植物耐盐性研究是改良和利用土壤盐碱化的重要手段。申请人在前期研究杨树VQ蛋白家族中，发现在盐诱导下多外显子基因PtVQ3表达下调，其同源基因PtVQ12（单外显子基因）表达显著上调；但杨树中过量表达两个基因的cDNA均表现出对盐胁迫的高敏感性，并且它们在转录和蛋白表达水平上未检测到显著差异。目前，调控PtVQ3、PtVQ12表达差异的遗传调控机制尚不清楚。申请人拟从内含子和启动子的角度出发，通过创建PtVQ3内含子敲除转基因杨树和PtVQ3基因全长过量表达转基因杨树，鉴定和比较转基因株系的耐盐性，明确PtVQ3中内含子的功能；此外通过置换PtVQ3、PtVQ12的启动子创建转基因杨树，并与对照组的耐盐性进行比较，明确启动子对基因表达的影响。本项目的开展为明确盐胁迫下PtVQ3、PtVQ12表达差异的遗传调控机制，揭示内含子和启动子的重要性奠定了坚实基础。

Research on salt tolerance in plants is an important method to improve and utilize soil salinization. In previous study on the VQ protein family in poplar, it was found that the expression of PtVQ3 that is a multi-exon genes was down-regulated by salt induction, whereas significantly up-regulated of PtVQ12. PtVQ12 is an intronless genes that is homologous genes with the PtVQ3. However, the excessive expression of cDNA in the two genes showed high sensitivity to salt stress, and they did not detect significant differences in transcription and protein expression levels. At present, it is not clear the genetic regulation mechanism of PtVQ3 and PtVQ12 expression differences. From the perspective of intron and promoter, applicant will create transgenic poplar by knockout the intron of PtVQ3 and over expression of full-length of PtVQ3, respectively. By identification and comparison among different transgenic poplars under salt resistance, the function of introns in PtVQ3 will be clear. In addition, transgenic poplar will be created by replacing the promoter of PtVQ3 and PtVQ12, and the effect of promoter on gene expression was determined by comparing the salt tolerance of the control groups. The purpose of this project is to clarify the genetic regulation mechanism of PtVQ3 and PtVQ12 expression differences under salt stress and to reveal the importance of introns and promoters.