VIEW ARTICLE

Molecular Plant Pathology

A DNA Hybridization Probe for Detection of Soybean Cyst Nematode. E. A. Besal, Graduate student, Department of Plant Pathology, University of Nebraska, Lincoln 68583-0722; T. O. Powers(2), A. D. Radice(3), and L. J. Sandall(4). (2)(4)Assistant professor, and Research technologist, respectively, Department of Plant Pathology, University of Nebraska, Lincoln 68583-0722; (3)Graduate student, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. Phytopathology 78:1136-1139. Accepted for publication 25 February 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-1136.

A DNA hybridization probe, constructed from mitochondrial DNA (mtDNA), was developed for the detection of the soybean cyst nematode (SCN) Heterodera glycines. The probe can detect a single female nematode applied as an unpurified homogenate to nitrocellulose filters, mtDNA was extracted from nematode eggs of an Arkansas race 3 population. MboI-digested mtDNA was inserted into the BamHI site of the molecular cloning vector pBR322. Transformants were screened by colony hybridization with intact ³²P-nick-translated SCN mtDNA. Potential probes were evaluated for species specificity by hybridization to homogenized cysts immobilized on nitrocellulose. Several techniques were evaluated for homogenizing and applying cyst DNA to filters. One probe of approximately 500 base pairs hybridized consistently to eight widely geographically divergent SCN populations. An SCN population from Java displayed weak hybridization. No hybridization was observed with H. leuceilyma, H. weissi, and Globodera virginiae. Occasional weak cross-hybridization was observed with H. trifolii, and slightly stronger cross-hybridization was observed in three populations of H. schachtii. Hybridization at high stringency reduced cross-hybridization to barely detectable levels.