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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Mycology and Nematology Genetic Diversity and Biology Laboratory » Research » Publications at this Location » Publication #356520
Research Project: Management of Specimens and Associated Information in the U.S. National Fungus Collections, with Emphasis on Critically Important Plant Pathogenic Fungi

Location: Mycology and Nematology Genetic Diversity and Biology Laboratory

Title: DNA barcoding evidence for the North American presence of alfalfa cyst nematode, Heterodera medicaginis

Author
item POWERS, THOMAS - University Of Nebraska
item Skantar, Andrea
item HARRIS, TIM - University Of Nebraska
item HIGGINS, REBECCA - University Of Nebraska
item MULLIN, PETER - University Of Nebraska
item HAFEZ, SAAD - University Of Idaho
item Handoo, Zafar
item TODD, TIM - Kansas State University
item POWERS, KIRSTEN - University Of Nebraska

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2018
Publication Date: 5/1/2019
Publication URL: https://handle.nal.usda.gov/10113/6471226
Citation: Powers, T., Skantar, A.M., Harris, T., Higgins, R., Mullin, P., Hafez, S., Handoo, Z.A., Todd, T., Powers, K. 2019. DNA barcoding evidence for the North American presence of alfalfa cyst nematode, Heterodera medicaginis. Journal of Nematology. 51(1):1-17. https://doi.org/10.21307/jofnem-2019-016.
DOI: https://doi.org/10.21307/jofnem-2019-016

Interpretive Summary: Plant-parasitic nematodes cause nearly $10 billion in crop losses annually in the United States. One such nematode species is the alfalfa cyst nematode, which was originally described from the former Soviet Union in 1971, but had never been detected in North America. In collaboration with scientists from Nebraska, Idaho, and Kansas, USDA ARS scientists from Beltsville, Maryland, have recently discovered juvenile and adult nematodes collected from alfalfa fields in Kansas and Montana with features that appear to be consistent with those of the alfalfa cyst nematode. DNA sequence analysis distinguishes these nematodes from the closely related soybean cyst, sugar beet cyst, and clover cyst nematodes. Initial host testing demonstrated that the nematode reproduced on alfalfa, but not on soybeans, tomato, or corn. Collectively the evidence suggests that this finding represents the first record of alfalfa cyst nematode in North America. This information will be used by plant pest management specialists and regulatory officials to manage and potentially contain this nematode to prevent inadvertent movement to additional areas.

Technical Abstract: Specimens of Heterodera have been collected from alfalfa fields in Kearny County Kansas and Carbon County Montana. DNA barcoding with the COI mitochondrial gene indicate that the species is not Heterodera glycines, soybean cyst nematode, H. schachtii, sugar beet cyst nematode, or H. trifolii, clover cyst nematode. Maximum likelihood phylogenetic trees show that the alfalfa specimens form a sister clade most closely related to H. glycines, with a 4.7% mean pairwise sequence divergence across the 862 nucleotides of the COI marker. Morphological analyses of juveniles and cysts conform to the measurements of H. medicaginis, the alfalfa cyst nematode originally described from the USSR in 1971. Initial host testing demonstrated that the nematode reproduced on alfalfa, but not on soybeans, tomato, or corn. Collectively the evidence suggests that this finding represents the first record of H. medicaginis in North America. Definitive confirmation of this diagnosis would require COI sequence of eastern European isolates of this species.