Dehydrin-like proteins in soybean seeds in response to drought stress during seed filling

There is no information on accumulation of dehydrin proteins during seed development and maturation of soybean [Glycine mar (L.) Merr.] in response to drought stress. Our objective was to study accumulation of dehydrin-like proteins in developing soybean seeds in response to drought stress. A greenhouse experiment and a field experiment were conducted. In the greenhouse experiment, three treatments were imposed on soybean plants after beginning of linear seed filling ([R.sub.5]): well-watered (WW), gradual stress (GS) imposed before severe stress, and sudden severe stress (SS). In the field treatments were irrigation (I) and nonirrigation (NI) (rainfed) conditions imposed from [R.sub.5] to [R.sub.8] (mature seeds). Greenhouse results indicated dehydrin-like proteins (28 and 32 kDa) were detected 18 d after [R.sub.5] ([R.sub.5,8]) in developing seeds from drought-stressed plants but not in seeds from the well-watered plants. In the mature seeds, dehydrin-like proteins (28, 32, and 34 kDa) were detected in seeds from drought-stressed plants as well as the well-watered plants. In the field, dehydrin-like proteins accumulated similarly under irrigation and nonirrigation conditions, with the first detection for dehydrins (28 and 32 kDa) at 22 d after [R.sub.5] ([R.sub.6]). Accumulation of dehydrin-like proteins was maximalin seeds harvested at 43 d after [R.sub.5] (seed physiological maturity).