INRA, UMR Diversité, Génomes et Interactions Microorganismes-Insectes (DGIMI), Université Montpellier, CC 54, 34095, Montpellier, Cedex 05, France.
Université Montpellier (UM), UMR DGIMI, Montpellier, France.
Curr Top Microbiol Immunol. 2017;402:39-51. doi: 10.1007/82_2016_53.
There is a complex interplay between the regulation of flagellar motility and the expression of virulence factors in many bacterial pathogens. Here, we review the literature on the direct and indirect roles of flagellar motility in mediating the tripartite interaction between entomopathogenic bacteria (Photorhabdus and Xenorhabdus), their nematode hosts, and their insect targets. First, we describe the swimming and swarming motility of insect pathogenic bacteria and its impact on insect colonization. Then, we describe the coupling between the expression of flagellar and virulence genes and the dynamic of expression of the flagellar regulon during invertebrate infection. We show that the flagellar type 3 secretion system (T3SS) is also an export apparatus for virulence proteins in X. nematophila. Finally, we demonstrate that phenotypic variation, a common property of the bacterial symbionts of nematodes, also alters flagellar motility in Photorhabdus and Xenorhabdus. Finally, the so-called phenotypic heterogeneity phenomenon in the flagellar gene expression network will be also discussed. As the main molecular studies were performed in X. nematophila, future perspectives for the study of the interplay between flagellum and invertebrate interactions in Photorhabdus will be discussed.
在许多细菌病原体中，鞭毛运动的调节与毒力因子的表达之间存在着复杂的相互作用。在这里，我们回顾了有关鞭毛运动在介导昆虫病原细菌（发光杆菌属和类黄杆菌属）与其线虫宿主及其昆虫靶标之间的三方相互作用中的直接和间接作用的文献。首先，我们描述了昆虫致病性细菌的游动和群体运动及其对昆虫定殖的影响。然后，我们描述了鞭毛和毒力基因表达与在无脊椎动物感染过程中鞭毛调节子表达的动态之间的耦合。我们表明，鞭毛类型 3 分泌系统（T3SS）也是 X. nematophila 中毒力蛋白的外排装置。最后，我们证明了表型变异（线虫共生细菌的共同特性）也改变了 Photorhabdus 和 Xenorhabdus 中的鞭毛运动。最后，还将讨论在鞭毛基因表达网络中所谓的表型异质性现象。由于主要的分子研究是在 X. nematophila 中进行的，因此将讨论在 Photorhabdus 中研究鞭毛与无脊椎动物相互作用之间相互作用的未来前景。
