Implication of a regulator of G protein signalling (BbRGS1) in conidiation and conidial thermotolerance of the insect pathogenic fungus Beauveria bassiana
Implication of a regulator of G protein signalling (BbRGS1) in conidiation and conidial thermotolerance of the insect pathogenic fungus Beauveria bassiana
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DOI：
10.1111/j.1574-6968.2007.00978.x
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发表时间：
2008-02-01
影响因子：
2.1
通讯作者：
Bidochka, Michael J.
中科院分区：
文献类型：
--
作者：
Fang, Weiguo;Scully, Lisa R.;Bidochka, Michael J.
白僵菌是一种昆虫病原真菌，广泛用作感染和控制害虫的生物防治剂。分生孢子启动发病机制并介导疾病传播，然而，人们对控制分生孢子的遗传元件知之甚少。在此，报道了白僵菌的调节性 G 蛋白信号传导 (RGS) 基因 Bbrgs1 的克隆和表征。系统发育分析表明，BbRGS1 与构巢曲霉的 RGS 蛋白 FlbA 是直系同源的。 Bbrgs1 的破坏导致琼脂平板上或受感染昆虫的分生孢子产量显着减少。 Delta Bbrgs1 分生孢子也表现出耐热性和分生孢子活力降低，但发芽速度明显快于野生型。尽管疏水蛋白与分生孢子的热敏感性有关，但分生孢子表面的疏水蛋白的量和疏水蛋白样蛋白基因hl的转录水平没有改变。对昆虫的毒力与野生型或反向互补转化体相似，并且几丁质酶（Bbchit）和枯草杆菌蛋白酶（cdep1）的毒力因子基因的mRNA水平在Delta Bbrgs1中没有变化。白僵菌单个 RGS 基因 Bbrgs1 的表征表明，它的功能与其他真菌中的 RGS 蛋白不同。然而，白僵菌中可能存在额外的 RGS 蛋白和信号通路来控制菌落发育。
Beauveria bassiana is an insect pathogenic fungus widely used as a biocontrol agent to infect and control insect pests. The conidium initiates pathogenesis and mediates disease transmission, however, little is known about genetic elements that control conidiation. Here, the cloning and characterization of a regulatory G protein-signalling (RGS) gene Bbrgs1 from B. bassiana is reported. Phylogenetic analysis showed that BbRGS1 was orthologous to the RGS protein, FlbA from Aspergillus nidulans. The disruption of Bbrgs1 resulted in significantly reduced conidial production on agar plates or from infected insects. The Delta Bbrgs1 conidia also demonstrated reduced thermotolerance and conidial viability but germinated significantly faster than the wild type. Although hydrophobins have been implicated in conidial thermal sensitivity, the amount of hydrophobin on the conidial surface and the level of transcription of the hydrophobin-like protein gene hl were unaltered. Virulence toward insects was similar to that of the wild-type or reverse complementation transformants, and the mRNA levels of virulence factor genes for chitinase (Bbchit) and subtilisin-like protease (cdep1), were unchanged in Delta Bbrgs1. Characterization of a single RGS gene Bbrgs1 of B. bassiana suggests that it functions differently than RGS proteins in other fungi. However, there may be additional RGS proteins and signalling pathways that control colony development in B. bassiana.