Open AccessRole of the σ D -Dependent Autolysins in Bacillus subtilis Population Heterogeneity
Author(s) -
Rui Chen,
Sarah B. Guttenplan,
Kris M. Blair,
Daniel B. Kearns
Publication year - 2009
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.00521-09
Subject(s) - biology , flagellin , flagellum , bacillus subtilis , motility , population , swarming motility , mutant , autolysin , genetics , peptidoglycan , gene , microbiology and biotechnology , bacteria , demography , quorum sensing , sociology , virulence
Exponentially growing populations ofBacillus subtilis contain two morphologically and functionally distinct cell types: motile individuals and nonmotile multicellular chains. Motility differentiation arises because RNA polymerase and the alternative sigma factor σD activate expression of flagellin in a subpopulation of cells. Here we demonstrate that the peptidoglycan-remodeling autolysins under σD control, LytC, LytD, and LytF, are expressed in the same subpopulation of cells that complete flagellar synthesis. Morphological heterogeneity is explained by the expression of LytF that is necessary and sufficient for cell separation. Moreover, LytC is required for motility but not at the level of cell separation or flagellum biosynthesis. Rather, LytC appears to be important for flagellar function, and motility was restored to aLytC mutant by mutation of eitherlonA , encoding the LonA protease, or a gene encoding a previously unannotated swarming motility inhibitor, SmiA. We conclude that heterogeneous activation of σD -dependent gene expression is sufficient to explain both the morphological heterogeneity and functional heterogeneity present in vegetativeB. subtilis populations.