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

Authors

Tom Powers, University of Nebraska-LincolnFollow
Andrea Skantar, Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL)
Timothy Harris, University of Nebraska-LincolnFollow
Rebecca Higgins, University of Nebraska-LincolnFollow
Peter Mullin, University of Nebraska-LincolnFollow
Saad Hafez, University of Idaho
Zafar Handoo, Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL)
Tim Todd, Kansas State University
Kirsten S. Powers, University of Nebraska-LincolnFollow

Date of this Version

8-4-2018

Citation

2019 Authors.

Comments

Article | DOI: 10.21307/jofnem-2019-016 e2019-16 | Vol. 51

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.