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。在北美，树皮甲虫每年造成数十亿立方英尺的针叶树立木损失。棉铃象平均每年造成的产量损失和防治成本超过3亿美元。树皮甲虫和棉铃象甲虫在动物中是独一无二的，因为它们都会产生交配和繁殖所需的单萜类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的害虫管理策略。要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虫的行为，深入了解这些信号的来源、表达和活性是很重要的。最近在Bloomquist/TiTiger实验室的研究表明，雄性松材线虫iPS Pini从头合成ipsdienol de nevo，并受保幼激素(JH)控制，它诱导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。单萜类信息素生产中的另一个关键酶是香叶基二磷酸合成酶(GPPS)，它控制着类异戊二烯产物的链长。这项工作是为了了解这种酶的活性与信息素产生的关系的调节，并对该酶进行克隆、测序和建模。这项建议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氧戊酸途径合成，使iPS spp。和沙打旺是研究甲氧戊酸类单萜生物合成调控的较新系统。此外，很少有其他昆虫模型研究过异戊二烯基二磷酸合成酶的分子生物学，这些模型中没有一个涉及到GPPS或模型研究。此外，这些其他型号都没有一种单萜类最终产物，可以很容易地回收镁的数量，这是一种情况下的I.pini和A.grais。最后，iPS Pini和大枣信息素的生物合成，特别是关键的类异戊二烯酶的转录，代表了一个研究JH调控基因表达的非发育模型系统。这项工作建立在Blomquist/TiTiger实验室对昆虫信息素调节的分子生物学研究的开创性工作的基础上，并对其进行了扩展。

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.