The complete chloroplast genome and phylogenetic analysis of Urceola huaitingii (Chun & Tsiang) D. J. Middleton 1994 (Apocynaceae).

Urceola huaitingii (Chun & Tsiang) D. J. Middleton 1994, a member of the Apocynaceae family, is widely distributed across southern and southwestern China and has been traditionally used in folk medicine to treat hemiplegia and paralysis. In this study, we report the first complete chloroplast genome of U. huaitingii and perform phylogenetic analysis with 30 related species within the Apocynaceae. The chloroplast genome of U. huaitingii is 155,182 bp in length and has a GC content of 38.11%. It displays a typical quadripartite structure, consisting of a large single-copy (LSC) region of 85,254 bp, a small single-copy (SSC) region of 18,242 bp, and two inverted repeat (IR) regions of 25,843 bp each. A total of 111 unique genes were annotated, including 77 protein-coding genes, 30 transfer RNA (tRNA) genes, and 4 ribosomal RNA (rRNA) genes. Phylogenetic analysis revealed that U. huaitingii is closely related to the genera Aganosma, Trachelospermum, and Amalocalyx. This study provides the first chloroplast genomic resource for the genus Urceola, laying a foundation for future investigations into its evolutionary relationships. It also contributes to future molecular and phylogenetic studies within the Apocynaceae family.