The Metasequoia genome and evolutionary relationships among redwoods  

作　　者：Fangfang Fu Chi Song Chengjin Wen Lulu Yang Ying Guo Xiaoming Yang Ziqiang Shu Xiaodong Li Yangfan Feng Bingshuang Liu Mingsheng Sun Yinxiao Zhong Li Chen Yan Niu Jie Chen Guibin Wang Tongming Yin Shilin Chen Liangjiao Xue Fuliang Cao 

机构地区：[1]State Key Laboratory of Tree Genetics and Breeding,Co-Innovation Center for Sustainable Forestry in Southern China,Nanjing Forestry University,Nanjing 210037,China [2]Institute of Herbgenomics,Chengdu University of Traditional Chinese Medicine,Chengdu 611137,China [3]Wuhan Benagen Technology Company Limited,Wuhan 430000,China [4]Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,China [5]China Academy of Chinese Medical Sciences,Institute of Chinese Materia Medica,Beijing 100070,China

出　　处：《Plant Communications》2023年第6期342-355,共14页植物通讯（英文）

基　　金：supported by the National Key Research and Development Program of China(2017YFD0600701).

摘　　要：Redwood trees(Sequoioideae),including Metasequoia glyptostroboides(dawn redwood),Sequoiadendron giganteum(giant sequoia),and Sequoia sempervirens(coast redwood),are threatened and widely recognized iconic tree species.Genomic resources for redwood trees could provide clues to their evolutionary relationships.Here,we report the 8-Gb reference genome of M.glyptostroboides and a comparative analysis with two related species.More than 62%of the M.glyptostroboides genome is composed of repetitive sequences.Clade-specific bursts of long terminal repeat retrotransposons may have contributed to genomic differentiation in the three species.The chromosomal synteny between M.glyptostroboides and S.giganteum is extremely high,whereas there has been significant chromosome reorganization in S.sempervirens.Phylogenetic analysis of marker genes indicates that S.sempervirens is an autopolyploid,and more than 48%of the gene trees are incongruent with the species tree.Results of multiple analyses suggest that incomplete lineage sorting(ILS)rather than hybridization explains the inconsistent phylogeny,indicating that genetic variation among redwoods may be due to random retention of polymorphisms in ancestral populations.Functional analysis of ortholog groups indicates that gene families of ion channels,tannin biosynthesis enzymes,and transcription factors for meristem maintenance have expanded in S.giganteum and S.sempervirens,which is consistent with their extreme height.As a wetland-tolerant species,M.glyptostroboides shows a transcriptional response to flooding stress that is conserved with that of analyzed angiosperm species.Our study offers insights into redwood evolution and adaptation and provides genomic resources to aid in their conservation and management.

关 键 词：Metasequoia glyptostroboides redwood incomplete lineage sorting POLYPLOIDY flooding stress 

分 类 号：Q94[生物学—植物学]