The complete chloroplast genome of Thalictrum baicalense Turcz. ex Ledeb

Abstract Thalictrum baicalense Turcz. ex Ledeb. is a well-known herbaceous perennid that has been used as a traditional medicine to treat influenza, hepatitis, and detoxfeaction. In this study, we release and detail the complete chloroplast genome sequences of T. baicalense. The whole chloroplast genome was 155,859 bp in length and comprised 130 genes, including 84 protein-coding genes, 37 tRNA genes, eight rRNA genes. The T. baicalense chloroplast genome had a GC content of 38.39%. The phylogenetic relationships inferred that T. baicalense, T. tenue, T. minus and T. petaloideum are closely related to each other within the genus Thalictrum.

Thalictrum baicalense Turcz. ex Ledeb. (Ranunculaceae) is a herbaceous perennid distributed in China, Korea, Russia and other north warm regions (Wang et al. 2001). The dried root of T. baicalense have the effects of clearing heat, anti-inflammatory and antiviral. It has been used in the treatment of hepatitis, dysentery and detoxfeaction in traditional Chinese medicine. In addition, it is reported in the literature that the genus Thalictrum comprises about 150 species worldwide. There are 76 species throughout China, of which about 30 species have been used as traditional folk medicines to treat influenza, cancer, and conjunctivitis (Chen et al. 2003;Xue et al. 2020).
The complete chloroplast (cp) genome can provide valuable genomic information for the phylogenetics study and the conservation of rare species (Weng et al. 2014). However, the cp genome of T. baicalense has not been fully sequenced. In this study, we sequenced and analyzed the cp genome of T. baicalense based on Illumina pair-end sequencing and compared it with other genus cp genome sequences. it would not only promote the phylogenetics study in family Ranunculaceae but also provide useful genetic information for the protection of T. baicalense and other related species.
The samples of T. baicalense were collected in the Qingshashan mountain (102 01 0 6.42 00 E, 36 17 0 14.25 00 N) and the voucher specimens (He202008) are deposited in the Herbarium of College of Pharmacy, Qinghai Nationalities University, Xining, China. The total DNA of T. baicalense was extracted using Plant Genomic DNA Kit (DP350; TIANGEN Biotech(Beijing) Co.,Ltd.). High-throughput sequencing was performed using an Illumina NovaSeq 6000 series sequencer (PE150) by Nanjing Genepioneer Biotechnologies Inc. (Nanjing, China), and 8.04 GB of raw data was generated. The raw paired-end reads were filtered using the fastp program (Chen et al. 2018). The high-quality reads were applied to a de novo assembly performed using the program SPAdes assembler v3.10.1 (Bankevich et al. 2012). The assembled genome was annotated using CPGAVAS2 (Shi et al. 2019).
In order to reveal the phylogenetic position of T. baicalense with its close relatives of Ranunculaceae, a phylogenetic analysis was performed based on 21 complete chloroplast genomes of Ranunculaceae. The complete chloroplast genomes were aligned by MAFFT v7.307 (Katoh and Standley 2013) and the maximum-likelihood tree (Figure 1) was built using MEGA7 (Kumar et al. 2016). Using the Tamura-Nei model model the ML phylogenetic analysis were conducted with MEGA v7.0.26 generating 1000 bootstrap replicates to determine measures of nodal support with each run initiating from a random starting tree. According to the result ( Figure  1), T. baicalense has close relationship with the species T. tenue, T. minus and T. petaloideum.

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