ARS | Publication request: NON-HOST RESISTANCE OF BARLEY TO THE SEPTORIA TRITICI BLOTCH PATHOGEN OF WHEAT INVOLVES AN ACTIVE DEFENSE RESPONSE

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2004
Publication Date: January 15, 2005
Citation: Goodwin, S.B., Breeden, J.D., Stevens, J., Doerge, R.W. 2005. Non-host resistance of barley to the septoria tritici blotch pathogen of wheat involves an active defense response. Plant and Animal Genome Conference XIII, January 15-19, 2005, San Diego, CA. p. 688. Available: http://www.intl-pag.org/13/abstracts/PAG13_P688.html

Technical Abstract: Barley possesses specific resistance (R) genes against the speckled leaf blotch pathogen Septoria passerinii and is a non host for the Septoria tritici blotch pathogen of wheat, Mycosphaerella graminicola. The specific mechanisms of resistance to these hemibiotrophic pathogens, and whether they involve active host responses, are not known. The Affymetrix Barley GeneChip Array was used to test the hypothesis that non-host resistance of barley to M. graminicola is an active response. Barley plants inoculated with i) a compatible isolate of S. passerinii (susceptible response) ii) an incompatible isolate of S. passerinii (R-gene response), and iii) an isolate of M. graminicola (non-host response), were collected at 0, 5, 12 and 24 hours after inoculation with two biological replications and water-inoculated controls at each time point. Numerous genes were significantly up or down regulated during each treatment. From 99 to 1,789 genes had significantly increased expression during the non-host resistance response relative to the water-inoculated controls among the four sampling times. Many of these genes are the same as those induced during R-gene resistance responses of barley to biotrophic pathogens and in other host species, including pathogenesis-related proteins,transporters, jasmonate-induced proteins, and transcription factors. Recognition and signal-transduction genes included NBS-LRR-type and other leucine-rich-repeat receptor proteins and numerous kinases. Genes with significantly down-regulated expression also were identified, mostly involving photosynthesis and DNA replication. These data and analyses demonstrate that non-host resistance in barley to M. graminicola is an active response similar to those induced during R-gene interactions with biotrophic pathogens.