Parasitic plants obtain nutrients from host plants via a unique organ (the haustorium) and, thus, may negatively impact the survival and reproductive success of the host. Many parasites are completely dependent on their host, having lost the ability to make their own food through photosynthesis. This proposal focuses on a poorly known and diverse lineage of tropical parasitic plants through field studies in diversity hotspots on three continents. Variation in morphology and host preference will be documented and DNA sequence data will be used to assess evolutionary relationships. This evolutionary framework will be used to create a revised classification system and to investigate transitions in modes of parasitism, such as the loss of photosynthetic capability.
This project investigates a plant lineage which includes parasites that infest crops, resulting in annual losses worth several billion $US. An introduction of witchweed (Striga asiatica) was so damaging to the US corn crop that most tropical parasites are classified as noxious weeds. However, USDA agents have no means of differentiating a dangerous parasite from a harmless one. This project will provide an important online resource to assist border agents, farmers, and researchers in identifying noxious parasites wherever they occur, whether at points of entry into the US or in their native ranges.