Stable Isotope Labeling Assisted Tandem Mass Spectrometry For Amine-containing Compounds Analysis In Plant Response To Abiotic Stress

Environmental stresses have negative impact on plant development and productivity.The main factors leading to agricultural production are extreme temperature,soil salinisation,atmospheric CO2,mechanical damage and heavy metal stress.When population growth exceeds food supply and quality,finding the reason for plant yields decrement and the solution are of great importance.The study of in vivo metabolite variation can't be ignored when investigating the behavior of plants dealing with abiotic stress.Toxicity in leaves of rice exposed to cadmium is caused by hydrogen peroxide accumulation,while polyamines(PAs)could reduce this oxidative damage.However,current analysis methods of polyamines in plants have disadvantages,like low sensitivity,large plant use and severe matrix effect.The small molecule metabolites involving in plant mechanical damage remain uncomprehensive at present.Amines are widely distributed small molecules in plants,thus finding the potential amine biomarkers has vital significance.Our goal is to find the amine metabolites related to mechanical damage in qualitative and quantitative profiling by metabonomics research.In our work,we combined the stable isotope labeling strategy with liquid chromatography-triple quadrupole mass spectrometer for non-targeted profiling,relative quantitation or absolute quantitation of amines in plants.The methods we established could improve the identification sensitivity,selectivity and accuracy.The research contents were as follows:1.We synthesized d6-dansyl chloride(d6-DNS-Cl);d6-DNS-Cl and DNS-Cl worked together as a pair of isotope mass probes.By introducing stable isotope labeling through chemical derivatization,we achieved absolute quantification of 6 PAs by UPLC-ESI-MS/MS without thier isotope internal standards.This method was successfully applied for the Spatio-temporal distribution of polyamines in rice seedings under cadmium stress.2.Herein we developed a novel strategy for isotope labeling in combination with high performance liquid chromatography-double neutral loss scan-mass spectrormetry(IL-LC-DNL-MS)analysis for non-targeted profiling of amine-containing compounds in tomato seedings.We synthesized DMAA(4-(dimethylamino)butanoic acid)and d4-DMAA,which worked together as a pair of isotope mass probes.By using this strategy,7 potential amine biomarkers associated with mechanical damage were discovered in tomato seedings.