Plastome sequencing for accurate and effective authentication of Polygonatum kingianum (Asparagaceae)

Polygonatum kingianum (Asparagaceae) is a traditional Chinese medicinal plant commercially valued by the pharmaceutical industry and rural development. The taxonomic delimitation of the species remains ambiguous. Due to previous poorly delineated species boundary, P. hunanense (syn. P. kingianum var. grandifolium) has been mistaken for P. kingianum in herbal cultivation, products sale, and drug production. In this study, we aimed to clarify the taxonomic confusion in the species boundary of P. kingianum, and to develop an accurate and efficient authentication tool to monitor the trade of P. kingianum related plant products. Based on dense intraspecific plastome sequencing and phylogenetic analyses, our data confirm that all the synonymized taxa, except for P. kingianum var. grandifolium (= P. hunnanense), really belong to P. kingianum. On this basis, a molecular authentication system, which uses complete plastomes as molecular tags, is developed for authentication of P. kingianum related products. To validate its efficacy, we experimentally applied the system to authenticate commercial seedlings and processed rhizomes marketed as P. kingianum. The high performance of the authentication system indicates that the plastome super-barcoding approach can be used as an effective tool for authentication of P. kingianum related plant products. The findings can be useful for guaranteeing the quality, safety, and effectiveness of P. kingianum, and thus have great significance for herbal cultivation and drug production.