蓝星睡莲CBF基因家族的全基因组鉴定与分析

Genome-wide Identification and Analysis of CBF Gene Family in Nymphaea colorata

CBF(C-repeat binding factor)是一类转录激活因子,在植物应对低温等非生物胁迫中起重要作用。为探究蓝星睡莲(Nymphaea colorata)CBF基因家族的生物学特性,本研究从蓝星睡莲全基因组中筛选到11个CBF家族成员,依次命名为NcCBF1~NcCBF11,并对其理化性质和基因表达等进行了分析。结果表明,蓝星睡莲CBF基因编码蛋白的长度为181~397 aa,分子量在20.17~43.11 kD之间,大多表现为酸性亲水蛋白,亚细胞定位于细胞质和细胞核中。系统进化分析发现,蓝星睡莲与拟南芥亲缘关系最近,与水稻同源性较远。NcCBFs基因中存在2对旁系同源基因(NcCBF2~NcCBF5,NcCBF4~NcCBF9),Ka/Ks值分别0.2977和0.1892,在进化过程中受到了较强的纯化选择作用。NcCBFs家族成员除NcCBF9和NcCBF4外,均为内含子缺失型,基因家族在染色体上呈现不均等分布,编码的蛋白序列均含有motif 1保守基序。预测蛋白二级结构主要由无规则卷曲和α-螺旋构成,三维结构均由1个α-螺旋和2个β-折叠构成。蛋白互作分析表明,NcCBFs基因与拟南芥中BREBs和CBFs基因有着密切的关联,且功能注释结果多与低温响应和植物激素信号通路相关。NcCBFs家族成员启动子区域有多个参与植物的生长发育、激素响应以及逆境响应的顺式元件。基因表达结果表明,NcCBFs基因在蓝星睡莲不同组织中存在表达差异性,且NcCBFs基因在蓝星睡莲花蕾期发挥重要作用。本研究为进一步研究NcCBFs基因参与逆境胁迫的分子机制提供参考。

CBF(C-repeat binding factor),a class of transcription factors,play an important role in plant response to abiotic stress such as low temperature.In order to explore the biological characteristics of CBF gene family in Nymphaea colorata,11 CBF genes family members were selected from the whole genome,named NcCBF1~NcCBF11 in turn,and the physicochemical properties and gene expression were analyzed.The results showed that the number of amino acids encoded by NcCBFs genes ranged from 181 aa to 397 aa,and the molecular weight ranged from 20.17 to 43.11 kD,most of them were acidic hydrophilic proteins,and subcellular localization were in cytoplasm and nucleus.Phylogenetic analysis showed that N.colorata had the closest relationship with Arabidopsis thaliana,and had lower homology with rice.There were two pairs of homologous genes(NcCBF2~NcCBF5,Nc CBF4~NcCBF9)in NcCBFs genes,with Ka/Ks values of 0.2977 and 0.1892 respectively,which were highly purified and selected in the evolution process.Except NcCBF9 and NcCBF4,all members of NcCBFs gene family were intron deletion type.The distribution of NcCBFs on chromosome were uneven and the protein sequences encoded by Nc-CBFs all contained motif 1.It is predicted that the secondary structures of the proteins were mainly composed of random curl and alpha helix,and the three-dimensional structures were composed of one alpha helix and two beta folds.Protein interaction analysis showed that NcCBFs genes were closely related to DREBs and CBFs genes in Arabidopsis thaliana,and the functional annotation results were mostly related to low temperature response and plant hormone signaling pathway.There were many cis-acting elements in the promoter region of NcCBFs gene family members involved in plant growth and development,hormone response and stress responses.Gene expression analysis showed that NcCBFs genes were expressed differently in different tissues of N.colorata,and played an important role in bud stage.This study provided a reference for further study on the molecular mechanism of NcCBFs genes involved in stress responses.