This project addresses the shortage of specialists capable of identifying nematodes (roundworms) by training new scientists to discover and describe roundworms using traditional and molecular methods. This research focuses on a natural group of nematodes that includes the most economically damaging plant parasites, certain animal parasites, and species feeding on soil microbes. The main problem to be addressed is the need for comprehensive understanding of genealogical relationships among these nematodes so that comparative studies can determine how these organisms have parasitized plants and animals. Involvement of a worldwide network of experts provides knowledge transfer essential for training new scientists.
The key role of nematodes in ecosystems, agriculture, veterinary science, and medicine contrasts starkly with the shortage of nematode taxonomists and the corresponding lack of information about nematode natural history. The main research objective is to narrow this gap by providing professional training in methods essential for identifying nematodes and assessing their relationships. This includes advanced microscopy and imaging techniques, standards for describing new species, procedures for obtaining and sequencing DNA, and methods for evaluating nematode relationships. This training will be focused on a nematode group (Tylenchina) that is pivotal to understanding mechanisms of parasitism. The broader impact of this research is through strengthening access of scientists to value-added products including nematode cultures, identification aids (morphological and molecular) and genealogies that will support advances in basic biology, ecology, agriculture, parasitology, and medicine.
Nematodes or "roundworms" are among the most abundant animals on earth. Most species are so small that they cannot be observed without the aid of a microscope. Yet, these small animals are essential for maintaining processes in soil that enhance soil health for the growth of plants. In addition, some types of nematodes live as parasites of plants or animals. These parasites often cause damage to their hosts, which may include food crops, farm and companion animals, and even humans. Despite the significance of nematodes to soil health, agriculture, veterinary science and human medicine, comparatively little is known about their biodiversity and taxonomy in comparison to other groups of animals. For example, it has been estimated that millions of nematode species may exist, but only about 28,000 are known to science. This means that many of the nematodes encountered by scientists cannot be identified. Improving upon the underdeveloped understanding of nematode taxonomy has been the central effort of this NSF research. This has been achieved by focused research and training on a group of nematodes that includes parasites of plants and animals, as well as non-parasitic or free-living species. Outcomes of this project can be categorized into two main areas: 1) training and outreach, and 2) basic and applied research. Training scientists how to identify and investigate nematodes was an important broader impact of this work. This outcome was achieved through formal university training of undergraduate and graduate students, postdoctoral scholars, and visiting scientists. Education and training outreach were also achieved through two summer workshops on nematode identification: one based on using traditional microscopic methods to identify important plant-parasites, and the second based on using modern molecular tools for nematode identification and taxonomy. Student trainees attended these workshops from the USA and several foreign countries. Basic and applied research outcomes of the project provide both a broader comparative context for understanding the nematodes studied, and provide new molecular information for identifying many species. Furthermore, new research publications resulting from this project include descriptions of several new species previously unknown to science. These include important plant parasites such as species of root lesion nematodes. Specimens representing these new species have been deposited in museum collections to serve as a basis for future study and comparison. Morphological comparisons of these nematodes, many of them less than .03 inches long, are crucial to refining identification tools and to understanding relationships and function; approaches have utilized techniques such as scanning electron microscopy to reveal detailed images of the specimens (Figure 1). The project has resulted in more than 65 research papers and one book. These research publications, which have involved collaborations with international scientists, have broader impacts beyond nematode taxonomy. For example, project publications have revealed aspects of organismal development, practical and theoretical considerations involving discovery of species, identification of new species of regulatory concern, and methods to restore damaged specimens so they can be used for identification and research.
