Ganusova Elena E, Vo Lam T, Mukherjee Tanmoy, Alexandre Gladys
Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, United States.
Front Microbiol. 2021 Apr 22;12:664826. doi: 10.3389/fmicb.2021.664826. eCollection 2021.
Bacterial chemotaxis is the directed movement of motile bacteria in gradients of chemoeffectors. This behavior is mediated by dedicated signal transduction pathways that couple environment sensing with changes in the direction of rotation of flagellar motors to ultimately affect the motility pattern. uses two distinct chemotaxis pathways, named Che1 and Che4, and four different response regulators (CheY1, CheY4, CheY6, and CheY7) to control the swimming pattern during chemotaxis. Each of the CheY homologs was shown to differentially affect the rotational bias of the polar flagellum and chemotaxis. The role, if any, of these CheY homologs in swarming, which depends on a distinct lateral flagella system or in attachment is not known. Here, we characterize CheY homologs' roles in swimming, swarming, and attachment to abiotic and biotic (wheat roots) surfaces and biofilm formation. We show that while strains lacking CheY1 and CheY6 are still able to navigate air gradients, strains lacking CheY4 and CheY7 are chemotaxis null. Expansion of swarming colonies in the presence of gradients requires chemotaxis. The induction of swarming depends on CheY4 and CheY7, but the cells' organization as dense clusters in productive swarms appear to depend on functional CheYs but not chemotaxis . Similarly, functional CheY homologs but not chemotaxis, contribute to attachment to both abiotic and root surfaces as well as to biofilm formation, although these effects are likely dependent on additional cell surface properties such as adhesiveness. Collectively, our data highlight distinct roles for multiple CheY homologs and for chemotaxis on swarming and attachment to surfaces.
细菌趋化性是运动性细菌在化学效应物梯度中的定向运动。这种行为由专门的信号转导途径介导，该途径将环境感知与鞭毛马达旋转方向的变化相耦合，最终影响运动模式。[具体细菌名称]使用两种不同的趋化途径，即Che1和Che4，以及四种不同的应答调节因子（CheY1、CheY4、CheY⑥和CheY⑦）来控制趋化过程中的游动模式。已表明每个CheY同源物对极鞭毛的旋转偏向和趋化性有不同影响。这些CheY同源物在群体游动（依赖于独特的侧鞭毛系统）或附着中的作用（如果有的话）尚不清楚。在这里，我们描述了CheY同源物在游动、群体游动以及附着于非生物和生物（小麦根）表面及生物膜形成中的作用。我们发现，虽然缺乏CheY1和CheY⑥的菌株仍能在空气梯度中导航，但缺乏CheY4和CheY⑦的菌株趋化性缺失。在有梯度存在的情况下群体菌落的扩展需要趋化性。群体游动的诱导依赖于CheY4和CheY⑦，但细胞在有效群体中组织成密集簇似乎依赖于功能性CheY而不是趋化性。同样，功能性CheY同源物而不是趋化性有助于附着于非生物和根表面以及生物膜形成，尽管这些影响可能依赖于其他细胞表面特性，如粘附性。总体而言，我们的数据突出了多种CheY同源物以及趋化性在群体游动和附着于表面方面的不同作用。
