Abscisic acid （ABA） is a major plant hormone that plays an important role in responses to abiotic stresses. The ABA-responsive element binding protein/ABRE-binding factor （AREB/ABF） gene subfamily contains crucial transcription factors in the ABA-mediated signaling pathway. In this study, a total of 14 putative AREB/ABF members were identified in the Populus trichocarpa Torr. ＆ Gray. genome using five AREB/ABF amino acid sequences from Arabidopsis thaliana L. as probes. The 14 putative Populus subfamily members showed high protein similarities, especially in the basic leucine zipper （bZIP） domain region. A neighbor-joining analysis combined with gene structure data revealed homology among the 14 genes. The expression patterns of the Populus AREB/ABF subfamily suggested that the most abundant transcripts of 11 genes occurred in leaf tissues, while two genes were most transcribed in root tissues. Significantly, eight Populus AREB/ABF gene members were upregulated after treatment with 100 t^M exogenous ABA, while the other six members were downregulated. We identified the expression profiles of the subfamily members in Populus tissues and elucidated different response patterns of Populus AREB/ABF members to ABA stress. This study provided insight into the roles of Populus AREB/ABF homologues in plant response to abiotic stresses.
Lexiang JiJia WangMeixia YeYing LiBin GuoZhong ChenHao LiXinmin An
以毛白杨为材料,采用同源基因克隆法从毛白杨中分离了FT(FLOWERING LOCUS T)同源基因PtFT1和PtFT2编码区序列。测序结果表明PtFT1和PtFT2编码区长度均为525bp,可编码174个氨基酸。蛋白序列比对发现这两个基因与拟南芥、葡萄等物种中FT同源基因所编码的氨基酸同源性达到75%以上,PtFT1和PtFT2所推测的氨基酸序列包含FT类蛋白保守基序(LGRQTVYAPGWRQN)和两个关键性氨基酸残基Tyr84(Y),Gln139(Q)。系统进化分析进一步表明PtFT1和PtFT2属于FT亚家族成员。采用Real-time qRT-PCR技术检测PtFT1和PtFT2在各个组织部位中的表达模式,结果表明PtFT1和PtFT2在各个组织部位均有表达,但这两个基因的表达水平存在差异;两个基因在早期雌雄花芽(7月5日)表达量明显高于成熟雌雄花芽(翌年3月10日)表达量,进而推测在毛白杨中PtFT1和PtFT2的表达响应日照长短,长日照条件促进这两个基因的表达,它们可能在光周期调控的开花途径中促进花芽分化和开花发挥特定作用。这些研究对于阐明PtFT1和PtFT2在光周期开花调控途径中的作用机制具有重要意义,为进一步开展毛白杨开花调控基因工程研究奠定了工作基础。
