钾对茶叶低萜类中间体异戊烯焦磷酸合成关键酶的调节研究

The pool of Isopentenyl pyrophosphate and Dimethylallyl pyrophosphate (IPP/DMAPP) can provide a driving force for synthesis of low-molecule terpenoid at downstream, and 1-Deoxy-D-xylulose 5-phosphate synthase (DXS) and 1-Deoxy-D-xylulose 5-phosphate reductase (DXR) are key enzymes for synthesis of IPP. Based on the fact that regulation function of potassium to phosphate transformase and that lower than critical value for the content of potassium in the tea-cultivated soil, we propose the idea that different level of potassium has strong effect on the synthesis of IPP/DMAPP in tea leave, in which necessary experiments are conducted to verify the change of DXS and DXR. Firstly, water-culture experiment for tea is carried out to investigate effect of different content of potassium on the gene expression, enzyme activity of DXS and DXR, and on the synthesis amount of IPP/DMAPP and other relative precursors, from which to explore the key influence mechanism. By the experiment procedure, some theoretical exception is formed, and analytical techniques about enzyme and precursor are optimized. Thus using these techniques and methods investigate the effect of potassium, by pot experiment, on the gene expression and enzyme activity of DXS and DXR, production of IPP/DMAPP and other precursors, and then construct relational network and confirm endogenous mechanism among the target compounds by obtained data. Because this study combines biological method, such as gene expression and enzyme identification, with chromatography-mass spectrometry technique to investigation, the data obtained are convincing and precision, and can be checked each other. The research content covers subject-cross of plant nutrition, plant physiology, and apparatus analysis, and result will provide fundamental theory for high-quality tea production.

IPP/DMAPP库存量对下游低萜类合成提供必要驱动力，DXS和DXR是IPP合成关键酶，本项目结合钾对磷酸转移酶具有调节作用及茶园土壤钾含量多低于临界值实际，提出了不同钾水平对茶树叶片IPP/DMAPP合成有重要影响的设想，通过试验验证关键酶DXS及DXR的变化。项目先通过茶苗水培法研究不同梯度的钾对DXS及DXR基因表达、酶活性、IPP/DMAPP及其它中间体合成量的影响，探索其中关键性的影响机制。在此基础上，明确相关理论依据、完善分析表征技术，然后采用盆栽法培养茶苗，循环研究土壤钾不同含量、DXS和DXR基因表达及活性、IPP及其它中间体变化之间关系网络，探明内在关联机制。本研究以基因差异表达、酶活性鉴定等分子生物学手段，结合色谱与质谱联用分析技术，获取的结果准确可靠，并能相互验证。研究内容涉及植物营养学、植物生理学、仪器分析化学等多学科交叉。研究结果可为优质茶叶生产提供科学依据。