Monoterpenoid Pheromone Production in Coleoptera: Characterization of Geranyl Diphosphate Synthase

鞘翅目昆虫是美国最具破坏性的害虫之一。 树皮甲虫每年造成北美数十亿立方英尺的针叶立木损失。 棉铃象甲 Anthonomas grandis 造成的平均年产量损失和控制成本超过 3 亿美元。 树皮甲虫和棉铃象甲虫在动物中是独一无二的，因为它们都产生交配和繁殖所需的单萜、C10 信息素成分。 该项目的长期目标是开发基于昆虫信息素系统的新的有效害虫管理策略。 为了从管理的角度充分利用信息素介导的树皮甲虫和棉铃象甲行为，彻底了解这些信号的起源、表达和活动非常重要。 Blomquist/Tittiger 实验室最近的工作表明，雄性松木刻甲虫 Ips pini 从头合成 ipsdienol，其合成受保幼激素 (JH) 控制，保幼激素诱导 3-羟基-3-甲基戊二酰辅酶 A 还原酶 (HMG-R) 和 HMG-CoA 合成酶 (HMG-S) 转录水平。 单萜信息素生产中的另一个关键酶是香叶基二磷酸合酶 (GPPS)，它控制类异戊二烯产物的链长。建议开展工作以了解这种酶的活性调节与信息素产生的关系，并对该酶进行克隆、测序和建模。 该提案中概述的研究具有重要意义，因为它们对类异戊二烯生物化学和基础昆虫分子生物学产生了影响。 越来越清楚的是，植物单萜完全通过非甲羟戊酸途径合成，使得 Ips spp.和 A. grandis 相对新颖的系统，用于研究基于甲羟戊酸的单萜生物合成的调节。 此外，很少有其他昆虫模型对异戊二烯基二磷酸合酶的分子生物学进行了研究，而且这些模型都没有涉及 GPPS 或建模研究。 此外，这些其他模型都没有像 I. pini 和 A. grandis 那样具有可以轻松回收毫克量的单萜最终产物。 最后，Ips pini 和 A. grandis 信息素生物合成，特别是关键类异戊二烯酶的转录，代表了用于研究 JH 调节基因表达的非发育模型系统。 这项工作建立并扩展了 Blomquist/Tittiger 实验室进行的昆虫信息素调节分子生物学研究的开创性工作。

Insects in the order Coleoptera are among the most destructive pests in the United States. Bark beetles are responsible for losses of billions of cubic feet of coniferous standing timber each year in North America. The cotton boll weevil Anthonomas grandis accounts for over $300 million average annual yield loss and control costs. The bark beetles and the boll weevil are unique among animals in that both produce monoterpenes, C10 pheromone components that are required for mating and reproduction. The long term goal of this project is to develop new and effective pest management tactics based on insect pheromone systems. To fully exploit pheromone-mediated bark beetle and cotton boll weevil behavior from a management standpoint, a thorough understanding of the origin, expression and activity of these signals is important. Recent work in the Blomquist/Tittiger laboratory has demonstrated that the male pine engraver beetle, Ips pini, synthesizes ipsdienol de novo, and that production is controlled by juvenile hormone (JH) which induces 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-R) and HMG-CoA synthase (HMG-S) transcript levels. Another key enzyme in monoterpenoid pheromone production is geranyl diphosphate synthase (GPPS), which controls the chain length of the isoprenoid product. Work is proposed to gain an understanding of the regulation of the activity of this enzyme in relationship to pheromone production and to clone, sequence and model the enzyme. The studies outlined in this proposal are significant because of their impact on isoprenoid biochemistry and basic insect molecular biology. It is becoming clear that plant monoterpenes are synthesized entirely via the non-mevalonate pathway, making Ips spp. and A. grandis relatively novel systems for the study of the regulation of mevalonate-based monoterpenoid biosynthesis. Furthermore, there are few other insect models in which the molecular biology of isoprenyl diphosphate synthases have been studied, and none of these have involved GPPS or modeling studies. Also, none of these other models has a monoterpenoid end product that can be readily recovered in mg quantities as is the case with I. pini and A. grandis. Finally, Ips pini and A. grandis pheromone biosynthesis, and specifically the transcription of key isoprenoid enzymes, represents a non-developmental model system for the study of JH regulated gene expression. This work builds upon and expands the pioneering work on the molecular biological studies of insect pheromone regulation performed in the Blomquist/Tittiger laboratories.