Invited Speaker

Abstract: The ascomycete fungus Magnaporthe oryzae is a hemibiotrophic pathogen that causes rice blast disease. M. oryzae infects rice leaves, stems and panicles, and induces severe reductions in yield. Effector proteins secreted by M. oryzae in planta are thought to be involved its virulence activity. Here, using RNA-sequencing (RNA-Seq), we generated transcriptome data for M. oryzae isolate Ina168 during the initial stages of infection. We prepared samples from conidia (the inoculum) and from peeled epidermal cotyledon tissue of susceptible barley Hordeum vulgare ‘Nigrate’ at 12, 24, 36 and 48 hours post-inoculation (hpi). We also generated a draft genome sequence of M. oryzae isolate Ina168 and used it as a reference for mapping the RNA-Seq reads. Gene expression profiling across all stages of M. oryzae infection revealed 1728 putative secreted effector protein genes. We selected seven such genes that were strongly up-regulated at 12 hpi and down-regulated at 24 or 36 hpi and performed gene knockout analysis to determine their roles in pathogenicity. Knockout of MoSVP, encoding a small putative secreted protein with a hydrophobic surface binding protein A domain, resulted in a reduction in pathogenicity, suggesting that MoSVP is a novel virulence effector of M. oryzae.

Biography: Dr. Hiromasa Saitoh received B.S. in 1993 from Teikyo University, Tochigi, Japan; received M.S. in 1995 from Mie University, Mie, Japan; received Ph.D. in Agriculture in 1999 from Osaka Prefecture University, Osaka, Japan; worked as a researcher at Iwate Biotechnology Research Center in Iwate, Japan from 1998 to 2002; worked as a Postdoc at Max Planck Institute for Plant Breeding Research in Cologne, Germany from 2003 to 2005; worked as a Postdoc, then a senior researcher at Iwate Biotechnology Research Center from 2005 to 2017; became a professor at Tokyo University of Agriculture, Tokyo, Japan in 2017. He has authored or co-authored more than 60 research papers in refereed journals and conference proceedings. Currently, he focuses on the function of secreted pathogenicity protein genes and search for novel virulence genes of the rice blast fungus Magnaporthe oryzae.