Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824.
Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
Proc Natl Acad Sci U S A. 2020 Nov 17;117(46):29046-29054. doi: 10.1073/pnas.2010199117. Epub 2020 Nov 2.
The cell morphology of rod-shaped bacteria is determined by the rigid net of peptidoglycan forming the cell wall. Alterations to the rod shape, such as the curved rod, occur through manipulating the process of cell wall synthesis. The human pathogen typically exists as a curved rod, but straight rods have been observed under certain conditions. While this appears to be a regulated process, the regulatory pathways controlling cell shape transitions in and the benefits of switching between rod and curved shape have not been determined. We demonstrate that cell shape in is regulated by the bacterial second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) by posttranscriptionally repressing expression of , a gene encoding an intermediate filament-like protein necessary for curvature formation in This regulation is mediated by the transcriptional cascade that also induces production of biofilm matrix components, indicating that cell shape is coregulated with 's induction of sessility. During microcolony formation, wild-type cells tended to exist as straight rods, while genetically engineering cells to maintain high curvature reduced microcolony formation and biofilm density. Conversely, straight mutants have reduced swimming speed when using flagellar motility in liquid. Our results demonstrate regulation of cell shape in bacteria is a mechanism to increase fitness in planktonic and biofilm lifestyles.
杆状细菌的细胞形态由形成细胞壁的刚性肽聚糖网络决定。通过操纵细胞壁合成过程，可以改变杆状形状，例如弯曲的杆状。人类病原体通常以弯曲的杆状存在，但在某些条件下也观察到了直杆。虽然这似乎是一个受调控的过程，但尚未确定控制 和之间细胞形状转变的调控途径以及在杆状和弯曲形状之间切换的益处。我们证明， 中的细胞形状受细菌第二信使环二鸟苷酸（c-di-GMP）的调节，通过转录后抑制编码中间丝样蛋白的基因的表达，该蛋白对于 在 中的弯曲形成是必需的。这种调节是由转录级联介导的，该级联还诱导生物膜基质成分的产生，表明细胞形状与 的诱导定居性是共同调节的。在微菌落形成过程中，野生型 细胞往往呈直杆状，而通过基因工程使细胞保持高曲率会降低微菌落形成和生物膜密度。相反，直 的突变体在使用鞭毛运动在液体中时，游动速度降低。我们的结果表明，细菌细胞形状的调节是增加浮游生物和生物膜生活方式适应性的一种机制。
