DISSERTATION RESEARCH: Systematics, host-specificity, and genome evolution of holoparasitic plants: A case study in Orobanche (Orobanchaceae)

寄生是一种独特的生活史策略，在植物、动物和其他生物体中独立进化了数十次。由于其高度的生物多样性和很好的了解其寄生模式，非光合寄生植物属列当提供了一个显着的机会，了解独特的宏观和微观进化的后果，寄生在系统发育框架。最近的工作已经确定了进化和遗传的后果，包括许多主机特定的谱系以及主机到寄生虫的水平基因转移。这项研究将使用新世界列当的基因组规模测序和北美各地的实地研究来开发以下内容：（1）对寄生植物基因组进化的克里思和模式的精细理解，（2）更好地了解宿主宽度，（3）非生物和生物栖息地特征，并进行分类学修订。除了推进进化生物学和生态学领域外，对宿主特异性和寄生虫基因组学的更好理解可能有助于对抗对欧洲，亚洲和美洲的番茄，向日葵和其他作物造成严重农业损害的几种列当。一名研究生和几名本科生将接受实验室和博物馆研究技术的培训，并将有机会在区域和国家会议上展示结果。具体来说，我们将使用基因组略读方法，结合北美的实地研究来研究（1）新世界列当中质体和线粒体进化的精细尺度克里思和模式，（2）众多谱系的寄主宽度，（3）非生物和生物生境特征，以更好地了解分布，（4）谱系的可诊断特征，直接导致分类修订。在几种可用的基因组还原技术中，基因组撇取（全基因组鸟枪测序）将提供最具成本效益的方法来捕获基因组DNA的高拷贝部分，包括核核糖体顺反子，质体和有丝分裂基因组，甚至从降解的材料中，如在植物标本上发现的材料。

Parasitism is a unique life history strategy that has evolved independently dozens of times in plants, animals, and other organisms. Due to its high biodiversity and a good understanding of its mode of parasitism, the non-photosynthetic parasitic plant genus Orobanche provides a remarkable opportunity for understanding the unique macro- and microevolutionary consequences of parasitism in a phylogenetic framework. Recent work has identified both evolutionary and genetic consequences, including numerous host specific lineages as well as host-to-parasite horizontal gene transfer. This research will use genomic-scale sequencing of new-world Orobanche and field studies across North America to develop the following: (1) a fine-scale understanding of tempo and mode of genome evolution in parasitic plants, (2) a better understanding of host-breadth, and (3) abiotic and biotic habitat characteristics, with a taxonomic revision to follow. In addition to advancing the fields of evolutionary biology and ecology, an improved understanding of host specificity and parasite genomics may be of use in combating several species of Orobanche that cause severe agricultural damage to tomato, sunflower, and other crops in Europe, Asia, and the Americas. One graduate and several undergraduate students will receive training in laboratory and museum research techniques, and will have the opportunity to present the results at regional and national meetings.Specifically, we will use a genome skimming approach, coupled with field studies across North America to study (1) fine-scale tempo and mode of plastid and mitochondrial evolution in new-world Orobanche, (2) host-breadth of numerous lineages, (3) abiotic and biotic habitat characteristics to better understand distributions, and (4) diagnosable features of lineages, leading directly to taxonomic revision. Out of several genome reduction techniques available, genome-skimming (whole-genome shotgun sequencing) will provide the most cost-effective way to
capture the high-copy fraction of genomic DNA, including the
nuclear ribosomal cistron, plastome, and mitogenome, even from degraded material such as that found on herbarium sheets.