Collaborative Research: RUI: Introgression of Plant Resistance Traits: Selection on Hybrid Willows by an Herbivorous Slug

科林·M.Orians DEB-9981568和Robert S.Fritz DEB 9981406塔夫茨大学瓦萨学院合作研究Ri：植物抗性性状的导入：食草动物对杂交柳树的选择将研究导入在适应进化中的重要性。他们将检验这样一种假设，即由于食草性鼻涕的选择，适应植物抗性的性状可能在杂交柳树基因型中受到青睐。这个系统是一对杂交的柳树物种，它们具有广泛的共域范围，目前在它们的重叠区域内发生氢化，似乎经历了过去的渗入。PI将从每个柳树物种的纯亲本中产生F2后代，然后让这些后代中的一些通过引入的鼻涕虫来食草。初步证据表明，苗木的鼻涕虫食草性和死亡率与植物化学有关。第一个实验将测试鼻涕虫食草性是否导致选择有利于F2表型和较高浓度的酚苷。实验二将确定与双亲相比，在F2后代中选择性喂养鼻涕虫的化学基础。在实验3中，PI将测量选择的和对照的F2后代对另外两种主要的柳树植食性昆虫--日本甲虫和柳叶锈病的抗性。这将决定在F2代的S中，是否存在选择对鼻涕虫更高抗性的生态成本，或者对鼻塞的抗性是协同作用的还是独立于对这些其他物种的抗性的。实验4将包括两个世代的回交和选择，以确定酚苷性状是否在回交中持续存在，并改善某些基因相对于未选择的回交对柳树的适合度。这项实验将直接测试导入模型，并将允许测试具有不同化学防御的导入植物之间的分配和生态成本。

Abstract Colin M .Orians DEB-9981568 & Robert S. Fritz DEB 9981406Tufts University Vassar CollegeCollaborative Research RUI: Introgression of Plant Resistance Traits: Selection on Hybrid Willows by an Herbivorous SlugOrians and Fritz will study the importance of introgression in the evolution of adaptations. They will test the hypothesis that adaptive plant resistance traits can be favored among hybrid willow genotypes due to selection by a herbivorous slug. The system is a hybridizing pair of willow species that have broadly sympatric ranges, currently hydridize throughout their zone of overlap and appear to have undergone past introgression. The PI's will make F2 progeny from pure parents of each willow species and then subject some of these progeny to herbivory by the introduced slug, A. fasciatus. Preliminary evidence suggests that slug herbivory and mortaility of seedlings is related to plant chemistry. The first experiment will test if slug herbivory causes selection favoring F2 phenotypes with higher concentrations of phenolic glycosides. Experiment two will involve determination of the chemical basis of selective slug feeding among F2 progeny compared to parentals. For Experiment 3, the PI's will measure the resistance of selected and control F2 progenies to two other major willow phytophages, Japanese beetles and willow leaf rust. This will determine if there are ecological costs of selection for higher resistance to slugs in F2's ,or, if resistance to slugs is synergistic or independent of resistance to these other species. Experiment 4 will include two generations of backcrossing and selection by slugs to determine if phenolic glycoside traits persist in backcrosses and improve the fitness of some genotypes relative to non-selected backcrosses to the willow S. eriocephala. This experiment will directly test the Introgression model, and will permit tests of allocational and ecological costs among introgressed plants with different chemical defenses.