Studying the interplay between sulfur nutrition and water stress tolerance in pea by proteomics : a focus on seed development and composition

National audienceWater stress and sulfur-deficiency are two constraints increasingly faced by crops due to climatechange and low-input practices. To investigate their interplay in the grain legume pea (Pisum sativumL.), sulfate was depleted at mid-vegetative stage and a moderate 9-day water stress period was imposedduring the early reproductive phase. The combined stress accelerated seed production, lowering yield,one-seed weight and seed number per plant, but rebalanced seed protein composition. In fact, themoderate water stress mitigated the negative effect of sulfur-deficiency on the accumulation of sulfurrichproteins in seeds, probably due to a lower seed sink strength for nitrogen, enabling a readjustmentof the sulfur-poor/sulfur-rich globulin ratio. These results uncovered the importance of sulfur forstabilizing seed yield in pea facing short and moderate water stress episodes, and showed that theadaptive response of sulfur-deprived plants to water stress is much more complicated than a simpleadditive response. Developing seeds were subjected to shotgun proteomics and transcriptomics toadvance our knowledge of the seed response to the single or double stresses. Among the results thatwill be presented is the building of a protein network together with a differential analysis, highlightinghubs potentially implicated in seed development and stress response