Involvement of Shewanella oneidensis MR-1 LuxS in Biofilm Development and Sulfur Metabolism

The role of LuxS inShewanella oneidensis MR-1 has been examined by transcriptomic profiling, biochemical, and physiological experiments. The results indicate that a mutation inluxS alters biofilm development, not by altering quorum-sensing abilities but by disrupting the activated methyl cycle (AMC). TheS. oneidensis wild type can produce a luminescence response in the AI-2 reporter strainVibrio harveyi MM32. This luminescence response is abolished upon the deletion ofluxS . The deletion ofluxS also alters biofilm formations in static and flowthrough conditions. Genetic complementation restores the mutant biofilm defect, but the addition of synthetic AI-2 has no effect. These results suggest that AI-2 is not used as a quorum-sensing signal to regulate biofilm development inS. oneidensis . Growth on various sulfur sources was examined because of the involvement of LuxS in the AMC. A mutation inluxS produced a reduced ability to grow with methionine as the sole sulfur source. Methionine is a key metabolite used in the AMC to produce a methyl source in the cell and to recycle homocysteine. These data suggest that LuxS is important to metabolizing methionine and the AMC inS. oneidensis .