Title: Expression Profiling in a Non-model Organism: Using Transcriptional Profiling in Wheat To Identify and Characterize Genes Responding To Insect, Viral and Fungal Pests
Speaker: Joe Anderson and Steve Scofield
Co-investigators: Charles Crane, Steve Goodwin, Christie Williams, and Herb Ohm
Place: LILLY G126; Tuesday, 4:30pm


The most desirable method for limiting losses due to pests and pathogens of wheat is through host-plant resistance. Although many resistance genes are known in wheat, whether resistance to different organisms occurs by the same or multiple pathways is not known. To identify resistance pathways, wheat tissue treated with pests and pathogens was analyzed by GeneCalling, an open-architecture transcript-profiling technology (www.curagen.com). The pests/pathogens tested were: Mycosphaerella graminicola (cause of septoria tritici leaf blotch); Fusarium graminearum (head scab); Mayetiola destructor (Hessian fly); and Barley and Cereal Yellow Dwarf Viruses. The GeneCalling experiments profiled >12,000 cDNA fragments per sample, many of which were differentially modulated by at least 1.5 times. Among all four treatments, 11,719 fragments were differentially modulated at one or more time points, divided nearly equally between those that were up (6,011) or down (5,708) regulated. Responses began by the earliest time points sampled. Sequencing of ~4600 cDNA fragments revealed many genes known to be activated during defense responses including phenylalanine ammonia lyase, glucanases, chitinases, peroxidases, and thaumatin-like proteins. Additional genes probably were involved in cell signaling including a high number of kinases and phosphatases. Analysis of 685 clones showed that approximately 10% of the sequences had no matches in any of the six databases searched and an additional 8% had only weak matches (E-values > 1e-08). These analyses revealed a rapid, coordinated resistance response in wheat that may vary depending on the pest or pathogen encountered.