Analysis Of Metabolome Of Quinoa Under Water Stress Based On GC-MS

Quinoa(Chenopodium quinoa willd)is native to Andes,and has good resistance to barren,drought,saline-alkali and low temperature stress.It is rich in nutrition and contains a variety of amino acids,flavonoids and polyphenols,and has good edible and medicinal value.It has attracted much attention at home and abroad.In recent years,there have been many studies on the nutrition of quinoa,but there is a lack of research on quinoa under water stress.In this study,PEG6000 was used to simulate drought stress and double basin method was used to simulate waterlogging stress to treat quinoa at different growth stages,and the mechanism of drought resistance and waterlogging resistance of quinoa was explained by physiological indexes and metabolomics analysis.(1)The results of drought simulation of quinoa seedlings with 5%,15%and 30%PEG6000showed that 5%and 15%PEG6000 were not significantly effective,so only 30%PEG6000and double basin method were used to treat quinoa at different growth stages.The 3~rdd leaf from the terminal bud down were used as materials to detect drought and waterlogging resistance.The treatment time was 48 hours.The mechanism of water resistance was studied by measuring the changes of soluble protein,soluble sugar,total antioxidant capacity,POD enzyme activity and MDA in normal group,drought treatment group and waterlogging treatment group.It was found that there was no obvious change of the POD enzyme activity of quinoa under drought stress at grain filling stage,but the content of soluble sugar and POD enzyme activity of quinoa increased significantly at different stages under drought stress,and the MDA content decreased to resist the stress.It was also found that the drought resistance of quinoa was relatively weak at flowering stage and relatively strong at grain filling stage.(2)In order to obtain better metabolic results,the conditions of sample derivation were optimized.The volume of derivatization reagent,reaction temperature and time were optimized by single factor experiment and response surface method.The number and area of detected peaks and identified were used to measure the effect of derivatization.The results showed that the best derivatization condition were that the volume was 100μl,the temperature was 40℃and the time was 27min.(3)The changes of metabolites and metabolic pathways of quinoa in four growing periods were analyzed by means of metabolic techniques after drought and waterlogging stress.Under drought stress,43 different metabolites were detected,42 were up-regulated,1 was down-regulated and 10 significant pathways were screened;44 differentially metabolites were detected under waterlogging stress,and 11 pathways were screened.The most significant of which was Glutathione metabolism;57 different metabolites were detected under drought stress in squaring period,10 pathways were screened out;64 different metabolites were detected under waterlogging stress,58 metabolites were up-regulated,6 metabolites were down-regulated and 13 pathways were screened out,the most significant of which was Tyrosine metabolism.Under drought stress,60 metabolites were detected,7 were up-regulated,53 were down-regulated and 14 pathways were screened,the most significant of which was Sulfur metabolism;74 different metabolites were detected under waterlogging stress,in which there were 57 up-regulated and 17 down-regulated.16 and 3 pathways were screened respectively,the most significant of which were Isoquinoline alkaloid biosynthesis and Alanine-aspartate-glutamate metabolism.28 different metabolites were up-regulated and9 pathways were screened out under drought stress at filling stage,the most significant of which was Tryptophan metabolism;46 metabolites were detected under waterlogging stress,44 were up-regulated,2 were down-regulated and 16 pathways were screened.The most significant of which wasβ-alanine metabolism.The number of different metabolites is different in different periods,but except for the flowering stage of drought stress,most of the metabolites are up-regulated and the main types of metabolites are amino acids,organic acids,sugars and their derivatives and alkaloids.The main metabolic pathways were amino acids,organic acids,sugars and their derivatives and alkaloids.