Growth characteristics and expression levels of RyhB-1 and RyhB-2 in SE50336 when cultured in SIE. A Growth characteristics of SE50336 in SIE. “SIE = 1:4 and SIE = 1:9” indicate the inoculation ratios of WT seed solution to SIE medium are 1:4 and 1:9, respectively. B Expression level of RyhB-1 and RyhB-2 in WT after culturing for 2 h in SIE. C Expression levels of RyhB-1 and RyhB-2 in WT after culturing for 3 h in SIE. RQ indicate relative quantification values of RyhB-1 and RyhB-2 expression in WT under SIE culture condition versus under LB broth aerobic conditions. All assays were performed in triplicate. *p < 0.05, **p < 0.01, one-way ANOVA.