The goal of this work is to investigate in plants the function and evolution of a novel class of regulatory small RNAs. Prior work demonstrated that plant genes like those known to confer resistance to pathogens are the targets of a set of "microRNAs"--suppressive regulatory RNAs just 22 nucleotides in length. These microRNAs are believed to function as master regulators of a very large family of protein coding disease-resistance genes, and part of their activity is to trigger the production of additional small RNAs (21 nucleotides in length) that have an unusual, regularly spaced pattern, or "phasing" of biogenesis. The regulation of this gene family, and several others targeted by microRNAs in the same way, is a new paradigm for microRNA function. The investigators have identified these small RNAs as conserved in many crop plants, including soybean, an alfalfa relative, tomato and potato. The aim of this project is to investigate this novel gene regulatory circuit to understand its function in plants, its role in plant defenses or beneficial microbial interactions, and whether it can ultimately be developed as a tool for improving plants or altering plant-microbe interactions to reduce disease or improve beneficial interactions. The project will utilize methods that include plant genomics, plant cell biology, plant-microbial interactions, and RNA analysis. The expected result is the dissection and understanding of a novel and complex gene regulatory mechanism. The broader impacts of the project range from a local impact on the training of students and a post-doc who will be directly involved in the project, to national and international impact to the scientific community in the databases and web tools that the project will release.
