青冈栎原花青素合成基因的鉴定与分析

Identification and analysis of proanthocyanidin synthesis genes in Quercus glauca

【目的】对青冈栎原花青素(缩合单宁)合成基因进行鉴定及生物信息学分析,可为青冈栎果实资源开发利用和品种改良奠定分子基础。【方法】基于已公布的青冈栎全基因组测序数据,利用生物信息学方法对原花青素合成基因进行鉴定,并分析其蛋白质序列、染色体定位、种间共线性、基因结构及系统发育关系。【结果】青冈栎中11种原花青素合成基因有42个家族成员,分布在11条染色体上;蛋白质理化性质在具有多拷贝数的QgPAL、QgC4H、Qg4CL、QgF3′H基因家族成员间存在差异;Qg4CL8、Qg4CL14、Qg4CL17、QgF3’H2、QgC4H4蛋白具有2~3个跨膜区域,表明这些蛋白可能在细胞内外信号转导中发挥重要作用;基因家族成员在栎属中进化比较保守,通过栎属古老的全基因组复制及串联重复和片段重复扩张;QgPAL2~QgPAL6和Qg4CL15基因分别与拟南芥中参与原花青素合成的AtPAL1~2和At4CL3聚为同一分支,可能在原花青素生物合成中发挥重要作用;Qg4CL基因家族在系统发育树中进化出新的分支,其家族成员表现出基因结构的多样性,并在4CL基因的高度保守基序中发生氨基酸位点的突变,推测这些基因可能因进化出新功能而被保留下来。【结论】青冈栎原花青素合成基因通过多种复制方式进行扩张,复制基因在栎属中相对保守,在青冈栎中表现出理化性质、蛋白结构和进化模式的多样化。采用生物信息学方法分析了原花青素合成基因的特征和进化模式,这为深入解析栎属植物单宁合成机制奠定了分子基础。

【Objective】This study was conducted to identify and bioinformatically analysis of proanthocyanidin(PA,condensed tannin)synthesis genes of Quercus glauca,which could lay a molecular foundation for development and utilization of Q.glauca fruit resources and variety improvement.【Method】Based on published whole genome sequencing data of Q.glauca,the PA synthesis genes were identified,and the protein sequence,chromosome location,interspecific collinearity,gene structure and phylogenetic relationship were analyzed using bioinformatic methods.【Result】The 11 PA synthesis genes of Q.glauca contain 42 family members,which are distributed on 11 chromosomes;The physical and chemical characters of protein are different among QgPAL,QgC4H,Qg4CL and QgF3′H gene family members with multiple copies;Qg4CL8,Qg4CL14,Qg4CL17,QgF3’H2 and QgC4H4 proteins had 2-3 transmembrane regions,suggesting that these proteins might play an important role in intracellular and extracellular signal transduction;The members of the gene family were relatively conservative in evolution in genus Quercus,through the ancient whole genome duplication,tandem duplication and fragment duplication expansion of genus Quercus;QgPAL2-6 and Qg4CL15 genes clustered in the same branch as AtPAL1-2 and At4CL3 involved in PA biosynthesis in Arabidopsis thaliana,respectively,which might play an important role in PA biosynthesis;The Qg4CL gene family had evolved into new branches in the phylogenetic tree,in which family members exhibit diversity of gene structure,and mutation of amino acid sites occurs in the highly conservative motif of 4CL gene.It was speculated that these genes may be preserved due to the evolution of new functions.【Conclusion】The PA synthesis genes of Q.glauca expand through various replication methods.The replication genes are relatively conservative in the Quercus,and show a diversity of physicochemical properties,protein structures and evolutionary patterns in Q.glauca.The characteristics and evolutionary patterns of proanthocyanidin synthesis genes are analyzed by bioinformatics methods,which lay the molecular foundation for an in-depth analysis of the mechanism of tannin synthesis in genus Quercus.