百合bHLH家族系统进化和花香相关基因克隆及表达分析

Evolutionary of bHLH Transcription Factor Family in Lilium and Cloning and Expression Analysis of Floral Scent Related Genes

bHLH转录因子家族是植物中最大的转录因子家族之一。当前越来越多的植物bHLH转录因子家族被鉴定,然而百合bHLH转录因子家族的系统分析尚未见报道。本研究基于百合转录组数据,共鉴定出74个bHLH家族蛋白,均为亲水性蛋白,93%为不稳定蛋白,61%为酸性蛋白。结构域分析发现有25个保守残基的一致性≥50%,其中R16、R17、L27、L49和L59位点高度保守。此外,64个b HLH蛋白能与DNA结合,包含58个E-box结合物和46个G-box结合物。系统进化分析将百合bHLHs分为21个亚家族,基于进化树发现百合bHLHs可能执行信号转导、非生物胁迫、植物生长发育和物质合成等功能。对3个可能与罗勒烯和芳樟醇相关的基因Unigene23213_All、CL1682.Contig2_All和CL8286.Contig2_All进行了克隆,发现它们在品种间存在97.30%~99.89%的同源性。表达模式分析结果显示,三者在花、叶和鳞中均有表达。该研究为开展百合bHLH转录因子的功能研究提供了重要的序列信息。

The bHLH transcription factor families is one of the largest families of transcription factors in plants.More and more plant bHLH transcription factor families have been identified presently.However,systematic analysis of the lily bHLH transcription factor family has not been reported.Based on the transcriptome data of Lilium,this study identified a total of 74 bHLH family members.All the bHLH proteins were hydrophilic,93%of which were unstable proteins,and 61%were acidic proteins.Through the domain analysis,25 conserved residues were accounted for≥50%consistence,with R16,R17,L27,L49 and L59 being highly conserved.Sixty-four bHLH proteins were predicted to bind to DNA,including 58 E-box and 46 G-box bindings.Based on the phylogenetic analysis,lily bHLHs were assigned into 21 subfamilies,and they were annotated with functions on signal transduction,abiotic stress,plant growth and development,and substance synthesis.Three genes Unigene23213_All,CL1682.Contig2_All and CL8286.Contig2_All,which associated with ocimene and linalool biosynthesis,were cloned showing 97.30%-99.89%homology among varieties at each locus.The three genes were expressed in flowers,leaves and scales.The fundings of this research provided a valuable information in further study deciphering the functions of lily bHLH transcription factors.