Abstract
Murraya exotica L. (Rutaceae) has important horticultural and medicinal values. Here, we reported the complete chloroplast (cp) genome of M. exotica using the next-generation sequencing method. The cp genome is 160,179 bp in length, including a large single-copy region (LSC, 87,726 bp), a small single-copy region (SSC, 18,465 bp), and a pair of inverted repeats (IR) regions 26,994 bp. A maximum-likelihood phylogenomic analysis showed that M. exotica was sister to Murraya paniculate. These findings will provide useful information for further investigation of cp genome evolution in Murraya.
Keywords: Chloroplast genome, Murraya exotica, phylogenetic tree
Murraya exotica (Rutaceae) is a perennial tree widely cultivated in tropical and subtropical regions (Zhang and Hartley 2008). It is an important ornamental plant and medicine used for treating fever, cough, infectious wounds, and eliminating pain from injury and trauma (Forkuo et al. 2020). Previous studies have shown that many types of secondary coumarin compounds that occur in M. exotica are widely used in the medical, spice, and seasoning industries. The chloroplast (cp) genome can be used as a tool for phylogenetic analysis, and it can be used for other usages such as species identification (Li et al. 2015) or highly variable regions selection (Cui et al. 2020). In the present study, we assembled the complete cp genome of M. exotica to provide genomic and genetic sources for further research.
The fresh leaves of M. exotica were collected from Xishuangbanna Tropical Botanical Garden (E101°16′34.51′′, N21°55′10.87′′), Yunnan Province, China. The voucher specimen was deposited in the herbarium of Kunming Institute of Botany (KUN), Chinese Academy of Sciences (KUN1513863, http://www.kun.ac.cn/, dengtao@mail.kib.ac.cn). The genomic DNA was extracted following the modified CTAB method from leaf tissue (Doyle and Doyle 1987). Genome sequencing was performed on the Illumina HiSeq Platform (Illumina, San Diego, CA) at Genepioneer Biotechnologies Inc., Nanjing, China, and 6.9 GB of sequence data were generated. The low-quality reads and adapters were removed using CLC Genomics Workbench version 7.5 software (CLC Bio, Aarhus, Denmark) and the resulting high-quality reads were assembled via SPAdes (Bankevich et al. 2012). The assembled genome was annotated using Getorganelle (Jin et al. 2020). The cp genome was annotated using Geneious v10.2(Kearse et al. 2012). The annotated complete cp genome of M. exotica was deposited in GenBank (Genbank accession number: MW722359).
The cp genome of M. exotica was 160,179 bp in length, including a large single-copy region (LSC, 87,726 bp), a small single-copy region (SSC, 18,465 bp), and a pair of inverted repeats (IR) regions of 26,994 bp. The overall GC content was 38.6%, with the LSC, SSC, and IR regions being 37.10%, 34.80%, and 43.00%, respectively.
The phylogenetic analysis was performed using the complete cp genome of M. exotica and other species classified in the family Rutaceae and two species of Meliaceae designated as outgroups. The alignment was conducted using MAFFT (Katoh and Standley 2013). The phylogenetic tree was built using MEGA X (Kumar et al. 2018) with 1,000 bootstrap replicates and the Tamura–Nei model (Tamura and Nei 1993). Murraya exotica was sister to Murraya paniculata, especially, these two species and Atalantia kwangtungensis belonged to one clade (Figure 1). Therefore, the genus Murraya is not a monophyletic taxon, the result support previous systematic findings (Samuel et al. 2001; Groppo et al. 2008), and Atalantia, Murraya, Glycosmis, and Clausena in Aurantioideae formed monophyly (Wang et al. 2021). This baseline genomic study lays the foundation for future population genomic studies investigations, phylogenetic analyses, and genetic engineering studies of M. exotica.
Figure 1.
The maximum-likelihood phylogenetic tree constructed from 25 species chloroplast genomes. Numbers below or above branches are assessed by ML bootstrap.
Funding Statement
This research was financially supported by the National Natural Science Foundation of China [31800189] and the Natural Science Foundation of Yunnan Province [202001AU070071].
Disclosure statement
None of the authors have any financial or non-financial conflict of interest.
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. MW722359. The associated BioProject, SRA, and Bio-Sample numbers are PRJNA732890, SUB9737033, and SAMN19349668 respectively.
References
- Bankevich A, Nurk S, Antipov D, Gurevich AA, Dvorkin M, Kulikov AS, Lesin VM, Nikolenko SI, Pham S, Prjibelski AD, et al. 2012. SPAdes: a new genome assembly algorithm and its applications to single-cell sequencing. J Comput Biol. 19(5):455–477. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cui N, Liao B-S, Liang C-L, Li S-F, Zhang H, Xu J, Li X-W, Chen S-L.. 2020. Complete chloroplast genome of Salvia plebeia: organization, specific barcode and phylogenetic analysis. Chin J Nat Med. 18(8):563–572. [DOI] [PubMed] [Google Scholar]
- Doyle JJ, Doyle JL.. 1987. A rapid DNA isolation procedure from small quantities of fresh leaf tissues. Phytochem Bull. 19:11–15. [Google Scholar]
- Forkuo AD, Mensah KB, Ameyaw EO, Antwi AO, Kusi-Boadum NK, Ansah C.. 2020. Antiplasmodial and antipyretic activity and safety evaluation of the methanolic leaf extract of Murraya exotica (L.). J Parasitol Res. 2020:1308541. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Groppo M, Pirani JR, Salatino MLF, Blanco SR, Kallunki JA.. 2008. Phylogeny of Rutaceae based on twononcoding regions from cpDNA. Am J Bot. 95(8):985–1005. [DOI] [PubMed] [Google Scholar]
- Jin JJ, Yu WB, Yang JB, Song Y, dePamphilis CW, Yi TS, Li DZ.. 2020. GetOrganelle: a fast and versatile toolkit for accurate de novo assembly of organelle genomes. Genome Biol. 21(1):241. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Katoh K, Standley DM.. 2013. MAFFT multiple sequence alignment software version 7: improvements in performance and usability. Mol Biol Evol. 30(4):772–780. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Buxton S, Cooper A, Markowitz S, Duran C, et al. 2012. Geneious Basic: an integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics. 28(12):1647–1649. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kumar S, Stecher G, Li M, Knyaz C, Tamura K.. 2018. MEGA X: Molecular Evolutionary Genetics Analysis across computing platforms. Mol Biol Evol. 35(6):1547–1549. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Li X, Yang Y, Henry RJ, Rossetto M, Wang Y, Chen S.. 2015. Plant DNA barcoding: from gene to genome. Biol Rev Camb Philos Soc. 90(1):157–166. [DOI] [PubMed] [Google Scholar]
- Samuel R, Ehrendorfer F, Chase MW, Greger H.. 2001. Phylogenetic analyses of Aurantioideae (Rutaceae) based on non-coding plastid DNA sequences and phytochemical features. Plant Biol . 3(1):77–87. [Google Scholar]
- Tamura K, Nei M.. 1993. Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees. Mol Biol Evol. 10(3):512–526. [DOI] [PubMed] [Google Scholar]
- Wang XQ, Song WW, Gao XY, Lin Y, Guo H.. 2021. Chloroplast genome structural and phylogenetic relationships of Rutaceae. Mol Plant Breed. 1–22. https://kns.cnki.net/kcms/detail/46.1068.S.20210419.1547.019.html [Google Scholar]
- Zhang DX, Hartley TG.. 2008. Murraya J. Koenig ex Linnaeus. In: Wu ZY, Raven PH, and Hong DY, editors. Flora of China. Beijing (China): Science Press; St Louis (MO): Missouri Botanical Garden; p. 85–87. [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
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. MW722359. The associated BioProject, SRA, and Bio-Sample numbers are PRJNA732890, SUB9737033, and SAMN19349668 respectively.

