Climate change is pushing species beyond their evolved tolerances. Plant populations must acclimatize, adapt, or migrate to avoid extinction. However, because plants associate with diverse microbial communities that shape their phenotypes, shifts in microbial associations may provide an alternative source of climate tolerance. Here we show that tree seedlings inoculated with microbial communities originating from drier, warmer or colder locations exhibited higher survival when faced with drought, heat or cold stress. Microbially mediated drought tolerance was associated with increased diversity of arbuscular mycorrhizal fungi, whereas cold tolerance was associated with lower fungal richness, likely reflecting reduced burden by non-adapted fungal taxa.

(ISABELLE GEORGE)