The global carbon metabolism regulator Crc is a component of a signal transduction pathway required for biofilm development by Pseudomonas aeruginosa.
The transition from a planktonic (free-swimming) existence to growth attached to a surface in a biofilm occurs in response to environmental factors, including the availability of nutrients. We show that the catabolite repression control (Crc) protein, which plays a role in the regulation of carbon metabolism, is necessary for biofilm formation in Pseudomonas aeruginosa. Using phase-contrast microscopy, we found that a crc mutant only makes a dispersed monolayer of cells on a plastic surface but does not develop the dense monolayer punctuated by microcolonies typical of the wild-type strain. This is a phenotype identical to that observed in mutants defective in type IV pilus biogenesis. Consistent with this observation, crc mutants are defective in type IV pilus-mediated twitching motility. We show that this defect in type IV pilus function is due (at least in part) to a decrease in pilA (pilin) transcription. We propose that nutritional cues are integrated by Crc as part of a signal transduction pathway that regulates biofilm development.
O'Toole
G A
GA
Department of Microbiology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA. George.O'Toole@Dartmouth.edu
Gibbs
K A
KA
Hager
P W
PW
Phibbs
P V
PV
Kolter
R
R
D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms; D002244:Carbon / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D001426:Bacterial Proteins; D012097:Repressor Proteins; C101896:crc protein, Pseudomonas; D002244:Carbon