Title: Characterization of Second-site RPP8 Mutants in Arabidopsis thaliana

(Research Advisor: Jeffrey Dangl, PhD, Mentor: Ben Holt, PhD)

Lan Chi Tran

Agricultural producers lose millions of dollars worth of crops to plant diseases every year. Advancing our knowledge about the immune defense system of plants at the genetic level is crucial for the development of biotechnology that can resolve this dilemma.  In general, plants possess resistance (R) genes, which encode receptors that recognize and interact with specific pathogenic proteins termed avirulence (avr) factors. The detection of avr factors by R-proteins initiates a series of events that ultimately leads to resistance.  Working with Arabidopsis thaliana, four mutations were discovered that limit the function of one type of R-gene, RPP8 (Resistance to Peronospora  parasitica).  These second-site mutations potentially encode signaling components of an unidentified signaling pathway.  My project goals are to genetically characterize these mutants and identify the causative genes with map-based cloning.  These results will further our understanding of the genetic mechanism behind the plant immune system.