Specific Detection of the Root-Lesion Nematode Pratylenchus scribneri Using Conventional and Real-Time PCR.

Pratylenchus scribneri is a plant-parasitic root-lesion nematode causing economic damage to various crops worldwide. Identifying root-lesion nematodes to species using traditional morphological methods is an arduous task requiring extensive training on nematode taxonomy and years of experience. Thus, molecular methods for P. scribneri detection and identification were developed. Conventional and real-time polymerase chain reaction (PCR) assays with new species-specific primers were used in this study, which exclusively amplified DNA of P. scribneri but not DNA from other Pratylenchus spp. or non-Pratylenchus spp. tested. Compared with conventional PCR that was able to detect an equivalent to 1/4 of the DNA of a single nematode, real-time PCR was more sensitive and could amplify an equivalent to 1/128 of the DNA of one nematode. Both conventional and real-time PCR assays successfully identified P. scribneri and distinguished it from P. penetrans and P. neglectus isolated from field samples collected from various locations in North Dakota and Minnesota. The Blast-search based on the sequence information confirmed the reliability of the PCR assays for species identification. This is the first report of P. scribneri identification using a real-time PCR assay. The developed PCR assays are suitable for use in diagnostic laboratories and detection of field infestations with this nematode species.