The SnRK1A protein kinase plays a key role in sugar signaling during germination and seedling growth of rice
The SnRK1A protein kinase plays a key role in sugar signaling during germination and seedling growth of rice
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DOI：
10.1105/tpc.105.037887
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发表时间：
2007-08-01
期刊：
影响因子：
11.6
通讯作者：
Yu, Su-May
中科院分区：
文献类型：
--
作者：
Lu, Chung-An;Lin, Chih-Cheng;Yu, Su-May
糖通过α-淀粉酶基因启动子中的糖反应复合体(SRC)及其相互作用的转录因子MYBS1抑制水稻萌发胚胎和细胞培养中α-淀粉酶的表达。Snf1蛋白激酶是酵母中葡萄糖抗性基因去阻遏所必需的。在这项研究中，我们探索了水稻中酵母Snf1的同源基因SnRK1在糖信号转导和植物生长中的作用。水稻胚胎瞬时表达分析表明，SnRK1A和SnRK1B作用于MYBS1和αAmy3 SRC启动子的上游，缓解了葡萄糖抑制。两个SnRK1都含有作为SRC激活剂的N-末端激动域和作为SRC主要负调节因子的C-末端调节域。SnRK1A的积累和活性在转录后受到糖的调节，SnRK1A通过SRC中的TA盒特异性地缓解葡萄糖抑制。一种转基因RNA干扰方法表明，在葡萄糖饥饿条件下，SnRK1A也是激活MYBS1和aAmy3表达所必需的。获得了SnRK1a和Snrk1b两个突变体，并对两个SnRK1s的功能进行了进一步研究。我们的研究表明，SnRK1A是糖信号转导途径中的一个重要中间体，在MYBS1和aAmy3 SRC之间的相互作用中起上游作用，在调节水稻种子萌发和幼苗生长方面发挥关键作用。
Sugars repress alpha-amylase expression in germinating embryos and cell cultures of rice (Oryza sativa) through a sugar response complex (SRC) in alpha-amylase gene promoters and its interacting transcription factor MYBS1. The Snf1 protein kinase is required for the derepression of glucose-repressible genes in yeast. In this study, we explored the role of the yeast Snf1 ortholog in rice, SnRK1, in sugar signaling and plant growth. Rice embryo transient expression assays indicated that SnRK1A and SnRK1B act upstream and relieve glucose repression of MYBS1 and alpha Amy3 SRC promoters. Both SnRK1s contain N-terminal kinase domains serving as activators and C-terminal regulatory domains as dominant negative regulators of SRC. The accumulation and activity of SnRK1A was regulated by sugars posttranscriptionally, and SnRK1A relieved glucose repression specifically through the TA box in SRC. A transgenic RNA interference approach indicated that SnRK1A is also necessary for the activation of MYBS1 and aAmy3 expression under glucose starvation. Two mutants of SnRK1s, snrk1a and snrk1b, were obtained, and the functions of both SnRK1s were further studied. Our studies demonstrated that SnRK1A is an important intermediate in the sugar signaling cascade, functioning upstream from the interaction between MYBS1 and aAmy3 SRC and playing a key role in regulating seed germination and seedling growth in rice.