Poster: Plant-symbiont interactions

Abs # 599: Using RNA interference to study genes involved in Medicago truncatula root and nodule development

Presenter:	Ivashuta, Sergey , ivash001@tc.umn.edu
Authors	Ivashuta, Sergey  (A) (C)  Haridas, Sajeet  (A) (C)  Noorduin, Bauke  (A) (C)  Vance, Carroll P. (B) (C)  VandenBosch, Kathryn A. (A) (C)  Gantt, Steve  (A) (C)
Affiliations:	(A): Department of Plant Biology (B): Department of Agronomy and Plant Genetics (C): University Of Minnesota

The symbiotic interaction between roots of legume plants and rhizobial bacteria is associated with complex alterations in the temporal and spatial expression of a large number of plant genes. It also appears to involve a complex signal transduction pathway that has been intensively investigated by numorous researchers. While very important, these studies have probably identified just a fraction of the genes involved in the sophisticated signaling network that is necessary to establish a successful symbiosis. Reverse genetics may provide an alternative approach to identify additional components of the signal transduction network. We are using double-stranded RNA to induce gene silencing in transgenic hairy roots of Medicago truncatula to study the function of more than 100 genes that are potentially involved in signal transduction events. Candidate genes were selected based on their expression profile and predicted function. We have optimized systems for generating and analyzing transgenic roots in which the candidate gene has been silenced. The system was tested using reporter genes and genes with known functions in symbiosis. The efficiency of gene silencing and phenocopying known mutants was clearly demonstrated. Using this approach, we have identified several new genes that may function in symbiosis. Our data demonstrate that RNAi-based suppression of gene expression in hairy roots provides a fast and powerful approach for functional gene analysis in M. truncatula. Detail analysis of the RNAi phenotype of several genes will be provided.