Volatile blends from MeSA-treated soybean plants modulate drought responses in neighboring receivers: evidence for volatile-mediated infopriming.

Drought stress triggers complex biochemical and physiological adjustments in plants, including the release of volatile organic compounds (VOCs) that can influence neighboring individuals. Here we show that such volatiles, particularly those induced by methyl salicylate (MeSA), can convey chemical information that modulates the drought response of nearby soybean plants. Using an emitter-receiver chamber system, we exposed receiver plants under water deficit to volatiles from emitters subjected to either drought, MeSA application, or both. Drought reduced total VOC profile emission of emitters plants, whereas MeSA treatment during drought generated a distinct and more diverse volatile blend enriched in terpenoids such as β-ocimene and α-farnesene. Receiver plants exposed to these MeSA-induced blends exhibited higher stomatal conductance, transpiration rate, and photosynthetic efficiency than those exposed to volatiles from droughted emitters. In parallel, they accumulated less proline and glycine betaine and showed lower catalase and ascorbate peroxidase activities, indicating reduced oxidative and osmotic stress. These integrated responses define a physiological state distinct from both control and drought-only conditions, consistent with a primed-like configuration. We propose that MeSA-triggered volatile blends act as carriers of chemical information capable of inducing infopriming, i.e., a non-contact form of stress memory transfer that prepares neighboring plants for environmental challenges. This mechanism represents an emergent dimension of plant-plant interaction, linking volatile signaling, stress physiology, and memory processes.