Morphological, Biochemical, and Proteomic Analyses to Understand the Promotive Effects of Plant‐Derived Smoke Solution on Wheat Growth under Flooding Stress

Wheat is an important staple food crop for one‐third of the global population; however, its growth is reduced by flooding. On the other hand, a plant‐derived smoke solution enhances plant growth; however, its mechanism is not fully understood. To reveal the effects of the plant‐derived smoke solution on wheat under flooding, morphological, biochemical, and proteomic analyses were conducted. The plant‐derived smoke solution improved wheat‐leaf growth, even under flooding. According to the functional categorization of proteomic results, oppositely changed proteins were correlated with photosynthesis, glycolysis, biotic stress, and amino‐acid metabolism with or without the plant‐derived smoke solution under flooding. Immunoblot analysis confirmed that Ru‐ BisCO activase and RuBisCO large/small subunits, which decreased under flooding, were recovered by the application of the plant‐derived smoke solution. Furthermore, the contents of chlorophylls a and b significantly decreased by flooding stress; however, they were recovered by the application of the plant‐derived smoke solution. In glycolysis, fructose‐bisphosphate aldolase and glyceraldehyde‐3‐phosphate dehydrogenase decreased with the application of the plant‐derived smoke solution under flooding as compared with flooding alone. Additionally, glutamine, glutamic acid, aspartic acid, and serine decreased under flooding; however, they were recovered by the plantderived smoke solution. These results suggest that the application of the plant‐derived smoke solution improves the recovery of wheat growth through the regulation of photosynthesis and glycolysis even under flooding conditions. Furthermore, the plant‐derived smoke solution might promote wheat tolerance against flooding stress through the regulation of amino‐acid metabolism.