The expression patterns of α- and β-amylase genes in germinating rice seeds under low temperature and hypoxia condition.

This study was conducted to determine a-amylase gene expression during the rice seedling emergence in submerged (paddy field) condition and low temperature, which is practically important condition for farmers in temperate regions. Grown in aerobic condition at 30degreesC, seedling elongation rate of Suwon 287 and Janghyangdo were faster than Norin 6. The rate of elongation in aerobic condition at 30degreesC was the same in both Suwon 287 and Janghyangdo. However, germination was delayed and seedling growth rates are lower in submerged soil (hypoxia) at 18*C. Especially, Suwon 287 can not germinate under the submerged soil at 18degreesC.,6-amylase activity of Janghyangdo as well as Suwon 287 was detected in the second day at aerobic condition at 30degreesC. beta-amylase activity of Janghyangdo is detected in the third day, and strong expression was detected in their cultivar in submerged soil (hypoxia) at 18degreesC. However,8-amylase activity of Suwon 287 was not detected in that condition. In case of cv. Janghyangdo, Ramy1A was expressed in scutellar epithelium (5 day imbibition and 3 day treatment at submerged soil at 18degreesC) and then it was observed in the aleurone layer(5 day imbibition and 5 day treatment at submerged soil at 18*C). In case of cv. Suwon 287, although Ramy1A was expressed in scutellar epithelium (5 day imbibition and 3 day treatment), but not in aleurone layer. These results suggest why Janghyangdo can emergenate under the low temperature and hypoxia condition but Suwon 287 can not emergenate under the low temperature and hypoxia condition.