Analysis Of Chitin-binding Protein Genes In Magnaporthe Grisea

The rice blast fungus,Magnaporthe grisea,is a very important pathogen causing rice important disease.It shares many important characteristics both in infection and life cycle with other plant fungal pathogens,being regarded as a model organism to study molecular pathogenic mechanism.The interaction involves a complex process of signal recognition and transduction,at which the signal molecules from plant fungal pathogens may be recognized as elicitors or virulence factors.Bioinformatics analysis showed that there are 17 putative chitin-binding protein(CBP) in M.grisea genome.All of these proteins have a signal peptide and are located either extracellualr compartments or at diffierent cytoplasmic organelles.Based on the results of phylogenetic analysis for CBP in pathogenic and non-pathogenic fungi,we couldsee that the number of CBP gene in non-pathogenic fungi is not amplified obviously.It may be related to the evolution process.In this study,we further characterized the function of MGG₀0227.5 out of the 17 putative CBP genes.First,we constructed the MGG₀0227.5 and MGG₀3784.5 gene knock-out vector,and tranferred the vector to the protoplasts of the wild type.Three knock-out mutants AMG0227-1,AMG0227-2,AMG0227-3 and one ectopic mutant MG0227Ectopic of MGG₀0227.5 gene were obtained.Phenotype analysis of mutants showed that there was no visible diffierence bewteen their spore germination,the formation of appressorium.However, mycelial growth rate of knock-out mutants were slower than that of ectopic and the wild-type; there was slightly different in conidiation at the unit aera.But the pathogenicity assay showed that the mutants could penetrate cause barley and rice disease as in the ectopic and wild type strains.