Proteomics And Metabolomics Analysis To Cold Stress In Two Desert Chenopodiaceae Plants Seedlings

Haloxylon ammodendron and Anabasis aphylla are the main dominant species and constructive species in the desert area of the Junggar Basin in Xinjiang.They play an important role in saline and cracked land reform,wind and sand fixation and maintain the water and soil safety of the piedmont alluvial fan.Cold stress is one of the most important abiotic stress factors affecting the growth and geographical distribution of plants.The snow-melting period in the Gurbantunggut desert in the Junggar Basin lasts for about 10 days,during which the surface is repeatedly the freezing and thawing state,in addition,in the global environment of climate change,the “spring frost following warm spell” phenomenon also occurs from time to time.This unfavorable environmental condition has affected the survival and growth of H.ammodendron and A.aphylla seedlings.Therefore,this study used the method of artificial cold simulation to determination of physiological indexes of H.ammodendron and A.aphylla seedlings.In addition,isobaric tags for relative and absolute quantitative(i TRAQ)and gas chromatography-mass spectrometer(GC/MS)techniques were used to identify and analyze the differential protein and differential metabolites under the cold stress in these two species,and studied the response of H.ammodendron and A.aphylla seedlings to cold stress.The main results are as follows:1.Several physiological indexes of H.ammodendron and A.aphylla seedlings in the control and cold stress treatment were compared.It was found that in the H.ammodendron seedlings under cold stress,the activities of superoxide dismutase(SOD),peroxidase(POD),malate dehydrogenase(MDH)and glutathione peroxidase(GSH-Px)were increased;except that the activity of POD enzyme was decreased under cold stress,the activities of SOD,MDH,and GSH-Px enzymes were increased under cold stress conditions in A.aphylla seedlings.2.In this paper,i TRAQ technology was used to identify and analyze the proteins in H.ammodendron and A.aphylla seedlings under cold stress.It was found that there were a total of 339 differentially expressed proteins in H.ammodendron seedlings,of which 191 were up-regulated and 148 were down-regulated.A total of 211 differentially expressed proteins were identified in the seedlings of A.aphylla seedlings.Among them,102 were up-regulated and 109 were down-regulated.The gene function(GO)classification analysis of the differentially expressed proteins in H.ammodendron and A.aphylla seedlings was found that the biological functions of these differentially expressed proteins are carbohydrate and energy metabolism,protein synthesis,processing and degradation,stress response,transcriptional regulation,transmembrane and intracellular transport,amino acid metabolism,signal transduction,etc.Most of the differentially expressed proteins in two species are associated with their carbohydrate and energy metabolism processes in response to cold stress,respectively.3.In this study,GC/MS technology was used to analyze the characteristics of metabolite changes of H.ammodendron and A.aphylla seedlings exposed to cold stress.In H.ammodendron seedlings,a total of 98 kinds of differential metabolites were detected,and 64 of them were up-regulated,34 were down-regulated expression,most of the metabolites were sugars and sugar alcohols,amino acids and organic acids.A totalof 116 differential metabolites were detected in A.aphylla seedlings,of which 41 were up-regulated and 75 were down-regulated.The main metabolites were also sugar and sugar alcohols,amino acids and organic acids.Cold stress had significant effects on the differential metabolites of H.ammodendron and A.aphylla seedlings,the glycolate metabolic pathway and the pentose phosphate pathway in H.ammodendron seedlings are inhibited under cold stress,but can be enriched by succinic acid,L-malic acid,citric acid and fumaric acid reduce the degree of plant damage caused by adverse conditions.Cold stress has no obvious inhibitory effect on the TCA cycle in A.aphylla seedlings.However,the metabolic pathways such as sugar signal pathway,ornithine cycle,photosynthesis and respiration in A.aphylla seedlings were significantly affected.4.After comparing the physiological,proteome,and metabolome studies of H.ammodendron and A.aphylla seedlings under cold stress,it was found that the three antioxidant enzyme activities were increased in both species,and that one antioxidant enzyme activity was decreased in A.aphylla seedlings,but increased in H.ammodendron seedlings under cold stress.There were 47 differentially expressed proteins were found in both plants,and 25 of them showed the same expression trends.There were 12 differential metabolites were found in the seedlings of H.ammodendron and A.aphylla seedlings,including 4 amino acids and 8 organic acids,these differential metabolites showed consistent or opposite enrichment in H.ammodendron and A.aphylla seedlings.