Plastome characteristics and species identification of Chinese medicinal wintergreens (, Ericaceae).

Wintergreen oil is a folk medicine widely used in foods, pesticides, cosmetics and drugs. In China, nine out of 47 species within (Ericaceae) are traditionally used as Chinese medicinal wintergreens; however, phylogenetic approaches currently used to discriminating these species remain unsatisfactory. In this study, we sequenced and characterized plastomes from nine Chinese wintergreen species and identified candidate DNA barcoding regions for . Each plastome contained 110 unique genes (76 protein-coding, 30 tRNA, and four rRNA genes). Duplication of , , and genes were detected, while all plastomes lacked and genes. plastomes shared substantially contracted SSC regions that contained only the gene. Moreover, plastomes of var. contained an inversion in the LSC region and an IR expansion to cover the gene. Multiple rearrangement events apparently occurred between the plastomes and those from several previously reported families in Ericales. Our phylogenetic reconstruction using 42 plastomes revealed well-supported relationships within all nine species. Additionally, seven mutational hotspot regions were identified as potential DNA barcodes for Chinese medicinal wintergreens. Our study is the first to generate complete plastomes and describe the structural variations of the complicated genus In addition, our findings provide important resources for identification of Chinese medicinal wintergreens.