Dissertation Research: Insect Selection on Tropane Alkaloids

众所周知，伯格森的9623387种植物可以产生各种各样的化合物，其中一些今天被用于医药。许多解释这些化合物多样性的理论认为，植物产生这些化合物是为了防御食草性昆虫，但几乎没有实验工作来证明这一想法的有效性。该奖项将资助实验，以解决一类特殊的植物化学物质的作用，这种化学物质是由土豆家族(茄科)成员生产的托烷生物碱。将采用三种策略来确定主要的托拉烷生物碱的功能重要性，使用茄科的两个密切相关的成员，致命的茄子和紫荆花。第一种方法是将生物碱单独或混合添加到昆虫人工饲料中，以确定它们对昆虫生长和生存的影响。第二种策略是测试实验室中对昆虫食草动物毒性最大的生物碱的组合或数量是否在自然种群中具有防御功能。最后一种策略是最新颖的，它利用最新的生物技术将基因植入植物。产生生物碱所必需的一种酶的基因将被插入实验室中的植物中，从质的角度改变它们的生物碱生产。拥有这些‘突变’生物碱特征的个体将与普通或野生类型的植物一起种植在田间，并将测量这两种植物的损害量和总种子产量。这个项目对我们理解植物化学的进化和对CRMP的应用管理都有意义。特别是，这些发现将有助于指导对更具抗性的植物进行基因工程，并通过这样做，使农民减少对杀虫剂使用的依赖。

9623387 Bergelson Plants are known to produce a wide variety of chemical compounds, some of which are used in medicine today. Many theories explaining the diversity of these compounds propose that plants produce them as defenses against herbivorous insects, but there is little experimental work to demonstrate the validity of this idea. This award will fund experiments to address the role of a particular class of plant chemicals, the tropane alkaloids, produced by members of the potato family (Solanaceae). Three strategies will be adopted to determine the functional importance of the major tropane alkaloids using two closely related members of the Solanaceae, deadly nightshade and jimson weed. The first approach is to add the alkaloids, both individually and in mixtures, to insect artificial diet in order to ascertain their effects on insect growth and survival. The second strategy is to test whether combinations or amounts of the alkaloids showing greatest toxicity to insect herbivores in the laboratory have a defensive function in natural populations. The final strategy is the most novel, and takes advantage of recent biotechnology to insert genes into plants. A gene for one of the enzymes necessary to create the alkaloids will be inserted into plants in the laboratory, qualitatively changing their alkaloid production. Individuals having these 'mutant' alkaloid profiles will be planted out in the field with ordinary or wild type plants, and the amount of damage and total seed production for plants of both kinds will be measured. This project has both implications for our understanding of the evolution of plant chemistry, and for the applied management of crmps. In particular, findings will help guide genetic engineering of more resistant plants and, in so doing, allow farmers to be less dependent on pesticide application.