Plant Adaptation in a Changing Climate: From Molecular Mechanisms to Ecosystem Resilience

Climate change exposes plants to recurrent and interacting drought, heat and salinity while simultaneously reorganising the microbial communities that influence plant nutrition, development and stress physiology. The plant holobiont therefore offers a useful systems lens for examining climate resilience, but the concept is often used more broadly than the evidence warrants. This critical narrative review evaluates how plant-microbiome interactions link stress perception and signalling to community assembly, plant performance, soil feedbacks and ecosystem stability. Literature published primarily from 2010 to 15 July 2026 was selected from multidisciplinary and agriculture-relevant scholarly sources, with older foundational studies retained where conceptually necessary. Evidence was appraised according to experimental control, ecological realism, temporal scale, causal manipulation and the extent to which microbial composition was connected to function. Drought provides the strongest replicated evidence for stress-associated restructuring of root microbiomes, including recurrent enrichment of drought-tolerant bacterial lineages, yet compositional change alone does not establish adaptive host recruitment. Mechanistic studies increasingly show that root metabolites, nutrient-signalling pathways and microbial traits can alter both community membership and host phenotype, while synthetic-community and reintroduction experiments provide stronger causal tests than association-based profiling. Evidence for heat, salinity and combined stresses is growing but remains less replicated and more context-dependent. At broader scales, microbial diversity, network properties, plant-soil feedbacks and stress legacies can affect recovery and ecosystem functions, although improved plant tolerance may not translate automatically into ecosystem stability and can involve biogeochemical trade-offs. The most defensible path towards climate-resilient holobionts is therefore not the identification of universally beneficial taxa, but the development of context-aware, functionally explicit and field-validated plant-genotype-by-environment-by-microbiome frameworks. Future progress depends on time-resolved causal experiments, realistic multi-stressor designs, linked plant and ecosystem endpoints, and rigorous validation of microbiome interventions across soils, seasons and management systems.