Two direct gene targets contribute to Clp-dependent regulation of type IV pilus-mediated twitching motility in Lysobacter enzymogenes OH11
Two direct gene targets contribute to Clp-dependent regulation of type IV pilus-mediated twitching motility in Lysobacter enzymogenes OH11
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DOI：
10.1007/s00253-018-9196-x
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发表时间：
2018-09-01
影响因子：
5
通讯作者：
Qian, Guoliang
中科院分区：
文献类型：
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作者：
Chen, Jiaojiao;Shen, Danyu;Qian, Guoliang
产酶溶杆菌（Lysobacter enzymogenes）是农业上重要的革兰氏阴性细菌，其采用多种抗真菌机制来抑制和感染丝状真菌病原体，通过分泌抗真菌抗生素HSAF（热稳定抗真菌因子）、形成T4 P（IV型菌毛）介导的抽搐运动以及产生胞外几丁质酶。有趣的是，所有这些关键的抗真菌因子似乎都是由L.酶基因;然而，基本机制知之甚少。在这里，采用菌株OH 11作为工作模型，我们表明，Clp在控制OH 11抽搐运动中起着双重作用。pilA是一种主要的T4 P结构菌毛蛋白基因，它通过直接结合到其启动子区来控制pilA的转录，以及通过直接结合到类似的启动子序列来调节pilMONOPQ操纵子的基因转录，其产物是T4 P组装所必需的。我们还将pilA启动子片段的Clp结合区截短至41 bp以鉴定潜在的Clp结合序列。此外，Clp识别的L.酶基因菌株与pilA启动子类似地保守，都具有保守的5 ′-GTG和保守的CAC-3 ′，间隔有10个高度可变的核苷酸。因此，这项研究确定了两个直接的和以前未表征的基因靶标的Clp有助于其在L。酶基因抽搐运动。总的来说，我们的研究结果进一步阐明了溶杆菌中Clp依赖性抽搐运动的分子遗传学。
Lysobacter enzymogenes is an agriculturally important Gram-negative bacterium that employs a multitude of antifungal mechanisms to inhibit and infect filamentous fungal pathogens, through secretion of antifungal antibiotic HSAF (heat-stable antifungal factor), formation of T4P (type IV pilus)-mediated twitching motility, and production of extracellular chitinase. Interestingly, all such key antifungal factors seem to be controlled by Clp, a master regulator in L. enzymogenes; however, the underlying mechanisms are poorly understood. Here, employing strain OH11 as a working model, we show that Clp plays a dual role in controlling OH11 twitching motility. It controls transcription of pilA, a major T4P structure pilin gene, via directly binding to its promoter region, as well as regulates the gene transcription of pilMONOPQ operon, whose products were essential for T4P assembly, by directly binding to a similar promoter sequence. We also truncated the Clp-binding region of the pilA promoter fragment down to 41 bp to identify the potential Clp-binding sequence. In addition, the Clp-recognized pilM promoter motif of the L. enzymogenes strains is similarly conserved as the pilA promoter, both with a conserved 5'-GTG and a conserved CAC-3', spaced by ten highly variable nucleotides. Thus, this study identified two direct and previously uncharacterized gene targets of Clp contributing to its regulation in the L. enzymogenes twitching motility. Overall, our findings further elucidate the molecular genetics of Clp-dependent twitching motility in Lysobacter.