Proteomic Analysis Reveals Salt-Tolerant Mechanism in Soybean Applied with Plant-Derived Smoke Solution

Salt stress of soybean is a serious problem because it reduces plant growth and seed yield. To investigate the salt-tolerant mechanism of soybean, a plant-derived smoke (PDS) solution was used. Three-day-old soybeans were subjected to PDS solution under 100 mM NaCl for 2 days, resulting in PDS solution improving soybean root growth, even under salt stress. Under the same condition, proteins were analyzed using the proteomic technique. Differential abundance proteins were associated with transport/formaldehyde catabolic process/sucrose metabolism/glutathione metabolism/cell wall organization in the biological process and membrane/Golgi in the cellular component with or without PDS solution under salt stress. Immuno-blot analysis confirmed that osmotin, alcohol dehydrogenase, and sucrose synthase increased with salt stress and decreased with additional PDS solution; however, H⁺ATPase showed opposite effects. Cellulose synthase and xyloglucan endotransglucosylase/hydrolase increased with salt and decreased with additional PDS solution. Furthermore, glycoproteins decreased with salt stress and recovered with additional treatment. As mitochondrion-related events, the contents of ATP and gamma-aminobutyric acid increased with salt stress and recovered with additional treatment. These results suggest that PDS solution improves the soybean growth by alleviating salt stress. Additionally, the regulation of energy metabolism, protein glycosylation, and cell wall construction might be an important factor for the acquisition of salt tolerance in soybean.