Page 96 - 《广西植物》2023年第10期
P. 96

1 8 5 0                                广  西  植  物                                         43 卷
                 Abstract: Syzygium grijsiiꎬ an evergreen shrub of Myrtaceae and Syzygiumꎬ has good prospects for exploitationꎬ but its
                 chloroplast genome characteristics and phylogenetic relationships have not been reported. To fill the gap in the genomics
                 of S. grijsiiꎬ a systematic study of the chloroplast genome of S. grijsii was conducted in this paper. Illumina high ̄
                 throughput sequencing was used to perform complete assembly in the GetOrganelle platformꎬ and the assembled data
                 were also used to analyze the structural features and phylogenetic relationships of the S. grijsii chloroplast genomeꎬ
                 including the structureꎬ function and characteristics of the S. grijsii chloroplast genomeꎬ codon preference analysisꎬ
                 comparative analysis of the chloroplast genome and phylogenetic analyses. The results were as follows: ( 1) The
                 chloroplast genome of S. grijsii was 158 591 bp in sizeꎬ which contained 129 genes. Among themꎬ 8 were rRNA genesꎬ
                 37 were tRNA genes and 84 were protein ̄coding genes. The analysis detected 39 repetitive sequences and 84 SSR
                 loci. (2) Codon preference analysis revealed that there was a bias towards A/ U at the ends of the S. grijsii chloroplast
                 genomeꎬ and the most used codon was the one encoding leucine. (3) In comparison with closely related speciesꎬ the
                 boundary length of S. grijsii was conservedꎬ and the gene species at the boundary were similar to several Syzygium
                 speciesꎻ the S. grijsii chloroplast genome had a high degree of variability in the LSC and SSC regionsꎬ with 45 sites of
                 0.010 < P < 0.015 and a high level of nucleotide diversity. (4) Phylogenetic analysis showed that S. grijsii was most
                        i
                 closely related to S. jambosꎬ S. forrestii and S. cuminiꎬ followed by S. malaccense. The study concluded that S. grijsii had
                 a conserved chloroplast genome structure with distinct featuresꎬ sequence similarity and nucleotide diversity compared to
                 Syzygium speciesꎬ and affinity between it and various Myrtaceae species. In this paperꎬ the genomic characterization and
                 phylogenetic analysis of the chloroplast genome of S. grijsii are conducted to lay the theoretical foundation for the
                 identification and exploitation of the germplasm resources of S. grijsii.
                 Key  words:  Syzygium  grijsiiꎬ  chloroplast  genomeꎬ  phylogenetic  relationshipꎬ  genomic  characteristicsꎬ
                 comparative analysis



                叶绿体(chloroplastꎬ cp)是绿色植物进行光合                  属(Dianthus)(Lin et al.ꎬ 2022) 等ꎬ这些分析为研
            作用的场所ꎬ也是绿色植物所特有的细胞器ꎮ 叶                             究物种变异、物种遗传和系统发育关系等方面做
            绿体具有相对自主的遗传系统ꎬ有自己的遗传物                              出了卓越的贡献ꎮ

            质ꎬ能够进行半自主的复制( Xue et al.ꎬ 2019)ꎮ                       桃金娘科(Myrtaceae)主要分布于热带和近热
            在高等植物中ꎬ大多数植物的叶绿体基因组包括                              带地区ꎬ多为乔木或者灌木ꎬ约有 150 属 5 600 种ꎬ
            一个大单拷贝区( large single copyꎬ LSC)、一个小               我国现有近 100 种ꎮ 蒲桃属( Syzygium) 是桃金娘
            单拷贝区( small single copyꎬ SSC ) 和两个反向的              科下的一个重要属ꎬ全世界约有 500 种ꎬ中国约有

            重复区( inverted repeatsꎬ IRs) ( Li et al.ꎬ 2013)ꎮ    72 种(陈介ꎬ2007)ꎮ 因为蒲桃属植物外形美观ꎬ
            叶绿体基因组按功能可分为参与叶绿体生物合成                              抗逆性强ꎬ所以大多用于城市绿化ꎬ但随着近年研
            的基因、参与叶绿体基因表达的基因、参与光合作                             究的深入ꎬ蒲桃属中的轮叶蒲桃、蒲桃和洋蒲桃等
            用的基因和一些功能未知的开放阅读框( 孙志轩                             也被发掘出了药用价值ꎮ 轮叶蒲桃根和叶可用于
            等ꎬ2022)ꎮ 叶绿体拥有简单的基因组结构ꎬ它包                          祛风散寒ꎬ活血化瘀ꎬ治疗跌打损伤、伤风感冒和
            含大量的遗传信息ꎬ基因组内碱基交换的速度处                              风湿性头痛ꎬ具有巨大的开发利用价值( 罗德志
            于中间水平ꎬ分子进化速度在编码区和非编码区                              等ꎬ2020)ꎮ 目前ꎬ在蒲桃属中ꎬ仅有 8 个物种通过
            的差别很大ꎬ所以叶绿体基因组也被广泛利用在                              高通量测序获得了完整的叶绿体基因组ꎬ学者们
            系统发育推断和群体遗传学等领域( 赵玉芬等ꎬ                             对蒲桃属的主要研究重点包括植物化学成分的分
            2022)ꎮ 近年来ꎬ随着高通量测序技术越发成熟ꎬ                          离鉴定以及药物研发等方面ꎮ 一些学者也探讨过
            近 6 000 个物种的叶绿体基因组成功被组装和注                          桃金娘科的系统发育关系ꎬ但只停留于系统发育
            释ꎮ 目前ꎬ叶绿体基因组分析已经涵盖了大部分                             分析(王雪芹等ꎬ2021)ꎮ 在蒲桃属中ꎬ仅有肖蒲桃
            被子植物ꎬ例如姜科( Zingiberaceae) ( Liew et al.ꎬ           的叶绿体基因组被详细分析过ꎬ但包括轮叶蒲桃
            2022)、兰科(Orchidaceae)(Xie et al.ꎬ 2022)、石竹         在内的其余物种的叶绿体基因组特征和系统发育
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