Analysis of rice RNA-dependent RNA polymerase 6 (OsRDR6) gene in response to viral, bacterial and fungal pathogens

RNA-dependent RNA polymerases (RDRs) play key roles in gene silencing. The rice RDR6 gene was analyzed in response to viral, bacterial and fungal pathogens, after inoculation of a rice mutant line of OsRDR6, shl2-rol, with Cucumber mosaic virus, Rice necrosis mosaic virus, Xanthomonas oryzae pv. oryzae or Magnaporthe oryzae. Compared with the wild type, the mutant line accumulated more viral RNA after inoculation with the viruses and developed more severe symptoms after inoculation with the bacterium or fungus. Thus, the OsRDR6-mediated RNA silencing pathway seems to participate in defense against not only viruses, but also bacterial and fungal pathogens.