==== Front Mitochondrial DNA B Resour Mitochondrial DNA B Resour Mitochondrial DNA. Part B, Resources 2380-2359 Taylor & Francis 10.1080/23802359.2019.1677521 1677521 Version of RecordResearch Article Mitogenome Announcement The complete chloroplast genome sequence of Melliodendron xylocarpum (Styracaceae) Z. Zhao et al.Zhao Zixun ab Xu Xiaogang ab Tong Lili c Zhang Yaoqin ab Wang Yabo ab a College of Biology and Environment, Nanjing Forestry University, Nanjing, China; b Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China; c School of Horticulture & Landscape Architecture, Jinling Institute of Technology, Nanjing, China CONTACT Xiaogang Xu xiaogangb.xu@gmail.comCo-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China; College of Biology and Environment, Nanjing Forestry University, Nanjing, China 21 10 2019 2019 4 2 3677 3678 © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.2019The Author(s)This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.http://creativecommons.org/licenses/by/4.0/Abstract Melliodendron xylocarpum Handel-Mazzetti is a rare tree, distinct member of the family Styracaceae. In this study, we determined the complete chloroplast (cp) genome sequence of M. xylocarpum in an effort to provide genomic resources useful for promoting its conservation. The entire cp genome was determined to be 157,165 bp in length. It contains the typical structure and gene content of angiosperm plastome, The plastome contains a large single-copy (LSC) and a small single-copy (SSC) regions of 90,193 and 18,486 bp, respectively, which were separated by a pair of 24,243 bp inverted repeat (IR) regions. The genome contained 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The GC content of M. xylocarpum genome is 37.21%. The complete plastome sequence of M. xylocarpum will provide a useful resource for the conservation genetics of this species as well as for the phylogenetic studies for Styracaceae. Phylogenetic analysis revealed that M. xylocarpum is closely related to Changiostyrax dolichocarpus H.S.Lo & D.Fang, but forms an independent evolutionary branch. Keywords PhylogenomicsStyracaceae familycomplete chloroplast genome ==== Body Melliodendron xylocarpum Handel-Mazzetti, one of the rare Chinese trees, is a broad-leaved tree species with beautiful flowers. Melliodendron xylocarpum is distributed southern China which has high medicinal value and can be as applied for ornamental purposes. Despite this progress in understanding Styracaceae systematics, many of the relationships among genera in the family remain poorly resolved. Comparison of complete plastome sequences further provides the opportunity to explore sequence variation and molecular evolutionary patterns associated with gene loss, rearrangements, duplication, and transfer events (Walker et al. 2014; Weng et al. 2014). Here, we characterised the complete cp genome sequence of M. xylocarpum (GeneBank accession number: MN175625) based on Illumina pair-end sequencing to provide a valuable complete cp genomic resource. The total genomic DNA was extracted from the fresh leaves of M. xylocarpum grown in Qixia Mountain (N 32.1566, E 118.9690) in Nanjing, Jiangsu, China. The voucher specimen was kept in the herbarium of Nanjing Forestry University (accession number: NF2018689). The whole genome sequencing was conducted by Nanjing Genepioneer Biotechnologies Inc. (Nanjing, China) on the Illumina Hiseq platform. The raw reads were filtered by CLC Genomics Workbench v9, and the obtained clean reads were assembled into chloroplast genome using SPAdes(Bankevich et al. 2012). Finally, gene structure annotation was carried out with CpGAVAS (Liu et al. 2012) and the physical map was generated with OGDRAW (Lohse et al. 2013). A phylogenetic tree was infered based on the Maximum Likelihood (ML) by using MAFFT (Katoh and Standley 2013). The plastome of M. xylocarpum was determined to comprise double-stranded, circular DNA of 157,165 bp containing two inverted repeat (IR) regions of 24,243 bp each, separated by large single-copy (LSC) and small single-copy (SSC) regions of 90,193 and 18,486 bp, respectively. The genome contained 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Five protein-coding genes, seven tRNA genes, and four rRNA genes were totally duplicated in IR region. Twelve genes contained one intron and two genes (clpP and rps12) contained two introns. The overall GC content of M. xylocarpum cp genome is 37.21% and the corresponding values in LSC, SSC, and IR regions are 35.34%, 30.57%, and 43.23%, respectively. To ascertain the phylogenetic evolution of M. xylocarpum, the fasta format file containing all the chloroplast genome sequences of 25 species (20 Styracaceae chloroplast genomes and 5 taxa as outgroup). The results of phylogenetic analysis show that M. xylocarpum forms a separate branch when compared with other plants in this study, which is more closely related to Changiostyrax dolichocarpus (Figure 1). The complete plastome sequence of M. xylocarpum provides an important data set for the conservation genetics of this species. Figure 1. Phylogenetic tree inferred by maximum-likelihood (ML) method based on the complete chloroplast genome of 25 representative species. The bootstrap support values are shown at the branches. Disclosure statement No potential conflict of interest was reported by the authors. ==== Refs References Bankevich A , Nurk S , Antipov D , Gurevich AA , Dvorkin M , Kulikov AS , Lesin VM , Nikolenko SI , Pham S , Prjibelski AD , Pyshkin AV , et al. 2012 SPAdes: a new genome assembly algorithm and its applications to single-cell sequencing . J Comput Biol . 19 :455 –477 .22506599 Katoh K , Standley DM 2013 MAFFT multiple sequence alignment software version 7: improvements in performance and usability . Mol Biol Evol . 30 :772 –780 .23329690 Liu C , Shi LC , Zhu YJ , Chen HM , Zhang JH , Lin XH , Guan XJ 2012 CpGAVAS, an integrated web server for the annotation, visualization, analysis, and GenBank submission of completely sequenced chloroplast genome sequences . 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