title: The PacC transcription factor regulates secondary metabolite production and stress response, but has only minor effects on virulence in the insect pathogenic fungus Beauveria bassiana.
abstract: The PacC transcription factor is an important component of the fungal ambient pH-responsive regulatory system. Loss of pacC in the insect pathogenic fungus Beauveria bassiana resulted in an alkaline pH-dependent decrease in growth and pH-dependent increased susceptibility to osmotic (salt, sorbitol) stress and SDS. Extreme susceptibility to Congo Red was noted irrespective of pH, and ΔBbpacC conidia showed subtle increases in UV susceptibility. The ΔBbPacC mutant showed a reduced ability to acidify media during growth due to failure to produce oxalic acid. The ΔBbPacC mutant also did not produce the insecticidal compound dipicolinic acid, however, production of a yellow-colored compound was noted. The compound, named bassianolone B, was purified and its structure determined. Despite defects in growth, stress resistance, and oxalate/insecticidal compound production, only a small decrease in virulence was seen for the ΔBbpacC strain in topical insect bioassays using larvae from the greater waxmoth, Galleria mellonella or adults of the beetle, Tenebrio molitor. However, slightly more pronounced decreases were seen in virulence via intrahemcoel injection assays (G. mellonella) and in assays using T. molitor larvae. These data suggest important roles for BbpacC in mediating growth at alkaline pH, regulating secondary metabolite production, and in targeting specific insect stages.
authors.affiliation: Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China.|Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, 32611, USA.
authors.forename: Zhibing
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ren
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA.
authors.forename: Jarrod J
authors.initials: JJ
authors.lastname: Mousa
authors.affiliation: Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 746050-50, Brazil.
authors.forename: Drauzio E N
authors.initials: DE
authors.lastname: Rangel
authors.affiliation: Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Bruner
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, 32611, USA.|Genetic Engineering Research Center School of Life Sciences, Chongqing University, Chongqing, 400045, P.R. China.
authors.forename: Nemat O
authors.initials: NO
authors.lastname: Keyhani
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D052982:Beauveria / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity*; D007814:Larva / Q000254:growth & development / Q000382:microbiology; D007915:Lepidoptera / Q000254:growth & development / Q000382:microbiology*; D064210:Secondary Metabolism; D017384:Sequence Deletion; D013172:Spores, Fungal / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013712:Tenebrio / Q000382:microbiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors