ANALYSIS OF PRIMARY METABOLITE MANAGEMENT ON THE INDUCTION OF SECONDARY METABOLISM IN PL ANTS

在本研究中，我们开发了一种方法，允许动态通量分析，而不需要先验的动力学知识在植物的次生代谢。利用脉冲进料实验数据，建立并验证了该方法，测定了外源l -苯丙氨酸-d5与马铃薯块茎中7种苯丙氨酸代谢物的掺入情况。在确定了这些生物合成途径的代谢网络拓扑结构后，该系统被动态质量平衡与幂律动力学相结合来描述。作为下一步，幂律动力学的指数被确定，然后在进一步分析中保持固定值。利用蒙特卡罗模拟对该模型进行了统计可靠性检验。大多数通量的识别精度较高。对照和诱导后两种试验用例区分明显，诱导后对n -对香豆素胺（pCO）和n -对香豆素乙胺（pCT）的通量显著增加，而对绿原酸（CGA）和对香豆素莽草酸的通量显著降低。根据该模型，前两个通量的增加是由诱导/抑制机制引起的。后两种通量的减少是由它们的底物浓度降低引起的，而底物浓度降低又是由产生pCO-和pct的酶的活性增加引起的。通量控制分析表明，在大多数情况下，在使用激发剂后，通量控制发生了变化。因此，研究结果揭示了改善组织损伤和病原体攻击的潜在靶点。

In the present study we have developed a method that allows dynamic flux analysis without a priori kinetic knowledge in the secondary metabolism of plants. This method was developed and validated using the pulse-feeding experimental data, in which incorporation of exogenously applied L-phenylalanine-d5 into seven phenylpropanoid metabolites in potato tubers was determined. After identification of the topology of the metabolic network of these biosynthetic pathways, the system was described by dynamic mass balances in combination with power-law kinetics. As a next step, the exponents of the power-law kinetics were identified and then kept at fixed values during further analysis. The model was tested for statistical reliability using Monte Carlo simulations. Most fluxes could be identified with high accuracy. The two test cases, control and after elicitation, were clearly distinguished, and with elicitation fluxes to N-p-coumaroyloctopamine (pCO) and N-p-coumaroyltyramine (pCT) increased significantly, whereas those for chlorogenic acid (CGA) and p-coumaroylshikimate decreased significantly. According to the model, increases in the first two fluxes were caused by induction/derepression mechanisms. The decreases in the latter two fluxes were caused by decreased concentrations of their substrates, which in turn were caused by increased activity of the pCO- and pCT-producing enzymes. Flux-control analysis showed that, in most cases, flux control was changed after application of elicitor. Thus the results revealed potential targets for improving actions against tissue wounding and pathogen attack.