Rice alcohol dehydrogenase 1 promotes survival and has a major impact on carbohydrate metabolism in the embryo and endosperm when seeds are germinated in partially oxygenated water
Rice alcohol dehydrogenase 1 promotes survival and has a major impact on carbohydrate metabolism in the embryo and endosperm when seeds are germinated in partially oxygenated water
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DOI：
10.1093/aob/mct305
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发表时间：
2014-04-01
期刊：
影响因子：
4.2
通讯作者：
Nakazono, Mikio
中科院分区：
文献类型：
--
作者：
Takahashi, Hirokazu;Greenway, Hank;Nakazono, Mikio
水稻（Oryza sativa）具有罕见的在缺氧和低氧条件下萌发和伸长胚芽鞘的能力。先前已经通过使用水稻ADH 1缺陷突变体，降低的adh活性（rad）的研究表明，乙醇脱氢酶1（ADH 1）是淹水水稻幼苗胚芽鞘中细胞分裂和细胞伸长所必需的。本研究的目的是了解如何低ADH 1在水稻影响胚和胚乳中的碳水化合物代谢，以及乳酸和丙氨酸的合成在胚萌发和随后的胚芽鞘生长在淹没million. Wild型和RAD突变体水稻种子发芽和生长完全淹没。在吸胀后1，3，5和7天，胚和胚乳分离和几个代谢产物的测量和比较。在rad胚，乙醇发酵率减半，而乳酸和丙氨酸浓度的突变体是24和57倍，高于野生型。葡萄糖和果糖浓度在胚胎中的野生型随着时间的推移而增加，但不是在rad突变体。RAD突变体胚乳的-淀粉酶RAMY 1A和RAMY 3D的量较低，导致较少的淀粉降解和较低的葡萄糖concentrations.These结果表明，ADH 1是必不可少的糖代谢通过糖酵解乙醇发酵在胚胎和胚乳。在胚乳中，淀粉酶的合成和胚乳中蔗糖的合成以及糖向胚的运输可能需要能量。
Rice (Oryza sativa) has the rare ability to germinate and elongate a coleoptile under oxygen-deficient conditions, which include both hypoxia and anoxia. It has previously been shown that ALCOHOL DEHYDROGENASE 1 (ADH1) is required for cell division and cell elongation in the coleoptile of submerged rice seedlings by means of studies using a rice ADH1-deficient mutant, reduced adh activity (rad). The aim of this study was to understand how low ADH1 in rice affects carbohydrate metabolism in the embryo and endosperm, and lactate and alanine synthesis in the embryo during germination and subsequent coleoptile growth in submerged seedlings.Wild-type and rad mutant rice seeds were germinated and grown under complete submergence. At 1, 3, 5 and 7 d after imbibition, the embryo and endosperm were separated and several of their metabolites were measured and compared.In the rad embryo, the rate of ethanol fermentation was halved, while lactate and alanine concentrations were 24- and 57- fold higher in the mutant than in the wild type. Glucose and fructose concentrations in the embryos increased with time in the wild type, but not in the rad mutant. The rad mutant endosperm had lower amounts of the -amylases RAMY1A and RAMY3D, resulting in less starch degradation and lower glucose concentrations.These results suggest that ADH1 is essential for sugar metabolism via glycolysis to ethanol fermentation in both the embryo and endosperm. In the endosperm, energy is presumably needed for synthesis of the amylases and for sucrose synthesis in the endosperm, as well as for sugar transport to the embryo.