Molecular and cellular analysis of the biotrophic interaction between rice and Magnaporthe oryzae - Exploring situations in which the blast fungus controls the infection

作者：Nishizawa Yoko^*; Mochizuki Susumu; Yokotani Naoki; Nishimura Takeshi; Minami Eiichi

来源：Physiological and Molecular Plant Pathology, 2016, 95: 70-76.

DOI：10.1016/j.pmpp.2016.02.001

• Oryza sativa
• Magnaporthe oryzae
• Transcription factor
• Live-cell fluorescence imaging
• Vacuolar membrane

Biotrophic pathogens need to contend with host defense mechanisms to develop within living host cells. To understand the biotrophic interactions between rice and Magnaporthe oryzae, the fungus causing rice blast disease, we studied molecular mechanisms of rice susceptibility using transgenic rice plants overexpressing a transcriptional repressor, OsWRKY76. In addition, we analyzed host cellular dynamics during the biotrophic interaction using live-cell fluorescence imaging systems. The overexpression of OsWRKY76 caused the transcriptional suppression of a specific set of defense-responsive genes and generation of phytoalexins after fungal infection. The invasive hyphae were surrounded by the host central vacuole without disruption of the vacuolar membrane. Moreover, high-resolution imaging of the biotrophic interfacial complex (BIC) revealed that the host cytosol accumulates at the BIC together with host-derived membranes excluding the vacuolar membrane. A symplastic effector was detected in a punctate localization pattern enclosed by the membranes. These results imply that the down-regulation of phytoalexin synthesis and the maintenance of host vacuolar membranes constitute part of the infection strategy of M. oryzae, and that vesicle budding is involved in the effector internalization into the host cytoplasm.

• 出版日期2016-7