Bacteria flagella are highly organized and complex organelles that play a central role in many aspects of adapting to ever-changing environment due to its swimming and swarming motilities.In general,the transcriptional hierarchy in the assembly process of flagellum is conserved and well-studied in many bacteria phyla.In our work,Shewanella oneidensis might use different mode to coordinate the highly ordered process.We discovered the FlrB-C negatively regulates the motility while it is a two-component system which is located classed Ⅱ in Vibrio cholerea.Further motility and expression of flagellin proteins analyses revealed that the flagellin protein was largely increased expressed and the motility dramatically reduced compared to wild type on condition that the regulator flrC is over-expressed in double mutant △flrB-C.This result indicates cross-regulation between flrB-C and other regulatory pathway constitutes a complex regulatory network to mediate the motility of this strain.