基于基因组学构建兰属珍稀濒危植物系统发育关系  

Constructing Phylogenetic Relationships of Rare and Endangered Plants of Cymbidium (Orchidaceae)Based on Genomics

作　　者：张梅 李媛媛[1] 李晓芳 杨加文 童琪 何选泽 ZHANG Mei;LI Yuanyuan;LI Xiaofang;YANG Jiawen;TONG Qi;HE Xuanze(Guizhou Botanical Garden,Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China,Guiyang Guizhou 550004,P.R.China)

机构地区：[1]贵州省植物园西南喀斯特山地生物多样性保护国家林业和草原局重点实验室,贵州贵阳550004

出　　处：《西部林业科学》2024年第6期8-18,共11页Journal of West China Forestry Science

基　　金：贵州省科技支撑项目(黔科合支撑[2022]一般203);贵州省基础研究计划项目(黔科合基础-ZK[2022]一般291);贵州省林业科研项目(黔林科合[2022]01)。

摘　　要：兰属(Cymbidium)隶属于兰科(Orchidaceae),草本植物,在喀斯特地区最为常见。由于在野生环境中的自然杂交现象十分普遍,该属植物存在中间类型繁多、种内和种间问题突出、物种鉴定边界不清晰、本底数据尚未明确等一系列分类学问题。为了厘清该属植物亚属间、种内和种间的分类学问题,本研究选取44个兰属植物作为研究对象,1个百合科植物:滇百合(Lilium bakerianum)作为外类群,通过对获取的1个核基因(ITS)和4个叶绿体基因片段(matK,trnL_trnF,rbcL,trnH_psbA)进行基因组学分析,以期重建兰属植物的系统发育关系,并探讨其物种演化过程。结果显示:核基因单一片段单独建树,兰属中3个亚属的类群聚集明显,但树形拓扑结构的分辨率较低;叶绿体4个片段综合建树,分辨率明显提高,并清晰地显示了物种的进化痕迹。基于核基因与叶绿体基因共计五个片段的基因数据联合分析,整体树形可划分为3个大的进化枝和8个Clade,且树形分枝结构的支持率和分辨率进一步提高。从进化树分析结果来看,兰属植物生境进化的方向趋于附生,栖息地越来越狭窄。由于生境变窄是物种灭绝的重要原因,兰属植物的保护需要重点关注基部类群,尽快建立该类群的种子库和基因库。本研究重建了兰属的系统发育关系,为全面理解该属演化关系与地理分布式样提供重要的参考依据。Cymbidium,a herbaceous plant belonging to the Orchidaceae,is most common in karst areas.Due to the widespread occurrence of natural hybridization in wild environments,this genus of plants faces a series of taxonomic challenges,including a wide variety of intermediate types,prominent intra-and inter species problems,unclear species identification boundaries,and unclear background data.In order to clarify the taxonomic issues among subgenera,intra species,and inter species of this genus of plants,this study selected 44 Cymbidium and one outgroup(Lilium bakerianum)as research objects.Genomic analysis was conducted on one nuclear gene(ITS)and four chloroplast gene fragments(mat K,trn L_trn F,rbc L,trn H_psb A)obtained to reconstruct the phylogenetic relationships of Cymbidium and explore their species evolution process.The results showed that when a single fragment of the nuclear gene was used to construct a tree,the clustering of the three subgenera in Cymbidium was significant,but the resolution of the tree topology structure was low.The comprehensive construction of four chloroplast fragments has significantly improved the resolution and clearly displayed the evolutionary traces of species.Based on the joint analysis of gene data from five fragments of nuclear and chloroplast genes,the overall tree structure can be divided into three large evolutionary branches and eight Clades,and the support and resolution of the tree branch structure are further improved.From the perspective of phylogenetic trees,the habitat evolution of orchids tends to be epiphytic,with increasingly narrow habitats.Narrowing habitats are also an important reason for species extinction.Therefore,the conservation of orchid plants requires a particular focus on the basal groups.It is imperative to establish seed and gene banks for these groups promptly.The reconstruction of the phylogenetic relationship of this system has important reference value for a comprehensive understanding of the evolutionary relationship and geographical distribution of

关 键 词：形态地理学 植物分类学 分子系统学 兰科 兰属 

分 类 号：S769.7[农业科学—森林保护学]