title: MrpacC regulates sporulation, insect cuticle penetration and immune evasion in Metarhizium robertsii.
abstract: pH-responsive transcription factor of the PacC/Rim101 family governs adaptation to environment, development and virulence in many fungal pathogens. In this study, we report the functions of a PacC homologue, MrpacC, in an insect pathogenic fungus Metarhizium robertsii. The gene was highly transcribed in the fungus in alkaline conditions, and deletion of MrpacC impaired fungal responses to ambient pH and salt/metal challenges but not osmotic stress. We found that MrpacC is required for fungal full virulence by contributing to penetration of insect cuticles, mycosis of insect cadavers and evasion of host immunity. In MrpacC deletion strains, the chitinase but not protease activity was reduced, which was consistent with the downregulation of groups A and C chitinase genes. Further, the glucosyltransferase genes involved in cell wall remodelling and protein glycosylation were upregulated in ΔMrpacC. MrpacC transcriptional control of chitinase and glucosyltransferase genes was verified both by the presence of PacC consensus binding motif in gene promoter regions and the promoter DNA-binding assays. The results of this study not only advances the understanding of PacC function in fungal development and virulence, but will also facilitate future studies on the mechanism(s) behind the selective control of target genes by PacC.
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Shang
authors.forename: Peilin
authors.initials: P
authors.lastname: Chen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Gao
authors.forename: Chengshu
authors.initials: C
authors.lastname: Wang
mesh_terms: D000818:Animals; D002473:Cell Wall / Q000378:metabolism; D002688:Chitinases / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005964:Glucosyltransferases / Q000096:biosynthesis / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D057131:Immune Evasion / Q000235:genetics / Q000276:immunology; D007313:Insecta / Q000382:microbiology*; D052981:Metarhizium / Q000235:genetics* / Q000472:pathogenicity*; D010447:Peptide Hydrolases / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D014157:Transcription Factors; D005964:Glucosyltransferases; D002688:Chitinases; D010447:Peptide Hydrolases