Regulation of Isoprenoid Biosynthesis in Higher Plants

本研究的总体目标是开发一种 对调节机制的理解 生理二萜类物质的生物合成 在植物生命中的重要性。 第一实验 目标是贝壳杉烯合成酶，一种关键的调节酶， 导致赤霉素家族的生物合成途径 植物激素 一种新的方法来评估 正在尝试开展这项活动。 贝壳杉烯的成分 合成酶复合物将被纯化至均质，抗体 制备并分离cDNA克隆。 这些工具将 用于衡量可翻译和总的水平 植物器官中可杂交的贝壳杉烯合成酶mRNAs， 在不同的生理环境下发生变化。 的 二萜类植物抗毒素的生物合成途径 水稻（Oryza sativa）中的生物合成是 兴趣 这些生物合成的生物化学特性 将进一步明确路径。 激发子的性质 启动二萜类植物抗毒素生物合成的分子将 追究 转录调控在 参与环化的酶的表达 将研究二萜烃中间体。 这些结果将有助于我们了解 植物对环境和生物的反应 压力。% 环状二萜类代谢物通常被表征为 次级代谢产物 这些物质似乎有助于 产生它们的生物体具有专门的调节作用 使生物体能够适应环境的变化 和生物压力与入侵 病原体、捕食者和竞争者。 符合本 认为，许多环状二萜类化合物分离自高等植物， 植物已被证明具有生理活性。 的 正在考虑代谢的二萜类物质 在这项研究中，有一些例子。 对映贝壳杉烯是环状的 天然植物赤霉素家族的二萜前体 生长调节剂，而casbene，momilactones和 谷抗毒素是植物抗毒素， 宿主植物对微生物病原体的抵抗力。*//

The general objective of this research is to develop an understanding of the mechanisms of regulation of the biosynthesis of diterpenoid substances of physiological importance in the life of the plant. The first experimental target is kaurene synthetase, a key regulatory enzyme in the biosynthetic pathway leading to the gibberellin family of plant hormones. A new approach to assessing the levels of this activity is being attempted. Components of the kaurene synthetase complex will be purified to homogenity, antibodies prepared and cDNA clones isolated. These tools will then be utilized to measure the levels of translatable and total hybridizable kaurene synthetase mRNAs in plant organs, and their changes under different physiological circumstances. The biosynthetic pathways involved in diterpenoid phytoalexin biosynthesis in rice (Oryza sativa) is a second area of interest. The biochemical characteristics of these biosynthetic pathways will be further defined. The nature of elicitor molecules that initiate diterpenoid phytoalexin biosynthesis will be investigated. And the role of transcriptional regulation in the expression of the enzymes involved in cyclization of diterpene hydrocarbon intermediates will be investigated. These results will contribute to our knowledge of the manner in which plants respond to environmental and biological stresses.%%% Cyclic diterpenoid metabolites are often characterized as secondary metabolites. Such substances appear to serve the organism that produces them in specialized regulatory roles that enable the organism to adapt to environmental changes and biological stresses associated with encroachments by pathogens, predators and competitors. Consistent with this view, many cyclic diterpenoid compounds isolated from higher plants have been shown to be physiologically active. The diterpenoid substances whose metabolism is being considered in this research are examples. ent-Kaurene is the cyclic diterpene precursor of the gibberellin family of natural plant growth regulators, while casbene, the momilactones and the oryzalexins are phytoalexins that are thought to be important in the host plant's resistance to microbial pathogens.***//