毛果杨ptHsfA4a转录因子对锌胁迫的抗性机理研究

In plants, heat shock transcription factors (Hsfs) are important for tolerance to various abiotic stresses. In the previous study, we identified 31 Hsf genes in Populus trichocarpa, qRT-PCR analysis result showed that PtHsfA4a was specially expressed at high levels under zinc stress. Therefore, the zinc tolerance of transgenic Arabidopsis thaliana increased, and zinc ion influx into protoplast of transgenic A. thaliana was fewer than that into WT plant, and most ions were localized outside of membrane, which demonstrating that PtHsfA4a probably response to zinc stress in Populus trichocarpa by regulating downstream zinc transporter that localized on membrane. The aim of this study was to investigate the mechanism on PtHsfA4a gene in Populus trichocarpa response to zinc tolerance .. The promoter of PtHsfA4a was cloned, and the cis-acting elements in zinc stress regulation will be identified. The identified cis-elements are employed for determination of the upstream regulators of PtHsfA4a by yeast one hybrid. The physiological changes and growth characteristics of PtHsfA4a over- and inhibit expression of P. trichocarpa were confirmed to elucidate the physiology regulation. The downstream target genes were identified by gene expression profiles. Moreover, functions and metabolic pathway regulated by these genes are determined to reveal zinc tolerance mechanism of PtHsfA4a in forest tree at molecular and physiological level.

Hsfs是植物在多种胁迫条件下基因转录激活信号转导通路中的重要成员。我们对31个毛果杨Hsfs基因进行表达分析，发现PtHsfA4a基因特异性地受高锌诱导表达。PtHsfA4a转基因拟南芥的锌抗性显著提高，而且与对照相比吸收的锌离子主要积累在细胞膜外，很少进入原生质体内，表明该基因可能调控细胞膜锌转运子基因的表达。本项目拟以毛果杨为对象开展PtHsfA4a基因抗锌机制。克隆PtHsfA4a基因启动子，确定启动子中的抗锌相关顺式调控元件；利用酵母单杂交技术筛选PtHsfA4a基因的上游调控基因；分析比较过表达和抑制表达PtHsfA4a毛果杨抗锌相关生长、生理指标的变化；用表达谱测序技术确定PtHsfA4a所调控的下游靶基因，同时对这些靶基因进行功能分析，研究它们所参与的抗锌代谢过程，从而在分子和生理水平上揭示PtHsfA4a转录因子对林木的抗锌调控途径。

Hsfs是植物在多种胁迫条件下基因转录激活信号转导通路中的重要成员。我们对31个毛果杨Hsfs基因进行表达分析，发现PtHsfA4a基因特异性地受高锌诱导表达。PtHsfA4a转基因拟南芥的锌抗性显著提高，而且与对照相比吸收的锌离子主要积累在于细胞膜外，很少进入原生质体内，表明该基因可能调控细胞膜锌转运子基因的表达。本项目拟以毛果杨为对象开展PtHsfA4a基因抗锌机制。克隆PtHsfA4a基因启动子，确定启动子中的抗锌相关顺式调控元件；酵母单杂交技术，筛选PtHsfA4a基因的上游调控基因；分析比较过表达和抑制表达PtHsfA4a毛果杨抗锌相关生长、生理指标的变化；用表达谱测序技术确定PtHsfA4a所调控的下游靶基因，同时对这些靶基因进行功能分析，研究它们所参与的抗锌代谢过程，从而在分子和生理水平上揭示PtHsfA4a转录因子对林木的抗锌调控途径。