frames (“ORFs”) or partial open reading frames encoding polypeptides and functional portions of polypeptides. Additionally, open reading frames encoding polypeptides may be identified in extended or full length sequences corresponding to the sequences set out as SEQ ID NO: 1-266, 350-375, 404 and 406. Open reading frames may be identified using techniques that are well known in the art. These techniques include, for example, analysis for the location of known start and stop codons, most likely reading frame identification based on codon frequencies, etc. . Tools and software for ORF analysis, include, for example, GeneWise, available from The Sanger Center, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, United Kingdom; Diogenes, available from Computational Biology Centers, University of Minnesota, Academic Health Center, UMHG Box 43 Minneapolis Minn. 55455; and GRAIL, available from the Informatics Group, Oak Ridge National Laboratories, Oak Ridge, Tenn. Open reading frames and portions of open reading frames are present and may be identified in the polynucleotides of the present invention. Once a partial open reading frame is identified, the polynucleotide may be extended in the area of the partial open reading frame using techniques that are well known in the art until the polynucleotide for the full open reading frame is identified. Thus, open reading frames encoding polypeptides may be identified using the polynucleotides of the present invention.
Once open reading frames are identified in the polynucleotides of the present invention, the open reading frames may be isolated and/or synthesized. Expressible genetic constructs comprising the open reading frames and suitable promoters, initiators, terminators, etc., which are well known in the art, may then be constructed. Such genetic constructs may be introduced into a host cell to express the polypeptide encoded by the open reading frame. Suitable host cells may include various prokaryotic and eukaryotic cells, including plant cells, mammalian cells, bacterial cells, algae and the like.
Polypeptides encoded by the polynucleotides of the present invention may be expressed and used in various assays to determine their biological activity. Such polypeptides may be used to raise antibodies, to isolate corresponding interacting proteins or other compounds, and to quantitatively determine levels of interacting proteins or other compounds.
The present invention also contemplates methods for modulating the polynucleotide and/or polypeptide content and composition of a forestry species, such methods involving stably incorporating into the genome of the organism a genetic construct comprising one or more polynucleotides of the present invention. In one embodiment, the target organism is a forestry species, preferably a woody plant, more preferably a woody plant of the Pinus or Eucalyptus species, and most preferably Eucalyptus grandis or Pinus radiata. In a related aspect, a method for producing a forestry plant having an altered genotype or phenotype is provided, the method comprising transforming a plant cell with a genetic construct of the present invention to provide a transgenic cell, and cultivating the transgenic cell under conditions conducive to regeneration and mature plant growth. Forestry plants having an altered genotype or phenotype as a consequence of modulation of the level or content of a polynucleotide or polypeptide of the present invention compared to a wild-type organism, as well as components (seeds, etc.) of such forestry plants, and the progeny of such forestry plants, are contemplated by and encompassed within the present invention.
The isolated polynucleotides of the present invention also have utility in genome mapping, in physical mapping, and in positional cloning of genes. Additionally, the polynucleotide sequences identified as SEQ ID NO: 1-266, 350-375, 404 and 406, and their variants, may be used to design oligonucleotide probes and primers. Oligonucleotide probes and primers have sequences that are substantially complementary to the polynucleotide of interest over a certain portion of the polynucleotide. Oligonucleotide probes designed using the polynucleotides of the present invention may be used to detect the presence and examine the expression patterns of genes in any organism having sufficiently similar DNA and RNA sequences in their cells using techniques that are well known in the art, such as slot blot DNA hybridization techniques. Oligonucleotide primers designed using the polynucleotides of the present invention may be used for PCR amplifications. Oligonucleotide probes and primers designed using the polynucleotides of the present invention may also be used in connection with various microarray technologies, including the microarray technology used by Synteni (Palo Alto, Calif.).
The polynucleotides of the present invention may also be used to tag or identify an organism or reproductive material therefrom. Such tagging may be accomplished, for example, by stably introducing a non-disruptive non-functional heterologous polynucleotide identifier into an organism, the polynucleotide comprising one of the polynucleotides of the present invention.
The polypeptides of the present invention and the polynucleotides encoding the polypeptides have activity in lignin biosynthetic pathways in plants. The polynucleotides were identified by DNA and polypeptide similarity searches. The polynucleotides and polypeptides of the present invention have demonstrated similarity to the following polypeptides that are known to be involved in lignin biosynthetic processes:
In one embodiment, isolated polynucleotides of the present invention comprise a sequence selected from the group consisting of: (a) sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406; (b) complements of the sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406; (c) reverse complements of the sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406; (d) reverse sequences of the sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406; and (e) sequences having at least 50%, 75%, 90%, 95% or 98% identity, as defined herein, to a sequence of (a)-(d) or a specified region of a sequence of (a)-(d).
In a further aspect, isolated polypeptides encoded by the polynucleotides of the present invention are provided. In one embodiment, such polypeptides comprise an amino acid sequence recited in SEQ ID NO: 267-349, 376-401, 405 and 407, and variants thereof, as well as polypeptides expressed by polynucleotides of the present invention, including polynucleotides comprising a sequence of SEQ ID NO: 1-266, 350-375, 404 and 406.
In another aspect, the invention provides genetic constructs comprising a polynucleotide of the present invention, either alone, in combination with one or more additional polynucleotides of the present invention, or in combination with one or more known polynucleotides, together with cells and target organisms comprising such constructs.
In a related aspect, the present invention provides genetic constructs comprising, in the 5′-3′ direction, a gene promoter sequence, an open reading frame coding for at least a functional portion of a polypeptide encoded by a polynucleotide of the present invention, and a gene termination sequence. The open reading frame may be oriented in either a sense or antisense direction. Genetic constructs comprising a gene promoter sequence, a polynucleotide of the present invention, and a gene termination sequence are also contemplated, as are genetic constructs comprising a gene promoter sequence, an Lintranslated region of a polynucleotide of the present invention, or a nucleotide sequence complementary to an untranslated region, and a gene termination sequence. The genetic construct may further include a marker for the identification of transformed cells.
The gene promoter and termination sequences are preferably functional in a host plant and, most preferably, are those native to the host plant. Promoter and termination sequences that are generally used in the art, such as the Cauliflower Mosaic Virus (CMV) promoter, with or without enhancers such as the Kozak sequence or Omega enhancer, and Agrobacterium tumefaciens nopaline synthase terminator, are useful. Tissue-specific promoters may be employed in order to target expression to one or more desired tissues.
In a further aspect, methods for producing forestry plants having a modified content of a polynucleotide or polypeptide of the present invention compared to a native organism are provided. The methods involve transforming a target forestry plant with a genetic construct of the present invention to provide a transgenic cell, and cultivating the transgenic cell under conditions conducive to regeneration and mature plant growth. Cells comprising the genetic constructs of the present invention are provided, together with tissues and forestry plants comprising such transgenic cells, and fruits, seeds and other products, derivatives, or progeny of such forestry plants.
The word “polynucleotide(s),” as used herein, means a polymeric collection of nucleotides and includes DNA and corresponding RNA molecules and both single and double stranded molecules, including HnRNA and mRNA molecules, sense and anti-sense strands of DNA and RNA molecules, and cDNA, genomic DNA, and wholly or partially synthesized polynucleotides. An HnRNA molecule contains introns and “corresponds to” a DNA molecule in a generally one-to-one manner. An mRNA molecule “corresponds to” an HnRNA and DNA molecule from which the introns have been excised. A polynucleotide of the present invention may be an entire gene, or any portion thereof. A gene is a DNA sequence which codes for a functional protein or RNA molecule. Operable anti-sense polynucleotides may comprise a fragment of the corresponding polynucleotide, and the definition of “polynucleotide” therefore includes all operable anti-sense fragments. Anti-sense polynucleotides and techniques involving anti-sense polynucleotides are well known in the art and are described, for example, in Robinson-Benion et al., “Antisense techniques,” Methods in Enzymol. 254(23):363-375, 1995; and Kawasaki et al., Artific. Organs 20(8):836-848, 1996.
Complements of such isolated polynucleotides, reverse complements of such isolated polynucleotides, and reverse sequences of such isolated polynucleotides, together with variants of such sequences, are also provided. The definition of the terms “complement”, “reverse complement” and “reverse sequence”, as used herein, is best illustrated by the following example. For the sequence 5′ AGGACC 3′, the complement, reverse complement and reverse sequence are as follows:
As used herein, the term “oligonucleotide” refers to a relatively short segment of a polynucleotide sequence, generally comprising between 6 and 60 nucleotides, and comprehends both probes for use in hybridization assays and primers for use in the amplification of DNA by polymerase chain reaction.
Identification of genomic DNA and heterologous species DNAs can be accomplished by standard DNA/DNA hybridization techniques, under appropriately stringent conditions, using all or part of a cDNA sequence as a probe to screen an appropriate library. Alternatively, PCR techniques using oligonucleotide primers that are designed based on known genomic DNA, cDNA and protein sequences can be used to amplify and identify genomic and cDNA sequences. Synthetic DNAs corresponding to the identified sequences and variants may be produced by conventional synthesis methods. All of the polynucleotides described herein are isolated and purified, as those terms are commonly used in the art.
In another aspect, the present invention provides isolated polypeptides encoded, or partially encoded, by the above polynucleotides. As used herein, the term “polypeptide” encompasses amino acid chains of any length, including full length proteins, wherein the amino acid residues are linked by covalent peptide bonds. The term “polypeptide encoded by a polynucleotide” as used herein, includes polypeptides encoded by a polynucleotide which comprises an isolated DNA sequence or variant provided herein. In specific embodiments, the inventive polypeptides comprise an amino acid sequence selected from the group consisting of sequences provided in SEQ ID NO: 267-349, 376-401, 405 and 407, as well as variants of such sequences.
Polypeptides of the present invention may be produced recombinantly by inserting a DNA sequence that encodes the polypeptide into an expression vector and expressing the polypeptide in an appropriate host. Any of a variety of expression vectors known to those of ordinary skill in the art may be employed. Expression may be achieved in any appropriate host cell that has been transformed or transfected with an expression vector containing a DNA molecule that encodes a recombinant polypeptide. Suitable host cells include prokaryotes, yeast and higher eukaryotic cells. Preferably, the host cells employed are E. coli, insect, yeast or a mammalian cell line such as COS or CHO. The DNA sequences expressed in this manner may encode naturally occurring polypeptides, portions of naturally occurring polypeptides, or other variants thereof.
In a related aspect, polypeptides are provided that comprise at least a functional portion of a polypeptide having an amino acid sequence selected from the group consisting of sequences provided in SEQ ID NO:267-349, 376-401, 405 and 407, and variants thereof. As used herein, the “functional portion” of a polypeptide is that portion which contains the active site essential for affecting the function of the polypeptide, for example, the portion of the molecule that is capable of binding one or more reactants. The active site may be made up of separate portions present on one or more polypeptide chains and will generally exhibit high binding affinity.
Functional portions of a polypeptide may be identified by first preparing fragments of the polypeptide by either chemical or enzymatic digestion of the polypeptide, or by mutation analysis of the polynucleotide that encodes the polypeptide and subsequent expression of the resulting mutant polypeptides. The polypeptide fragments or mutant polypeptides are then tested to determine which portions retain biological activity, using, for example, the representative assays provided below.
A functional portion comprising an active site may be made up of separate portions present on one or more polypeptide chains and generally exhibits high substrate specificity. The term “polypeptide encoded by a polynucleotide” as used herein, includes polypeptides encoded by a polynucleotide comprising a partial isolated polynucleotide of the present invention.
Portions and other variants of the inventive polypeptides may also be generated by synthetic or recombinant means. Synthetic polypeptides having fewer than about 100 amino acids, and generally fewer than about 50 amino acids, may be generated using techniques well known to those of ordinary skill in the art. For example, such polypeptides may be synthesized using any of the commercially available solid-phase techniques, such as the Merrifield solid-phase synthesis method, where amino acids are sequentially added to a growing amino acid chain. See Merrifield, J. Am. Chem. Soc. 85: 2149-2146, 1963. Equipment for automated synthesis of polypeptides is commercially available from suppliers such as Perkin Elmer/Applied Biosystems, Inc. (Foster City, Calif.), and may be operated according to the manufacturer's instructions. Variants of a native polypeptide may be prepared using standard mutagenesis techniques, such as oligonucleotide-directed site-specific mutagensis (Kunkel, T., Proc. Natl. Acad. Sci. USA 82: 488-492, 1985). Sections of DNA sequences may also be removed using standard techniques to permit preparation of truncated polypeptides.
In general, the polypeptides disclosed herein are prepared in an isolated, substantially pure form. Preferably, the polypeptides are at least about 80% pure; more preferably at least about 90% pure; and most preferably, at least about 99% pure.
As used herein, the term “variant” comprehends nucleotide or amino acid sequences different from the specifically identified sequences, wherein one or more nucleotides or amino acid residues is deleted, substituted, or added. Variants may be naturally occurring allelic variants, or non-naturally occurring variants. Variant sequences (polynucleotide or polypeptide) preferably exhibit at least 50%, more preferably at least 75%, and most preferably at least 90%, 95% or 98% identity to a sequence of the present invention. The percentage identity is determined by aligning the two sequences to be compared as described below, determining the number of identical residues in the aligned portion, dividing that number by the total number of residues in the inventive (queried) sequence, and multiplying the result by 100.
Polynucleotide and polypeptide sequences may be aligned, and percentage of identical nucleotides in a specified region may be determined against another polynucleotide, using computer algorithms that are publicly available. Two exemplary algorithms for aligning and identifying the similarity of polynucleotide sequences are the BLASTN and FASTA algorithms. Polynucleotides may also be analyzed using the BLASTX algorithm, which compares the six-frame conceptual translation products of a nucleotide query sequence (both strands) against a protein sequence database. The similarity of polypeptide sequences may be examined using the BLASTP algorithm. The BLASTN, BLASTX and BLASTP programs are available on the NCBI anonymous FTP server and from the National Center for Biotechnology Information (NCBI) National Library of Medicine, Building 38A, Room 8N805, Bethesda, Md. 20894 USA. The BLASTN algorithm Version 2.0.4 [Feb. 24, 1998] and Version 2.0.6 [Sep. 16, 1998], set to the default parameters described in the documentation and distributed with the algorithm, are preferred for use in the determination of polynucleotide variants according to the present invention. The BLASTP algorithm, set to the default parameters described in the documentation and distributed with the program, is preferred for use in the determination of polypeptide variants according to the present invention. The use of the BLAST family of algorithms, including BLASTN, BLASTP, and BLASTX, is described at NCBI's website and in the publication of Altschul Stephen F, et al., “Gapped BLAST and PSI-BLAST: a new generation of protein database search programs,” Nucleic Acids Res. 25: 3389-3402, 1997.
The computer algorithm FASTA is available on the Internet and from the University of Virginia by contacting David Hudson, Assistant Provost for Research, University of Virginia, PO Box 9025, Charlottesville, Va. 22906-9025 USA. FASTA Version 2.0.4, February 1996, set to the default parameters described in the documentation and distributed with the algorithm, may be used in the determination of variants according to the present invention. The use of the FASTA algorithm is described in Pearson W R and Lipman D J, “Improved Tools for Biological Sequence Analysis,” Proc. Natl. Acad. Sci. USA 85: 2444-2448, 1988; and Pearson W R, “Rapid and Sensitive Sequence Comparison with FASTP and FASTA,” Methods in Enzymology 183: 63-98, 1990.
The following running parameters are preferred for determination of alignments and similarities using BLASTN that contribute to the E values and percentage identity for polynucleotide sequences: Unix running command: blastall -p blastn -d embldb -e 10 -GO -E0 -r 1 -v 30 -b 30 -i queryseq -o results; the parameters are: -p Program Name [String]; -d Database [String]; -e Expectation value (E) [Real]; -G Cost to open a gap (zero invokes default behavior) [Integer]; -E Cost to extend a gap (zero invokes default behavior) [Integer]; -r Reward for a nucleotide match (blastn only) [Integer]; -v Number of one-line descriptions (V) [Integer]; -b Number of alignments to show (B) [Integer]; -i Query File [File In]; and -o BLAST report Output File [File Out] Optional. The following running parameters are preferred for determination of alignments and similarities using BLASTP that contribute to the E values and percentage identity of polypeptide sequences: blastall -p blastp -d swissprotdb -e 10 -G 0 -E 0 -v 30 -b 30 -i queryseq -o results; the parameters are: -p Program Name [String]; -d Database [String]; -e Expectation value (E) [Real]; -G Cost to open a gap (zero invokes default behavior) [Integer]; -E Cost to extend a gap (zero invokes default behavior) [Integer]; -v Number of one-line descriptions (v) [Integer]; -b Number of alignments to show (b) [Integer]; -I Query File [File In]; -o BLAST report Output File [File Out] Optional. The “hits” to one or more database sequences by a queried sequence produced by BLASTN, FASTA, BLASTP or a similar algorithm, align and identify similar portions of sequences. The hits are arranged in order of the degree of similarity and the length of sequence overlap. Hits to a database sequence generally represent an overlap over only a fraction of the sequence length of the queried sequence.
The BLASTN, FASTA, and BLASTP algorithms also produce “Expect” (E) values for alignments. The Expect value (E) indicates the number of hits one can “expect” to see over a certain number of contiguous sequences by chance when searching a database of a certain size. The Expect value is used as a significance threshold for determining whether the hit to a database, such as the preferred EMBL database, indicates true similarity. For example, an E value of 0.1 assigned to a polynucleotide hit is interpreted as meaning that in a database of the size of the EMBL database, one might expect to see 0.1 matches over the aligned portion of the sequence with a similar score simply by chance. By this criterion, the aligned and matched portions of the polynucleotide sequences then have a probability of 90% of being the same. For sequences having an E value of 0.01 or less over aligned and matched portions, the probability of finding a match by chance in the EMBL database is 1% or less using the BLASTN or FASTA algorithm.
According to one embodiment, “variant” polynucleotides and polypeptides, with reference to each of the polynucleotides and polypeptides of the present invention, preferably comprise sequences having the same number or fewer nucleic or amino acids than each of the polynucleotides or polypeptides of the present invention and producing an E value of 0.01 or less when compared to the polynucleotide or polypeptide of the present invention. That is, a variant polynucleotide or polypeptide is any sequence that has at least a 99% probability of being the same as the polynucleotide or polypeptide of the present invention, measured as having an E value of 0.01 or less using the BLASTN, FASTA, or BLASTP algorithms set at parameters described above. According to a preferred embodiment, a variant polynucleotide is a sequence having the same number or fewer nucleic acids than a polynucleotide of the present invention that has at least a 99% probability of being the same as the polynucleotide of the present invention, measured as having an E value of 0.01 or less using the BLASTN or FASTA algorithms set at parameters described above. Similarly, according to a preferred embodiment, a variant polypeptide is a sequence having the same number or fewer amino acids than a polypeptide of the present invention that has at least a 99% probability of being the same as a polypeptide of the present invention, measured as having an E value of 0.01 or less using the BLASTP algorithm set at the parameters described above.
Alternatively, variant polynucleotides or polypeptides of the present invention comprise a sequence exhibiting at least 50%; more preferably at least 75%; more preferably yet at least 90%; and most preferably at least 98% similarity to a polynucleotide or polypeptide of the present invention, determined as described below. Polynucleotides and polypeptides having a specified percentage similarity to a polynucleotide or polypeptide specified in one of the SEQ ID NOS. thus share a high degree of similarity in their primary structure. In addition to a specified percentage similarity to a polynucleotide of the present invention, variant polynucleotides and polypeptides preferably have additional structural and/or functional features in common with a polynucleotide of the present invention.
Polynucleotides having a specified degree of identity to, or capable of hybridizing to, a polynucleotide of the present invention preferably additionally have at least one of the following features: (1) they contain an open reading frame or partial open reading frame encoding a polypeptide, or a functional portion of a polypeptide, having substantially the same functional properties as the polypeptide, or functional portion thereof, encoded by a polynucleotide in a recited SEQ ID NO.; or (2) they contain identifiable domains in common. Similarly, polypeptides, or functional portions of polypeptides, having a specified degree of identity to a polypeptide of the present invention shares a high degree of identity in their primary structure and have substantially similar functional properties.
As noted above, the percentage identity is determined by aligning sequences using one of the BLASTN, FASTA, or BLASTP algorithms, set at the running parameters described above, and identifying the number of identical nucleic or amino acids over the aligned portions; dividing the number of identical nucleic or amino acids by the total number of nucleic or amino acids of the polynucleotide or polypeptide of the present invention; and then multiplying by 100 to determine the percentage identity. For example, a polynucleotide of the present invention having 220 nucleic acids has a hit to a polynucleotide sequence in the EMBL database having 520 nucleic acids over a stretch of 23 nucleotides in the alignment produced by the BLASTN algorithm using the parameters described above. The 23 nucleotide hit includes 21 identical nucleotides, one gap and one different nucleotide. The percentage identity of the polynucleotide of the present invention to the hit in the EMBL library is thus 21/220 times 100, or 9.5%. The polynucleotide sequence in the EMBL database is thus not a variant of a polynucleotide of the present invention.
Alternatively, variant polynucleotides of the present invention hybridize to the polynucleotide sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406, or complements, reverse sequences, or reverse complements of those sequences, under stringent conditions. As used herein, “stringent conditions” refers to prewashing in a solution of 6×SSC, 0.2% SDS; hybridizing at 65° C., 6×SSC, 0.2% SDS overnight; followed by two washes of 30 minutes each in 1×SSC, 0.1% SDS at 65° C. and two washes of 30 minutes each in 0.2×SSC, 0.1% SDS at 65° C.
The present invention also encompasses polynucleotides that differ from the disclosed sequences but that, as a consequence of the discrepancy of the genetic code, encode a polypeptide having similar enzymatic activity as a polypeptide encoded by a polynucleotide of the present invention. Thus, polynucleotides comprising sequences that differ from the polynucleotide sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406, or complements, reverse sequences, or reverse complements of those sequences as a result of conservative substitutions are contemplated by and encompassed within the present invention. Additionally, polynucleotides comprising sequences that differ from the polynucleotide sequences recited in SEQ ID NO: 1-266, 350-375, 404 and 406, or complements, reverse complements, or reverse sequences as a result of deletions and/or insertions totaling less than 10% of the total sequence length are also contemplated by and encompassed within the present invention. Similarly, polypeptides comprising sequences that differ from the polypeptide sequences recited in SEQ ID NO: 267-349, 376-401, 405 and 407 as a result of amino acid substitutions, insertions, and/or deletions totaling less than 10% of the total sequence length are contemplated by and encompassed within the present invention, provided the variant polypeptide has activity in a lignin biosynthetic pathway.
The polynucleotides of the present invention, including variants, may be isolated from various libraries assembled from plant or non-plant organisms, or may be synthesized using techniques that are well known in the art. Polynucleotides of the present invention may be isolated by high throughput sequencing of cDNA libraries prepared from Eucalyptus grandis and Pinus radiata as described below in Examples 1 and 2. Alternatively, oligonucleotide probes based on the sequences provided in SEQ ID NO: 1-266, 350-375, 404 and 406 may be synthesized and used to identify positive clones in either cDNA or genomic DNA libraries from Eucalyptus grandis and Pinus radiata by means of hybridization or PCR techniques. Probes may be shorter than the sequences provided herein but should be at least about 10, preferably at least about 15 and most preferably at least about 20 nucleotides in length. Hybridization and PCR techniques suitable for use with such oligonucleotide probes are well known in the art. Positive clones may be analyzed by restriction enzyme digestion, DNA sequencing or the like.
Variants of the polynucleotides of the present invention derived from other eucalyptus and pine species, as well as from other commercially important species utilized by the lumber industry, are contemplated. These include the following gymnosperms, by way of example: loblolly pine Pinus taeda, slash pine Pinus elliotti, sand pine Pinus clausa, longleaf pine Pinus palustrus, shortleaf pine Pinus echinata, ponderosa pine Pinus ponderosa, Jeffrey pine Pinus jeffrey, red pine Pinus resinosa, pitch pine Pinus rigida, jack pine Pinus banksiana, pond pine Pinus serotina, Eastern white pine Pinus strobus, Western white pine Pinus monticola, sugar pine Pinus lambertiana, Virginia pine Pinus virginiana, lodgepole pine Pinus contorta, Caribbean pine Pinus caribaea, P. pinaster, Calabrian pine P. brutia, Afghan pine P. eldarica, Coulter pine P. coulteri, European pine P. nigra and P. sylvestris; Douglas-fir Pseudotsuga menziesii; the hemlocks which include Western hemlock Tsuga heterophylla, Eastern hemlock Tsuga canadensis, Mountain hemlock Tsuga mertensiana; the spruces which include the Norway spruce Picea abies, red spruce Picea rubens, white spruce Picea glauca, black spruce Picea mariana, Sitka spruce Picea sitchensis, Englemann spruce Picea engelmanni, and blue spruce Picea pungens; redwood Sequoia sempervirens; the true firs include the Alpine fir Abies lasiocarpa, silver fir Abies amabilis, grand fir Abies grandis, nobel fir Abies procera, white fir Abies concolor, California red fir Abies magnifica, and balsam fir Abies balsamea, the cedars which include the Western red cedar Thuja plicata, incense cedar libocedrus decurrens, Northern white cedar Thuja occidentalis, Port Orford cedar Chamaecyparis lawsoniona, Atlantic white cedar Chamaecyparis thyoides, Alaska yellow-cedar Chamaecyparis nootkatensis, and Eastern red cedar Huniperus virginiana; the larches which include Eastern larch Larix laricina, Western larch Larix occidentalis, European larch Larix decidua, Japanese larch Larix leptolepis, and Siberian larch Larix siberica; bold cypress Taxodium distichum and Giant sequoia Sequoia gigantea; and the following angiosperms, by way of example: Eucalyptus alba, E. bancroftii, E. botyroides, E. bridgesiana, E. calophylla, E. camaldulensis, E. citriodora, E. cladocalyx, E. coccifera, E. curtisii, E. dalrympleana, E. deglupta, E. delagatensis, E. diversicolor, E. dunnii, E. ficifolia, E. globulus, E. gomphocephala, E. gunnii, E. henryi, E. laevopinea, E. macarthurii, E. macrorhyncha, E. maculata, E. marginata, E. megacarpa, E. melliodora, E. nicholii, E. nitens, E. nova-angelica, E. obliqua, E. obtusiflora, E. oreades, E. pauciflora, E. polybractea, E. regnans, E. resinifera, E. robusta, E. rudis, E. saligna, E. sideroxylon, E. stuartiana, E. tereticornis, E. torelliana, E. urnigera, E. urophylla, E. viminalis, E. viridis, E. wandoo and E. youmanni.
The polynucleotides of the present invention may alternatively be synthesized, for example, using automated oligonucleotide synthesizers (e.g., Beckman Oligo 1000M DNA Synthesizer) to obtain polynucleotide segments of up to 50 or more nucleic acids. A plurality of such polynucleotide segments may then be ligated using standard DNA manipulation techniques that are well known in the art of molecular biology. One conventional and exemplary polynucleotide synthesis technique involves synthesis of a single stranded polynucleotide segment having, for example, 80 nucleic acids, and hybridizing that segment to a synthesized complementary 85 nucleic acid segment to produce a 5 nucleotide overhang. The next segment may then be synthesized in a similar fashion, with a 5 nucleotide overhang on the opposite strand. The “sticky” ends ensure proper ligation when the two portions are hybridized. In this way, a complete polynucleotide of the present invention may be synthesized entirely in vitro.
The polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406 represent both “partial” and full length sequences. Partial sequences do not represent the full coding portion of a gene encoding a naturally occurring polypeptide. The partial polynucleotide sequences disclosed herein may be employed to obtain the corresponding full length genes for various species and organisms by, for example, screening DNA expression libraries using hybridization probes based on the polynucleotides of the present invention, or using PCR amplification with primers based upon the polynucleotides of the present invention. In this way one can, using methods well known in the art, extend a polynucleotide of the present invention upstream and downstream of the corresponding mRNA, as well as identify the corresponding genomic DNA, including the promoter and enhancer regions, of the complete gene.
The present invention thus comprehends isolated polynucleotides comprising a sequence identified in SEQ ID NO: 1-266, 350-375, 404 and 406, or a variant of one of the specified sequences, that encode a functional polypeptide, including full length genes. Such extended polynucleotides may have a length of from about 50 to about 4,000 nucleic acids or base pairs, and preferably have a length of less than about 4,000 nucleic acids or base pairs, more preferably a length of less than about 3,000 nucleic acids or base pairs, more preferably yet a length of less than about 2,000 nucleic acids or base pairs. Under some circumstances, extended polynucleotides of the present invention may have a length of less than about 1,800 nucleic acids or base pairs, preferably less than about 1,600 nucleic acids or base pairs, more preferably less than about 1,400 nucleic acids or base pairs, more preferably yet less than about 1,200 nucleic acids or base pairs, and most preferably less than about 1,000 nucleic acids or base pairs.
Polynucleotides of the present invention also comprehend polynucleotides comprising at least a specified number of contiguous residues (x-mers) of any of the polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406 or their variants. According to preferred embodiments, the value of x is preferably at least 20, more preferably at least 40, more preferably yet at least 60, and most preferably at least 80. Thus, polynucleotides of the present invention include polynucleotides comprising a 20-mer, a 40-mer, a 60-mer, an 80-mer, a 100-mer, a 120-mer, a 150-mer, a 180-mer, a 220-mer a 250-mer, or a 300-mer, 400-mer, 500-mer or 600-mer of a polynucleotide identified as SEQ ID NO: 1-266, 350-375, 404 and 406, or a variant of any x-mer. That is, the definitions for variants described above in terms of E values, % similarity and hybridization, apply also to any x-mer of any polynucleotide of the present invention.
Polynucleotide probes and primers complementary to and/or corresponding to SEQ ID NO: 1-266, 350-375, 404 and 406, and variants of those sequences, are also comprehended by the present invention. Such oligonucleotide probes and primers are substantially complementary to the polynucleotide of interest. An oligonucleotide probe or primer is described as “corresponding to” a polynucleotide of the present invention, including one of the sequences set out as SEQ ID NO: 1-266, 350-375, 404 and 406 or a variant, if the oligonucleotide probe or primer, or its complement, is contained within one of the sequences set out as SEQ ID NO: 1-266, 350-375, 404 and 406 or a variant of one of the specified sequences.
Two single stranded sequences are said to be substantially complementary when the nucleotides of one strand, optimally aligned and compared, with the appropriate nucleotide insertions and/or deletions, pair with at least 80%, preferably at least 90% to 95%, and more preferably at least 98% to 100%, of the nucleotides of the other strand. Alternatively, substantial complementarity exists when a first DNA strand will selectively hybridize to a second DNA strand under stringent hybridization conditions. Stringent hybridization conditions for determining complementarity include salt conditions of less than about 1 M, more usually less than about 500 mM and preferably less than about 200 mM. Hybridization temperatures can be as low as 5° C., but are generally greater than about 22° C., more preferably greater than about 30° C. and most preferably greater than about 37° C. Longer DNA fragments may require higher hybridization temperatures for specific hybridization. Since the stringency of hybridization may be affected by other factors such as probe composition, presence of organic solvents and extent of base mismatching, the combination of parameters is more important than the absolute measure of any one alone. The DNAs from plants or samples or products containing plant material can be either genomic DNA or DNAs derived by preparing cDNA from the RNAs present in the sample.
In addition to DNA-DNA hybridization, DNA-RNA or RNA-RNA hybridization assays are also possible. In the first case, the mRNAs from expressed genes would then be detected instead of genomic DNA or cDNA derived from mRNA of the sample. In the second case, RNA probes could be used. In addition, artificial analogs of DNA hybridizing specifically to target sequences could also be used.
In specific embodiments, the oligonucleotide probes and/or primers comprise at least about 6 contiguous residues, more preferably at least about 10 contiguous residues, and most preferably at least about 20 contiguous residues complementary to a polynucleotide sequence of the present invention. Probes and primers of the present invention may be from about 8 to 100 base pairs in length or, preferably, from about 10 to 50 base pairs in length or, more preferably, from about 15 to 40 base pairs in length. The probes can be easily selected using procedures well known in the art, taking into account DNA-DNA hybridization stringencies, annealing and melting temperatures, potential for formation of loops and other factors, which are well known in the art. Tools and software suitable for designing probes and PCT primers are well known in the art. Preferred techniques for designing PCR primers are disclosed in Dieffenbach C W and Dvksler G S, PCR primer: a laboratory manual, CSHL Press: Cold Spring Harbor, N.Y., 1995. A software program suitable for designing probes, and especially for designing PCR primers, is available from Premier Biosoft International, 3786 Corina Way, Palo Alto, Calif. 94303-4504.
A plurality of oligonucleotide probes or primers corresponding to polynucleotides of the present invention may be provided in a kit form. Such kits generally comprise multiple DNA or oligonucleotide probes, each probe being specific for a polynucleotide sequence. Kits of the present invention may comprise one or more probes or primers corresponding to a polynucleotide of the present invention, including a polynucleotide sequence identified in SEQ ID NO: 1-266, 350-375, 404 and 406.
In one embodiment useful for high-throughput assays, the oligonucleotide probe kits of the present invention comprise multiple probes in an array fonnat, wherein each probe is immobilized in a predefined, spatially addressable location on the surface of a solid substrate. Array formats which may be usefully employed in the present invention are disclosed, for example, in U.S. Pat. Nos. 5,412,087, 5,545,531, and PCT Publication No. WO 95/00530, the disclosures of which are hereby incorporated by reference.
The significance of high-throughput screening systems is apparent for applications such as plant breeding and quality control operations in which there is a need to identify large numbers of seed lots and plant seedlings, to examine samples or products for unwanted plant materials, to identify plants or samples or products containing plant material for quarantine purposes etc. or to ascertain the true origin of plants or samples or products containing plant material. Screening for the presence or absence of polynucleotides of the present invention used as identifiers for tagging plants is valuable for later detecting the amount of gene flow in plant breeding, introgression of genes via dispersed pollen, etc.
In this manner, oligonucleotide probe kits of the present invention may be employed to examine the presence/absence (or relative amounts in case of mixtures) of polynucleotides of the present invention in different samples or products containing different materials rapidly and in a cost-effective manner. Examples of plant species that may be examined using the present invention, include forestry species, such as pine and eucalyptus species, other tree species, agricultural plants including crop and forage plants, and horticultural plants.
Another aspect of the present invention involves collections of polynucleotides of the present invention. A collection of polynucleotides of the present invention, particularly the polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406, and variants and x-mers thereof, may be recorded and/or stored on a storage medium and subsequently accessed for purposes of analysis, comparison, etc. Suitable storage media include magnetic media such as magnetic diskettes, magnetic tapes, CD-ROM storage media, optical storage media, and the like. Suitable storage media and methods for recording and storing information, as well as accessing information such as polynucleotide sequences recorded on such media, are well known in the art. The polynucleotide information stored on the storage medium is preferably computer-readable and may be used for analysis and comparison of the polynucleotide information.
Another aspect of the present invention thus involves storage medium on which are recorded a collection of the polynucleotides of the present invention, particularly a collection of the polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406, and variants thereof, as well as x-mers of the polynucleotides of SEQ ID NO: 1-266, 350-375, 404 and 406, and extended sequences, probes and primers comprising or correspond to a polynucleotide of SEQ ID NO: 1-266, 350-375, 404 and 406. According to one embodiment, the storage medium includes a collection of at least 20, preferably at least 50, more preferably at least 100, and most preferably at least 200 of the polynucleotides of the present invention, preferably the polynucleotides identified as SEQ ID NO: 1-266, 350-375, 404 and 406, or variants of those polynucleotides.
In another aspect, the present invention provides genetic constructs comprising, in the 5′-3′ direction, a gene promoter sequence; an open reading frame coding for at least a functional portion of a polypeptide encoded by a polynucleotide of the present invention; and a gene termination sequence. As used herein, the “functional portion” of an enzyme is a portion that contains an active site essential for affecting a metabolic step, i.e. a portion of the molecule that is capable of binding one or more reactants or is capable of improving or regulating the rate of reaction. An active site may be made up of separate portions present on one or more polypeptide chains and will generally exhibit high substrate specificity. The term “enzyme encoded by a nucleotide sequence” as used herein, includes enzymes encoded by a nucleotide sequence which includes the partial isolated polynucleotides of the present invention.
The open reading frame may be orientated in either a sense or antisense direction. For applications where amplification of lignin synthesis is desired, the open reading frame may be inserted in the construct in a sense orientation, such that transformation of a target organism with the construct will lead to an increase in the number of copies of the gene and therefore an increase in the amount of enzyme. When down-regulation of lignin synthesis is desired, the open reading frame may be inserted in the construct in an antisense orientation, such that the RNA produced by transcription of the polynucleotide is complementary to the endogenous mRNA sequence. This, in turn, will result in a decrease in the number of copies of the gene and therefore a decrease in the amount of enzyme. Alternatively, regulation may be achieved by inserting appropriate sequences or subsequences (e.g., DNA or RNA) in ribozyrne constructs.
Genetic constructs comprising a non-coding region of a gene coding for an enzyme encoded by the above DNA sequences or a nucleotide sequence complementary to a non-coding region, together with a gene promoter sequence and a gene termination sequence, are also provided. As used herein the term “non-coding region” includes both transcribed sequences which are not translated, and non-transcribed sequences within about 2000 base pairs 5′ or 3′ of the translated sequences or open reading frames. Examples of non-coding regions which may be usefully employed in the inventive constructs include introns and 5′- non-coding leader sequences. Transformation of a target plant with such a DNA construct may lead to a reduction in the amount of lignin synthesized by the plant by the process of cosuppression, in a manner similar to that discussed, for example, by Napoli et al., Plant Cell 2:279-290, 1990; and de Carvalho Niebel et al., Plant Cell 7:347-358, 1995.
The genetic constructs of the present invention further comprise a gene promoter sequence and a gene termination sequence, operably linked to the polynucleotide to be transcribed, which control expression of the gene. The gene promoter sequence is generally positioned at the 5′ end of the polynucleotide to be transcribed, and is employed to initiate transcription of the polynucleotide. Gene promoter sequences are generally found in the 5′ non-coding region of a gene but they may exist in introns (Luehrsen K R, Mol. Gen. Genet. 225:81-93, 1991, or in the coding region, as for example in PAL of tomato (Bloksberg, Studies on the Biology of Phenylalanine Ammonia Lyase and Plant Pathogen Interaction, Ph.D. Thesis, University of California, Davis, 1991, University Microfilms International Order No. 9217564). When the construct includes an open reading frame in a sense orientation, the gene promoter sequence also initiates translation of the open reading frame. For genetic constructs comprising either an open reading frame in an antisense orientation or a non-coding region, the gene promoter sequence consists only of a transcription initiation site having a RNA polymerase binding site.
A variety of gene promoter sequences which may be usefully employed in the genetic constructs of the present invention are well known in the art. The promoter gene sequence, and also the gene termination sequence, may be endogenous to the target plant host or may be exogenous, provided the promoter is functional in the target host. For example, the promoter and termination sequences may be from other plant species, plant viruses, bacterial plasmids and the like. Preferably, gene promoter and termination sequences are from the inventive sequences themselves.
Factors influencing the choice of promoter include the desired tissue specificity of the construct, and the timing of transcription and translation. For example, constitutive promoters, such as the 35S Cauliflower Mosaic Virus (CaMV 35S) promoter, will affect the activity of the enzyme in all parts of the plant. Use of a tissue specific promoter will result in production of the desired sense or antisense RNA only in the tissue of interest. With genetic constructs employing inducible gene promoter sequences, the rate of RNA polymerase binding and initiation can be modulated by external stimuli, such as light, heat, anaerobic stress, alteration in nutrient conditions and the like. Temporally regulated promoters can be employed to effect modulation of the rate of RNA polymerase binding and initiation at a specific time during development of a transformed cell. Preferably, the original promoters from the enzyme gene in question, or promoters from a specific tissue-targeted gene in the organism to be transformed, such as eucalyptus or pine are used. Other examples of gene promoters which may be usefully employed in the present invention include, mannopine synthase (mas), octopine synthase (ocs) and those reviewed by Chua et al., Science 244:174-181, 1989.
The gene termination sequence, which is located 3′ to the polynucleotide to be transcribed, may come from the same gene as the gene promoter sequence or may be from a different gene. Many gene termination sequences known in the art may be usefully employed in the present invention, such as the 3′ end of the Agrobacterium tumefaciens nopaline synthase gene. However, preferred gene terminator sequences are those from the original enzyme gene or from the target species to be transformed.
The genetic constructs of the present invention may also contain a selection marker that is effective in plant cells, to allow for the detection of transformed cells containing the inventive construct. Such markers, which are well known in the art, typically confer resistance to one or more toxins. One example of such a marker is the NPTII gene whose expression results in resistance to kanamycin or hygromycin, antibiotics which are usually toxic to plant cells at a moderate concentration (Rogers et al., in Weissbach A and H, eds., Methods for Plant Molecular Biology, Academic Press Inc.: San Diego, Calif., 1988). Alternatively, the presence of the desired construct in transformed cells can be determined by means of other techniques well known in the art, such as Southern and Western blots.
Techniques for operatively linking the components of the inventive genetic constructs are well known in the art and include the use of synthetic linkers containing one or more restriction endonuclease sites as described, for example, by Maniatis et al., (Molecular cloning: a laboratory manual, CSHL Press: Cold Spring Harbor, N.Y., 1989). The genetic construct of the present invention may be linked to a vector having at least one replication system, for example, E. coli, whereby after each manipulation, the resulting construct can be cloned and sequenced and the correctness of the manipulation determined.
The genetic constructs of the present invention may be used to transform a variety of plants, both monocotyledonous (e.g., grasses, corn, grains, oat, wheat and barley), dicotyledonous (e.g., Arabidopsis, tobacco, legumes, alfalfa, oaks, eucalyptus, maple), and Gymnosperms (e.g., Scots pine; see Aronen, Finnish Forest Res. Papers, Vol. 595, 1996), white spruce (Ellis et al., Biotechnology 11:94-92, 1993), and larch (Huang et al., In Vitro Cell 27:201-207, 1991). In a preferred embodiment, the inventive genetic constructs are employed to transform woody plants, herein defined as a tree or shrub whose stem lives for a number of years and increases in diameter each year by the addition of woody tissue. Preferably the target plant is selected from the group consisting of eucalyptus and pine species, most preferably from the group consisting of Eucalyptus grandis and Pinus radiata. As discussed above, transformation of a plant with a genetic construct including an open reading frame coding for an enzyme encoded by an inventive polynucleotide wherein the open reading frame is orientated in a sense direction will produce a modified lignin content in the plant. Transformation of a plant with a genetic construct comprising an open reading frame in an antisense orientation or a non-coding (untranslated) region of a gene will also produced a modification in the lignin content of the transformed plant.
Polynucleotides of the present invention may also be used to specifically suppress gene expression by methods that operate post-transcriptionally to block the synthesis of products of targeted genes, such as RNA interference (RNAi) and quelling. Briefly, traditional methods of gene suppression, employing anti-sense RNA or DNA, operate by binding to the reverse sequence of a gene of interest such that binding interferes with subsequent cellular processes and therefore blocks synthesis of the corresponding protein. RNAi also operates on a post-translational level and is sequence specific, but suppresses gene expression far more efficiently. Exemplary methods for controlling or modifying gene expression using RNAi are provided in WO 99/49029 and WO 99/53050. In these methods, post-transcriptional gene silencing is brought about by a sequence-specific RNA degradation process which results in the rapid degradation of transcripts of sequence-related genes. Studies have shown that double-stranded RNA may act as a mediator of sequence-specific gene silencing (see, for example, Montgomery and Fire, Trends in Genetics, 14:255-258, 1998). Gene constructs that produce transcripts with self-complementary regions are particularly efficient at gene silencing. A unique feature of this post-transcriptional gene silencing pathway is that silencing is not limited to the cells where it is initiated. The gene-silencing effects may be disseminated to other parts of an organism and even transmitted through the germ line to several generations.
The polynucleotides of the present invention may thus be employed to generate gene silencing constructs and/or gene-specific self-complementary RNA sequences that can be delivered by conventional art-known methods to plant tissues, such as forage grass tissues. Within genetic constructs, sense and antisense sequences can be placed in regions flanking an intron sequence in proper splicing orientation with donor and acceptor splicing sites, such that intron sequences are removed during processing of the transcript and sense and antisense sequences, as well as splice junction sequences, bind together to form double-stranded RNA. Alternatively, spacer sequences of various lengths may be employed to separate self-complementary regions of sequence in the construct. During processing of the gene construct transcript, intron sequences are spliced-out, allowing sense and anti-sense sequences, as well as splice junction sequences, to bind forming double-stranded RNA. Select ribonucleases then bind to and cleave the double-stranded RNA, thereby initiating the cascade of events leading to degradation of specific mRNA gene sequences, and silencing specific genes. Alternatively, rather than using a gene construct to express the self-complementary RNA sequences, the gene-specific double-stranded RNA segments are delivered to one or more targeted areas to be internalized into the cell cytoplasm to exert a gene silencing effect. The double-stranded RNA must have sufficient homology to the targeted gene to mediate RNAi and is preferably at least 25 nucleotides in length. Preferably, the double-stranded RNA corresponds specifically to a polynucleotide of the present invention. Gene silencing RNA sequences comprising the polynucleotides of the present invention are useful for creating genetically modified plants with desired phenotypes as well as for characterizing genes (for example, in high-throughput screening of sequences), and studying their functions in intact organisms.
The production of RNA in target cells may be controlled by choice of the promoter sequence, or by selecting the number of functional copies or the site of integration of the polynucleotides incorporated into the genome of the target organism. A target plant may be transformed with more than one construct of the present invention, thereby modulating the lignin biosynthetic pathway for the activity of more than one enzyme, affecting enzyme activity in more than one tissue or affecting enzyme activity at more than one expression time. Similarly, a construct may be assembled containing more than one open reading frame coding for an enzyme encoded by a polynucleotide of the present invention or more than one non-coding region of a gene coding for such an enzyme. The polynucleotides of the present invention may also be employed in combination with other known sequences encoding enzymes involved in the lignin biosynthetic pathway. In this manner, it may be possible to add a lignin biosynthetic pathway to a non-woody plant to produce a new woody plant.
Techniques for stably incorporating genetic constructs into the genome of target plants are well known in the art and include Agrobacterium tumefaciens mediated introduction, electroporation, protoplast fusion, injection into reproductive organs, injection into immature embryos, high velocity projectile introduction and the like. The choice of technique will depend upon the target plant to be transformed. For example, dicotyledonous plants and certain monocots and gymnosperms may be transformed by Agrobacterium Ti plasmid technology, as described, for example by Bevan (Nucl. Acid Res. 12:8711-8721, 1984). Targets for the introduction of the genetic constructs of the present invention include tissues, such as leaf tissue, disseminated cells, protoplasts, seeds, embryos, meristematic regions; cotyledons, hypocotyls, and the like. One preferred method for transforming eucalyptus and pine is a biolistic method using pollen (see, for example, Aronen, Finnish Forest Res. Papers, Vol. 595:53, 1996) or easily regenerable embryonic tissues. Other transformation techniques which may be usefully employed in the inventive methods include those taught by Ellis et al. (Plant Cell Reports, 8:16-20, 1989), Wilson et al. (Plant Cell Reports 7:704-707, 1989) and Tautorus et al. (Theor. Appl. Genet. 78:531-536, 1989).
Once the cells are transformed, cells having the inventive genetic construct incorporated in their genome may be selected by means of a marker, such as the kanamycin resistance marker discussed above. Transgenic cells may then be cultured in an appropriate medium to regenerate whole plants, using techniques well known in the art. In the case of protoplasts, the cell wall is allowed to reform under appropriate osmotic conditions. In the case of seeds or embryos, an appropriate germination or callus initiation medium is employed. For explants, an appropriate regeneration medium is used. Regeneration of plants is well established for many species. For a review of regeneration of forest trees, see Dunstan et al., “Somatic embryogenesis in woody plants,” in Thorpe T A, ed., In vitro embryogenesis of plants, Current Plant Science and Biotechnology in Agriculture 20(12):471-540, 1995. Specific protocols for the regeneration of spruce are discussed by Roberts et al., (“Somatic embryogenesis of spruce,” in Redenbaugh K, ed., Synseed: applications of synthetic seed to crop improvement, CRC Press: Chapter 23, pp. 427-449, 1993). The resulting transformed plants may be reproduced sexually or asexually, using methods well known in the art, to give successive generations of transgenic plants.
In yet a further aspect, the present invention provides methods for modifying the level (concentration) or activity of a polypeptide in a host organism, comprising stably incorporating into the genome of the plant a construct comprising a polynucleotide of the present invention. The genetic constructs of the present invention may be used to transform a variety of organisms. Such organisms include plants, such as monocotyledonous angiosperms (e.g., grasses, corn, grains, oat, wheat and barley), and dicotyledonous angiosperms (e.g., Arabidopsis, tobacco, legumes, alfalfa, oaks, eucalyptus, maple), and gymnosperms (e.g., Scots pine; see Aronen, Finnish Forest Res. Papers, Vol. 595, 1996), white spruce (Ellis et al., Biotechnology 11:94-92, 1993), and larch (Huang et al., In Vitro Cell 27:201-207, 1991).
In preferred embodiments, the genetic constructs of the present invention are employed to transform woody plants, herein defined as a tree or shrub having a stem that lives for a number of years and increases in diameter each year as a consequence of the addition of woody tissue. The target plant is preferably selected from the group consisting of eucalyptus and pine species, most preferably from the group consisting of Eucalyptus grandis and Pinus radiata, but also including any of the species in the following list:
Pines: Pinus banksiana, Pinus bnitia, Pinus caribaea, Pinus clausa, Pinus contorta, Pinus coulteri, Pinus echinata, Pinus eldarica, Pinus ellioti, Pinus jeffreyi, Pinus lambertiana, Pinus monticola, Pinus nigra, Pinus palustrus, Pinus pinaster, Pinus ponderosa, Pinus resinosa, Pinus rigida, Pinus serotina, Pinus strobus, Pinus sylvestris, Pinus taeda, Pinus virginiana.
Other gymnosperms: Abies amabilis, Abies balsamea, Abies concolor, Abies grandis, Abies lasiocarpa, Abies magnifica, Abies procera, Chamaecyparis lawsoniona, Chamaecyparis nootkatensis, Chamaecyparis thyoides, Huniperus virginiana, Larix decidua, Larix laricina, Larix leptolepis, Larix occidentalis, Larix siberica, Libocedrus decurrens, Picea abies, Picea engelmanni, Picea glauca, Picea mariana, Picea pungens, Picea rubens, Picea sitchensis, Pseudotsuga menziesii, Sequoia gigantea, Sequoia sempervirens, Taxodium distichum, Tsuga canadensis, Tsuga heterophylla, Tsuga mertensiana, Thuja occidentalis, Thuja plicata.
Eucalypts: Eucalyptus alba, Eucalyptus bancroftii, Eucalyptus botyroides, Eucalyptus bridgesiana, Eucalyptus calophylla, Eucalyptus camaldulensis, Eucalyptus citriodora, Eucalyptus cladocalyx, Eucalyptus coccifera, Eucalyptus curtisii, Eucalyptus dalrympleana, Eucalyptus deglupta, Eucalyptus delagatensis, Eucalyptus diversicolor, Eucalyptus dunnii, Eucalyptus ficifolia, Eucalyptus globulus, Eucalyptus gomphocephala, Eucalyptus gunnii, Eucalyptus henryi, Eucalyptus laevopinea, Eucalyptus macarthurii, Eucalyptus macrorhyncha, Eucalyptus maculata, Eucalyptus marginata, Eucalyptus megacarpa, Eucalyptus melliodora, Eucalyptus nicholii, Eucalyptus nitens, Eucalyptus nova-anglica, Eucalyptus obliqua, Eucalyptus obtusiflora, Eucalyptus oreades, Eucalyptus pauciflora, Eucalyptus polybractea, Eucalyptus regnans, Eucalyptus resinifera, Eucalyptus robusta, Eucalyptus rudis, Eucalyptus saligna, Eucalyptus sideroxylon, Eucalyptits stuartiana, Eucalyptus tereticornis, Eucalyptus torelliana, Eucalyptus urnigera, Eucalyptus urophylla, Eucalyptus viminalis, Eucalyptus viridis, Eucalyptus wandoo, Eucalyptus youmanni; and hybrids of any of the above species.
Further, the polynucleotides of the present invention have particular application for use as non-disruptive tags for marking organisms, particularly plants. Other organisms may, however, be tagged with the polynucleotides of the present invention, including commercially valuable animals, fish, bacteria and yeasts. Constructs comprising polynucleotides of the present invention may be stably introduced into an organism as heterologous, non-functional, non-disruptive tags. It is then possible to identify the origin or source of the organism at a later date by determining the presence or absence of the tag(s) in a sample of material.
Detection of the tag(s) may be accomplished using a variety of conventional techniques, and will generally involve the use of nucleic acid probes. Sensitivity in assaying the presence of probe can be usefully increased by using branched oligonucleotides, as described in Horn T, Chang C A and Urdea M S, “Chemical synthesis and characterization of branched oligodeoxyribonucleotides (bDNA) for use as signal amplifiers in nucleic acid quantification assays,” Nucleic Acids Research 25(23):4842-4849, 1997), enabling detection of as few as 50 DNA molecules in the sample.
The following examples are offered by way of illustration and not by way of limitation.
Two Eucalyptus grandis cDNA expression libraries (one from a mixture of various tissues from a single tree and one from leaves of a single tree) were constructed and screened as follows.
mRNA was extracted from the plant tissue using the protocol of Chang et al. (Plant Molecular Biology Reporter 11:113-116, 1993) with minor modifications. Specifically, samples were dissolved in CPC-RNAXB (100 mM Tris-Cl, pH 8.0; 25 mM EDTA; 2.0 M NaCl; 2% CTAB; 2% PVP and 0.05% Spermidine*3 HCl) and extracted with chloroform:isoamyl alcohol, 24:1. mRNA was precipitated with ethanol and the total RNA preparate was purified using a Poly(A) Quik mRNA Isolation Kit (Stratagene, La Jolla, Calif.). A cDNA expression library was constructed from the purified mRNA by reverse transcriptase synthesis followed by insertion of the resulting cDNA clones in Lambda ZAP using a ZAP Express cDNA Synthesis Kit (Stratagene), according to the manufacturer's protocol. The resulting cDNAs were packaged using a Gigapack II Packaging Extract (Stratagene) employing 1 μl of sample DNA from the 5 μl ligation mix. Mass excision of the library was done using XL1-Blue MRF′ cells and XLOLR cells (Stratagene) with ExAssist helper phage (Stratagene). The excised phagemids were diluted with NZY broth (Gibco BRL, Gaithersburg, Md.) and plated out onto LB-kanamycin agar plates containing X-gal and isopropylthio-beta-galactoside (IPTG).
Of the colonies plated and picked for DNA miniprep, 99% contained an insert suitable for sequencing. Positive colonies were cultured in NZY broth with kanamycin and cDNA was purified by means of alkaline lysis and polyethylene glycol (PEG) precipitation. Agarose gel at 1% was used to screen sequencing templates for chromosomal contamination. Dye primer sequences were prepared using a Turbo Catalyst 800 machine (Perkin Elmer/Applied Biosystems, Foster City, Calif.) according to the manufacturer's protocol.
DNA sequences for positive clones were obtained using a Perkin Elmer/Applied Biosystems Prism 377 sequencer. cDNA clones were sequenced first from the 5′ end and, in some cases, also from the 3′ end. For some clones, internal sequence was obtained using subcloned fragments. Subcloning was performed using standard procedures of restriction mapping and subcloning to pBluescript II SK+ vector.
The determined cDNA sequences were compared to known sequences in the EMBL database (release 46, March 1996) using the FASTA algorithm of February 1996 (Version 2.0.4) or the BLASTN algorithm Version 2.0.4 [Feb. 24, 1998], or Version 2.0.6 [Sep. 16, 1998], set to the preferred parameters described above. Multiple alignments of redundant sequences were used to build up reliable consensus sequences. Based on similarity to known sequences from other plant species, the isolated polynucleotides of the present invention were identified as encoding a specified enzyme.
Using the procedures described above, cDNA sequences derived from the Eucalyptus graitdis library encoding the following polypeptides were isolated: PAL (SEQ ID NO: 16, 100, 242-246); C4H (SEQ ID NO: 17, 153, 154, and 161); C3H (SEQ ID NO: 18, 101, 149 and 150); F5H (SEQ ID NO: 19-21, 102, 103, 169-171 and 404); OMT (SEQ ID NO: 22-25, 104-107, 173 and 174); CCR (SEQ ID NO: 26-29 and 108-111); CAD (SEQ ID NO: 1, 30 and 112); CGT (SEQ ID NO: 31-33 and 113-115); CBG (SEQ ID NO: 34, 165 and 166); PNL (SEQ ID NO: 35,36 and 116); LAC (SEQ ID NO: 37-41, 117 and 118); POX (SEQ ID NO: 42-44, 119-121, 179, 249-250 and 350-358); 4CL (SEQ ID NO: 266); caffeic acid methyl transferase (SEQ ID NO: 187-192); caffeoyl CoA methyl transferase (SEQ ID NO: 193-195); coumarate Co-A ligase (SEQ ID NO: 196-198); cytochrome P450 LXX1A (SEQ ID NO: 201-206); diphenol oxidase (SEQ ID NO: 207-217); flavonol glucosyl transferase (SEQ ID NO: 218); flavonoid hydroxylase (SEQ ID NO: 219-223); and isoflavone reductase (SEQ ID NO: 234-240).
As shown in Table 1, above, the amino acid sequences encoded by SEQ ID NO: 187-191, 193-198, 201-217, 219-223, 234-239, 242-246, 249, 250, 266 and 350-358 are provided in SEQ ID NO: 270-274, 276-281, 284-300, 302-306, 317-322, 325-329, 332, 333, 349 and 376-384, respectively. SEQ ID NO: 107 is a full-length version of SEQ ID NO: 24 and 106; SEQ ID NO: 108 is a full-length version of SEQ ID NO: 26; SEQ ID NO: 266 is a full-length version of SEQ ID NO: 196 and 197; and SEQ ID NO: 404 is a full-length version of SEQ ID NO: 20 and 103.
a) Isolation of cDNA Clones by High Through-Put Screening
A Pinus radiata cDNA expression library was constructed from xylem and screened as described above in Example 1. DNA sequences for positive clones were obtained using forward and reverse primers on a Perkin Elmer/Applied Biosystems Prism 377 sequencer and the determined sequences were compared to known sequences in the EMBL database as described above.
Based on similarity to known sequences from other plant species, the isolated DNA sequences were identified as encoding the enzymes C4H (SEQ ID NO: 2, 3, 48, 49, 92, 124, 125, 155-160, 162 and 163); C3H (SEQ ID NO: 4, 50-52, 93, 126, 127, 151 and 152); PNL (SEQ ID NO: 5, 81 and 183 ); OMT (SEQ ID NO: 6, 53-55, 94 and 175); CAD (SEQ ID NO: 7, 71, 95 and 164); CCR (SEQ ID NO: 8, 58-70, 96, 128-134 and 167); PAL (SEQ ID NO: 9-11, 45-47, 97, 98, 122, 123 and 176, 247 and 248); 4CL (SEQ ID NO: 12, 56, 57, 90, 99, 147, 148, 199, 200, 265 and 406); CGT (SEQ ID NO: 72, 135 and 168); CBG (SEQ ID NO: 73-80 and 136-141); LAC (SEQ ID NO: 82-84, 142-144 and 172); POX (SEQ ID NO: 85-89, 91, 145, 146, 177, 178, 180-182, 264, 359-375); alpha amylase (SEQ ID NO: 184-186); flavonoid hydroxylase (SEQ ID NO: 224-233); isoflavone reductase (SEQ ID NO: 241); and diphenol oxidase (SEQ ID NO: 251-263).
As shown in Table 1, above, the amino acid sequences encoded by SEQ ID NO: 184-186, 192, 199-200, 218, 224-233, 240-241, 247-248, 251-265, 359-375 and 406 are provided in SEQ ID NO: 267-269, 275, 282-283, 301, 307-316, 323-324, 330-331, 334-348, 385-401 and 407, respectively. SEQ ID NO: 90 is a full-length version of SEQ ID NO: 12 and 56; SEQ ID NO: 94 is a full-length version of SEQ ID NO: 53; SEQ ID NO: 265 is a full-length version of SEQ ID NO: 57; SEQ ID NO: 363 is a full-length version of SEQ ID NO: 372; and SEQ ID NO: 406 is a full-length version of SEQ ID NO: 200.
b) Isolation of cDNA Clones by PCR
Two PCR probes, hereinafter referred to as LNB010 and LNB011 (SEQ ID NO: 14 and 15, respectively) were designed based on conserved domains in the following peroxidase sequences previously identified in other species: vanpox, hvupox6, taepox, hvupox1, osapox, ntopox2, ntopox1, lespox, pokpox, luspox, athpox, hrpox, spopox, and tvepox (Genbank Accession Nos. D11337, M83671, X56011, X58396, X66125, J02979, D11396, X71593, D 1102, L07554, M58381, X57564, Z22920, and Z31011, respectively).
RNA was isolated from pine xylem and first strand cDNA was synthesized as described above. This cDNA was subjected to PCR using 4 μM LNB010, 4 μM LNB011, 1× Kogen's buffer, 0.1 mg/ml BSA, 200 mM dNTP, 2 mM Mg2+, and 0.1 U/μl of Taq polymerase (Gibco BRL). Conditions were 2 cycles of 2 min at 94° C., 1 min at 55° C. and 1 min at 72° C.; 25 cycles of 1 min at 94° C., 1 min at 55° C., and 1 min at 72° C.; and 18 cycles of 1 min at 94° C., 1 min at 55° C., and 3 min at 72° C. in a Stratagene Robocycler. The gene was re-amplified in the same manner. A band of about 200 bp was purified from a TAE agarose gel using a Schleicher & Schuell Elu-Quik DNA purification kit and clones into a T-tailed pBluescript vector (Marchuk D et al., Nucleic Acids Res. 19:1154, 1991). Based on similarity to known sequences, the isolated gene (SEQ ID NO: 13) was identified as encoding pine peroxidase (POX).
a) Transformation of Tobacco Plants with a Pinus radiata OMT Gene
Sense and anti-sense constructs containing a polynucleotide including the coding region of OMT (SEQ ID NO: 53) from Pinus radiata were inserted into Agrobacterium tumefaciens LBA4301 (provided as a gift by Dr. C. Kado, University of California, Davis, Calif.) by direct transformation using published methods (see, An G, Ebert P R, Mitra A, Ha S B, “Binary Vectors,” in Gelvin S B, Schilperoort R A, eds., Plant Molecular Biology Manual, Kluwer Academic Publishers: Dordrecht, 1988). The presence and integrity of the transgenic constructs were verified by restriction digestion and DNA sequencing.
Tobacco (Nicotiana tabacum cv. Samsun) leaf sections were transformed using the method of Horsch et al. (Science, 227:1229-1231, 1985). Five independent transformed plant lines were established for the sense construct and eight independent transformed plant lines were established for the anti-sense construct for OMT. Transformed plants containing the appropriate lignin gene construct were verified using Southern blot experiments. A “+” in the column labeled “Southern” in Table 2 below indicates that the transformed plant lines were confirmed as independent transformed lines.
b) Expression of Pinus OMT in Transformed Plants
Total RNA was isolated from each independent transformed plant line created with the OMT sense and anti-sense constructs. The RNA samples were analysed in Northern blot experiments to determine the level of expression of the transgene in each transformed line. The data shown in the column labeled “Northern” in Table 2 shows that the transformed plant lines containing the sense and anti-sense constructs for OMT all exhibited high levels of expression, relative to the background on the Northern blots. OMT expression in sense plant line number 2 was not measured because the RNA sample showed signs of degradation. There was no detectable hybridisation to RNA samples from empty vector-transformed control plants.
c) Modulation of OMT Enzyme Activity in Transformed Plants
The total activity of OMT enzyme, encoded by the Pinus OMT gene and by the endogenous tobacco OMT gene, in transformed tobacco plants was analysed for each transformed plant line created with the OMT sense and anti-sense constructs. Crude protein extracts were prepared from each transformed plant and assayed using the method of Zhang et al. (Plant Physiol., 113:65-74, 1997). The data contained in the column labeled “Enzyme” in Table 1 shows that the transformed plant lines containing the OMT sense construct generally had elevated OMT enzyme activity, with a maximum of 199%, whereas the transformed plant lines containing the OMT anti-sense construct generally had reduced OMT enzyme activity, with a minimum of 35%, relative to empty vector-transformed control plants. OMT enzyme activity was not estimated in sense plant line number 3.
d) Effects of Pinus OMT on Lignin Concentration in Transformed Plants
The concentration of lignin in the transformed tobacco plants was determined using the well-established procedure of thioglycolic acid extraction (see, Freudenberg et al., Constitution and Biosynthesis of Lignin, Springer-Verlag: Berlin, 1968). Briefly, whole tobacco plants, of an average age of 38 days, were frozen in liquid nitrogen and ground to a fine powder in a mortar and pestle. 100 mg of frozen powder from one empty vector-transformed control plant line, the five independent transformed plant lines containing the sense construct for OMT and the eight independent transformed plant lines containing the anti-sense construct for OMT were extracted individually with methanol, followed by 10% thioglycolic acid and finally dissolved in 1 M NaOH. The final extracts were assayed for absorbance at 280 nm. The data shown in the column labelled “TGA” in Table 2 shows that the transformed plant lines containing the sense and the anti-sense OMT gene constructs all exhibited significantly decreased levels of lignin, relative to the empty vector-transformed control plant lines.
These data clearly indicate that lignin concentration, as measured by the TGA assay, can be directly manipulated by either sense or anti-sense expression of a lignin biosynthetic gene such as OMT.
a) Transformation of Tobacco Plants with a Pinus radiata 4CL Gene
Sense and anti-sense constructs containing a polynucleotide including the coding region of 4CL (SEQ ID NO: 56) from Pinus radiata were inserted into Agrobacterium tumefaciens LBA4301 by direct transformation as described above. The presence and integrity of the transgenic constructs were verified by restriction digestion and DNA sequencing.
Tobacco (Nicotiana tabacum cv. Samsun) leaf sections were transformed as described above. Five independent transformed plant lines were established for the sense construct and eight independent transformed plant lines were established for the anti-sense construct for 4CL. Transformed plants containing the appropriate lignin gene construct were verified using Southern blot experiments. A “+” in the column labeled “Southern” in Table 3 indicates that the transformed plant lines listed were confirmed as independent transformed lines.
b) Expression of Pinus 4CL in Transformed Plants
Total RNA was isolated from each independent transformed plant line created with the 4CL sense and anti-sense constructs. The RNA samples were analysed in Northern blot experiments to determine the level of expression of the transgene in each transformed line. The data shown in the column labelled “Northern” in Table 3 below shows that the transformed plant lines containing the sense and anti-sense constructs for 4CL all exhibit high levels of expression, relative to the background on the Northern blots. 4CL expression in anti-sense plant line number 1 was not measured because the RNA was not available at the time of the experiment. There was no detectable hybridisation to RNA samples from empty vector-transformed control plants.
c) Modulation of 4CL Enzyme Activity in Transformed Plants
The total activity of 4CL enzyme, encoded by the Pinus 4CL gene and by the endogenous tobacco 4CL gene, in transformed tobacco plants was analysed for each transformed plant line created with the 4CL sense and anti-sense constructs. Crude protein extracts were prepared from each transformed plant and assayed using the method of Zhang et al. (Plant Physiol., 113:65-74, 1997). The data contained in the column labeled “Enzyme” in Table 3 shows that the transformed plant lines containing the 4CL sense construct had elevated 4CL enzyme activity, with a maximum of 258%, and the transformed plant lines containing the 4CL anti-sense construct had reduced 4CL enzyme activity, with a minimum of 59%, relative to empty vector-transformed control plants.
d) Effects of Pinus 4CL on Lignin Concentration in Transformed Plants
The concentration of lignin in samples of transformed plant material was determined as described in Example 3. The data shown in the column labelled “TGA” in Table 3 shows that the transformed plant lines containing the sense and the anti-sense 4CL gene constructs all exhibited significantly decreased levels of lignin, relative to the empty vector-transformed control plant lines. These data clearly indicate that lignin concentration, as measured by the TGA assay, can be directly manipulated by either sense or anti-sense expression of a lignin biosynthetic gene such as 4CL.
Sense and anti-sense constructs containing polynucleotides including the coding regions of C3H (SEQ ID NO: 18), F5H (SEQ ID NO: 19), CCR (SEQ ID NO: 26) and CGT (SEQ ID NO: 31) from Eucalyptus grandis, and OMT (SEQ ID NO: 6), PAL (SEQ ID NO: 45 and 47), C4H (SEQ ID NO: 48 and 49), PNL (SEQ ID NO: 81) and LAC (SEQ ID NO: 83) from Pinus radiata were inserted into Agrobacterium tumefaciens LBA4301 by direct transformation as described above. The presence and integrity of the transgenic constructs were verified by restriction digestion and DNA sequencing.
Tobacco (Nicotiana tabacum cv. Samsun) leaf sections were transformed as described in Example 3. Up to twelve independent transformed plant lines were established for each sense construct and each anti-sense construct listed in the preceding paragraph. Transformed plants containing the appropriate lignin gene construct were verified using Southern blot experiments. All of the transformed plant lines analysed were confirmed as independent transformed lines.
a) Determination of Transgene Expression by Northern Blot Experiments
Total RNA was isolated from each independent transformed plant line described in Example 5. The RNA samples were analysed in Northern blot experiments to determine the level of expression of the transgene in each transformed line. The column labelled “Northern” in Table 4 shows the level of transgene expression for all plant lines assayed, relative to the background on the Northern blots. There was no detectable hybridisation to RNA samples from empty vector-transforned control plants.
b) Determination of Lignin Concentration in Transformed Plants
The concentration of lignin in empty vector-transforned control plant lines and in up to twelve independent transformed lines for each sense construct and each anti-sense construct described in Example 5 was determined as described in Example 3. The column labelled “TGA” in Table 4 shows the thioglycolic acid extractable lignins for plant lines transformed with C3H, F5H, CCR, PAL, C4H, PNL and LAC, expressed as the average percentage of TGA extractable lignins in transformed plants versus control plants. The range of variation is shown in parentheses.
Transformed plant lines containing the sense and the anti-sense lignin biosynthetic gene constructs exhibited a mean level of lignin content that was significantly lower than that of empty vector-transformed control plant lines. The most dramatic effects on lignin concentration were seen in the OMT sense plants, and in the PAL sense plants. These data clearly indicate that lignin concentration, as measured by the TGA assay, can be directly manipulated by conventional anti-sense methodology and also by sense over-expression using the inventive lignin biosynthetic genes.
The activities and substrate specificities of selected lignin biosynthetic enzymes were assayed in crude extracts from transformed tobacco plants containing sense and anti-sense constructs for PAL (SEQ ID NO: 45), PNL (SEQ ID NO: 81) and LAC (SEQ ID NO: 83) from Pinus radiata, and CGT (SEQ ID NO: 31) from Eucalyptus grandis.
Enzyme assays were performed using published methods for PAL (Southerton S G and Deverall B J, Plant Path. 39:223-230, 1990), CGT (Vellekoop P et al., FEBS, 330:36-40, 1993), PNL (Espin C J et al., Phytochemistry 44:17-22, 1997) and LAC (Bao W et al., Science, 260:672-674, 1993). The data shown in the column labelled “Enzyme” in Table 5 shows the average enzyme activity from replicate measures for all plant lines assayed, expressed as a percent of enzyme activity in empty vector-transformed control plants. The range of variation is shown in parentheses.
All of the transformed plant lines, except the PNL anti-sense transformed plant lines, showed average lignin enzyme activities which were significantly lower than the activities observed in empty vector-transformed control plants. The most dramatic effects on lignin enzyme activities were seen in the PAL anti-sense transformed plant lines in which all of the lines showed reduced PAL activity and in the LAC anti-sense transformed plant lines which showed as little as 14% of the LAC activity in empty vector-transformed control plant lines.
Sense constructs containing polynucleotides including the coding regions for PAL (SEQ ID NO: 47), OMT (SEQ ID NO: 53), 4CL (SEQ ID NO: 56 and 57) and POX (SEQ ID NO: 86) from Pinus radiata, and OMT (SEQ ID NO: 23 and 24), CCR (SEQ ID NO: 26-28), CGT (SEQ ID NO: 31 and 33) and POX (SEQ ID NO: 42 and 44) from Eucalyptus grandis were inserted into the commercially available protein expression vector, pProEX-1 (Gibco BRL). The resultant constructs were transformed into E. coli XL1-Blue (Stratagene), which were then induced to produce recombinant protein by the addition of IPTG. Purified proteins were produced for the Pinus OMT and 4CL constructs and the Eucalyptus OMT and POX constructs using Ni column chromatography (Janknecht R et al., Proc. Natl. Acad. Sci., 88:8972-8976, 1991). Enzyme assays for each of the purified proteins conclusively demonstrated the expected substrate specificity and enzymatic activity for the genes tested.
The data for two representative enzyme assay experiments, demonstrating the verification of the enzymatic activity of a Pinus radiata 4CL gene (SEQ ID NO: 56) and a Pinus radiata OMT gene (SEQ ID NO: 53), are shown in Table 6. For the 4CL enzyme, one unit equals the quantity of protein required to convert the substrate into product at the rate of 0.1 absorbance units per minute. For the OMT enzyme, one unit equals the quantity of protein required to convert 1 pmole of substrate to product per minute.
The data shown in Table 6 indicate that both the purified 4CL enzyme and the purified OMT enzyme show high activity in enzyme assays, confirming the identification of the 4CL and OMT genes described in this application. Crude protein preparations from E. coli transformed with empty vector show no activity in either the 4CL or the OMT enzyme assay.
Transgenic tobacco plants were created using unique identifier sequences which are not found in tobacco. The unique identifier sequences inserted were isolated from Pinus radiata, SEQ ID NO: 402, and Eucalyptus grandis, SEQ ID NO: 403. The unique identifier sequences were inserted into Agrobacterium tumefaciens LBA4301 (provided as a gift by Dr. C. Kado, University of California, Davis, Calif.) by direct transformation using published methods (see, An G, Ebert P R, Mitra A, Ha S B, “Binary Vectors,” in Gelvin S B, Schilperoort R A, eds., Plant Molecular Biology Manual, Kluwer Academic Publishers: Dordrecht, 1988). The presence and integrity of the unique identifier sequences in the Agrobacterium transgenic constructs were verified by restriction digestion and DNA sequencing.
Tobacco (Nicotiana tabacum cv. Samsun) leaf sections were transformed using the method of Horsch et al. (Science, 227:1229-1231, 1985). Three independent transformed plant lines were established for each unique sequence identifier used. Two empty-vector control plant lines were established using an empty gene transfer vector which lacked a unique sequence identifier.
The uniqueness of the sequence identifiers was assayed using Southern blot analyses to test for the presence of the sequence identifier in the genome of the plants. If the sequence identifier is unique and therefore useful as a tag, then the sequence identifier should be clearly absent in plants which have not been tagged and it should be clearly present in plants which have been tagged. In the present example, the unique identifiers would be expected to be absent in the empty-vector transformed control plants. The unique identifier would be expected to be present in the transgenic plants transformed with the unique sequence identifiers.
Genomic DNA was prepared from empty-vector transformed control plants and plants transformed with unique sequence identifiers using the cetyltrimethyl-ammonium bromide (CTAB) extraction method of Murray and Thompson (Nucleic Acids Research 8:4321-4325, 1980). The DNA samples were digested with the restriction enzyme EcoRi in the case of the plants transformed with the Pinus unique sequence identifier (SEQ ID NO: 402) and the restriction enzyme XbaI in the case of the plants transformed with the Eucalyptus unique sequence identifier (SEQ ID NO: 403). The DNA fragments produced in the restriction digests were resolved on a 1% agarose gel; the left panel of
After the agarose gel electrophoresis step, the DNA samples were transferred to Hybond-N+ brand nylon membranes (Amersham Life Science, Little Chalfont, Buckinghamshire, England) using methods established by Southern (J. Mol. Bio. 98:503-517). The nylon membranes were probed with radioactively-labeled probes for the unique sequence identifiers identified above and washed at high stringency (final wash: 0.5× salt sodium citrate buffer (SSC) plus 0.1% sodium dodecyl sulfate (SDS), 15 minutes at 65° C.). The hybridisation of the probes to complementary sequences in the genomic DNA samples was detected using auto-radiography. The results are shown in
The present example clearly demonstrates the utility of the sequences disclosed in this specification for the purposes of unambiguously tagging transgenic materials. A unique sequence was selected from a large number of potential tags and shown to be absent in the genome of the organism to be tagged. The tag was inserted into the genome of the organism to be tagged and a well-established DNA detection method was used to clearly detect the unique sequence identifier used as the tag.
Because of the sequence-specific detection methods used in the example, a user of the invention disclosed in this specification has both a high likelihood of finding a sequence identifier, among the list which has been disclosed, which will be useful for tagging any given organism and an unequivocal method for demonstrating that a tagged organism could only have acquired a given tag through the deliberate addition of the unique sequence to the genome of the organism to be tagged. If the user of this invention maintains the precise sequence of the tag used in a given organism as a secret, then any disputes as to the origin and history of the organism can be unambiguously resolved using the tag detection techniques demonstrated in the present example.
SEQ ID NO: 1-407 are set out in the attached Sequence Listing. The codes for nucleotide sequences used in the attached Sequence Listing, including the symbol “n,” conform to WIPO Standard ST.25 (1998), Appendix 2, Table 1.
All references cited herein, including patent references and non-patent publications, are hereby incorporated by reference in their entireties.
While in the foregoing specification this invention has been described in relation to certain preferred embodiments, and many details have been set forth for purposes of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein may be varied considerably without departing from the basic principles of the invention.
This application is a continuation of U.S. patent application Ser. No. 10/174,693, filed Jun. 18, 2002, which is a continuation-in-part of U.S. application Ser. No. 09/615,192, filed Jul. 12, 2000, now U.S. Pat. No. 6,410,718, which claims priority from U.S. Application No. 60/143,833, filed Jul. 14, 1999 and is a continuation-in-part of U.S. application Ser. No. 09/169,789, filed Oct. 9, 1998, now U.S. Pat. No. 6,653,528, which is a continuation-in-part of U.S. patent application Ser. No. 08/975,316, filed Nov. 21, 1997, now U.S. Pat. No. 5,952,486, which is a continuation-in-part of U.S. patent application Ser. No. 08/713,000, filed Sep. 11, 1996, now U.S. Pat. No. 5,850,020.
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