Inactivation of fliY attenuates the manganese-oxidizing capacity of Bacillus safensis ST7

Abstract:

[Background] Bacillus safensis ST7 has strong ability of oxidizing manganese, the molecular mechanism of which, however, remains unclear. [Objective] The aim is to study the effect of the flagellar motor switch protein FliY on the manganese-oxidizing ability of B. safensis. [Methods] Based on the principle of homologous recombination, a fliY -deleted mutant (△fliY) was constructed using B. safensis ST7 as the starting strain. The changes in mobility, biofilm formation, and manganese-oxidizing capacity of △fliY were evaluated based on colony migration, biofilm production, and Mn(II)-oxidizing rate. [Results] After cloning and sequencing, it was confirmed that fliY was inactivated with the last part replaced by kanamycin resistance gene in △fliY. The growth of △fliY in LB medium was similar to that of the starting strain. However, △fliY showed retarded logarithmic growth, small colonies, and reduced biofilm production in the PYCM medium containing Mn(II). The motility and Mn(II)-oxidizing rate of △fliY decreased by about 65% and 20%, respectively. [Conclusion] The gene fliY not only affects the growth and motility but also participates in biological processes such as chemotaxis and manganese oxidation of B. safensis.

Key words:Bacillus safensis;fliY;biofilm;flagellum;manganese oxidation