| Abstract |
Colonization on a solid surface is influenced by the cell surface appendages such as flagella and curli, of which expressions are regulated by rpoS gene encoding a sigma factor. In this study, we investigated the effect of rpoS or yggE (a rpoS-related and stress-responsive gene) deficiency on the colonization of Escherichia coli BW25113. Under a static condition, the deletion of rpoS or yggE induced 3.9- and 3.7-fold higher colonization as compared to wild-type cells, respectively, on the solid surfaces. However, under a liquid flow condition, only ΔyggE cells maintained the stable colonization on the surface, and the values of cell layer thickness and cell coverage on the surface were 17 and 9.2 times as high as those of wild-type cells, respectively. Gene expression analyses revealed that the deletion of rpoS or yggE positively impacted the expressions of genes involved in flagellum formation. On the other hand, curli assembly was severely prohibited by the rpoS deficiency. Here, we proposed that the plentiful flagella on the ΔrpoS and ΔyggE cell surfaces facilitated mainly the colonization under the static condition. Meanwhile, curli existing on the ΔyggE cell surface played an important role in keeping stable cell attachment and developing attached colonies under the flow stress condition.
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