Identification of rice blast fungal elicitor-responsive genes by differential display analysis

In order to study molecular interactions that occur between rice and rice b last fungus upon infection, we isolated fungal elicitor-responsive genes fr om rice (Oryza sativa cv. Milyang 117) suspension-cultured cells treated wi th fungal elicitor prepared from the rice blast fungus (Magnaporthe grisea) employing a method that combined mRNA differential display and cDNA librar y screening. Data base searches with the isolated cDNA clones revealed that the OsERG1 and OsERG2 cDNAs share significant similarities with the mammal ian Ca2+-dependent lipid binding (C2) domains. The OsCPX1 cDNA is highly ho mologous to peroxidases. The OsHin1 cDNA exhibits homology to the tobacco h in1 gene, whose expression is Induced by avirulent pathogens. The OsLPL1 an d OsMEK1 cDNAs share homologies with lysophospholipases and serine/threonin e mitogen-activated protein (MAP) kinase kinases, respectively. The OsWRKY1 and OsEREBP1 cDNAs are homologous to transcription factors, such as the WR KY protein family and the AP2/EREBP family, respectively. Transcripts of th e OsERG1, OsHin1, and OsMEK1 genes were specifically elevated only in respo nse to the avirulent race KJ301 of the rice blast fungus. Our study yielded a number of elicitor-responsive genes that will not only provide molecular probes, but also contribute to our understanding of host defense mechanism s against the rice blast fungus.