Protein homeostasis and cell wall remodeling in response to jasmonate and gibberellin signals improve flood tolerance in soybean (Glycine max L.)

The establishment of soybean seedlings is sensitive to flooding, and colocalization of proteins and quantitative trait loci (QTLs) advances to narrow down the hub genes. To reveal soybean seedling tolerance to flooding, Qihuang34 (QH34), Jidou17(JD17), and their recombinant inbred lines were used in this study. Severe plant death, shorter root length, and more stress-induced proteins were observed in JD7 compared to QH34 under flooding. The major functional categories of proteins altered by flooding were similar in both cultivars, and formed a cohesive network. Protein abundance and gene expression of ribosomal protein S3 decreased in flooded JD17 compared to QH34. Through proteomics and QTL mapping, beta-glucosidase 44 and dehydrin were involved in flood tolerance. Beta-glucosidase 44 abundance, beta-glucosidase activity, and glucose content decreased in QH34 compared to JD17 during flooding. The dehydrin contained the cis-acting elements of methyl jasmonate (Me-JA) and gibberellin (GA), accompanied by increased levels of Me-JA and GA₃ in flooded QH34 and JD17, respectively. These findings suggest that integrating proteomics with QTL is advantageous to identify genes associated with flood tolerance, proposing that enhanced protein homeostasis and cell wall stiffening in root tips may confer soybean seedling tolerance to flooding via GA and JA signals.