Abstract
Euphorbia pekinensis Rupr. 1859 is a medicinal herb endemic to China and distributed throughout the country, particularly across the northern part of the mainland. However, the systematic classification of Euphorbiaceae remains controversial. Therefore, studying the chloroplast genome of E. pekinensis is crucial for the resolution of this taxonomic dispute, clarification of the systematic status of Euphorbia, and establishment of an accurate classification system for Euphorbiaceae. In this study, we sequenced the complete chloroplast genome of E. pekinensis using Illumina sequencing technology and annotated it using GeSeq. The complete chloroplast genome was 162,002-bp-long with a guanine-cytosine (GC) content of 35.7%. It included one large single-copy (LSC), one small single-copy (SSC), and two inverted repeat sequence regions (IRa and IRb), which were 90,225 bp, 18,067 bp, and 26,855 bp in length, respectively, and are indicative of a typical tetrad structure. The genome encoded 129 functional genes, comprising 85 protein-coding genes, 36 tRNA genes, and eight rRNA genes. According to the maximum-likelihood phylogenetic tree that was constructed using 16 complete chloroplast genomes, E. pekinensis was found to be closely related to E. ebracteolata. Therefore, the complete chloroplast genome of E. pekinensis provides a better understanding of Euphorbia genetics.