Regulation of Diterpene Biosynthesis in Higher Plants

这项研究的总体目标是发展对 在高等植物中， 二萜类代谢物的生物合成， 植物在环境和生物胁迫下生存的能力。 重点是环化酶的调节，催化 第一个承诺的步骤的途径导致一个 生理活性二萜类代谢物，因此是一种 合理的监管场所。 一种靶酶是casbene 合成酶，它催化合成推定的 蓖麻籽幼苗中的植物抗毒素，casbene。 卡斯宾 合成酶基因在转录上被激活， 用果胶片段诱导子处理幼苗。 基因组 含有casbene合成酶编码序列的克隆已经被 与世隔绝 研究的一个主要目标是描述 casbene合成酶基因以及顺式和反式作用因子， 参与基因的转录激活， 对果胶片段激发子的反应。 这些调查 在植物抗病性方面具有重要意义， 植物抗毒素是防御性成分之一， 抗性反应 另一个实验目标是贝壳杉烯 合成酶，一种关键的调节酶的途径，导致 赤霉素家族调节剂，有助于调节环境 影响植物生长发育。 一个主要目标是 将贝壳杉烯合成酶纯化至均质，并使用 纯化蛋白制备特异性抗体和贝壳杉烯 合成酶cDNA探针 这些探针将用于测量 植物组织中贝壳杉烯合成酶mRNA水平， 在不同环境条件下， 它们对赤霉素相对潜力指示剂 生物合成

The general objective of this research is to develop understanding of the mechanisms operating in higher plants to regulate the biosynthesis of diterpenoid metabolites that contribute to a plant's ability to survive environmental and biological stresses. The focus is on the regulation of cyclization enzymes that catalyze the first committed step of the pathway leading to a physiologically active diterpenoid metabolite(s), and thus is a logical site for regulation. One target enzyme is casbene synthetase, which catalyzes the synthesis of the putative phytoalexin, casbene, in castor bean seedlings. The casbene synthetase gene is transcriptionally activated in response to treatment of the seedlings with pectic fragment elicitors. Genomic clones containing casbene synthetase coding sequences have been isolated. A major goal of the research is to characterize the casbene synthetase gene and the cis- and trans-acting factors that participate in the transcriptional activation of the gene in response to pectic fragment elicitors. These investigations are of importance in connection with plant disease resistance since phytoalexins are among the defensive components that appear in a resistance response. Another experimental target is kaurene synthetase, a key regulatory enzyme in the pathway leading to the gibberellin family of regulators that help mediate environmental influences on plant growth and development. A major objective is to purify kaurene synthetase to homogeneity, and to use the purified protein to prepare specific antibodies and kaurene synthetase cDNA probes. These probes will be used to measure kaurene synthetase mRNA levels in plant tissues, and changes in their levels under different environmental conditions, as an indicator of their relative potentials for gibberellin biosynthesis.