| Abstract: | Soybean exhibits markedly reduced growth and yields under flooding stress. To determine the functional roles of four soybean proteins in post-flooding recovery, the organ/stress specificity and time-dependency of their enzymatic activities were analyzed. Peroxidase activity decreased in root and hypocotyl exposed to flooding and cold stresses, but increased during the post-stress recovery period. In contrast, its activity increased in both root and hypocotyl under drought stress. Acid phosphatase activity was suppressed in root treated with flooding and cold stresses, and slightly increased during the recovery period; however, the opposite profile was observed in hypocotyl. In response to drought stress, it did not change in root, but was decreased in hypocotyl. Beta-ketoacyl reductase activity did not change in root under flooding conditions, but was decreased in hypocotyl, although the activity increased slightly during the recovery period. In addition, it was decreased in both organs under drought and cold stresses, but again increased during the recovery period. Nucleotidylyl transferase activity was increased in root under flooding and drought stresses, but was decreased in hypocotyl. It was decreased in response to cold stress, but exhibited a slight increase during the recovery period. Furthermore, the treatment with jasmonate and salicylate suppressed the activities of peroxidase and acid phosphatase in root and hypocotyl under flooding stress; however, the activity of acid phosphatase increased during the recovery period. Nucleotidylyl transferase activity in root was also elevated by treatment with jasmonate, but gradually decreased during the recovery period. These results suggest that jasmonate-induced changes in nucleotidylyl transferase activity may facilitate soybean root recovery after flooding stress. |
