Phenotypic analysis of the ∆jhp0106 insertion mutant and site‐directed mutants. (A) The motility of the SW863, SW862, ∆jhp0106::S350A (SW871), ∆jhp0106::F376A (SW872), ∆jhp0106::E415A (SW869), and the WT strains was evaluated by a soft‐agar motility assay. (B) Motility diameters were quantified and calculated as the mean ±SD of three independent experiments. *** represents statistical significance (p < 0.001). ns stands for “not significant.” (C) Growth of the WT, SW863, SW871, SW872, and SW869 strains showed a comparable trend over a course of 48‐hour inoculation. The results were calculated as the mean ±SD of three independent experiments. (D) Expression of FlaA detected in the whole‐cell proteins of the site‐directed ∆jhp0106 mutants by Western blotting. To be noted, the molecular mass of FlaA in the SW871, and SW872, and SW869 strains were similar to that in the SW863 strain, but lower than the WT strain. Surprisingly, FlaA yield was reduced in the SW871, and SW872, and SW869 strains. (E) Expression of flaA mRNA examined using cDNA‐qPCR analysis. An increase of flaA transcripts (2.78‐fold) was detected in the SW863 strain, whereas no significant change of flaA expression observed in the SW871, SW872, and SW869 strains. The results were measured as the mean ±SD of three independent biological repeats