Flooding is a serious abiotic stress for soybean because it restricts growth and reduces grain yields. To investigate
the effect of gibberellic acid (GA) on soybean under flooding stress, root proteins were analyzed using a gel-free proteomic
technique. Proteins were extracted from the roots of 4-days-old soybean seedlings exposed to flooding stress in the
presence and absence of exogenous GA3 for 2 days. A total of 307, 324, and 250 proteins were identified from untreated,
and flooding-treated soybean seedlings without or with GA3, respectively. Secondary metabolism- and cell-related proteins,
and proteins involved in protein degradation/synthesis were decreased by flooding stress; however, the levels of
these proteins were restored by GA3 supplementation under flooding. Fermentation- and cell wall-related proteins were
not affected by GA3 supplementation. Furthermore, putative GA-responsive proteins, which were identified by the presence
of a GA-responsive element in the promoter region, were less abundant by flooding stress; however, these proteins
were more abundant by GA3 supplementation under flooding. Taken together, these results suggest that GA3 affects the
abundance of proteins involved in secondary metabolism, cell cycle, and protein degradation/synthesis in soybeans under
Flooding, gibberellic acid, GA-responsive elements, proteomics, root, soybean.
National Institute of Crop Science, National Agriculture and Food Research Organization, 2-1-18 Kannondai, Tsukuba 305-8518, Japan.