Detection of Panax quinquefolius in Panax ginseng using 'subtracted diversity array'

BACKGROUND: Food adulteration remains a major global concern. DNA fingerprinting has several advantages over chemical and morphological identification techniques. DNA microarray-based fingerprinting techniques have not been used previously to detect adulteration involving dried commercial samples of closely related species. Here we report amplification of low-level DNA obtained from dried commercial ginseng samples using the QiagenTM REPLI-g(R) Kit. Further, we used a subtracted diversity array (SDA) to fingerprint the two ginseng species, Panax ginseng and Panax quinquefolius, that are frequently mixed for adulteration. RESULTS: The two ginseng species were successfully discriminated using SDA. Further, SDA was sensitive enough to detect a deliberate adulteration of 10% P. quinquefolius in P. ginseng. Thirty-nine species-specific features including 30 P. ginseng-specific and nine P. quinquefolius-specific were obtained. This resulted in a feature polymorphism rate of 10.5% from the 376 features used for fingerprinting the two ginseng species. The functional characterization of 14 Panax species-specific features by sequencing revealed one putative ATP synthase, six putative uncharacterized proteins, and two retroelements to be different in these two species. CONCLUSION: SDA can be employed to detect adulterations in a broad range of plant samples. (C) 2011 Society of Chemical Industry