Vibrio fischeri 54 controls motility, biofilm formation, luminescence, and colonization

In this study, we demonstrated that the putative Vibrio fischeri rpoN gene, which encodes 54, controls flagellar biogenesis, biofilm development, and bioluminescence. We also show that rpoN plays a requisite role initiating the symbiotic association of V. fischeri with juveniles of the squid Euprymna scolopes. The sigma factor 54, encoded by rpoN, is distributed widely among bacteria. The ability of 54 to regulate nitrogen metab-olism is well established (reviewed in reference 16). In Esche-richia coli, about half of all 54-dependent operons function in the assimilation and metabolism of nitrogen (28). In other organisms, 54 regulates diverse functions in addition to con-trolling nitrogen metabolism. In Vibrio parahaemolyticus, it controls the biogenesis of the polar flagella required for swim-ming and the lateral flagella necessary for swarming (31). In Vibrio harveyi, it regulates motility and bioluminescence (14). In Pseudomonas aeruginosa, it activates transcription of both the flagellin and pilin genes, negatively affects quorum-sensin