Chloroplast genomic diversity in Bulbophyllum section Macrocaulia(Orchidaceae,Epidendroideae,Malaxideae):Insights into species divergence and adaptive evolution  

作　　者：Hanqing Tang Lu Tang Shicheng Shao Yulan Peng Lu Li Yan Luo 

机构地区：[1]Gardening and Horticulture Department,Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences,Menglun,Mengla,666303,Yunnan,China [2]College of Forestry,Shanxi Agricultural University,Taigu,Jinzhong,030800,Shanxi,China [3]Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization&Ecological Restoration Biodiversity Conservation,Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu,Sichuan,610041,China [4]Department of Biodiversity Conservation,Southwest Forestry University,Kunming,650224,Yunnan,China [5]Gardening and Horticulture Department,Core Botanical Gardens,Chinese Academy of Sciences,Menglun,Mengla,666303,Yunnan,China

出　　处：《Plant Diversity》2021年第5期350-361,共12页植物多样性（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.31870183,No.U1702235);Southeast Asia Biodiversity Research Institute,Chinese Academy of Sciences(Y4ZK111B01)。

摘　　要：Bulbophyllum is the largest genus in Orchidaceae with a pan tropical distribution.Due to highly significant diversifications,it is considered to be one of the most taxonomically and phylogenetically complex taxa.The diversification pattern and evolutionary adaptation of chloroplast genomes are poorly understood in this species-rich genus,and suitable molecular markers are necessary for species determination and phylogenetic analysis.A natural Asian section Macrocaulia was selected to estimate the interspecific divergence of chloroplast genomes in this study.Here,we sequenced the complete chloroplast genome of four Bulbophyllum species,including three species from section Macrocaulia.The four chloroplast genomes had a typical quadripartite structure with a genome size ranged from 156,182 to 158,524 bp.The chloroplast genomes included 113 unique genes encoding 79 proteins,30 tRNAs and 4 rRNAs.Comparison of the four chloroplast genomes showed that the three species from section Macrocaulia had similar structure and gene contents,and shared a number of indels,which mainly contribute to its monophyly.In addition,interspecific divergence level was also great.Several exclusive indels and polymorphism SSR loci might be used for taxonomical identification and determining interspecific polymorphisms.A total of 20 intergenic regions and three coding genes of the most variable hotspot regions were proposed as candidate effective molecular markers for future phylogenetic relationships at different taxonomical levels and species divergence in Bulbophyllum.All of chloroplast genes in four Bulbophyllum species were under purifying selection,while 13 sites within six genes exhibited sitespecific selection.A whole chloroplast genome phylogenetic analysis based on Maximum Likelihood,Bayesian and Parsimony methods all supported the monophyly of section Macrocaulia and the genus of Bulbophyllum.Our findings provide valuable molecular markers to use in accurately identifying species,clarifying taxonomy,and resolving the phylogeny and

关 键 词：Chloroplast genome Sequence divergence DNA markers SSR BULBOPHYLLUM ORCHIDACEAE 

分 类 号：Q943[生物学—植物学]