A significant effect of cultivar on

A significant effect of cultivar on the response of Actinobacteria to drought stress was detected through two-way ANOVA (Supplementary Table S4). Actinobacteria mainly accumulated in the rhizosphere of YL10, whereas an opposite pattern was found in the rhizosphere of HQR under droughtstress (Figure 3). Five of the 50 most dominant bacterial genera were affected by the cultivar and/or developmental stage of broomcorn millet (Supplementary Table S5). In these genera,developmental stage significantly affected the responses of Adhaeribacter and Acinetobacter to drought stress, whereas cultivar influenced the responses of Lysobacter, Cellvibrio, Streptomyces, and Acinetobacter (Supplementary Table S5).The ratio of drought-exposed Acinetobacter to the control was also significantly affected by the interactive effect of developmental stage and cultivar (Supplementary Table S5).The relative abundance of Acinetobacter was notably upregulated in the rhizosphere of HQR under drought stress but was downregulated in the rhizosphere of YL10 (Figure 4A). By contrast, the relative abundances of Lysobacter, Streptomyces, and Cellvibrio in the rhizosphere of YL10 were mainly stimulated by drought stress compared with that of HQR (Figures 4B–D).