Molecular mechanism of flexible development and differentiation in plants

○植物生长的分子机制研究我们鉴定了一种赤霉素（GA）受体。它是一种重要的生长植物激素。GA受体在合理的浓度下与生物活性GA相互作用。GA与受体的结合诱导了GID 1与DELLA蛋白之间的相互作用，DELLA蛋白作为GA信号传导的负因子发挥作用。细胞分裂素是另一种生长激素。我们确定了三个编码细胞分裂素受体的基因，并研究了它们在植物中的相关功能。我们还揭示了水稻的粒数是由花分生组织中细胞分裂素的水平控制的。利用粒数基因，我们增加了日本顶级水稻主栽品种越光的粒数。我们确定了一组组件（或基因），命名为PRRs，它们在（或剂量）拟南芥昼夜节律钟中起着协调的重要作用，这对植物开花时间的控制很重要。我们还鉴定了我们发现的植物肽激素受体pktosulfokine。○植物对物理环境响应的分子机制研究。我们发现了水稻的五种阳离子/H+交换剂的特征性质。Ktr/HKT型转运蛋白也被发现是植物和细菌适应盐胁迫和高渗透压所必需的。我们还发现，硝酸盐转运蛋白基因被多种机制激活，包括硝酸盐和/或亚硝酸盐，并且谷氨酰胺被证明在转录和翻译后水平调节硝酸盐转运活性。为了了解高渗应激反应的信号转导，我们已经确定了一个SnRK 2相互作用蛋白，它可以作为信号组分的支架。

○Study on molecular mechanism of plant growthWe identified a receptor of gibberellin (GA). which is an important growth phytohormone. The GAreceptor interacts with bioactive GAs at a reasonable concentration. The binding GA to the receptor induces the interaction between GID1 and a DELLA protein, which functions as a negative factor of GA signaling. Cytokinin is another growth phytohomone. We identified the three genes encoding cytokinin receptors and investigated their relevant in planta functions. We also revealed that a grain number in rice is controlled by the level of cytokinin in the floral meristems. Using the graining number gene, we increased the grain number of Koshihikari, the top rice leading variety of Japan. We identified a set of components (or genes), named PRRs, which play coordinately essential roles within (or dose to) the Arabidopsis circadian clock that is important for the control of the flowering time in plants. We also identified a receptor of plant peptide hormone, pktosulfokine, discovered by us.○Study on molecular mechanism of plant response to physical environments.We found characteristic properties of five cation/H+ exchangers of rice. Ktr/HKTtype transporters were also found to be essential for the adaptation of plants and bacteria to salinity stress and high osmolality We also revealed that nitrate transporter genes are activated by multiple mechanisms involving nitrate and/or nitrite, and also that glutamine was shown to regulate nitrate transport activity at both the transcriptional and post-translational levels. For understanding of signal transduction of responses to hyperosmotic stress, we have identified an SnRK2 interacting protein that would function as a scaffold for signaling components.