NSF Award
2305880
A gall is a tumor-like growth on a plant that is induced by another organism (i.e., bacteria, fungi, nematode, or insects). Insect-induced plant galls represent one of the most amazing and complex interspecific interactions in nature, capturing the interest of naturalists, ecologists and evolutionary biologists for centuries. Increasingly, gall-forming insects also act as economically important agricultural pests, reducing crop yields worldwide. Surprisingly, the general mechanisms behind insect gall induction and growth are unknown. This proposal aims to uncover the evolutionarily conserved molecular mechanisms of gall formation by harnessing the galling system of cynipid wasps on live oaks, in which many species of cynipids successfully gall the same plant. This system allows for powerful natural experiments to test the generality of how galling organisms manipulate plant genomes and to generate new hypotheses for investigating plant control strategies against galling herbivores and other pests that manipulate host plant defense and immunity. Additionally, galling research has great potential for the advancement of genetic engineering because gall-formation involves the simultaneous manipulation of thousands of genes in the plant – not possible with current technologies (e.g., RNAi, CRISPR). During the course of this research the PIs will co-host a seminar series and develop a series of labs with collaborators at Texas Southern University, a historically black college (HBCU); recruit summer undergraduate researchers at University of New Mexico, a federally recognized minority-serving institution; as well as actively participate in public engagement of scientific research in multiple institutions in Houston and Albuquerque.<br/><br/>Previous molecular studies on insect-induced plant galls have focused on one species at a time, which has created a patchwork of phylogenetically divergent hosts and galling insects that has made it challenging to identify common underlying mechanisms behind galling. The study system we have developed represents a solution to this problem; wherein seven distinct evolutionary lineages of wasp all form phenotypically unique galls on the same host plant species. This system gives us the power to reduce the noise from different gall phenotypes (e.g., color, hairs, size, starting tissue) to determine the core molecular mechanisms of this interaction. In Aim 1, we will identify potential effector molecules in seven species of cynipid wasps. Through transcriptomes and proteomes, the wasp genes needed to induce gall induction will be identified in the venom gland (responsible for gall induction) and larval salivary glands (responsible for gall growth). In Aim 2, we will determine the core plant response to cynipid gallers. By comparing the gene expression of the multiple gall morphologies to their matched control ungalled tissues throughout development, we can separate out phenotypic variation across galls to identify alterations in core genes and pathways required to initiate and maintain gall growth. In Aim 3, our results in oak will be assessed for conservation in other galling systems by conducting a large meta-analysis with 20+ previous published gall transcriptomes including several agricultural pests on soybean, wheat, rice, grape, and blueberry. This will ensure that our results will inform the entire galling research community.<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.
