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Title: Morphological and Molecular Identification of Globodera pallida associated with potatoes in Idaho

item Skantar, Andrea
item Handoo, Zafar
item Carta, Lynn
item Chitwood, David

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2007
Publication Date: 9/1/2007
Citation: Skantar, A.M., Handoo, Z.A., Carta, L.K., Chitwood, D.J. 2007. Morphological and molecular identification of Globodera pallida associated with potatoes in Idaho. Journal of Nematology. 39(2):133-144.

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that attack plant roots and cause an estimated ten billion dollars of crop loss each year in the United States and 100 billion dollars globally. Cyst nematodes are an important group damaging the roots of many kinds of plants worldwide. In the present study, ARS scientists used anatomical and molecular data to positively identify the pale potato cyst nematode from soil associated with potato fields in eastern Idaho, providing the first detailed description of this nematode from the United States. This research is significant because it describes a new diagnostic test that can distinguish pale potato cyst nematode from look-alike tobacco cyst nematode and the golden potato cyst nematode. Because the pale cyst nematode is regulated as a quarantine pest by many countries and causes economic damage to potato worldwide, scientists, regulators, and and extension agencies will use this research to better identify and prevent the spread of this nematode.

Technical Abstract: Identity of a new population of pale potato cyst nematode Globodera pallida (Stone, 1973) Behrens, 1975 associated with potatoes in eastern Idaho was established by morphological and molecular methods. Morphometrics of cysts and second-stage juveniles were generally within the expected ranges for G. pallida with some variations noted. The Idaho population and paratype material from Epworth, Lincolnshire, England both showed variations in tail shape, with bluntly rounded to finely pointed tail termini. Compared to the paratype, second-stage juveniles of the Idaho population had a shorter mean body length, and cysts had a slightly higher mean distance from the anus to the nearest edge of the fenestra. PCR-RFLP of the rDNA ITS region, sequence-specific multiplex PCR, and DNA sequence comparisons all confirmed the identity of the Idaho population as G. pallida. The ITS rDNA sequence of the Idaho isolate was identical to those from York, England and the Netherlands. Species-specific primers that can positively identify the tobacco cyst nematode Globodera tabacum were also identified, providing a new assay for distinguishing this species from G. pallida and the golden potato cyst nematode Globodera rostochiensis.