Page 24 - 《广西植物》2026年第9期
P. 24

1 4 6 0                                广  西  植  物                                         46 卷
                 provide a foundation for studies on phylogeography and organellar genome diversity. Picea likiangensisꎬ a species in the
                 genus Picea of Pinaceae familyꎬ is characterized by rapid growth and high ̄quality timber. It is widely used as an
                 industrial timber and reforestation speciesꎬ holding significant economic and ecological value. To dateꎬ the complete
                 chloroplast genome sequence of P. likiangensis has not been determined. In this studyꎬ the complete chloroplast genome
                 of P. likiangensis was sequenced using Illumina NovaSeq 6000 platform and assembled by GetOrganelle. Repeat
                 sequences within the chloroplast genome were identified using MISA and Tandem repeat finderꎬ while codon usage bias
                 was analyzed by CodonW. Furthermoreꎬ phylogenetic relationships among 17 Picea species were reconstructed using
                 PhyloSuite software. The results were as follows: (1) The chloroplast genome of P. likiangensis was 124 207 bp in length
                 with a GC content of 38.74%. It contained 113 genesꎬ including 74 protein ̄coding genesꎬ 35 transfer RNA (tRNA)
                 genesꎬ and 4 ribosome RNA (rRNA) genes. (2) A total of 29 simple sequence repeats (SSRs) and 29 tandem repeat
                 sequences were identified. Mononucleotide repeats ( 22) were the predominant SSRsꎬ followed by 7 dinucleotide
                 repeats. (3) A total of 30 codons were identified with a relative synonymous codon usage (RSCU)>1ꎬ among which the
                 AGA codon (encoding arginine) showed the highest usage. (4) Phylogenomic analysis revealed that P. sitchensis was the
                 basal taxon of Piceaꎬ while the remaining Picea species were divided into two major clades. P. likiangensis was most
                 closely related to P. brachytyla. This study clarified the chloroplast genome features of P. likiangensis and reconstructed
                 the phylogenetic relationships of Piceaꎬ thereby providing valuable data for future research on genetic diversity and the
                 breeding of superior varieties in this genus.
                 Key words: Picea likiangensisꎬ chloroplast genomeꎬ codon biasꎬ repeat sequenceꎬ phylogenomics




                叶绿体是植物细胞特有的细胞器ꎬ其最核心                            Lockwood et al.ꎬ 2013ꎻ Sullivan et al.ꎬ 2017)ꎮ 按
            的功能是进行光合作用ꎮ 叶绿体含有相对独立的                             照传统的分类ꎬ丽江云杉组只包括紫果云杉( Picea
            基因组ꎬ 大 部 分 植 物 的 叶 绿 体 基 因 组 大 小 介 于               purpurea)和丽江云杉(P. likiangensis)两种ꎬ而青杄
            115 ~ 165 kb 之间( Wang et al.ꎬ 2024)ꎬ为环状四           (P. wilsonii)则隶属于云杉组ꎬ但 Ran 等(2006) 对
            分体 结 构ꎬ 由 一 个 大 单 拷 贝 ( large single copyꎬ         云杉属植物的系统发育重建结果显示ꎬ青杄和紫
            LSC)区、一个小单拷贝( small single copyꎬSSC) 区             果云杉处于同一支上ꎬ它们在起源和进化上都非
            及两段序列相同和方向相反的反向重复( inverted                        常相近ꎮ 云杉属内不同植物之间常发生基因渐
            repeatꎬ IR ) 序 列 组 成 ( Daniell et al.ꎬ 2016ꎻ       渗、重组、不完全谱系分选等事件ꎬ如紫果云杉和
            Dobrogojski et al.ꎬ 2020)ꎮ 叶绿体基因组通常包含              丽江云杉的叶绿体 DNA 间常发生基因渐渗现象
            101 ~ 118 个基因ꎬ主要由参与光合作用、基因表达                       (Zou et al.ꎬ 2012)ꎬ导致物种之间的系统发育关系

            及生物合成的蛋白编码基因ꎬ以及 tRNA 和 rRNA                        常呈现网状( Sullivan et al.ꎬ 2017)ꎮ 叶绿体 DNA
            基因构成( Jansen & Ruhlmanꎬ 2012ꎻ Wang et al.ꎬ         进化速率适中ꎬ更适用于进行亲缘关系较近类群
            2024)ꎮ 相较于核基因组ꎬ叶绿体基因组的长度、                          的系统发育研究( Zou et al.ꎬ 2012)ꎮ 叶绿体基因
            所包含的基因种类及密码子组成等方面均十分保                              组序列可以用来解决云杉属内系统发育关系ꎬ同
            守ꎬ具有多拷贝、较少发生重组、进化速率居中等                             时有助于了解谱系地理学及细胞器基因组的多

            特点ꎬ突破了核基因组与线粒体基因组测序复杂、                             样性ꎮ
            易受干扰、分子水平变异程度高等限制ꎬ在系统发                                 目前ꎬ已有 16 种云杉属植物的叶绿体全基因

            育重 建 等 方 面 具 有 巨 大 优 势 ( Daniell et al.ꎬ           组序列被测定并公布于 NCBI( National Center for
            2021)ꎮ 叶绿体基因组已被广泛应用于系统发育                           Biotechnology Informationꎬ https: / / www. ncbi. nlm.

            重建、物种界定、DNA 条形码等多方面的研究( Li                         nih.gov / )上ꎬ其长度为 124 kb 左右ꎬ编码基因 110
            et al.ꎬ 2015ꎻ Wang et al.ꎬ 2022ꎻ Xia et al.ꎬ 2023)ꎮ  个左右ꎬ已公布的云杉属植物的叶绿体基因组结
                 云杉属共包含约 35 种ꎬ该属植物形态上高度                        构不同于标准的四分体结构ꎬ没有 IR 区( Li et al.ꎬ
            相似ꎬ属内物种之间系统发育关系复杂ꎮ 因此ꎬ很                            2020ꎻ Lo et al.ꎬ 2020ꎻ Parmar et al.ꎬ 2022)ꎮ 此
            多云杉属物种难以被准确界定( Ran et al.ꎬ 2006ꎻ                   外ꎬ云杉属通过种间杂交和重组产生了多种形式
   19   20   21   22   23   24   25   26   27   28   29