Functional Analysis Of Amino Acid Synthesis Related Gene MoLYS20 And MoCPA2 In Development And Pathogenicity Of Magnaporthe Oryzae

Rice blast caused by Magnaporthe oryza is one of the three major diseases of rice,which is the most destructive for rice.Nowadays,the main strategy to control this disease is selecting and breeding resistant rice cultivars,along with chemical prevention.Due to the reason that the physiological races of these pathogens,which are extremely variable,have a great diversity all around the world,fine resistant rice cultivars will soon lose their resistance.Thus,the further study of the growth and pathogenesis of pathogens and the function of all kinds of materials and structures in the process of infection process will have very important significance.In recent years,the announcement of the whole genome sequence of rice blast fungus and the improvement of the genetic transformation system have provided great convenience for further study of a variety of pathogenic genes and its important physiological functions.Besides,they provide new targets for the new fungicides against the rice blast and reliable theoretical basis for control strategies for rice blast.In M.oryzae,G protein plays a very important role in the process of signal transduction.G protein signaling pathways regulating factor RGS(Regulators of the G proteins signaling)is a negative regulatory factors of G protein signaling pathways.In M.oryzae,eight MoRGS was identified,biology function analysis of these genes are found that MoRgs involved in the regulation of the fungal growth and development,spore production,the formation of appressorium and the pathogenic process.,In our lab,to further elucidate the mechanism of regulation of MoRgs protein(MoRgsl,MoRgs2,MoRgs3,MoRgs4,MoRgs7)in M.oryzae,proteomics technology was applied to analyze the total proteins difference among ?Morgs mutants and wild type Guy 11,including amino acid synthesis metabolism related genes.Amino acid biosyntheses are complex but essential processes in growth and differentiation of eukaryotic cells.We showed that MoRgs proteins have distinct roles in amino acid metabolism and nutrient responses from growth assay.In this paper,we study from the protein screening amino acid metabolism genes and characterized MoLys20,a homocitrate synthase(HCS),whose abundance was significantly decreased in the AMorgs mutants.In S.cerevisiae,lysine biosynthesis of lysine is the way of the a-aminoadipate(AAA)pathway,ScLys20 participate in lysine biosynthesis,catalytic acetyl Co-A and a-oxoglutarate condensation to form homocitrate synthase,this is the first step and important step of the lysine biosynthesis pathway.This study adopts the ?Molys20 mutant.The ?Molys20 mutant is auxotrophic for lysine and exogenous lysine could partially rescue its auxotrophic defects.Deletion of MoLYS20 resulted in defects in conidiation and infection,as well as pathogenicity on rice.Overall,our results indicate that MoLys20 involved in lysine biosynthesis,thereby affecting fungal development and pathogenicity.Subcellular localization observation results show that the MoLys20 in each phase of the rice blast fungus are located in the nucleus.After a loss of NLS,the MoLys20 are distributed throughout the cell,rather than only in in the nucleus,indicate that MoLys20 NLS from entering the function of the cell nucleus has the vital role,also speculate that MoLys20 has a dual role in the metabolism and the nucleus.In addition,we study from the protein screening amino acid metabolism genes and characterized MoCpa2 encoding Carbamoyl phosphate(CPS).In s.cerevisiae,The step of Carbamyl phosphate synthetase is a branch of arginine synthesis pathway,resulting carbamoyl phosphate used to directly supplement arginine ornithine biosynthesis.In this chapter we illustrate the function of carbamyl phosphate synthase MoCpa2.Our results show that ?Mocpa2 mutant is auxotrophic for arginine and exogenous arginine could partially rescue the spore production and appressorium differentiation,at the same time also can restore pathogenic defects of barley leaf blades in vitro.Our research results show that MoCpa2 affected the growth?spore production and pathogenicity of M.oryzae,and MoCpa2 is required of arginine biosynthesis.This study does implicate the potential for targeting arginine biosynthesis for the development of novel fungicides against M.oryzae.In conclusion,MoLYS20 is necessary for lysine biosynthesis,MoCPA2 is necessary for arginine biosynthesis.MoLys20,MoCpa2 involved in growth,spore production and has a very important role in the pathogenic process in M.oryzae,to verify the MoRgs regulate amino acids metabolism provides strong evidence.