|Samac, Deborah - Debby|
Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/11/2002
Publication Date: N/A
Technical Abstract: The legume Medicago truncatula is a useful model plant not only for symbiotic studies but also for functional genomics of plant-pathogen systems. A major objective of the NSF Functional Genomics Program for M. truncatula is to develop tools for global gene expression analysis of plant-microbe interactions. As of October 2001, partial 5' sequencing of 15 5cDNA libraries has yielded more than 54,000 ESTs deposited in GenBank and the M. truncatula TIGR Gene Index (MtGI; www.tigr.org/tdb/mtgi). MtGI contains >140,000 ESTs with nearly 29,000 unique sequences compiled from worldwide M. truncatula genome research projects. A set of 30,000 non- redundant genes is being established for microarray-based gene expression studies. At present, glass slide microarrays containing 1,152 cDNAs including positive and negative controls are used for hybridization with labeled targets derived from pathogen infected and uninoculated leaf and root tissues. The selected subset of clones includes genes with putative functions in symbiotic or pathogenic responses, secondary metabolism, transcriptional regulation, cell division, signal transduction, and cell death among other functional classes. Several genes of unknown function are also present for gene discovery purposes. Both biological and technical replications are essential for generating statistically significant data that allow identification of differentially expressed genes as a response to pathogen attack. Comparison of gene expression profiles of M. truncatula interactions with two foliar pathogens (Colletotrichum trifolii and Erysiphe pisi) and one root pathogen (Phytophthora medicaginis) will be presented. Additional studies on differential expression among susceptible and resistant M. truncatula accessions are currently underway.