PhSDG8调控生长素糖基化转移酶基因PhUGT74E2影响矮牵牛分枝发育的分子机制

In flower cultivation, artificial topping is needed to promote branching with the aim of increasing the ornamental effects, while the production costs are greatly improved. In the early stage, we identified a new mutant sdg8-6 and found that SDG8 had the new function of regulating branch orders, which is of great application value in the cultivation of new varieties of flowers with multiple branches. On this basis, the full-length of PhSDG8 was cloned. Expression analysis and Arabidopsis transformation experiments preliminarily confirmed that PhSDG8 was able to regulate shoot branching, but the exact molecular mechanism was not yet clear. In this project, we will determine the biochemical characteristics of PhSDG8 by detecting the enzyme activity of PhSDG8. and determine the biological function of PhSDG8 by PhSDG8 overexpression and deletion experiments. Also we will clarify the regulation of PhSDG8 on PhUGT74E2 by detecting expression level and H3K9 methyl level of PhUGT74E2 in PhSDG8 overexpression or deletion transgenic plants, determining the biological function of PhUGT74E2, as well as the interaction between PhSDG8 and PhUGT74E2. This project has important theoretical significance and practical value for revealing the molecular mechanism of PhSDG8 regulating shoot branching, and creating new varieties of Petunia with multiple flowers and good plant architecture.

花卉栽培中需要多次人工打顶促进分枝发育以增加观赏效果，但生产成本大大提高。项目组前期通过鉴定新的突变体sdg8-6，发现SDG8具有调控分枝级数的新功能，这在花卉的多分枝新品种培育中具有极大的应用价值。在此基础上，克隆获得矮牵牛PhSDG8全长序列，并通过表达分析和转化拟南芥试验初步证实，PhSDG8能够调控植株的分枝发育，但确切的分子机理尚不明确。本项目拟通过PhSDG8酶活性检测以确定其生化特性；通过PhSDG8过表达及缺失试验，明确其生物学功能；分析PhSDG8过表达和缺失转基因植株中PhUGT74E2的表达水平和H3K9甲基化水平，PhUGT74E2的生物学功能以及PhSDG8与PhUGT74E2的互作，确定PhSDG8对PhUGT74E2的调控作用。本项目对于揭示PhSDG8调控矮牵牛分枝发育的分子机制和创制花头繁多、株型饱满的矮牵牛新品种具有重要的理论意义和实用价值。

花卉栽培中需要多次人工打顶促进分枝以增加观赏效果，但生产成本大大提高。项目组前期在拟南芥中鉴定得到一个新的突变体sdg8-6，表现为分枝数量和级数增加。前期实验初步证实，PhSDG8能够调控植株的分枝发育，但确切的分子机理尚不明确。本项目以矮牵牛为实验材料，通过PhSDG8过表达及病毒诱导基因沉默试验，明确了PhSDG8调控分枝的生物学功能。通过分析PhSDG8沉默植株中PhUGT74E2的表达水平，初步确定了PhSDG8对PhUGT74E2的调控作用。通过转录组数据分析，筛选到了分枝发育相关候选基因PhWRKY71和PhMYB37。通过对其表达特性、亚细胞定位以及转基因表型分析，明确了这两个基因在调控矮牵牛分枝发育中的具体功能。本项目对于丰富矮牵牛分枝发育的调控机理和创制不同株型的矮牵牛新品种具有重要的理论意义和实际应用价值。