Wang Jiaojiao, Yu Qingyue, Peng Qi, Slamti Leyla, Zhang Ruibin, Hou Shuo, Lereclus Didier, Song Fuping
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.
Front Microbiol. 2022 Aug 9;13:951830. doi: 10.3389/fmicb.2022.951830. eCollection 2022.
The novel protein MclX (mother cell lysis X) in subsp. strain HD73 ( HD73) was characterized in this work. MclX has no known domain and its gene deletion in HD73 resulted in Cry1Ac encapsulation in the mother cell and did not influence Cry1Ac protein production or insecticidal activity. cell wall hydrolysis experiments showed that MclX cannot hydrolyze the cell wall. In deletion mutants, the expression of (which encodes a key cell wall hydrolase) was significantly decreased, as shown by the β-galactosidase activity assay. MclX cannot directly bind to the promoter, based on the electrophoretic mobility shift assay (EMSA). The was reported to be regulated by σ and GerE. However, the transcriptional activities of and showed no difference between HD73 and the deletion mutant. It is indicated that MclX influenced expression independently of σ or GerE, through a new pathway to regulate expression. deletion could be a new approach for insecticidal protein encapsulation in .
本研究对亚种菌株HD73中的新型蛋白质MclX（母细胞裂解蛋白X）进行了表征。MclX没有已知结构域，其在HD73中的基因缺失导致Cry1Ac在母细胞中被包裹，且不影响Cry1Ac蛋白的产生或杀虫活性。细胞壁水解实验表明，MclX不能水解细胞壁。在缺失突变体中，通过β-半乳糖苷酶活性测定表明，编码关键细胞壁水解酶的基因表达显著降低。基于电泳迁移率变动分析（EMSA），MclX不能直接结合到该基因的启动子上。据报道，该基因受σ因子和GerE调控。然而，HD73和该基因缺失突变体之间，该基因和另一基因的转录活性没有差异。这表明MclX通过一条新的途径独立于σ因子或GerE影响该基因的表达，从而调控其表达。基因缺失可能是在该菌中进行杀虫蛋白包裹的一种新方法。
