|Adhikari, Tika - NORTH DAKOTA STATE UNIV|
|Boovaraghan, Balaji - PURDUE UNIVERSITY|
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2004
Publication Date: January 15, 2005
Citation: Adhikari, T.B., Boovaraghan, B., Breeden, J.D., Cavaletto, J.R., Goodwin, S.B. 2005. Expression of defense-related genes in wheat during compatible and incompatible interactions with mycosphaerella graminicola (abstract). Plant and Animal Genome XIII Conference, January 15-19, 2005, San Diego, CA. p. 759. Available: http://www.intl-pag.org/13/abstracts/PAG13_P759.html Technical Abstract: Large-scale cDNA-AFLP profiling experiments identified numerous genes with differential expression during the resistance response of wheat to the Septoria tritici blotch fungus Mycosphaerella graminicola. Primers were designed for 14 of the most strongly up-regulated genes and their levels of expression were quantified at 15 time points from 0 to 27 days after inoculation (DAI) in two incompatible (with the Stb4 and Stb8 genes for resistance) and two compatible cultivars by real-time quantitative PCR. The 14 genes showed four patterns of expression. (i) Four genes were induced early with increases of ' 2 to 60 fold over mock-inoculated plants in the resistant cultivars between 3 hr and 1 DAI. (ii) Seven genes were expressed late, with induction ' 200 to 1400 fold over mock-inoculated plants between 6 and 24 DAI. Six of these genes also had a smaller but significant early induction. (iii) Two genes had a bimodal pattern of expression at early and late stages with maximum induction at 18 DAI. (iv) One gene had maximum induction at 3 hr, 24 hr and 6 DAI in Stb4-resistant plants but with no expression in the other cultivars. These results indicate that the resistance response of wheat to M. graminicola is not completed during the first DAI, as thought previously, but instead can extend into the period from 18 to 24 DAI when fungal growth increases dramatically in susceptible interactions. The much higher induction of these genes in the resistant plants indicates that they may play a role in the resistance response.