A novel extracytoplasmic function sigma factor (RpoE6) regulates biogenesis of a minor flagellin and other functions in <i>Azospirillum brasilense</i> Sp7.

ABSTRACT: In Gammaproteobacteria, the biogenesis of the flagellar filaments is regulated by a flagellum-specific sigma factor (FliA). In Alphaproteobacteria, however, a flagellum-specific sigma factor is not known. In our search for a FliA-like sigma factor in Azospirillum brasilense Sp7, we found an extracytoplasmic function sigma factor (RpoE6) located in a gene cluster consisting of FlgK, FlgL, FliD, FliS, and FliC2. A strain lacking RpoE6 (ΔrpoE6) was compromised in expressing a small flagellin, FliC2, which contributes to the polar flagellum structure and function in swimming motility, though there was no detectable defect in swimming motility in swim plates. A non-polar inactivation of this sigma factor also led to a growth defect that depended on aeration. FliC2, like the major

SUBMITTER: Gupta P 

PROVIDER: S-EPMC12826043 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature