ARS | Publication request: RESISTANT WHEAT RESPONDS RAPIDLY TO CONTACT WITH MYCOSPHAERELLA GRAMINICOLA

Submitted to: International Symposium on Septoria/Stagonospora Disease of Cereals
Publication Type: Proceedings
Publication Acceptance Date: November 28, 2003
Publication Date: December 7, 2003
Citation: Goodwin, S.B., Rae, S., Urmeev, F.I., Anderson, J.M. 2003. Resistant wheat responds rapidly to contact with mycosphaerella graminicola. In: Global Insights into the Septoria and Stagonospora Diseases of Cereals. International Symposium on Septoria/Stagonospora Disease of Cereals, December 8-12, 2003, Tunis, Tunisia. p. 123-125.

Technical Abstract: Mycosphaerella graminicola, incitant of Septoria tritici blotch, is a widespread and significant pathogen of wheat. Eight resistance genes in wheat have been named, yet the molecular mechanisms of resistance are unknown. To test the timing and nature of the resistance response, expression profiles of resistant (Stb4 gene) and susceptible wheat lines, uninoculated or inoculated with M. graminicola, were compared by differential-display PCR. Among the differentially expressed genes was a protein disulfide isomerase (PDI), which is well known as a molecular chaperone and component of signal-transduction pathways in animal systems but had not been implicated previously in plant defense responses. Real-time quantitative reverse-transcription PCR revealed that PDI was induced within 3 hours of inoculation with highest induction in the pathogen-treated resistant lines. These responses of PDI were similar to those displayed by the pathogenesis-related (PR) proteins, PR-1, PR-2 and PR-5. Our results indicate that wheat responds much more rapidly than believed previously to signals produced by M. graminicola. These early responses begin prior to penetration of the host and may determine the outcome of the host-pathogen interaction.