Fig. 7

Effect of Sphingobium sp. TBBS4 on the growth and nodulation of soybean. (A-B) Effect on the growth of soybean at 14 dpi with Sphingobium sp. TBBS4 inoculation singly (n = 14) and (C) at 28 dpi with Sphingobium sp. TBBS4 and S. fredii CCBAU45436 co-inoculation (n = 7). Student’s t-test, * p < 0.05; ** p < 0.01; *** p < 0.001. (D) Detection of della gene expression level after 1, 3, 5, and 7 days of Sphingobium sp. TBBS4 inoculation. Different letters above the error bar indicate a significant difference between means (One-way ANOVA with Duncan’s test, p < 0.05). Data are means ± SD (n = 3). Expression levels were normalized against the reference gene GmActin. Con: control group, inoculated with sterilized PBS; TBBS4: Sphingobium sp. TBBS4 inoculation singly; Rhi: S. fredii CCBAU45436 inoculation singly; Rhi + TBBS4: co-inoculation of Sphingobium sp. TBBS4 with S. fredii CCBAU45436