"Systematics, evolution, biodiversity and biogeography of parasitic plants"

这项研究计划适用于寄生植物，这些植物从其他植物（称为宿主）那里获取部分或全部营养和水分。许多寄生植物的多样性，进化和生物学仍然知之甚少。我们的努力是针对菟丝子（“菟丝子”），其超过200种，是世界上最复杂和最多样化的寄生植物群之一。菟丝子在经济和生态上都很重要。菟丝子是第三大经济重要的寄生植物群，因为它的一些物种的侵染可能导致许多作物的显著产量损失。然而，本地菟丝子通过促进植物群落的多样性在生态系统中发挥着至关重要的作用。这项研究的目标之一是了解菟丝子物种在北美和南美的进化，并继续为这组植物开发生物多样性数据库。菟丝子具有明显的染色体数目变异（多倍性），因此另一个目的是揭示额外的染色体组是如何获得和维持的，以及这些变化在菟丝子进化中的作用。由于菟丝子属植物很少受到昆虫的攻击，本研究计划还研究了它们的防御机制，我们假设这是基于植物所有器官中分泌的乳胶，这些器官被称为乳管。最后，另一个短期目标是发现一些本地品种的菟丝子幼苗是否可以在发芽后立即与土壤真菌形成共生关系，当寄生虫没有附着在宿主上时。这种关系可能有助于它们在没有功能性根的情况下生存，直到它们找到并附着在宿主上，但同时也会将它们限制在特定的栖息地和土壤类型中。总的来说，这项研究是正在进行的全球努力的一部分，以编目地球上的生命，并了解其自然历史和进化。从实践的角度来看，研究结果将有助于更好地识别和管理杂草和濒危菟丝子物种。

This research program is applied to parasitic plants, which take some or all their nutrients and water from other plants, called hosts. The diversity, evolution and biology of many parasitic plants are still little known. Our efforts are directed at Cuscuta ("dodder"), which with its over 200 species, is one of the most complicated and diverse groups of parasitic plants in the world. Cuscuta species are important both economically and ecologically. Dodders are the third most economically important group of parasitic plants as infestation by some of its species can result in significant yield losses in numerous crops. However, native dodders play a crucial role in the ecosystems by promoting diversity in their plant communities. One of the goals of this research is to understand how species of Cuscuta have evolved in North and South America, as well as to continue developing a biodiversity database for this group of plants. Cuscuta has pronounced variation of the chromosome number (polyploidy) and thus another aim is to unravel how the extra sets of chromosomes have been acquired and maintained, and what was the role of these changes in the evolution of dodders. Since Cuscuta plants are attacked by very few insects, this research program also studies their defense mechanism, which we hypothesize is based on the latex secreted in all the organs of the plant by structures called laticifers. Finally, another short-term goal is to discover if the seedlings of some native species of Cuscuta can form symbiotic associations with soil fungi immediately after germination, when the parasites are not attached to a host. Such a relationship may help them survive without a functional root until they locate and attach themselves to a host, but at the same time it would restrict them to a particular habitat and soil type. Overall, this research is part of the ongoing global effort to catalog life on Earth and understand its natural history and evolution. From a practical point of view, the results will facilitate a better identification and management of both the weedy and endangered Cuscuta species.