The complete chloroplast genome sequence of an invasive plant Solanum rostratum (Solanaceae)

Abstract Solanum rostratum is native to Neotropics and southwestern United States and considered as an invasive plant in Americas, Europe, Asia, Africa, and Australia. However, information on the chloroplast (cp) genome of this species is limited. In this study, we present the complete chloroplast genome sequence of S. rostratum obtained by high-throughput nextgeneration sequencing technology. The whole cp genome was 155,559 bp long and comprised 130 genes, including 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The S. rostratum cp genome had a GC content of 37.76%. Based on the concatenated coding sequences of cp PCGs, phylogenetic analysis showed that Phylogenetic tree revealed that S. rostratum and S. elaeagnifolium are closely related to each other within the genus Solanum.

Solanum rostratum; chloroplast genome; Illumina sequencing; phylogeny Solanum rostratum (Solanaceae) is an annual herb native to Mexico and considered as an invasive plant in Americas, Europe, Asia, Africa, and Australia with a high reproductive ability, strong seed dispersal ability, and efficient seed germination ability (Lin and Tan 2007;Wei et al. 2009Wei et al. , 2010Eminniyaz et al. 2013). In China, this species is first found in Liaoning Province in northeast China in 1980s. Now, the species has spread across almost all regions of Northern China including Liaoning, Jilin, Beijing, Hebei, Shanxi, Xinjiang, and Inner Mongolia (Wei et al. 2007;He et al. 2011). It has been listed in the Checklist of the Invasive Plants in China (Wei and Yang 2013). This invasive species is treated as a noxious weed and causes livestock discouraged or poisoned as poisonous thorns cover the body of S. rostratum (Zhu et al. 2011). In this study, we characterized the complete chloroplast genome sequence of S. rostratum a resource for future genetic studies on this and other related species, which may provide valuable guidance for the utilization and management of S. rostratum.
Fresh leaves of S. rostratum were obtained from the Urumqi County, Urumqi, Xinjiang Province of China (87 46 0 E, 43 49 0 N) with voucher specimen deposited at the Xinjiang Agricultural University Herbarium (XN2019092603). After DNA extraction, high-throughput DNA sequencing (pair-end 150 bp) was conducted on an Illumina NovaSeq platform (Illumina, CA, USA) at Genepioneer Biotechnologies Inc., Nanjing, China. Approximately 5.0 Gb of sequence data were generated and used for the assembly of cp genome with SPAdes (Bankevich et al. 2012). The assembled genome was annotated using CpGAVAS (Liu et al. 2012). The cp genome of Solanum demissum (NC_041552.1) was included as the initial reference. The annotated genomic sequence has been submitted to GenBank with the accession number MN635796.
To identify the phylogenetic position of S. rostratum, phylogenetic analysis was conducted. The aligned complete chloroplast genome sequences of S. rostratum and 45 other species using MAFFT (Katoh and Standley 2013) were used for phylogenetic analysis. The neighbour-joining tree was constructed using MEGA 7.0 with 1000 bootstrap replicates (Kumar et al. 2016). Phylogenetic analysis showed that S. rostratum and S. elaeagnifolium are closely related to each other within the genus Solanum (Figure 1). The chloroplast resource may provide valuable guidelines for the management and utilization of S. rostratum.

Disclosure statement
No potential conflict of interest was reported by the authors.

Funding
This study was supported by the National Natural Science Foundation of China [Grant Nos. 31560067, U1603231]