Fig. 7

WatS1 controls acetate tolerance only in the presence of WatABO pump. A The effect of overexpressing the watS1 and watS5 genes on acid tolerance. The ΔfliE control strain (JHM16) and strains replacing the fliE gene with watS1 or watS5 overexpression cassette (JHM161 and JHM165) were grown in NMS media with 20% (v/v) methane without or with weak organic acids as indicated. Each value represents the average ± standard deviations from two independent experiments. B The effect of deleting the watS1 gene on acid tolerance. The wild-type and watS1 deletion (JHM17) strains were grown in NMS media with 20% (v/v) methane without or with weak organic acids as indicated. Each value represents the average ± standard deviations from two independent experiments. C The effect of deleting the watS1 and WatABO pump genes. The wild-type, ΔwatS1 (JHM17), ΔwatABO (JHM18), and ΔwatABO ΔwatS1 (JHM182) strains were grown in NMS media with 20% (v/v) methane without or with 0.6 g/L acetate. Each value represents the average ± standard deviations from two independent experiments. D The effect of overexpressing the watS1 gene without WatABO pump genes. The control ΔwatABO strain with fliE deletion (JHM181) and ΔwatABO strain overexpressing watS1 (JHM183) were grown in NMS media with 20% (v/v) methane without or with 0.6 g/L acetate. Each value represents the average ± standard deviations from two independent experiments