NSF Award
2322867
Plant starch is an important molecule for humans. In addition to being a primary source of nutrition for humans and many domestic animals, humans use starch in the laundry, food, pharmaceutical, and paper making industries. Despite the widespread use, our understanding of how starch is synthesized and degraded by plants is limited. Both processes affect the shape and form of starch, which affects the way the starch can be used by humans. This project aims to understand the regulation of starch degradation in the model plant Arabidopsis thaliana. This plant has several enzymes called amylases that degrade starch with distinct activities and apparent functions. This project will describe the molecular and biochemical action of two types of amylases, beta and alpha, as they work together to degrade starch during plant stress. One of the project’s goals is to develop new insights into how the structure of starch is controlled in plants. The experiments in this project will be carried out at a predominately undergraduate institution and involve at least 15 undergraduate students. These students will perform a majority of the experiments and develop their technical and professional skills as scientists which will aid them for future graduate education and careers in science. Additionally, teachers and students at a local elementary school will participate in a research project to develop the students’ understandings of the scientific process.<br/><br/>Starch is a complex biomolecule composed of two distinct sub-structures, amylose and amylopectin, which are polymers of glucose with different levels of branching. Starch accumulates and is degraded through several different mechanisms that are dependent on the plant species, plant tissue, and external factors such as time of day and stress. While there is a general understanding of these mechanisms, many of the details including the specific stimuli and regulatory steps of starch synthesis and degradation are unclear. This project aims to detail the structural, biochemical, and molecular mechanism for the involvement of the beta-amylase BAM9 in regulated starch degradation. This protein does not have apparent starch degrading activity but does appear to enhance the activity the alpha amylase, AMY3. This project will characterize how BAM9 interacts with AMY3 and the activation mechanism of BAM9. Further experiments will identify and describe the cellular events that regulate BAM9 leading to activation of AMY3 and starch degradation in response to stress. Ultimately, this project will provide the first biochemical and mechanistic characterization of the pseudo-amylase BAM9, and more broadly, how regulated enzyme complexes degrade starch.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
