Participation of a MADS-box transcription factor, Mb1, in regulation of the biocontrol potential in an insect fungal pathogen
Participation of a MADS-box transcription factor, Mb1, in regulation of the biocontrol potential in an insect fungal pathogen
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MADS-box 转录因子 Mb1 参与昆虫真菌病原体生物防治潜力的调节
DOI：
10.1016/j.jip.2020.107335
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发表时间：
2020-02-01
影响因子：
3.4
通讯作者：
Zhang, Yongjun
中科院分区：
文献类型：
--
作者：
He, Zhangjiang;Song, Yulin;Zhang, Yongjun
细胞壁是真菌生长、增殖以及与环境和寄主相互作用的关键。了解细胞壁完整性的调控机制有助于改进真菌生物防治剂。本研究发现，MADS-box转录因子Rlm1的同源物Mb1是细胞壁完整性通路相关的Slt2 MAP激酶的一个假定靶点，在一种具有重要经济意义的昆虫真菌病原体白僵菌（Beauveria bassiana）中得到了表征。Mb1断裂突变体（Delta Mb1）在低营养培养基上表现出生长减少和分生孢子产量增加的现象，而在富营养培养基上则没有表现出这种现象，这与Delta Slt2有很大的不同。Mb1的缺失导致对细胞壁干扰剂（刚果红和白钙）的敏感性显著增加，细胞组成的改变与Delta Slt2菌株不一致，包括在没有任何应激的情况下增加几丁质含量和降低几丁质结合的β - 1,3 /1,6-葡聚糖水平。在Delta Mb1菌株中，15个甲壳素合成代谢相关基因和17个Pkc1-Slt2 CWI（细胞壁完整性）通路、葡聚糖合成和细胞壁重塑酶合成相关基因的转录水平分别显著升高和抑制，其中一些基因被证实是Mb1的靶点。昆虫生物测定显示，在局部和血内注射试验中，Delta Mb1菌株的毒力降低。结果表明，Mb1控制球孢白僵菌的生长、分生和细胞壁完整性等生物防治潜力相关性状。讨论了Mb1和Slt2对细胞壁完整性贡献的差异。
The cell wall is crucial for fungal growth, proliferation and interaction with the environment and host. Understanding the regulatory mechanism of cell wall integrity may help with improvement of fungal biocontrol agents. Here, a putative target of the cell wall integrity pathway-involved Slt2 MAP kinase, Mb1, an orthologue of MADS-box transcription factor Rlm1, was characterized in an economically important insect fungal pathogen, Beauveria bassiana. Mb1 disruption mutant (Delta Mb1) displayed reduced growth and increased conidial production on minimal medium but not on rich-nutrient media, which is different from Delta Slt2 to a great extent. Loss of Mb1 resulted in a significant increase in sensitivity to cell wall-perturbing agents (Congo red and calcofluor white), with alteration in cell composition that was inconsistent with Delta Slt2 strain, including increased chitin content and reduced chitin-binding beta-1, 3/1,6-glucan levels in the absence of any stress. Transcription levels of 15 chitin synthesis and metabolism-associated and 17 Pkc1-Slt2 CWI (cell wall integrity) pathway, glucan synthesis, and cell wall remodeling enzyme synthesis-involved genes were significantly increased and repressed in Delta Mb1 strain, respectively, some of which were verified to be the targets of Mb1. Insect bioassays revealed decreased virulence for the Delta Mb1 strain in both topical and intrahemocoel injection assays. Our results demonstrated that Mb1 control fungal biocontrol potential-associated traits, including growth, conidiation and cell wall integrity, in B. bassiana. The difference of Mb1 and Slt2 in contribution to cell wall integrity is discussed.