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

在目前的研究中，我们开发了一种方法，可以在没有植物次生代谢的先验动力学知识的情况下进行动态通量分析。利用脉冲饲喂试验数据对该方法进行了验证，并测定了外源外源L-苯丙氨酸-d5在马铃薯块茎中7种苯丙烷代谢产物中的掺入。在确定了这些生物合成途径的代谢网络的拓扑结构后，用动态质量平衡和幂定律动力学相结合的方法描述了该系统。作为下一步，确定了幂定律动力学的指数，然后在进一步分析期间将其保持在固定值。使用蒙特卡罗模拟对模型的统计可靠性进行了检验。大多数助熔剂的识别准确率都很高。对照和激发后的两个测试案例被明显区分，并且随着激发通量的增加，对N-对香豆酰酪胺(PCO)和N-对香豆酰酪胺(PCT)的诱导通量显著增加，而对绿原酸(CGA)和对香豆酰莽草酸(P-香豆酰莽草酸)的诱导通量显著降低。根据该模型，前两种通量的增加是由诱导/去阻遏机制引起的。后两种通量的减少是由于底物浓度降低造成的，而底物浓度的降低又是PCO和PCT产生酶活性增加所致。通量控制分析表明，在大多数情况下，在使用激发子后，通量控制发生了变化。因此，这些结果揭示了改善抗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.