Functional Analysis Of GOX3 And PLD Genes From Penicillium Expansum

Penicillium expansum not only causes blue mould of various fruits,but also accumulates patulin in fruits.Glucose oxidase(GOX)can oxidize β-D-glucose to gluconic acid;phospholipase D(PLD)can specifically hydrolyze phosphatidylcholine in membrane lipid to generate phosphatidic acid and choline;GOX and PLD play an important role in the growth,development,pathogenicity and toxin production of fungi.In this study,we were based on the bioinformatic analysis of the PeGOX and PePLD gene families of P.expansum,constructed the ΔPeGOX3 and ΔPePLD mutants,and analyzed the effects of the mutants on the growth,development,pathogenicity and toxin production.The results show that:1.PeGOX3 has signal peptide,which mainly exists in mitochondria or extracellular,and PePLD mainly exists in nucleus.PeGOX3 has the homology of86% in P.digitatum,and PePLD has the homology of 91% in P.freii.2.Through homologous recombination,agrobacterium transformation and other methods,the ΔPeGOX3 and ΔPePLD mutants were obtained.Compared with the wild type,the spore germination,biomass,colony diameter and spore production of the mutants were significantly inhibited.In addition to spore germination,the inhibition of ΔPePLD was more obvious.3.The pathogenicity of apple fruit was significantly inhibited by ΔPeGOX3 andΔPePLD,especially by ΔPePLD.Similarly,the accumulation of patulin in ΔPeGOX3 and ΔPePLD decreased significantly,while ΔPePLD was lower.4.The expression of PeLaeA and PePacC in ΔPeGOX3 was significantly up-regulated;the expression of PeCreA,PeLaeA,PePacC,PeNoxA,PeNox R and PeRac A in ΔPePLD was significantly up-regulated.The expression of PePG was down-regulated in ΔPeGOX3,but there was no significant change in PePL,PePME,PePMG and PeCx.The expression of PePG was also down-regulated in ΔPePLD,but it was up-regulated in PePL,PePME,PePMG and PeCx.In ΔPeGOX3 and ΔPePLD,PePat K,PePat G and PePat E were significantly down-regulated,while PePat L was up-regulated.In conclusion,PeGOX3 and PePLD are involved in the regulation of growth,development,pathogenicity and toxin production of P.expansum,and the effect of PePLD is more significant.In addition,PePLD had significant effects on the expression of global secondary metabolism transcription factors PeLae A,carbon metabolism inhibition transcription factors PeCreA,pH dependent transcription factors PePacC,and NADPH oxidase genes PeNoxA,PeNoxR and PeRacA.