| Rice blast fungus is one of the most destructive pathogens in rice production.The rice blast caused 10% to 30% loss of rice yield every year,which seriously threatens the global agricultural production.Therefore,in-depth study on the pathogenic mechanism of rice blast fungus and its interaction mechanism with rice is the basis of green prevention and control of rice blast and has important economic significance.In eukaryotes,the retromer complex is a key member of the endosomal protein sorting machine,involved in protein transport from the endosome to trans Golgi network and cell surfaces.The retromer complex,composed of heterodimers(vps5-vps17)and heterotrimers(vps35-vps29-vps26),plays an important role by mediating transport of cargo proteins to specific organelles.SNAREs-mediated vesicle anchoring and fusion are the main pathways for material and information exchange between organelles in the eukaryotic secretory pathway.The preliminary results of the research group showed that the absence of MoVps35 in rice blast fungus would lead to the incorrect localization of SNARE protein MoSnc1,which further weakened the pathogenicity.Previous studies have shown that effector proteins play an important role in the pathogenic process of rice blast fungus infection,and its effectors will be transported to the specific space of host cells to assist in the successful infection and colonization of pathogenic fungi.For example,Bas4(apoplastic effector)is mainly located at EIHM(extra-invasive hyphal membrane),while Pwl2(cytoplasmic effector)is specifically located at the BIC(biotrophic interfacial complex)before being transported to rice cells.Currently,studies on the secretion of effectors in rice blast fungus and their transport to specific space of rice cells are still lacking.Since retromer complex and SNARE protein Snc1 generally have the function of protein sorting in eukaryotes,this study will investigate the effect of the deletion of retromer complex subunits Vps29,Vps26 and Snc1 on the secretion and localization of cytoplasmic effector Pwl2 and apoplastic effector Bas4.The results showed that after the wild-type strain infected the leaf sheath tissue of rice,Bas4 protein was located on EIHM and Pwl2 protein was located on BIC in the three infection stages(early,middle and late)of the invasive hyphae development.When the retromer complex subunit MoVPS26 or MoVPS29 was absent,the pathogenicity of pathogen infection was reduced,but a small number of infection sites could still be found.Importantly,Bas4 protein in rice leaf sheath invasive hyphae ofΔMovps26 and ΔMovps29 mutant showed abnormal positioning,more than 50% of Bas4 proteins in mutant invasive hyphae non-uniform located in EIHM,and incorrectly located in the vacuole of hyphae infected by the mutant.In addition,it was found that the Pwl2 protein was located abnormally in the mutant,not specifically on BIC,but in multiple discrete fluorescent signal regions.Similarly,when the MoSNC1 gene was missing,the Bas4 and Pwl2 effector proteins were located in a similar way.In order to determine the spatial location relationship between MoVps29 and MoSnc1 with effectors(Pwl2 and Bas4),GFP-MoSnc1 & Pwl2-mCherry,GFP-MoSnc1 & Bas4-mcherry and MoVps29-GFP&Pwl2-mCherry were constructed and transformed into rice blast fungus,respectively.It was found that GFP-MoSnc1 and MoVps29-GFP showed spot localization in the invasive hyphae cells,and some fluorescence spots were close to the fluorescence signals of Pwl2 and Bas4.But there is no obvious colocalization.In summary,these results confirmed that retromer complex and SNARE protein MoSnc1 both play a regulatory role in the localization of rice blast fungus effector proteins Pwl2 and Bas4. |
PDF Full Text Request