Title: Early and Late Peaks of Gene Expression During the Resistance Response of Wheat to Mycosphaerella Graminicola Authors
|Adhikari, Tika - NORTH DAKOTA STATE UNIV.|
Submitted to: Australian Society of Plant Physiologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: August 20, 2007
Publication Date: September 19, 2007
Citation: Goodwin, S.B., Adhikari, T.B. 2007. Early and Late Peaks of Gene Expression During the Resistance Response of Wheat to Mycosphaerella graminicola. Abstracts of the ComBio 2007 conference, Abstract SYM-16-01, Sydney, Australia, p. 44. Available at: http://www.asbmb.org.au/combio2007/abstracts/edited/GOODWIN-2007081011656.rtf. Technical Abstract: Large-scale cDNA-AFLP profiling identified numerous genes with increased expression during the resistance response of wheat to the Septoria tritici blotch fungus, Mycosphaerella graminicola. To test whether these genes were associated with resistance responses, their levels of expression were measured at 12 time points from 0 to 27 days after inoculation (DAI) in two resistant and two susceptible cultivars of wheat by real-time quantitative PCR. None of these genes was expressed constitutively in the resistant wheat cultivars. Instead, infection of wheat by M. graminicola induced changes in expression of each gene in both resistant and susceptible cultivars over time. Four genes were induced from about 10 to 60 fold only at early stages (3 h-1 DAI) during the incompatible interactions. Nine other genes had bimodal patterns with both early (1-3 DAI) and late (12-24 DAI) peaks of expression. The remaining gene had a trimodal pattern of expression in the resistant cultivar Tadinia. Therefore, the resistance response of wheat to M. graminicola is not completed during the first 24 hours after contact with the pathogen, as thought previously, but can extend into the period from 18 to 24 DAI when fungal biomass increases dramatically in compatible interactions. Significant differential expression of the defense-related genes between the resistant and susceptible wheat cultivars and RILs after inoculation with M. graminicola suggest that these genes may play a major role in the resistance mechanisms of wheat.