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

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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.