| In the process of growth, plants have suffered from some pathogens infection. In the coevolution with pathogens, plants have evolved complex, integrated defense mechanisms against pathogens infection. Systemic acquired resistance is an important component of plant disease resistance mechanisms, some disease resistance signals play an important role in this. In this paper, we studied the extraction and detection methods of disease resistance signal molecules. We also studied the variation of disease resistance signals,such as Jasmonic acid, Salicylic acid, Methyl jasmonate from peanut defense response to Ralstonia Solanacearum. The major results as follows:1. The dynamic adsorption device was designed and used to adsorb the trace volatile organic compounds (VOCs) emitted from peanut plant. The adsorbed VOCs were qualitative and quantitative analyzed by high performance liquid chromatography -tandem mass spectrometry. The VOCs were adsorbed by Tenax-TA, eluted with methanol solution containing 0.1% formic acid, and concentrated with nitrogen. The chromatographic separation was carried on a Agilent C18 column by using methanol and 0.05% formic acid-water as mobile phase at a flow rate of 300μL/min with a gradient elution mode. The samples were analyzed by hybrid triple quadrupole/linear ion trap mass spectrometer. The mass spectrometer was operated in positive ion mode using multiple reaction monitoring for qualitative and quantitative analysis by internal standard method. The method was simple, rapid and high efficiency, the detection limits for two VOCs were 2.0μg/L and 20μg/L (S/ N=3), and the quantitation limits were 5.0μg/L and 50μg/L (S/N=10), respectively. There was good linear relationship (r>0.98) between the concentration and the peak area ratio in the range of 1.0-1000μg/L.2. The solid-phase extraction method coupled with HPLC-MS/MS was developed for determination of three plant-signaling compounds (JA, SA and MeJA) in leaf tissue of peanut. JA and SA in peanut leaf were extracted by mixture of 1-propanol/H2O/concentrated HCL (2:1:0.002, V/V/V) and dichloromethane. MeJA was extracted by 80% methanol. The extraction was performed with C18 solid-phase extraction cartridge and the samples were subsequently analyzed by HPLC-MS/MS. Methanol and H2O with 0.05% formic acid was selected as mobile phase for HPLC, mass spectrometer used multiple reaction monitoring for qualitative and quantitative analysis by external standard method. The method has good linearity, high extraction recoveries and sensitivity and excellent reproducibility. The detection limits of the compounds were in the range of 0.005-0.2μg/L and the extraction recovery yields of plant-signaling compounds ranged from 67.03% to 103.34%.3. Using peanut seedlings as materials, we examined and compared the dynamic concentrations of SA, JA and MeJA in peanut after being treated 0, 3, 6, 9, 12, 24, 48 h by HPLC-MS/MS. We also studied the variation of volatile plant-signaling compounds MeJA and MeSA. The results show that the Ralstonia Solanacearum infects induced the concentrations of those disease resistance signals from peanut increasing in all the leaves. It could be concluded that some initial signals came from the cut and induced the defensive systems of the damaged plant. We also found, plant-signaling compounds in resistant variety were three hours earlier than sensitive variety to reach the maximum, preliminary reveals that the difference between resistant variety and sensitive variety respond to damage, it can provide evidence for breeding of stress-resistance variety and development of new ecological pesticide which is high efficiency and free from contamination.
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