Species identification of Chinese medicinal plant Fallopia multiflora (Thunb.) Haraldson by suppression subtraction hybridization.

Fallopia multiflora (Thunb.) Haraldson, a traditional Chinese medicinal plant, has been extensively used in preparations of herbal medicine, health products and personal hygiene products. However, the clinical safety and efficiency of F. multiflora (Thunb.) Haraldson is impaired because of the existence of various adulterants. In this study, genomic DNA (gDNA) suppression subtraction hybridization (SSH) was used to authenticate F. multiflora (Thunb.) Haraldson from its adulterants. First, differential gDNA fragments between F. multiflora (Thunb.) Haraldson and its most closely related species F. multiflora var. ciliinervis (Nakai) Yonek. & H. Ohashi by SSH were identified. The differential fragments were then hybridized with arrays constructed from multiple whole genomes of several species (adulterants and/or closely related plants) to screen for the unique gDNA fragments representing F. multiflora (Thunb.) Haraldson. The unique gDNA fragments could be used to design species-specific primers for the identification of F. multiflora (Thunb.) Haraldson. Using SSH, we obtained four differential gDNA fragments, and four pairs of primers were designed. The designed primers could differentiate F. multiflora (Thunb.) Haraldson from its adulterants and/or closely related species via PCR. The results confirmed that the SSH is an efficient method for screening and designing species-specific primers.