近日，PLoS Pathogens在线发表了南京农大张正光教授团队题为“MoYvh1 Subverts Rice Defense through Functions of Ribosomal Protein MoMrt4 inMagnaporthe oryzae”的研究论文，揭示了稻瘟病菌监控水稻免疫反应机制。
The accumulation of the reactive oxygen species (ROS) in rice is important in its interaction with the rice blast fungus Magnaporthe oryzae during which the pathogen scavenges ROS through the production of extracellular enzymes that promote blast. We previously characterized the MoYvh1 protein phosphatase from M. oryzae that plays a role in scavenging of ROS. To understand the underlying mechanism, we found that MoYvh1 is translocated into the nucleus following oxidative stress and that this translocation is dependent on MoSsb1 and MoSsz1 that are homologous to heat-shock protein 70 (Hsp70) proteins. In addition, we established a link between MoYvh1 and MoMrt4, a ribosome maturation factor homolog whose function also involves shuttling between the cytoplasm and the nucleus. Moreover, we found that MoYvh1 regulates the production of extracellular proteins that modulate rice-immunity. Taking together, our evidence suggests that functions of MoYvh1 in regulating ROS scavenging require its nucleocytoplasmic shuttling and the partner proteins MoSsb1 and MoSsz1, as well as MoMrt4. Our findings provide novel insights into the mechanism by which M. oryzaeresponds to and subverts host immunity through the regulation of ribosome biogenesis and protein biosynthesis.
ROS accumulation is important for the interaction between the blast fungus M. oryzae and its rice host. The protein phosphatase MoYvh1 affects the scavenging of host-derived ROS that promotes M. oryzae infection. We found that MoYvh1 is translocated to the nucleus under oxidative stress by a mechanism that is dependent on its interactions with MoSsb1 and MoSsz1. MoYvh1 triggers the release of MoMrt4 from the ribosome in the nucleus that contributes to ribosome maturation. Importantly, we have provided evidence to demonstrate that MoYvh1 is important for the synthesis of extracellular proteins that are involved in ROS scavenging. Our findings provide insight into the mechanism by which M. oryzae responds to host immunity through MoYvh1 that regulates ribosome function to evade the host defense response.