Alanine aminotransferase 1 (OsAlaAT1) plays an essential role in the regulation of starch storage in rice endosperm

作者：Yang Jungil; Kim Sung Ryul; Lee Sang Kyu; Choi Heebak; Jeon Jong Seong; An Gynheung^*

来源：Plant Science, 2015, 240: 79-89.

DOI：10.1016/j.plantsci.2015.07.027

• Alanine aminotransferase
• Carbon metabolism
• Floury endosperm
• Rice
• Starch synthesis

Alteration of storage substances, in particular the major storage form starch, leads to floury endosperm. Because floury mutants have physical attributes for milling processes, identification and characterization of those mutants are valuable. In this study we identified a floury endosperm mutant caused by a TDNA insertion in Oryza sativa alanine-aminotransferase1 (OsAlaAT1). OsAlaAT1 is localized in the cytosol and has aminotransferase enzyme activity. The osalaat1 mutant has less amylose and its amylopectin is structurally altered. OsAlaAT1 is predominantly expressed in developing seeds during active starch synthesis. AlaAT catalyzes the interconversion of pyruvate to alanine, and this pathway is activated under low-oxygen conditions. Consistently, OsAlaAT1 is induced by such conditions. Expression of the starch synthesis genes AGPases, OsSSI, OsSSIIa, and OsPPDKB is decreased in the mutant. Thus, our observations suggest that OsAlaAT1 plays an essential role in starch synthesis in developing seeds that are exposed to low concentrations of oxygen.

• 出版日期2015-11
• 单位中国水稻研究所