Bbmsn2 acts as a pH-dependent negative regulator of secondary metabolite production in the entomopathogenic fungus Beauveria bassiana
Bbmsn2 acts as a pH-dependent negative regulator of secondary metabolite production in the entomopathogenic fungus Beauveria bassiana
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Bbmsn2 作为昆虫病原真菌白僵菌次级代谢产物产生的 pH 依赖性负调节因子
DOI：
10.1111/1462-2920.12542
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发表时间：
2015-04-01
影响因子：
5.1
通讯作者：
Keyhani, Nemat O.
中科院分区：
文献类型：
--
作者：
Luo, Zhibing;Li, Yujie;Keyhani, Nemat O.
真菌次级代谢产物是对发育、环境适应以及潜在的生物技术和制药应用重要的化合物。卵孢子素是一种红色的苯醌，由许多真菌昆虫病原性白僵菌属产生，显示出显著的功能多样性，显示出抗微生物、抗病毒甚至抗增殖活性。在球孢白僵菌（Beauveria bassiana）随机T-DNA插入文库中鉴定了msn2/seb1转录因子的同源物。Bbmsn2的靶向基因敲除导致生长减少，对Calcofluor白色、H2O2和刚果红的敏感性增加。然而，当在26摄氏度下标准化生长时，Bbmsn2突变体比野生型亲本更耐受高温（32摄氏度）。Bbmsn2突变体还显示pH依赖性生长表型，在pH 8.0下几乎没有生长。出乎意料的是，在Bbmsn2突变体中发现了一种红色素（被鉴定为卵孢子素）的pH依赖性失调。Bbmsn2菌株在局部和血腔内注射对大蜡螟的生物测定中的毒力受损。bbmsn 2在宿主血淋巴中的增殖和在宿主尸体上的分生孢子减少。这些数据表明，Bbmsn2作为一个负调节卵孢子素生产，并有助于毒力和增长，响应外部pH值在球孢白僵菌。
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 degrees C, the Bbmsn2 mutant was more tolerant to high temperature (32 degrees C) than the wild type parent. The Bbmsn2 mutant also displayed a pH-dependent growth phenotype, with little growth seen at pH8.0). Unexpectedly, a pH-dependent deregulation of a red pigment, identified as oosporein, was seen in the Bbmsn2 mutant. The Bbmsn2 strain was impaired in virulence in both topical and intrahaemocoel injection bioassays against Galleria mellonella. Bbmsn2 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.