miR1444a参与毛果杨对锌胁迫的响应

MiR1444a Is Involved in the Response of Populus trichocarpa to Zinc Stress

miR1444a是杨树特异的miR1444家族中的一员,在植物对干旱、机械和铜等环境胁迫的响应中发挥重要作用.本研究通过RACE技术克隆得到毛果杨MIR1444a基因.该基因全长691bp,含单一外显子.生物信息学分析发现其启动子区存在大量胁迫响应相关的顺式作用元件,其中以前报道的5个与铜胁迫相关的CuRE元件中有4个位于转录本的5′末端,1个在转录起始点上游.qRT-PCR分析miR1444a成熟体及其靶基因PtPPO3和PtPPO6的表达与锌胁迫的关系,发现随着Zn2+浓度的增加,毛果杨根、茎、叶中miR1444a的表达均呈上升趋势,而PtPPO3和PtPPO6的表达均下降,说明miR1444a受Zn2+调控,参与毛果杨对锌胁迫的响应.

MiR1444a, a member of the Populus-specific miR1444 family, plays important roles in plant response to environmental stresses, such as dehydration, mechanical stress and copper stress. Here, we report the cloning of full-length MIR1444a gene from Populus trichacarpa using RACE-PCR technology. MIR1444a is a single-exon gene with 691 base pairs in length. Bioinformatic analysis showed the existence of many stress response-related cis-acting elements in the promoter region of MIR1444a gene. Additionally, a total of five Cu-response elements （CuREs） were previously predicted to be located in the 5＇-flanking region of MIR1444a gene; however, our results suggest that there is only one CURE. The other four are actually located in the transcriptional region. Analyses of the expression of mature miR1444a and its target genes （PtPP03 and PtPP06） in response to Zn stress in the roots, stems and leaves of P. trichacarpa by qRT-PCR showed that the levels of miR1444a were up-regulated with the increase of Zn2~ supply, where PtPP03 and PtPP06 were accordingly down-regulated. Our results suggest the invovlement of miR1444a in the response of P. trichacarpa to zinc stress.