Fig. 4

Colonization and interactions of candidate genera within the sterile seedlings and effects of different SynComs on the growth and Cd accumulation of S. alfredii. a Genus-level abundance differences in endophytic bacteria in shoots and roots of sterile S. alfredii seedlings after SynCom₁₃ inoculation. Log fold change and P-values of genera before and after inoculation were calculated using ANCOM-BC2, with the number of asterisks ranging from 1 to 4, denoting P-values less than 0.05, 0.01, 0.001, and 0.0001 (adjusted by Holm-Bonferroni method), respectively. Bolded genera indicate candidate genera used for constructing SynCom. b Genus-level sub-networks of endophytic bacteria associated with plant Cd concentration under different treatments. Correlations were inferred from the bias-adjusted genus abundance table using the Spearman method, selecting only genus significantly associated with plant Cd concentration (P < 0.001) to construct the sub-networks. The statistical test used was two sided. c Images of S. alfredii plants in solution culture experiments under no inoculation (CK), single-strain inoculation (L, P, N, O, S), and SynComs inoculation (A, NL, NP, NN, NO, NS) treatments. d Effects of different inoculation treatments on dry weight and Cd accumulation of S. alfredii in solution culture experiments. Significant differences among treatments were determined using Duncan’s multiple range test