Functional Analysis Of MaPepD Gene In Metarhizium Acridum

Metarhizium acridum is one of the most important entomopathogenic fungi,and widely studied as a model fungi.In fungi,peptidases play crucial roles in regulating fungal adaptability.Dipeptidase(PepD),an important class of peptidases,can cleave dipeptides into two amino acids,playing important roles for sugar and amino acid metabolism.The function of PepD is largely unknown in fungi.In this study,we analyzed the dipeptidase,enzymatic characteristices,and the relevant mechanism in M.acridum.The main results are as follows:1.The SDS-PAGE showed that MaPepD,a molecular mass of 56-kDa,displayed a high activity at specified conditions.The purified dipeptidase has an optimal activity at pH 6.0 and 55°C.2.Disruption of MaPepD increased conidial germination on 1/4SDAY and significantly improved the resistance to UV-B and heat-stock.Exceptionally,virulence was unaffected in ?MaPepD.3.Digital gene expression data revealed that ?MaPepD displayed increased UV-B and heat shock tolerances compared to wild type by mediating transcription of sets of genes involved in conidiation,polarized growth,cell cycle,DNA replication and repair,and some important signaling pathways,such as DNA repair and stress response.4.The MaPepD was upregulated in sucrose yeast extract agar(SYA)medium.Deletion of MaPepD resulted in a shift of conidiation pattern: from microcycle conidiation to normal conidiation.5.Amino acid metabolism analysis demonstrated that the levels of 19 amino acids and derivatives significantly changed in mutant ?MaPepD.6.RNA-Seq analysis revealed that MaPepD mediates transcription of sets of genes involved in conidiation,polarized growth,cell cycle,cell proliferation,stress tolerance,and some important cell growth signaling pathways.