毛白杨BABY BOOM基因的克隆及生物信息学分析

Cloning and bioinformatics analysis of BABY BOOM gene from Populus tomentosa

BBM(BABY BOOM)转录因子是植物细胞全能性和胚胎发生的关键调控因子。利用PCR技术从毛白杨‘BJHR01’幼叶cDNA中克隆得到PtoBBM1和PtoBBM2基因,利用生物信息学软件,对这两个基因的序列和功能进行分析。结果表明:毛白杨中PtoBBM1蛋白与毛果杨中PtrBBM1(B9HHX9)蛋白相似性高达96%;PtoBBM2与PtrBBM2(B9HYI0)蛋白相似性达到98%。此外,PtoBBM1和PtoBBM2蛋白均含有2个AP2保守结构域,三级结构预测它们均和乙烯反应性转录因子ERF096模型高度相似。理化性质分析推测PtoBBM1和PtoBBM2均是不稳定的亲水蛋白,不具有信号肽,亚细胞定位预测PtoBBM1和PtoBBM2蛋白均定位于细胞核,都具有跨膜结构。进化树分析显示,杨树BBM与蓖麻、棉花BBM归为一个分支,亲缘关系较近。组织表达分析表明,PtoBBM1主要在根中表达,叶和茎中表达量较低;PtoBBM2主要在叶和根中表达,茎中表达量较低,2个同源基因表达具有组织部位的差异性。在胚性愈伤组织形成过程中,PtoBBM1和PtoBBM2基因均在胚性愈伤组织形成期表达量最高,说明PtoBBM1和PtoBBM2基因可能在杨树胚性愈伤组织形成中发挥作用。

The BBM(BABY BOOM) transcription factor gene is a key regulator of plant cell totipotency and plant embryogenesis.The Pto BBM1 and Pto BBM2 genes were cloned from Populus tomentosa cv.BJHR01 leaf cDNA by PCR.The sequence and functions of the two genes were analyzed using bioinformatics software.The results showed that the similarity of PtoBBM1 protein in P.tomentosa and PtrBBM1(B9 HHX9)protein in P.trichocarpa was up to 96%,and the similarity between PtoBBM2 and PtrBBM2(B9 HYI0) protein was up to 98%.In addition,both PtoBBM1 and PtoBBM2 contained two conserved motifs of AP2.According to protein structure prediction,the putative three-dimensional structure of the protein of PtoBBM1 and PtoBBM2 were similar to the ERF096 model of ethylene reactive transcription factor.The analysis of physicochemical properties suggested that PtoBBM1 and PtoBBM2 were both unstable hydrophilic proteins with no signal peptide.Subcellular localization showed that they located in the nucleus and had transmembrane structure.Phylogenetic tree analysis indicated that BBM of P.trichocarpa,Ricinus communis and Gossypium hirsutum belonged to the same branch,and they had close genetic relationship.Real-time quantitative PCR results showed that PtoBBM1 gene expressed at the highest level in the roots,lower in leaves and stems;PtoBBM2 gene expressed at the highest level in the leaves and roots,lower in stems.Both Pto BBM1 and Pto BBM2 expressed at the highest level in embryogenic callus formation stage,which indicated that PtoBBM1 and PtoBBM2 might play a role in the formation of embryogenic callus in poplar.