Functional Analysis Of RGS Domain In RGS Protein Family And Dynamin Protein MoDnm2,MoDnm3 In Magnaporthe Oryzae During Development And Pathogenicity

Rice blast disease is a devastating disease affecting the world rice production,results in significant rice yield losses every year.Magnaporthe oryzae cause disease of rice blast disease,during the decades,prevention and control measures is mainly used by two ways:one is cropping resistant cultivars,the other is supplemented by chemical pesticides.However,the resistant cultivars decrease the resistance to M.oryzae due to easy variation of the pathogen races.Meanwhile,application of a single chemical pesticides lead to anti-fungicide population formation result in the loss of control effect of the rice blast.Therefor the prevention and control of the rice blast is still one of the worldwide problems on the rice production.The whole genome sequencing of rice blast fungus has now completed,provided new platform for us to discover the pathogenesis related genes of Magnaporthe oryzae,insight the process of growed and pathogenic mechanisms,provide specific targets for drug development and disease control research foundation.Magnaporthe oryzae use conidium to infect the plant host.The conidium germinate germ tube,at the top of the germ tube form a spherical appressorium.Due to the large amounts of glycerol solute accumulate in appressorium,huge turgor pressure can reach 8 MPa to help Magnaporthe oryzae penetrate the host epidermis,invade the host plant cells,and then extended to adjacent cells,eventually forming a typical rice blast.Under suitable conditions,will produce disease tissue conidium terrier,conidium formation,begin the next round of infection diseases.G protein(Guanine nucleotide-binding protein)is a kind of proteins involved in signal transduction process.G proteins are essential to normal appressorium formation.RGS proteins(Regulators of G-protein signaling),paly a important role in negative regulate the G protein signaling pathway.Previous study found that MoRgsl was well characterized as negative regulator of Ga subunits.IN Zhang’ study additionally identified another seven RGS proteins.Among them,MoRgsl,MoRgs3,MoRgs4,and MoRgs7 are required for full virulence.In order to gain futher insight into the mechanisms of disparate RGS domain functions,we construct domain chimeric strains.RGS7 domain from MoRgs7 have resemblance with RGS1 in influencing various aspects of asexual development,Hyphae hydrophobic,cyclic AMP pathway and protein target.Endocytosis plays a critical role in many physiological functions,maintain the normal cell morphology and physiological processes.Dynamin and its related proteins are essential to many cell functions,from endocytosis to organelle division and fusion.Dynamins are large superfamily GTPase proteins that participate in Cell membrane remodeling process,and are involved in the budding and scission of a wide range of vesicles and organelles.In this study,we identified two dynamin-related proteins in M.oryzae,named MoDnm2 and MoDnm3.Though gene knock out we obtained MoDNM2 and MoDNM3 null mutant.Compared with the wild type strain,we found that the △Modnm2 mutant lead to reduce rate on SDC medium.Deletion of the gene of MoDnm3 lead to appressorium formation delayed,appressorium formation rate significantly reduced.Otherwise,the sensitivity to osmotic stresses is also different between the △Modnm2,AModnm3 mutant and the wild type,as well as the cell wall integrity.We can conclude that the gene MoDnm2 and MoDnm3 is very important to the development and pathogenicity of Magnaporthe oryzae.