Characterization of the complete chloroplast genome of Arisaema erubescens (Wall.) Schott, a traditional Chinese medicinal herb

Abstract Arisaema erubescens is a well-known medicinal plant in China. In this study, we sequenced the complete chloroplast (cp) genome sequence of A. erubescens to investigate its phylogenetic relationship in the family Araceae. The cp genome was 167,607 bp in length, consisting of a pair of inverted repeats (IRa and IRb: 26,193 bp) separated by a large single-copy region (LSC: 93,660 bp) and a small single-copy region (SSC: 21,561 bp). The GC content of whole cp genome is 35.3%. De novo assembly and annotation showed the presence of 114 unique genes with 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis indicated that A. erubescens was closely related to A. franchetianum, and the genus Arisaema was sister to the genus Pinellia.

Arisaema erubescens (Wall.) Schott is a perennial herb of the Araceae family, which is widely distributed in south China and Southeast Asian countries. It is used medically as an important antidote to treat several biological disorders (Li et al. 2010). With the discovery of the great medicinal value of A. erubescens and the increasing demand of the market, the wild resources of A. erubescens are decreasing nowadays. It is necessary to develop genomic resources for A. erubescens to provide intragenic information for its utilization. Chloroplast genomes are valuable sources of genetic markers for phylogenetic analyses, genetic diversity evaluation, and plant molecular identification (Dong et al. 2018;Sun et al. 2020). In this study, the complete chloroplast genome of A. erubescens was assembled to provide genomic and genetic resources for further research, and the phylogeny of family Araceae was conducted to reveal the interspecific relationships.
Fresh samples of A. erubescens were collected from Hongjiang county, Hunan province, China (27 24 0 38 00 N, 110 25 0 19 00 E). Voucher specimen was deposited at the herbarium of Institute of Chinese Materia Medica (CMMI), China Academy of Chinese Medical Sciences with the specimen voucher number is 431281LY0254. Total genomic DNA was isolated using the CTAB method (Doyle and Doyle 1987). The library with 350 bp insertion size fragments was constructed and sequenced using the Illumina HiSeq platform. De novo assembly was conducted using GetOrganelle pipeline (Jin et al. 2018). The annotation was performed using Plann (Huang and Cronk 2015), with annotated complete chloroplast (cp) genome from A. ringens (NC044118) selected as reference. The annotated complete chloroplast cp genome of A. erubescens was submitted to the GenBank under the accession number MT676834.
To investigate the phylogenetic relationships between A. erubescens and other related species in family Araceae, 20 complete cp genomes were downloaded from GenBank to construct a phylogenetic maximum-likelihood (ML) tree using RAxML (Stamatakis 2014), under the GTR þ G model with 1000 rapid bootstrap replicates. Lemna minor (DQ400350) was taken as an outgroup. The phylogenetic tree showed that all 19 species forming a monophyletic group supported by a 100% bootstrap value. A. erubescens was inferred phylogenetically closest to A. franchetianum, and the genus Arisaema was sister to the genus Pinellia (Figure 1)

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

Data availability statement
The data that support the findings of this study are openly available in GenBank of NCBI https://www.ncbi.nlm.nih.gov/, reference number MT676834.