The molecular basis for broad spectrum resistance to rice blast
Rice blast, caused by Magnaporthe grisea is one of the most destructive diseases of rice costing farmers $5 billion a year. Relatively broad spectrum or durable resistance has been observed in some cultivars. For example, Tetep, an indica rice cultivar exhibits broad-spectrum resistance to rice blast and has been used as resistance donors in breeding programs.
Gihwan Yi, Sang-Kyu Lee, Yeonkyu Hong, Young-Chan Cho, He-Kyung Kim, Minhee Nam, Soon-Chul Kim, Seong-Sook Han, Guo-Liang Wang, Tae-Ryong Hahn, Pamela C. Ronald, Jong-Seong Jeon. 2004. Application of molecular markers linked to the rice blast resistance gene Pi5(t) for use in marker-assisted selection. TAG. (pdf)Greenhouse and field tests in the Philippines and Indonesia in locations where the blast fungal populations were shown to be diverse and broadly virulent suggest that the Pi5(t) locus itself confers broad-spectrum resistance to rice blast. We have recently identified a candidate Pi5 clone using a map-based cloning approach. Pi5 encodes a nucleotide binding site/leucine zipper protein with a novel N terminus that does not exist in the Arabidopsis database. In collaboration with a former postdoc JS Jeon, we are testing if the Pi5 gene alone confers broad-spectrum resistance and, using mutant, transgenic and yeast two hybrid analysis, identifying the Pi5 signaling partners. We will use the rice microarrays to determine if distinct R proteins (XA21 vs. Pi5) signal through common pathways.
Jeon J-S, Chen D, Yi G, Wang GL, and Ronald PC. 2003. Genetic and physical mapping of Pi5(t), a locus associated with broad-spectrum resistance to rice blast. Mol Gen Genomics. 269. 280-289(pdf)
