Page 6 - 广西植物2024年1期
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2                                      广  西  植  物                                         44 卷
             ( 1. Xishuangbanna Tropical Botanical Gardenꎬ Chinese Academy of Sciencesꎬ Mengla 666303ꎬ Yunnanꎬ Chinaꎻ 2. University of Chinese Academy
                 of Sciencesꎬ Beijing 100049ꎬ Chinaꎻ 3. School of Landscape Architectureꎬ Southwest Forestry Universityꎬ Kunming 650224ꎬ China )

                 Abstract: Paphiopedilum parishii is a rare and endangered species with few localities and fragmented populations found
                 in Chinaꎬ Myanmarꎬ Thailand and Laos. Environmental changes and over ̄harvesting have led to a decrease in its wild
                 populations. It is important to protect endangered species genetic diversity since it provides the species with the ability to
                 adapt and survive. Howeverꎬ little is known about the genetic information of this species. This study aims to detect
                 intraspecific variation and develop polymorphic genetic markers of P. parishii. The complete chloroplast genome of four
                 individuals of wild P. parishii was obtained by sequencingꎬ assembling and annotatingꎬ then compared with the existing
                 genomic data of two individuals available from GenBank to detect the intraspecific variation. Furtherꎬ simple sequence
                 repeats (SSRs)ꎬ single nucleotide polymorphisms (SNPs)ꎬ and insertions and deletions (InDels) were identified. The
                 results were as follows: (1) The four new sequencing chloroplast genomes were quadripartiteꎬ with a length between
                 154 403 bp and 154 809 bpꎬ with 129 genes (78 protein coding genesꎬ 39 tRNAsꎬ 8 rRNAs and four pseudogenes). (2)
                 As a result of comparison of six individualsꎬ 103 - 107 SSR loci were identified in the chloroplast genome of six
                 individuals of P. parishiiꎬ and 21 SSRs were polymorphic. And 60 long repeats were foundꎬ including 17-21 forward
                 repeatsꎬ 18-29 reverse repeatsꎬ 9-16 palindromic repeatsꎬ and 4-9 complement repeats. (3) In additionꎬ a total of 10
                 SNPs and 60 InDels were uncovered across the plastome. Three of the non ̄synonymous mutations caused amino acid
                 changes in functional domains. 19 InDels might be selected for possible chloroplast DNA markers to determine
                 intraspecific variation. (4) The value of nucleotide diversity (P ) was calculated ranging from 0-0.006 32 suggesting
                                                                i
                 sequences with low variation. Hyper ̄polymorphic regionsꎬ e.g. intergenic spacers rps3-rpl22ꎬ trnL ̄UAC-rpl32ꎬ rpoB-
                 trnC ̄GCA and ycf4 gene were identified as potential barcoding regions. (5) The phylogenetic analyses based on the
                 complete chloroplast genome supported three lineages in Paphiopedilumꎬ and six individuals of P. parishii form a
                 monophyletic group. SSRsꎬ long repeatsꎬ InDelsꎬ SNPs and nucleotide sequences showed sufficient intraspecific genetic
                 variation in P. parishii. The molecular markers developed here will contribute to further evolutionary studies and
                 conservation of P. parishii.
                 Key words: chloroplast genomeꎬ Paphiopedilum parishiiꎬ sequence divergenceꎬ polymorphic DNA markersꎬ
                 InDelsꎬ SSRs




                遗传多样性代表着物种适应环境和生存发展                            2011)ꎮ 叶绿体基因组虽然较小ꎬ但包含有大量遗
            的能力ꎬ保存珍稀濒危物种的遗传多样性是物种                              传信息ꎬ在核苷酸序列水平和结构重排上呈现出
            保护的重要目标 ( Guerrant & Pavlikꎬ 1998ꎻ 黄宏              进化与保守性ꎬ编码区和非编码区有不同进化速
            文ꎬ 2018)ꎮ 叶绿体是植物细胞内进行光合固碳                          率ꎬ在分子水平上有明显差异ꎬ可用于区分种间关
            和胁迫应答的重要半自主遗传细胞器ꎬ植物叶绿                              系、评估种间变异性等ꎬ被广泛用于群体遗传多样
            体基因组为环状 DNA 分子ꎬ单亲遗传ꎬ基因组大                           性、系统演化等研究领域 ( Wolfe et al.ꎬ 1987ꎻ 张
            小为 107 ~ 218 kbꎬ基因结构和组成稳定 ( 张韵洁                    韵洁和李德铢ꎬ 2011ꎻ He et al.ꎬ 2019ꎻ 黎若竹等ꎬ
            和李德铢ꎬ 2011ꎻ Ivanova et al.ꎬ 2017)ꎮ 叶绿体基            2022)ꎮ 近年来ꎬ利用种内不同个体叶绿体基因组
            因组通常为四分体结构ꎬ包括两个反向重复序列                              的种内变异ꎬ为物种进化研究、种质资源利用以及

            ( inverted repeatꎬ IR)、 一 个 大 单 拷 贝 区 ( large      濒危植物 保 护 提 供 了 基 础 遗 传 信 息 ( Ishizuka et
            single copy regionꎬ LSC) 和一个小单拷贝区 (small           al.ꎬ 2017ꎻ Muraguri et al.ꎬ 2020ꎻ Zhang RS et al.ꎬ
            single copy regionꎬ SSC) (Wolfe et al.ꎬ 1987ꎻ 田欣   2020)ꎮ
            和李德铢ꎬ 2002ꎻ Jansen et al.ꎬ 2005ꎻ 张韵洁和李                 兜 兰 属 ( Paphiopedilum ) 为 兰 科 ( Orchi ̄
            德铢ꎬ 2011ꎻ He et al.ꎬ 2019)ꎮ 叶绿体基因组编                daceae) 杓 兰 亚 科 ( subfamily Cypripedioideae) 植
            码 110 ~ 130 个基因ꎬ主要包括光合作用相关和叶                       物ꎬ有 80 余种ꎬ主要分布于亚洲至太平洋岛屿的
            绿体基因表达相关的基因等 ( 张韵洁和李德铢ꎬ                            热带亚热带地区的石灰岩山地 ( Cribbꎬ 1998ꎻ 刘
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