Drought and methyl jasmonate memory interact to determine plant functioning under current drought stress in a perennial grass
As droughts become more common due to climate change, survival may rely not only on a plants immediate response but also on what it has learned from past challenges. However, we still know little about how plants integrate different types of experiences, such as recurrent drought and hormonal cues, from previous generations. In this study, we examined whether clonal offspring of Festuca rubra plants previously exposed to drought or the stress hormone methyl jasmonate (MeJA) inherited biological memories that help them tolerate new drought stress. Using a factorial design, we combined untargeted LC- MS metabolomics with morpho-physiological measurements to evaluate these memory effects. We found that each type of memory changed plant metabolism and physiology, but the most notable changes occurred when both memories were present, and plants faced recurrent drought conditions again. This interaction between drought memory, MeJA memory, and current stress did not just add effects, it created entirely new metabolic responses, not seen in any single treatment. These combined memories fine-tuned water conservation, photosynthesis, and extensive metabolomic reshuffling, revealing a deeper level of drought resilience. Our results uncover a layered memory system in plants where past stresses do not act in isolation but interact to reshape future responses. This offers new insight into how plants prepare for stress and suggests practical strategies for priming drought tolerance across plant generations.