Molecular identification of two stubby root nematode species

Abstract

Stubby root nematodes are of increasing importance to the potato industry in the Pacific Northwest (PNW) of the USA as they transmitTobacco rattle virus (TRY), the causal agent of corky ringspot disease. In the PNW,Paratrichodorus allius is the most prevalent TRV vector nematode species in potato growing areas. A closely related species,P. teres, is also found in parts of the PNW.P. allius andP. teres are morphologically similar, thus creating problems for routine identification. Few studies have utilized molecular techniques to identify species belonging to the Trichodoridae. Species-specific reverse PCR primers for bothParatrichodorus species were designed and located in the ITS-1 rDNA region and used in combination with a universal nematode forward primer located in the 18S rDNA. Primer reliability was confirmed byin vitro screening of differentP. allius populations andin silico analysis ofP. teres on the respective target species. Furthermore, specificity was demonstrated by the absence of cross-reactions with a range of common plant-parasitic nematode species typical of potato growing areas in the PNW. A duplex PCR test was developed that was effective for simultaneous detection of both targetParatrichodorus species.