MoSET1-dependent transcription factors regulate different stages of infection-related morphogenesis in Pyricularia oryzae

MoSET1, an H3K4 histone methyltransferase in Pyricularia oryzae plays a key role in infection-related morphogenesis of the fungus. We previously identified approximately 400 genes for which expression might be regulated directly by MoSET1 during appressorium formation. Here, we focused on five MoSET1-dependent transcription factor (TF) genes that were induced during infection, using a gene deletion approach for three of the five genes (MGG_04699, MGG_06898, MGG_07450) and, for the remaining two genes (MGG_00472 and MGG_07386), a gene silencing technique due to difficulty in constructing a gene deletion mutant. Phenotypic characterization of the knockout and -down mutants revealed that MGG_06898 was crucial for sporulation, MGG_04699 was involved in appressorium formation, and MGG_00472 and MGG_04699 were required for full virulence of the fungus. These results demonstrated that MoSET1 contributes to the pathogenicity of the fungus by controlling transcription factors that further regulate different steps in the infection process of P. oryzae .