The cell biology of peritrichous flagella in B acillus subtilis

• Published in: Molecular microbiology Vol. 87; no. 1; pp. 211 - 229
• Main Authors: Guttenplan, Sarah B., Shaw, Sidney, Kearns, Daniel B.
• Format: Journal Article
• Language: English
• Published: 01-01-2013
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.12103

Bacterial flagella are highly conserved molecular machines that have been extensively studied for assembly, function and gene regulation. Less studied is how and why bacteria differ based on the number and arrangement of the flagella they synthesize. Here we explore the cell biology of peritrichous flagella in the model bacterium
B
acillus subtilis
by fluorescently labelling flagellar basal bodies, hooks and filaments. We find that the average
B
. subtilis
cell assembles approximately 26 flagellar basal bodies and we show that basal body number is controlled by
SwrA
. Basal bodies are assembled rapidly (< 5 min) but the assembly of flagella capable of supporting motility is rate limited by filament polymerization (> 40 min). We find that basal bodies are not positioned randomly on the cell surface. Rather, basal bodies occupy a grid‐like pattern organized symmetrically around the midcell and that flagella are discouraged at the poles. Basal body position is genetically determined by
FlhF
and
FlhG
homologues to control spatial patterning differently from what is seen in bacteria with polar flagella. Finally, spatial control of flagella in
B
. subtilis
seems more relevant to the inheritance of flagella and motility of individual cells than the motile behaviour of populations.