Microbes-mediated adaptive mechanisms support asymmetric drought resistance of clonal ramets for Moso bamboo

Clonal plants can persist under extreme environmental stress through the differential resource allocation between connected ramets. However, the microbes-mediated physiological and ecological mechanisms underlying such divergence remain poorly understood. Here, we use Moso bamboo (Phyllostachys edulis), a fast-growing clonal plant, to examine how temporary extreme drought affects the connected ramets and how they differentially recruit key drought-enriched microbiota in the rhizosphere via carbon rhizodeposition. Our results showed that the connected ramets exhibited distinct growth responses to drought, with one ramet displayed drought-resilient growth (D1) while the other exhibited drought-sensitive growth (D2). D1 maintained greater biomass, leaf area, and root length than D2. Moreover, the roots of D1 potentially released more soluble sugars and increased labile and dissolved organic carbon contents in the rhizosphere compared to D2. This led to the enrichment of four key drought-enriched microbial classes (Thermoleophilia, Bacteroidia, Alphaproteobacteria, Verrucomicrobiae), which were modelled to be associated with the increased exopolysaccharides production in the rhizosphere, abscisic acid and jasmonic acid synthesis in roots, and thus improved drought resistance in D1 culms. In contrast, D2 showed lower growth, reduced physiological activity (abscisic acid and non-structural carbohydrate) and soil active organic carbon, reflecting its disadvantaged resource status. These findings highlight that rhizosphere microbial associations, coupled with host plant carbon allocation and hormone regulation, enhance drought resistance of clonal plants, thereby advancing our understanding of plant–microbe interactions under global change.