|Ray, Suparna - PURDUE UNIVERSITY|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: July 29, 2002
Publication Date: July 29, 2002
Citation: Ray, S., Goodwin, S.B., Anderson, J.M. 2002. Genes expressed during the resistance response to mycosphaerella graminicola. Phytopathology. Technical Abstract: Mycosphaerella graminicola is a widespread and important pathogen of wheat. Differential display experiments to compare gene expression in inoculated resistant (Tadinia harboring Stb4) and susceptible (Yecora Rojo) wheat lines identified a putative differentially expressed gene with significant homology to protein disulfide isomerase (PDI). The association between PDI expression and the defense response in wheat to M. graminicola was examined in another resistant wheat line 9346A1. Treatments consisted of the resistant line inoculated with water (control) or M. graminicola (infected) and leaf tissue was collected at 0, 1, 3, 6, 12, 24 and 96 hrs after inoculation. Real-time quantitative PCR showed that PDI was induced early only in the infected tissue with maximal induction occurring within 12 hours of inoculation. In comparison, known defense response genes, PR-1, thaumatin and beta-1, 3-endoglucanase showed high levels of induction at 6 and 12 hours after inoculation only in the infected tissue. Another putative defense-response gene, WCI-2, was down-regulated in the treated tissue. To identify resistance-specific responses, the expression of PDI and the known defense-response genes was compared between Tadinia and Yecora Rojo, inoculated with water or the pathogen. PDI, PR-1 and beta-1, 3-endoglucanase were up-regulated to a greater extent in the resistant line while WCI-2 showed delayed and lower-fold expression in the resistant line compared to the susceptible line. Our future efforts will be directed towards identifying resistance-specific responses to M. graminicola in wheat, in an attempt to improve our understanding of the molecular basis of plant-pathogen interactions.