Genetic parallelism and allele reuse in herbivore-plant chemical phenotype matching

贸易全球化意味着美国不断受到外来植物物种入侵的威胁，这些物种一旦建立，就可能成为入侵性杂草。这些杂草有时可以通过生物控制来管理，方法是从它们祖先的土地上引进昆虫敌人。在新的环境中，祖先的敌人对其宿主植物的影响取决于杂草化学防御的毒性和昆虫解毒酶的功效。野生欧洲防风草和欧洲防风草webworms，都原产于欧洲，被意外引入北美和共同发生在整个大陆。该项目将确定防风草的化学防御概况和网虫的解毒酶概况如何共同进化，以应对彼此和当地条件。这种相互适应可能涉及重复使用相同的遗传变异，或者可能需要在不同的地方使用不同的变异。了解这些选择中哪一种是最常见的，可以为关于共同进化模式和过程的基础研究以及关于入侵植物如何逃离或屈服于食草动物的农业研究提供信息。该项目建立在过去NSF资助的研究基础上，将为学生和公众提供多样化的培训和推广机会。将通过RNAseq在来自不同种群的样品中测定线虫中细胞色素P450解毒基因和欧防风中细胞色素P450生物合成基因的表达。差异表达的基因，它们的等位基因变体，以及它们对化学防御和解毒的影响，将在欧洲防风草和蜘蛛的范围内进行表征。 基因分型测序，另一种基因组使能的方法，将用于确定在多种环境中相互作用的基因组中的分子多态性。将对这些数据进行统计分析，以确定这些物种在相互作用时是否重复使用相同的遗传变异，或者不同位置的不同遗传变异是否允许共同适应。

Globalization of trade means the United States is under constant threat of invasion by foreign plant species, which, once established, can become invasive weeds. Such weeds can sometimes be managed through biocontrol, by importing insect enemies from their ancestral land. Impacts of an ancestral enemy on its host plant in new environments depend on the toxicity of the weed's chemical defenses and the efficacy of the insect's detoxification enzymes. Wild parsnips and parsnip webworms, both native to Europe, were accidentally introduced to North America and co-occur across the continent. This project will determine how the parsnip's chemical defense profile and the webworm's detoxification enzyme profile coevolve in response to each other and local conditions. This reciprocal adaptation may involve re-use of the same genetic variants or it may require different variants in different places. Understanding which of these options is most common can inform both basic research on the patterns and processes of coevolution and agricultural research about how invasive plants either escape from or succumb to herbivores. This project builds on past NSF funded research and will provide diverse training and outreach opportunities for students and the general public. Expression of cytochrome P450 detoxification genes in webworms and of cytochrome P450 biosynthetic genes in parsnips will be assayed by RNAseq in samples from different populations. Differentially expressed genes, their allelic variants, and their impact on chemical defense and detoxification will be characterized in parsnips and webworms across their range. Genotyping-By-Sequencing, another genome-enabled method, will be used to identify molecular polymorphisms in the interacting genomes in multiple environments. These data will be statistically analyzed to determine if these species re-use the same genetic variants when they interact or whether different genetic variants in different locations permit coadaptation.