Microbial and metabolic crosstalk in the rhizosphere shapes the divergent drought resilience of contrasting rice genotypes

Drought is a major constraint on rice production, yet the coordinated responses of rhizosphere microbial communities and metabolites across rice genotypes with contrasting drought tolerance remain insufficiently understood. In this study, we combined metagenomic and metabolomic analyses to investigate drought-induced changes in the rhizosphere of three rice genotypes with distinct ecological backgrounds: the drought-sensitive cultivar Bhutan, the upland rice genotype TGR78, and Oryza rufipogon K111. Field experiments were conducted under well-watered and drought conditions, and rhizosphere soil samples were collected for multi-omics profiling. Drought stress reduced plant height and panicle number in all three genotypes, but the magnitude of these effects differed among genotypes. Bhutan showed the greatest reduction in plant height (42.1%) and the largest number of differential metabolites (146), indicating a stronger drought response at both phenotypic and metabolic levels. In contrast, TGR78 and K111 displayed relatively greater phenotypic stability under drought stress. Metagenomic analysis revealed pronounced genotype-dependent shifts in rhizosphere bacterial community composition, whereas metabolomic profiling showed distinct changes in metabolite accumulation patterns among genotypes. Correlation analysis further demonstrated that drought substantially reshaped rhizosphere microbe–metabolite associations, shifting the interaction network from broadly positive and highly connected under well-watered conditions to more selective associations under drought stress. Collectively, these results indicate that rice drought adaptation is associated with genotype-dependent reorganization of the rhizosphere microbiome and metabolic profile. This study provides new insight into rhizosphere-mediated drought responses in rice and offers a basis for developing microbiome-informed strategies for drought-resilient crop improvement.