“Sensing, learning but forgetting”: the inability of strawberry plants to transmit the infochemically-mediated stress priming under salinity

Volatile Organic Compounds (VOCs) are widely recognized for their role in priming neighbouring plants against pathogens and herbivores, whilst their involvement in airborne-mediated priming under abiotic stress remains largely unexplored. With a 3-step experiment, we tested the hypothesis that VOC emissions by salt-stressed plants can prime neighbouring conspecific individuals once subjected to salinity. In step 1, salt-stressed (60 mM NaCl for 20 days; emitters – C+NaCl) strawberry plants (Fragaria × ananassa var. Elsanta) were grown together with receiver individuals irrigated with water only (NaCl-S). In step 2, a subset of NaCl-S plants was exposed to salt stress (NaCl-S+NaCl), while others were co-grown in a plastic box with additional unstressed strawberry plants (super receiver - NaCl-SS). Lastly, in step 3, NaCl-SS plants were treated with salt stress (NaCl-SS+NaCl). Control (C) – irrigated with water only – and C+NaCl plants of the same age as treated plants, were maintained as references for each step. In step 2, no differences were detected in terms of biomass, gas exchange parameters and chlorophyll content in NaCl-S+NaCl compared to non-stressed plants, thus confirming an enhanced stress tolerance mediated by infochemicals from emitters. Furthermore, in step 3, NaCl-SS+NaCl mirrored the performances of emitters, suggesting that no efficient airborne signal transmission took place from NaCl-S to NaCl-SS. The dataset offers evidence that neighbouring plants can perceive airborne signals, altering their metabolic profile and enhancing stress tolerance when subsequently stressed. Moreover, we demonstrate that, despite being primed, receivers cannot propagate the signal to their neighbouring conspecific individuals.