Environmental Microbiology (2015) 17, 1189-1202

Zhibing Luo, Yujie Li, Jarrod Mousa, Steven Bruner, Yongjun Zhang, Yan Pei and Nemat O. Keyhani (2015)
Bbmsn2 acts as a pH-dependent negative regulator of secondary metabolite production in the entomopathogenic fungus Beauveria bassiana
Environmental Microbiology 17 (4), 1189-1202
Abstract: Fungal secondary metabolites are chemical compounds important for development, environmental adaptation and for potential biotechnological and pharmaceutical applications. Oosporein, a red-pigmented benzoquinone, produced by many fungal insect pathogenic Beauveria spp., shows remarkable functional diversity, displaying antimicrobial, antiviral and even anti-proliferative activities. A homologue of the msn2/seb1 transcription factor was identified in a Beauveria bassiana random T-DNA insertion library. Targeted gene-knockout of Bbmsn2 resulted in reduced growth and increased sensitivity to Calcofluor White, H₂O₂ and Congo Red. However, when normalized to growth at 26°C, the DeltaBbmsn2 mutant was more tolerant to high temperature (32°C) than the wild type parent. The DeltaBbmsn2 mutant also displayed a pH-dependent growth phenotype, with little growth seen at pH < 5.0 but, better growth at alkaline conditions (pH > 8.0). Unexpectedly, a pH-dependent deregulation of a red pigment, identified as oosporein, was seen in the DeltaBbmsn2 mutant. The DeltaBbmsn2 strain was impaired in virulence in both topical and intrahaemocoel injection bioassays against Galleria mellonella. DeltaBbmsn2 proliferation in the host haemolymph and conidiation on the host cadaver was reduced. These data indicate that Bbmsn2 acts as a negative regulator of oosporein production and contributes to virulence and growth in response to external pH in B. bassiana.
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Link to article at publishers website
Database assignments for author(s): Nemat O. Keyhani

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
Beauveria bassiana (entomopathogen)