Molecular mechanism and molecular breeding of phosphate storage during seed maturation in rice.

1 L-肌醇-1-磷酸[Ins（3）P_1]合成酶催化肌醇生物合成的第一步，即葡萄糖6-磷酸转化为Ins（3）P_1。在与Ins（3）P_1不同的多种代谢途径中，有一条是植酸钙的生物合成，植酸钙是种子中磷酸盐的一种贮存形式。我们从酵母和植物中分离到一个与Ins（3）P_1高度同源的水稻cDNA克隆pRINO 1。原位杂交和发育中的种子的组织学分析表明，RINO 1转录本的积累模式与含菲汀颗粒的定位相吻合。RINO 1转录物和颗粒在盾片和糊粉层内积累到高水平。此外，发现RINO 1转录物的积累先于菲汀颗粒的出现。这些结果表明，Ins（3）P_1合成酶在水稻种子发育过程中菲汀的生物合成中起着关键作用 ...更多信息 已知阿坝调节种子发育过程中的许多基因。葡萄糖-6-磷酸是蔗糖从源组织中转运出来的代谢产物之一，是Ins（3）P_1合成酶的底物。因此，我们研究了阿坝和蔗糖对水稻成熟种子盾片诱导的培养细胞中Ins（3）P_1合成酶基因表达的影响。蔗糖或阿坝处理后，Ins（3）P_1转录本的表达量明显增加，其表达量与蔗糖浓度（10 - 100 mM）和阿坝浓度（10 <-8>- 10 μ <-4>M）有关。蔗糖和葡萄糖对基因的诱导都有效，而甘露醇对基因的诱导无效。阿坝和蔗糖处理导致更高水平的转录积累。阿坝和蔗糖的联合处理表明，它们在诱导Ins（3）P_1合酶基因中具有协同作用。处理后2 ~ 4 h转录水平升高，随后逐渐下降。对RINO 1基因启动子的分析表明，RINO 1启动子中存在许多负责阿坝反应、种子特异性表达和重金属反应的顺式作用元件。少

1L-myo-inositol-1-phosphate [Ins(3)P_1] synthase catalyzes the first step of myo-inositol biosynthesis, represented by the formation of Ins(3)P_1 from glucose 6-phosphate. Of the various metabolic routes diverging from Ins(3)P_1, one is the biosynthesis of phytin (inositol hexakisphosphate), a storage form of phosphate in seeds. We have isolated a rice cDNA clone, pRINO1, which is highly homologous to Ins(3)P_1 from yeast and plants. In situ hybridization and histological analyses of developing seeds revealed that the accumulation pattern of the RINO1 transcripts coincided well With the localization of phytin-containing particles. Both the RINO1 transcripts and the particles accumulated to high levels within the scutellum and the aleurone layer. In addition, the accumulation of the RINO1 transcripts was found to precede the appearance of the phytin particles. These findings suggested that Ins(3)P_1 synthase plays a key role in phytin biosynthesis in developing seeds in rice.It is well … More known that ABA regulates many genes in developing seeds. Glucose 6-phosphate, the substrate of Ins(3)P_1 synthase, is one of the metabolites of sucrose that is translocated from the source tissues. Therefore, we investigated the effects of ABA and sucrose on the expression of the Ins(3)P_1 synthase gene in cultured cells induced from the scutellum of mature rice seeds. Higher levels of the Ins(3)P_1 transcript accumulation were evident after the treatment of either sugar or ABA.The expression level depended on sucrose concentration (10 to 100mM) and ABA concentration (10^<-8>M to 10^<-4>M). Both sucrose and glucose were effective in the gene induction but mannitol was not. Treatment with both ABA and sucrose resulted in much higher levels of transcript accumulation. A combined treatment of ABA and sucrose revealed that they work synergistically in the induction of the Ins(3)P_1 synthase gene. The level of transcript increased 2 to 4 hours after treatment, when it began to decrease gradually. The promoter analysis of the RINO1 gene revealed that many cis-acting elements responsible for ABA response, seed-specific expression, and heavy metal response existed in the RINO1 promoter. Less