DPC调控棉花CPS基因表达的分子机制

Mepiquat chloride (DPC), an important plant growth retardant, can inhibit the growth of plant. So far, application of DPC in field has become an important way to regulate the growth of cotton, which can significantly inhibit the excess vegetative growth, reduce the length of internode, decrease the leaf area and eatablish an ideal plant type. CPS is likely to be a key regulatory point in gibberellin biosynthesis and may be regulated by DPC. In the project, VIGS and PEG-mediated transformation of protoplast technology will be used to study the relationship between DPC and CPS gene by observing the phenotype and determining the expression of CPS gene and protein. The vectors for mutants of CPS gene will be constructed and was transformed into Arabidopsis by using the vacuum infiltration method. Candidate genes in the sigmals pathway of CPS regulattion are achieved by comparing the gene expression profiles in CPS mutants in response to DPC. A cDNA library of cotton by DPC treatment will be constructed. The genes of proteins binding to CPS will be screened by from cotton cDNA library by yeast two-hybrid system. The function of candidate genes is to be studied by trangene technology. Based on the results, the mechanism of CPS regulation by DPC can be elucidated, which will be important not only for revealing the molecular mechanism of DPC action on cotton in theory, but also for rational application of DPC to improving the output of cotton and development of new plant growth regulator in pratice.

缩节安（DPC）是一种抑制型植物生长调节剂，可控制棉花过剩的营养生长，使节间变短，叶面积变小，株型紧凑，已成为生产上调控棉花生长的主要化控手段。古巴基焦磷酸合酶（CPS）是调控GA生物合成的关键作用位点，也是DPC的作用位点。本项目拟采用VIGS和PEG介导的原生质体转化技术，通过表型及基因、蛋白表达量的分析，确定DPC与CPS的互作关系；构建CPS相关突变体，分析其DPC敏感性及DPC处理基因表达谱差异，获得DPC调控CPS信号通路中的候选基因；构建棉花DPC响应的cDNA文库，采用酵母双杂交筛选与CPS互作的蛋白基因；采用转基因方法对候选基因进行功能验证。从而揭示DPC对棉花CPS基因表达的调控作用，阐明DPC调控棉花CPS的信号转导途径。本项目研究结果不仅在揭示DPC调控棉花生长的分子机制有重要理论意义，而且对DPC的合理施用，调控棉花高产和新型生长调节剂的开发等具有重要的实践意义。

缩节安（N, N-dimethylpiperidinium chloride, DPC）是棉花生产上广泛应用的一种植物生长延缓剂，可有效控制棉花过度的营养生长。揭示DPC调控棉花生长的分子机制对其合理施用、调控棉花高产和新型生长调节剂开发等具有重要理论和实践意义。研究明确了DPC显著抑制棉花顶芽、叶片和节间中GA早期合成关键酶基因GhCPS的表达，且节间中GhCPS表达下调持续期长，同时抑制GhCPS蛋白表达；通过对GhCPS与AtCPS过表达植株和体外表达细胞工程的分析，GhCPS比AtCPS对DPC更为敏感；探明了DPC调节了细胞伸长相关基因GhEXP和GhXTH2的表达控制植株生长；明确了DPC处理能够显著降低了GA晚期合成关键酶基因Gh20oxs和GhGA3ox的表达，调节了DELLA蛋白基因（GhGAI4a和GhGAI4b）表达；利用RNA-Seq测序技术，筛选出与赤霉素和生长素相关的差异基因，并利用VIGS基因沉默技术对GhAux2 和 GhTDC进行了功能验证。发表论文4篇，其中SCI收录论文1篇，培养研究生4名。