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Molecular mechanism of regulation of rice seed germination

水稻种子萌发调控的分子机制

基本信息

批准号：
10640628
负责人：
MITSUI Toshiaki
金额：
$ 2.24万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

Aim of this research project is to clarify the molecular mechanism of germination of rice seeds. The results obtained in this research periods are as follow:1. The expression of α-amylase in the scutellar tissues and the aleurone layer of germinating rice seeds was differentially regulated by gibberellin (GA), abscisic acid (ABA), and metabolic sugars. The α-amylase expression in aleurone layer was induced by GA and the GA effect was suppressed by ABA, while the α-amylase expression in scutellum was strongly reduced by glucose and ABA but not ABA alone.2. Sucrose controlled the intracellular transport of α-amylase and stimulated its turnover in rice cells. Sugar also controlled the CaィイD12+ィエD1 uptake into rice cells, and there were a close relationship between the α-amylase expression and the CaィイD12+ィエD1 uptake.3. ABA stimulated the glucose uptake and sucrose synthesis in the scutellar tissues. It was also found that sucrose synthesis occurred in the aleurone layer, and that the sucrose synthesis was inhibited by GA and the GA effect was suppressed by ABA.4. The inositol 1,4,5-trisphosphate (IPィイD23ィエD2)-CaィイD12+ィエD1 signal transduction was suggested to be involved in the seed germination and the GA-inducible α-amylase expression. The level of IPィイD23ィエD2 in the aleurone layer was increased by GA. GA also induced the inositol phospholipid-specific phospholipase C in the aleurone.Overall results indicated that the close talk of GA, ABA and metabolic sugars is involved in the regulation of α-amylase expression and germination of rice seed.

本研究旨在阐明水稻种子萌发的分子机理。本研究取得的主要成果如下：1.赤霉素（GA）、脱落酸（阿坝）和代谢糖对萌发水稻种子的盾片组织和糊粉层中α-淀粉酶的表达具有不同的调节作用。GA诱导糊粉层α-淀粉酶的表达，阿坝抑制GA的诱导作用，而葡萄糖和阿坝均强烈抑制盾片中α-淀粉酶的表达，但单独阿坝对α-淀粉酶的表达无影响.蔗糖控制α-淀粉酶的胞内转运，促进其在水稻细胞中的周转。糖还控制水稻细胞对Ca ~（2+）D_1的吸收，α-淀粉酶的表达与Ca ~（2+）D_1的吸收密切相关.阿坝刺激盾叶组织中葡萄糖的吸收和蔗糖的合成。蔗糖的合成发生在糊粉层，GA抑制蔗糖的合成，ABA抑制GA的效应.结果表明：1，4，5-三磷酸肌醇（IP）D23-Ca ~（2+）D12+ Ca ~（2+）D1信号转导途径参与了种子萌发和GA诱导的α-淀粉酶表达。GA能提高糊粉层中IP_（60）D_23、IP_（60）D_2的含量。GA还诱导糊粉层中肌醇磷脂特异性磷脂酶C的表达，表明GA、阿坝和代谢糖的密切联系参与了水稻种子α-淀粉酶表达和萌发的调控。