Protein Phosphatase MoPpel And COPⅡ Vesicle Transport Mediate The Development And Pathogenicity Of Magnaporthe Oryzae

Rice as one of the global food crops are widely cultivated all over the world.In China,the cultivation area accounts for about 1/4 of the country’s arable land and the production accounts for about half of the country’s total grain production,which is about 60%people’s staple food.However,rice blast disease is still one of the most devastating diseases in rice.Each year,the disease causing about 3 billion kilograms of food loss to our country,which seriously threatening the food security all over the world and also affecting the quality of rice and commodity value.At present,the prevention and treatment of rice blast is mainly based on breeding disease-resistant varieties,scientific cultivation and supplemented by comprehensive control measures of chemical protection.However,the rice blast fungus is easily mutated in the field and bring resistance after 3-5 years due to the single efficiency of chemical chemicals.Therefore,a thorough study of the molecular mechanisms about the rice blast fungus can lay a solid theoretical foundation for the design and development of new fungicide targets and better control of the destruction of rice blast.In this paper,we studied the functions of a type-2A like protein phosphatase Ppel with its interacting proteins and investigated the functions of COPII vesicle transport in the growth and development of M.oryzae and the results were as follows:1.Protein phosphatase MoPpel partner with MoSapl regulate growth and pathogenicity of the rice blast fungus Magnaporthe oryzae.Previously,we characterized the mitogen-activated protein kinase(MAPK)kinase MoMkk1 as an integral component of the CWI pathway.By using the affinity purification assay,we have identified a MoMkkl interacting MoPpel as a homolog of Saccharomyces cerevisiae serine/threonine protein phosphatase Sit4/Ppe1.We found that MoPpel is important for the growth,conidition and virulence of M.oryzae.In addition,we found that MoPpel interacts with MoSapl which is a Ppel associated protein and functionally similar.Interestingly,we found that MoPpel-MoSapl interactions were associated with CWI pathway and the target of rapamycin(TOR)pathways.We present evidence that MoPpel and MoSapl play as a complex that mediate the signal transduction between CWI and TOR,and found that the activation of the TOR pathway leads to the inhibition of CWI signal conduction,leading to the defects of the formation of functional appressorium and pathogenicity.2.MoTip41,a MoPpel-interacting protein,mediates the cell wall integrity signaling pathway to control the infection of the rice blast fungus.In this study,we identified a MoPpe1 interacting protein MoTip41 that can activate MoPpe1 by interfering with the interaction between MoTap42 and MoPpel,reducing the inhibitory effect of MoTap42 on MoPpel,and finally activating CWI pathway to promote the infection of M.oryzae.MoTip41 also plays an important role in the transfer of glycogen,lipid degradation and autophagy.These findings will enhance our understanding of the role of CWI and TOR signals in regulating the growth,development and pathogenicity of the M oryzae.3.COPII vesicle receptor protein Erv regulate the development and pathogenicity of Magnaporthe oryzae.Our lab has previously characterized that the bZIP transcription factor MoHac1-mediated unfolded protein response(UPR)pathway that involved in the growth and pathogenesis of Magnaporthe oryzae.In this work,EMSA(electrophoretic mobility shift assay)was used to confirm that MoHacl binds to the promoter region of the six ERV genes.In Saccharomyces cerevisiae,the Erv protein are conserved transmembrane proteins located on COPII vesicles for recognizing specific cargo proteins,then packages them into vesicles and finally transports from the endoplasmic reticulum to the Golgi apparatus.By gene knockout strategy,we obtained all the ERV gene mutants and results showed that the growth rate of ΔMoerv14 mutant was significantly slower than that of wild type,and the sporulation and pathogenicity of mutants were significantly decreased.The growth rate of ΔMoerv29 mutant was not significantly different from that of wild type,but the aerial hyphae were obviously thinner than wild type Guy11 and the mutant unable to produce conidia and the pathogenicity is impaired.The other four EVR gene deletion mutants have no phenotypic phenotype.Further studies have shown that MoErv14 plays a crucial role in the formation of functional appressorium of Magnaporthe oryzae,and MoErv29 affects the secretion of apoplastic effectors and extracellular laccases which participate in the inhibition of host ROS production and clearance to regulate the pathogen to inhibit host defense response.In summary,our study not only revealed the important function of MoMkk1-MoPpel-MoSap1 interaction in the growth and pathogenicity of M.oryzae,but also find the regulating mechanism of the pathogenicity between TOR and CWI signal in M.oryzae.The study also elucidated the important role of vesicle transport of ER V family gene regulation in the growth,development and pathogenesis of M.oryzae.