Functional Analysis Of Magnaporthe Oryzae B-ZIP Transcription Factor MoIDI4 During Infection

Magnaporthe oryzae is the pathogen of rice blast and cause serious damage to rice production every year.The basic-leucine zipper(b-ZIP)domain-containing transcription factors(TFs)function as key regulators in fungi development and pathogenesis.However,the molecular mechanism of these transcription factors are rarely revealed.In this study,through transcriptional analysis,we screened and identified a Magnaporthe oryzae(Y34)b-ZIP transcription factor,Mo IDI4 in pathogenesis.Mo IDI4 localizes in the nucleus,and the Mo IDI4 gene is expressed in spores,germ tubes,appressoria,and infective hyphae.The virulence of the Mo IDI4 knockout strain(?Moidi4)was significantly reduced,and which was restored after expression of Mo IDI4,indicating that Mo IDI4 is required for full virulence to M.oryzae.Biochemical experiments show that Mo IDI4 can bind to H-box DNA sequences,suggesting that it can act as a transcription factor.Next,the transcriptomics analysis show that the esterrelated genes of M.oryzae were significantly down-regulated in ?Moidi4.The expression of the peroxisome gene Mo PTS1 and the observations of Nile Red and iodine staining further demonstrated the inhibition of blast fungus ester metabolism in ?Moidi4.Biochemical experiments revealed that Mo IDI4 can target the promoter of genes related to the ester metabolic pathway to regulate the process of ester metabolism.Besides,the further study shows that Mo IDI4 functions in rapid degradation of lipid droplets and glycogen which is essential for generation of turgor pressure during appressoria development.Taken together,these results revealed the new regulatory function of a b-ZIP transcription factors,Mo IDI4 in targeting to the promoter region of key genes of esters,regulating the metabolism of esters,helping building the tugor pressure of appressorium,and then affects the infection ability.In summary,this study revealed the molecular mechanism of Mo IDI4 in the pathogenesis and also provided new candidate genes in controlling rice blast disease.