Development and Detection Efficiency of SCAR Markers of Cuscuta reflexa and its Adulterant Cuscuta chinensis

摘要

Cuscuta reflexa is a perennial herb belonging to the Convolvulaceae family and is widely used as a valuable herbal drug in traditional medicine. Cuscuta chinensis, another species of Cuscuta , is traded under the same name in the local markets and is an identified adulterant of the genuine herbal drug, C. reflexa. In this study, we have developed sequence characterized amplified region (SCAR) markers to discriminate C. reflexa from its adulterant C. chinensis. The RAPD amplicons of 690 bp and 576 bp specific to C. reflexa and C. chinensis, respectively, were selected. The RAPD bands were converted into SCAR by designing specific internal primers (SCAR primers) for these sequences. The SCAR primer sets amplified 589 bp- and 464 bp-sized SCAR markers from C. reflexa and C. chinensis genomic DNA, respectively. The detection efficiency of designed SCAR primers was evaluated by mixing the powdered seed samples of both species in different ratios and amplifying DNAs extracted from these mixed seed samples using designed SCAR primer sets. The SCAR markers developed for a given species were able to detect as little as 10% of the powdered seed sample present in the mixture. To the best of our knowledge this is the first ever study that reports the detection efficiency of SCAR markers.