Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, 48149, Münster, Germany.
Appl Microbiol Biotechnol. 2015 Mar;99(5):2255-66. doi: 10.1007/s00253-014-6291-5. Epub 2014 Dec 19.
In Bacillus subtilis, natural genetic competence is subject to complex genetic regulation and quorum sensing dependent. Upon extracellular accumulation of the peptide-pheromone ComX, the membrane-bound sensor histidine kinase ComP initiates diverse signaling pathways by activating-among others-DegQ and ComS. While DegQ favors the expression of extracellular enzymes rather than competence development, ComS is crucial for competence development as it prevents proteolytic degradation of ComK, the key transcriptional activator of all genes required for the uptake and integration of DNA. In Bacillus licheniformis, ComX/ComP sensed cell density negatively influences competence development, suggesting differences from the quorum-sensing-dependent control mechanism in Bacillus subtilis. Here, we show that each of six investigated strains possesses both of two different, recently identified putative comS genes. When expressed from an inducible promoter, none of the comS candidate genes displayed an impact on competence development neither in B. subtilis nor in B. licheniformis. Moreover, disruption of the genes did not reduce transformation efficiency. While the putative comS homologs do not contribute to competence development, we provide evidence that the degQ gene as for B. subtilis negatively influences genetic competency in B. licheniformis.
在枯草芽孢杆菌中，天然遗传能力受到复杂的遗传调控和群体感应的依赖。当肽信号分子 ComX 在细胞外积累时，膜结合的组氨酸激酶 ComP 通过激活 DegQ 和 ComS 等多种信号通路。虽然 DegQ 有利于细胞外酶的表达，而不是促进遗传能力的发展，但 ComS 对遗传能力的发展至关重要，因为它可以防止关键转录激活因子 ComK 的蛋白水解降解，ComK 是所有参与 DNA 摄取和整合的基因的转录激活因子。在地衣芽孢杆菌中，ComX/ComP 感知细胞密度对遗传能力的发展有负面影响，这表明与枯草芽孢杆菌中依赖群体感应的调控机制存在差异。在这里，我们表明，在六种被研究的菌株中，每一种都拥有两种最近发现的不同的、可能的 comS 基因。当从诱导型启动子表达时，在枯草芽孢杆菌和地衣芽孢杆菌中，没有一个 comS 候选基因对遗传能力的发展有影响。此外，基因的缺失也没有降低转化效率。虽然假定的 comS 同源物对遗传能力的发展没有贡献，但我们提供的证据表明，degQ 基因像枯草芽孢杆菌一样，对地衣芽孢杆菌的遗传能力有负面影响。
