Characterization of a PR-10 pathogenesis-related gene family induced in rice during infection with Magnaporthe grisea

A partial cDNA with homology to the PR-10 class of pathogenesis-related pro teins was used to screen a rice genomic library. One 16-kb genomic clone co ntained three genes with PR-10 similarity. These genes, RPR10a, RPR10b, and RPR10c, were arranged in tandem and separated by approximately 2.5 kb. RPR 10a cDNA was obtained by reverse transcription-polymerase chain reaction, a nd sequence analysis revealed that RPR10a and RPR10b, encode predicted prot eins of 158 and 160 amino acids, respectively, and share 71% amino acid ide ntity, RPR10c appears to be a nonfunctional pseudogene. Gene-specific probe s were used to study transcript accumulations of the three RPR10 genes in r ice plants following inoculation with Magnaporthe grisea. RPR10a transcript s were induced from a low basal level within 12 h after inoculation and sho wed a second higher Level induction at 48 h, which continued throughout the 144 h it was examined. In addition, RPR10a was induced strongly by salicyl ic and jasmonic acid applications to rice plants. Transcripts of RPR10b als o were enhanced by M. grisea, but were not strongly visible until 48 h afte r inoculation. Tissue prints of M. grisea-infected rice leaves when the RPR 10a-specific probe was used indicate that RPR10a is expressed most strongly in a localized fashion in response to the pathogen.