Molecular mechanism of the elasticity of plant gene expression and signal transduction chains

与动物相比，植物在各个方面都具有独特的特征，因为它们由厚细胞壁覆盖的细胞组成。植物不能对环境变化做出反应，但植物已经发展出应对环境变化的独特策略。该项目旨在阐明这些独特特征的分子机制。在项目结束时，我们在以下几个方面取得了令人信服的成果。首先，我们确定parB是生长素调控的基因之一，它被发现编码谷胱甘肽S-转移酶。这是第一次将生长素调控的基因中的任何一个都赋予特定的功能。我们还分离了acrA作为另一个生长素调控的基因，它被发现编码G蛋白的β亚基样蛋白。这一发现开辟了一个新的领域，其中蛋白激酶C介导的信号转导链也参与植物的蛋白酶调节现象，因为arcA的基因产物可能是激活的C激酶的受体。另一方面，关于植物病原过程的信号转导链，一个激发子的受体被确定，而磷酸肌醇代谢的某些方面也得到了阐明。在这方面，还尝试了对病原真菌的抗性植物的再生。同时也证明了病毒基因组中某些特定的基因产物参与了植物对病毒侵染的抗性获得。因此，总体而言，本项目在植物分子生物学领域取得了一些积极成果。作为一种副产品，烟草BY-2细胞通过本项目研究人员的活动已被国际公认为植物中的模型实验材料，因为已经确定该细胞系生长非常快，并且可以在严格意义上同步，并且发现其对于分析植物细胞的基本方面是有用的。

Plants have unique characteristics in various aspects in compared to animals, as they are composed of cells covered by thick cell walls. Plants cannot move in response to environmental changes, however, plants have developed characteristic strategy against environmental changes. This project was proposed to elucidate the molecular mechanisms underlying these unique characteristics. When the term of this project finished, we have had some confident results in some aspects as follows. First, we identified parB as one of auxin-regulated genes, which was found to encode glutathione S-transferase. This is the first case, in which any one of auxinregulated genes has been ascribed to apecific functions. We have also isolated acrA as another auxin-regulated gene, which was found to encode a beta-subunit-like protein of G proteins. This discovery opened new area, in which signal transduction chains mediated by protein kinase C are also involved in plant hormone-regulated phenomena, as the gene product of arcA is likely to be a receptor for activated C kinases. On the other hand, as for the signal transduction chains regarding phytopathogenic processes, a receptor for an elicitor was identified, while some aspects of phosphoinositide metabolisms was also elucidated. In this regard, regeneration of resistant plants against pathogenic fungi was also tried. It was also demonstrated that some specific gene product of virus genomes was involved in the acquisition of resistance of plants against virus infection. Thus, overall, this project attained some positive results in the field of plant molecular biology. As a kind of byproducts, tobacco BY-2 cells have been internationally recognized as model experimental materials in plants through the activity of researchers of this project, as it was established that the cell line grows very fast and can be synchronized in a strict sense and found to be useful for the analysis of basic aspects of plant cells.