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Motility control through an anti-activation mechanism in Agrobacterium tumefaciens.
- Source :
-
Molecular microbiology [Mol Microbiol] 2021 Nov; Vol. 116 (5), pp. 1281-1297. Date of Electronic Publication: 2021 Oct 19. - Publication Year :
- 2021
-
Abstract
- Many bacteria can migrate from a free-living, planktonic state to an attached, biofilm existence. One factor regulating this transition in the facultative plant pathogen Agrobacterium tumefaciens is the ExoR-ChvG-ChvI system. Periplasmic ExoR regulates the activity of the ChvG-ChvI two-component system in response to environmental stress, most notably low pH. ChvI impacts hundreds of genes, including those required for type VI secretion, virulence, biofilm formation, and flagellar motility. Previous studies revealed that activated ChvG-ChvI represses expression of most of class II and class III flagellar biogenesis genes, but not the master motility regulator genes visN, visR, and rem. In this study, we characterized the integration of the ExoR-ChvG-ChvI and VisNR-Rem pathways. We isolated motile suppressors of the non-motile ΔexoR mutant and thereby identified the previously unannotated mirA gene encoding a 76 amino acid protein. We report that the MirA protein interacts directly with the Rem DNA-binding domain, sequestering Rem and preventing motility gene activation. The ChvG-ChvI pathway activates mirA expression and elevated mirA is sufficient to block motility. This study reveals how the ExoR-ChvG-ChvI pathway prevents flagellar motility in A. tumefaciens. MirA is also conserved among other members of the Rhizobiales suggesting similar mechanisms of motility regulation.<br /> (© 2021 John Wiley & Sons Ltd.)
- Subjects :
- Amino Acid Sequence
Genes, Bacterial
Protein Binding
Virulence
Agrobacterium tumefaciens physiology
Bacterial Outer Membrane Proteins physiology
Bacterial Proteins physiology
Gene Expression Regulation, Bacterial
Protein Kinases physiology
Stress, Physiological
Transcription Factors physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1365-2958
- Volume :
- 116
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Molecular microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 34581467
- Full Text :
- https://doi.org/10.1111/mmi.14823