Motility control through an anti‐activation mechanism in Agrobacterium tumefaciens

Abstract

The bacterial flagellum is one of the most complex and sophisticated externalized structures that bacteria produce. Flagellar biosynthesis genes in bacteria are under hierarchical regulation, resulting in morphogenetic control of flagellum assembly (Chevance & Hughes, 2008;Soutourina & Bertin, 2003). The proper temporal and stoichiometric control of flagellar biogenesis dictates the insideout assembly of flagella and provides checkpoints to ensure that the requisite flagellar components are produced in sufficient quantities (Chevance & Hughes, 2017). Based on the best-studied systems in Escherichia coli and Salmonella enterica as models, the top genes of the hierarchy (class I) encode transcription factors that activate the expression of genes specifying the flagellar machinery components (class II; Kawagishi et al., 1992). Class II genes encode proteins that make up the hook-basal body complex of the flagellum. The basal body includes the type III secretion system that exports hook and filament proteins outside of the cell for filament assembly and the torque-generating motor proteins required for filament rotation.Assembly of the basal body permits class II proteins to activate the expression of class III genes (Chevance & Hughes, 2008). In the Gammaproteobacteria (such as E. coli, S. enterica, and Pseudomonas aeruginosa) and the Gram-positive bacterium Bacillus subtilis, class II genes encode the entire hook-basal body complex, and class III

Activation of ChvG-ChvI regulon by cell wall stress confers resistance to β-lactam antibiotics and initiates surface spreading in Agrobacterium tumefaciens

“…ChvI induces transcriptional changes in many genes across several major pathways. For example, ChvI upregulates transcription of mirA , encoding a repressor of the motility response regulator Rem and ultimately resulting in suppression of genes for motility and chemotaxis [ 10 ]. ChvI also upregulates genes for exopolysaccharide production and, in A .…”

The motility and chemosensory systems of Rhizobium leguminosarum, their role in symbiosis, and link to PTSNtr regulation

“…However, the growth defect of the manX mutant (Sánchez‐Cañizares et al, 2020) needs to be considered. Since the ptsN 1 mutant does not show a growth defect, we speculate that the PTS Ntr control of motility exerted by PtsN 1 ~P might indeed be mediated by the two‐component regulatory system ChvGI, known to prevent motility gene activation in Agrobacterium tumefaciens (Alakavuklar et al, 2021; Heckel et al, 2014), and a direct target of phosphorylated PtsN 1 (Sánchez‐Cañizares et al, 2020), good evidence for a connection between the PTS Ntr system and motility. Future work needs to be done to elucidate this regulatory mechanism.…”

An Inducible T7 Polymerase System for High-Level Protein Expression in Diverse Gram-Negative Bacteria

“…The system is also effective for expression of cytoplasmic proteins, such as A. tumefaciens MirA ( Fig. 1F ) ( 12 ).…”