Effect of yeaI gene on biological characteristics of Escherichia coli of cattle origin

Abstract:

c-di-GMP is a widespread second messenger in bacteria and regulates many important bacterial biological characteristics (such as biofilm, motility and virulence) by binding effector proteins. YeaI protein containing EGEVF motifs can bind c-di-GMP and may regulate bacterial performance. [Objective] To study the roles of yeaI in Escherichia coli NJ17 strain. [Methods] The yeaI mutant (NJ17ΔyeaI) and complementary strain (cNJ17ΔyeaI) were constructed. Growth characteristics, biofilm formation ability, adhesion and other biological characteristics were analyzed in NJ17, NJ17ΔyeaI and cNJ17ΔyeaI. [Results] We successfully constructed NJ17ΔyeaI and cNJ17ΔyeaI. Compared with NJ17, there was no significant changes in growth characteristics and drug resistance of NJ17ΔyeaI (P>0.05). However, biofilm formation ability of NJ17ΔyeaI significantly decreased and motility of NJ17ΔyeaI significantly improved (P<0.05). Transmission electron micrographs shows that yeaI deletion affected the formation of NJ17 fimbriae and flagella. qPCR results also showthat the yeaI gene significantly inhibited the transcription level of the flagella-related genes motB and filG in NJ17. Furthermore, serum survival experiments results show that deletion of yeaI significantly enhanced survival abilities of NJ17 in rat serum (P<0.05). However, compared with NJ17, there was no significant change in adhesion rate of yeaI mutant to EpH₄-Ev (P<0.05). [Conclusion] The yeaI plays an important role in regulating the biological characteristics of E. coli of cattle origin.