The Plant Microbiome in a Changing World: Ecology, Evolution, Stress Resilience and Sustainable Applications

Climate instability is increasing the frequency of drought, salinity, heat episodes, nutrient limitation and disease complexes that challenge the reliability of crop production. Plant-associated microbiomes can modify host nutrition, immunity, water relations and stress signalling, but translation from mechanistic discovery to agronomic deployment remains constrained by context dependence and poor persistence of introduced microorganisms. This critical narrative review evaluates how climate-resilient plant microbiomes can be engineered by combining three complementary levers: host genetic control of microbial recruitment, rationally assembled synthetic microbial communities, and ecological strategies that improve establishment and function under field conditions. Literature published from 2012 to 15 July 2026 was prioritised, while earlier methodological sources were retained where necessary. Evidence was selected from peer-reviewed studies and major reviews identified through scholarly databases, citation chaining and DOI verification. The strongest causal evidence comes from gnotobiotic and reductionist systems showing that immune signalling, nutrient-response pathways and root-secreted metabolites can reshape microbiota and alter host phenotypes. Field studies demonstrate heritable components of crop rhizosphere composition, yet environmental effects often exceed host-genetic effects. Synthetic communities provide experimentally tractable systems for identifying keystone strains, functional redundancy and microbe-microbe interactions, but many successful laboratory consortia remain untested across realistic soils, climates and management regimes. Host-mediated microbiome selection, transplantation and climate-conditioned inocula indicate that community-level functions can be transferred, although stability, biosafety and generalisability remain unresolved. A deployment framework is therefore proposed in which host genotype, microbial function, ecological compatibility and production agronomy are co-optimised rather than treated as independent variables. Progress will depend on multi-environment trials, strain-resolved functional measurements, explicit tests of persistence and ecological displacement, and breeding targets that incorporate microbiome responsiveness. Climate-resilient microbiome engineering is promising, but its agronomic value will depend less on adding more candidate microbes than on achieving predictable host-microbe-environment matching.