Fig. 1

Strength comparison of the selected promoters and the effects of promoter C2up on the itu operon transcription and iturin A production. a Quantification of P_A2cup-, P_BJ27up-, P_C2up-, P_amyA- P₄₃- and P_bca-driven β-galactosidase (bgaB) activity at 24, 36 and 48 h; b changes in the transcriptional level of ituD, ituA, ituB and ituC after 12, 24 and 36 h of fermentation, and the transcriptional level of each itu gene in NK-∆LP was used as a control; c growth curves of B. amyloliquefaciens NK-∆LP and C2LP; d HPLC chromatograms of Sigma standard and the produced iturin A samples by C2LP, and NK-∆LP was used as a control. Data are mean values ± standard deviations of three replicates