Abstract text: Plants are continuously exposed to environmental stresses. Drought, osmotic and heat stress are particularly damaging, and their increasing frequency under climate change threatens yield stability and food security. A central component of abiotic stress adaptation is the plant cell wall. Pectin remodeling finely regulates wall porosity and elasticity, stress-related signaling and priming to maintain structural integrity. Pectin methylesterases (PMEs) play a key role by regulating the degree and pattern of pectin methylesterification. However, the specific PME isoforms involved in abiotic stress tolerance remain poorly defined. Furthermore, the precise mechanisms by which PME Inhibitors (PMEI), Subtilases (SBT), and hormone-mediated signaling coordinate pectin remodeling remain largely unknown. We aim to shed light on how PME activity and regulation shape cell wall plasticity under abiotic stress. Gene expression meta-analyses under single and combined stresses guided the selection of specific PME, PMEI and SBT isoforms. The isolation and the functional characterization of loss-of-function mutants are currently in progress. The mechanisms underlying the involvement of PME activity in abiotic stresses responses will be discussed.

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