Auxilin-like Protein MoSwa2 Functions As A Depolymerization Factor Of COPⅡ Vesicle To Promote The Effector Secretion And Virulence Of Magnaporthe Oryzae

Rice is the most important food crop in the world,and with the growth of the global population,the demand for rice is increasing.Thus its safe production is an extremely important global issue.Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases on rice and threatens the global rice production safety.The secretion of protein starts from the endoplasmic reticulum,goes through golgi body processing,and finally transports to the plasma membrane,secreting cargo proteins to the extracellular in eukaryotes.COPⅡ vesicles play an important role in secretion.In yeast,auxilin-like protein Swa2 regulates endocytosis as a depolymerization factor of clathrin-coated vesicles.Here,we found that MoSwa2,the Saccharomyces cerevisiae Swa2 homolog,not only regulates the process of endocytosis,but also regulates the secretion of extracellular proteins by binding to COPⅡ subunit in M.oryzae.And MoSwa2 interacts with COPⅡ subunits MoSec24-2 by co-IP in vivo.The deletion of MoSWA2 gene resulted in the failure to accumulate normally in the endoplasmic reticulum and golgi,while a large amount of MoSec24-2 was formed in vesicles.The result indicated that MoSwa2 may regulate the depolymerization of vesicles by intera?ting with MoSec24-2.Loss of MoSEC24-2 in M.oryzae led to defects of growth,sporulation and pathogenicity,and the infection hyphae could not expand normally.Through the observation of subcellular localization,it was found that MoSec24-2 regulated the secretion of Avr proteins Avr-Pia,Avr-Piz-t and Slpl,which further revealed the mechanism that MoSwa2 promoted the secretion of effector,and then regulated the pathogenicity of M.oryzae as a depolymerizing factor of COPⅡ.In the process of "arms race" between pathogens and plants,pathogens will secrete a large number of effector proteins into host cells to inhibit host immunity,and successfully colonize and infect host plants.MoSwa2 regulates secretion of a series of redox-enzyme proteins.We have identified and functional characterized a BBE-like protein MoSefl with oxidase activity in the apoplast,and it was found that loss of MoSEF1 in M.oryzae had significantly reduced pathogenicity,the infected hyphae could not expand normally,and the reactive oxygen species produced by host cells could not be properly cleared.In addition,it was found that MoSefl purified in vitro can suppress the ROS production in rice leaves induced by purification of mycelium.The results showed that the effector MoSefl had the function of interfering host immunity and promoting infection.In summary,MoSwa2 interacts with COPⅡ subunits MoSec24-2 to jointly regulate COPⅡ vesicle depolymerization mediated extracellular protein and redox-enzyme MoSefl,and participates in the suppression of host immune response.This study revealed the importance of vesicle transport process for extracellular protein secretion and its mechanism for regulating the pathogenicity of rice blast fungus,and provided guidance for other fungi to study the mechanism of extracellular protein transport.