Molecular Basis of Wrinkled Variants Isolated From Biofilms.

Many species are dominant biofilm-forming Gammaproteobacteria in the ocean. The formation of biofilms is often accompanied by the occurrence of variants with different colony morphologies that may exhibit increased marine antifouling or anticorrosion activities. However, the genetic basis of the occurrence of these variants remains largely unexplored. In this study, we identified that wrinkled variants of mainly arose due to mutations in the , a gene, that are associated with decreased swimming motility and increased cellulose production. Moreover, we found that the spontaneous mutation in , encoding a flagellar biosynthesis protein, also caused a wrinkled colony morphology that is associated with cellulose overproduction, indicating that plays a dual role in controlling flagellar assembly and polysaccharide production in . Investigation of wrinkled variants harboring spontaneous mutation in , encoding a GGDEF domain protein, also demonstrated plays an important role in regulating cellulose production and swimming motility. In addition, by screening the suppressor of the variant strain, we also identified that the spontaneous mutation in and directly abolished the wrinkled phenotype of the variant strain, suggesting that the chemosensory signaling transduction and cellulose production are crucial for the determination of the wrinkled phenotype in . Taken together, this study provides insights into the genetic variation within biofilms of .