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

Thomas Powers, Andrea Skantar, Tim Harris, Rebecca Higgins, Peter Mullin, Saad Hafez, Zafar Handoo, Tim Todd, Kirsten Powers

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1-17
Number of pages17
JournalJournal of Nematology
Issue number1
StatePublished - 2019


  • Alfalfa cyst nematode
  • COI DNA barcode
  • Detection
  • Diagnosis
  • Heterodera medicaginis
  • Taxonomy

ASJC Scopus subject areas

  • Agronomy and Crop Science


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