Figure 1

Construction and characterization of the qseC mutant and complementary strain C-qseC. A PCR confirmation of mutant and complementation strains. M: DNA marker; Lanes1-3: PmCQ2; Lanes 4–6: ΔqseC; Lanes 7–9: C-qseC. Lanes 1, 4, and 7: P. multocida detection by using species-specific primers KMT1-F/KMT1-R (positive control); Lanes 2, 5, and 8: qseC gene detection by using primers comqseC-F /comqseC-R; Lanes 3, 6, and 9: qseC gene detection by using primers qseC5'Arm-F/qseC3'Arm-R. B qseC gene transcripts measured by using qRT-PCR. C Growth curves of strains cultured in Martin broth media at 37 °C with shaking at 200 rpm. D Colony morphology of PmCQ2, ΔqseC and C-qseC cultured on Martin agar plates. E Capsular polysaccharide production. F The centrifugally packed state of bacterial cells centrifuged at 10 000 rpm for 5 min. G Quantification of biofilm production. Panels B, C: values are expressed as the mean ± SD, n = 3. Panels E, G: values are expressed as the mean ± SD, n = 5. * P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001; ns means not significant.