The complete chloroplast genome of Epimedium muhuangense (Berberidaceae)

Abstract Epimedium muhuangense S. Z. He & Y. Y. Wang 2017, one of the rare unifoliolate species in the Epimedium genus of Berberidaceae, is distributed in the Guizhou province of China. In present research, we sequenced the complete chloroplast genome of E. muhuangense with Illumina sequencing technology. The whole genome was 157,264 bp in length, which consisted of a large single-copy region (LSC, 88,588 bp), a small single-copy region (SSC, 17,036 bp), and a pair of inverted repeat regions (IRa and IRb, 25,820 bp). A total of 112 unique genes were successfully annotated, consisting of 78 protein-encoding genes, 30 rRNA, and four tRNA. Phylogenetic analysis demonstrated that E. muhuangense is closely related to E. elachyphyllum.

Epimedium L. is the largest herbaceous genus of Berberidaceae and contains about 62 species. China is the distribution and diversity center of Epimedium, in which there are about 52 species with continued evolution (Luo et al. 2021;Guo et al. 2022). As the traditional Chinese medicines, Epimedium plants have been identified with many pharmacological activities, such as improving cardiovascular function, anti-cancer, anti-osteoporosis and anti-aging activities (Zhou et al. 2021).
However, Epimedium is taxonomically and phylogenetically regarded as one of the most challengingly difficult taxa in plants, since abundant morphological variations complicate the interspecific relationship (Zhang YJ et al. 2016;Zhang Y et al. 2020). Chloroplast genome has been evidenced to be effective in plant phylogeny and species identification (Yang et al. 2013). In this study, we sequenced the complete chloroplast genomes of Epimedium muhuangense, aiming to provide valuable information for taxonomic and phylogenetic studies on the genus Epimedium.
In this study, E. muhuangense samples were collected from its type locality, Muhuang Town, Yinjiang County, Guizhou, China (E108 40 0 , N28 5 0 ). A specimen was deposited at the Herbarium of the Institute of Wuhan Botanical Garden, Chinese Academy of Medical Science (http://www.whiob.ac. cn/, Yanjun Zhang, yanjunzhang@wbgcas.cn) under the voucher number Yanjun Zhang 568. The genomic DNA was extracted from fresh leaves using the modified CTAB method (Doyle and Doyle 1987). The chloroplast genome was sequenced using Illumina Novaseq PE150. The sequenced clean reads were further assembled using the program GetOrganelle v1.7.4.1 (Jin et al. 2020) with E. acuminatum chloroplast genome (GenBank accession number: NC_029941) as a reference. The gene annotation was performed by online programs Geseq (Michael et al. 2017) and CPGAVAS2 (Shi et al. 2019), followed by manual correction. The chloroplast genome sequence of E. muhuangense was submitted to NCBI database with an accession number (OK166811).
To explore the phylogenetic position of E. muhuangense, the complete chloroplast genome sequences of 15 plant species were downloaded from the NCBI GenBank database. Sequences were aligned using MAFFT v.7 (Katoh et al. 2019) and trimmed using MEGA v.11 (Tamura et al. 2021). A maximum likelihood tree was constructed using raxmlGUI 2.0 (Edler et al. 2021) with Vancouveria hexandra (Hook.) C.
Morren & Decne as outgroup ( Figure 1). The results of the phylogenetic analysis show that E. muhuangense is closely related to E. elachyphyllum, both of which are distributed in northeastern Guizhou. Furthermore, E. muhuangense and E. elachyphyllum are the only two species only having unifoliolate leaves in Epimedium (Zhang YJ et al. 2011;Wang et al. 2017). The chloroplast genome of E. muhuangense will contribute to the research of phylogeny and evolution of Berberidaceae.

Authors' contributions
Jing Wang and Ruoqi Huang designed and performed the experiments; Jing Wang also analyzed the data and drafted the manuscript; Qiong Liang and Yanjun Zhang revised critically for intellectual content and approved the final version of the paper; and all authors agree to be accountable for all aspects of the work.

Ethical approval
The plant materials used in this study were transplanted into Wuhan Botanical Garden for cultivation through legal collection way. And the study was approved by the Wuhan Botanical Garden of the Chinese Academy of Sciences.

Disclosure statement
No potential conflict of interest was reported by the author(s).

Data availability statement
The genome sequence data that support the findings of this study are openly available in GenBank of NCBI at (https://www.ncbi.nlm.nih.gov/) under the accession no. OK166811. The associated BioProject, SRA, and Bio-Sample numbers are PRJNA774127, SRR16571520, and SAMN22555212, respectively.