Development of a Species-Specific SCAR-PCR Assay for Direct Detection of Sugar Beet Cyst Nematode () from Infected Roots and Soil Samples.

Sugar beet cyst nematode (SBCN, ) is an important nematode that causes significant yield losses of 25-50% or more in most areas of sugar beet production worldwide. Rapid and accurate identification of this species is essential to support decisions on pest management. However, the difference between and other spp. based on morphology is a challenging task. In the present study, a SCAR-PCR assay was developed to identify and differentiate in infected root and soil samples. -species-specific SCAR-PCR primers OPA06-HsF and OPA06-HsR were designed from the randomly amplified polymorphic DNA (RAPD) marker amplified with random primer OPA06. The developed primers specifically amplify a 922-bp fragment from the target populations but did not amplify DNA from non-target cyst nematodes including , , , and other related species tested in this study. The sensitivity detection indicated that 5 × 10 of a single cyst, 1/320 of a single second-stage juvenile (J2), or 10 pg of genomic DNA could be detected. The assay accurately identifies the different stages of in sugar beet and oilseed rape roots as well as a single J2 in 10 g of soil. Finally, the SCAR-PCR assay detected in seven samples out of the fifteen field samples. The assay will not only be useful for differentiating from mixed populations of spp. but also for effective detection of the species directly from infested samples. The assay also requires no expertise in the taxonomy and morphology of the species but serves to improve the diagnosis of in infested fields.