Characterization of protein function and differential protein expression in soybean under soaking condition.

Soybean is very useful crop to supply vegetable protein for human. However, cultivation arear of this economically important crop is gradually diminished in upland field. Hence, cultivation area of soybean is increased in paddy field. During the growth duration of soybean, excessive moisture injury is serious problem for sustainable production and supply. We investigated protein expression according to different period of seed soaking and germination after seed soaking. For comparison on expression of protein according to different condition, we performed two-dimensional electrophoresis. After electrophoresis analysis, we selected differentially expressed protein spots according to different condition such as soaking period and germination after soaking to identify protein function by using MALDI-TOF. Results revealed that pattern of expression of protein according to soaking period and germination after soaking were generally not different in major spots. However, degree of expression of protein in some protein spots was increased in accordance with decrease of soaking period. Especially, in Hwangkeum-Kong, Danyeop-Kon, and Pecking, the degree of expression of protein was remarkably increased for 4 days after soaking. But, according to germination after soaking, degree of expression of protein in germinated seeds of all cultivars was higher than un-germinated seeds. In results of MALDI-TOF analysis, specific proteins were identified by different soaking period such as Allergen Gly m Bd 28K, P24 oleosin isoform B. Also, in accordance with germination, degree of protein expression of the related protein, Gibberellin was increased in un-germinated seeds of Iksan-Kong. In ungerminated seeds of Sinpaldal-kong, proteins were identified as down-regulated by soaking such as ATP binding and Inhibitor II`, proteinase.