Metabonomics Analysis On The Difference Of Drought Resistance In Seedling Of Winter Wheat Variety

About 70% of China's winter wheat is distributed in arid and semi-arid areas.Drought is easy to be encountered in sowing season and seedling stage,which seriously affects the growth of wheat seedlings,and eventually leads to the decline of wheat yield and quality.Therefore,a thorough understanding of mechanism of drought resistance in wheat seedling stage can provide theoretical basis for breeding and improvement of wheat varieties.In this study,Yanzhan 4110 and Jiaomai 266,which have different drought tolerance,were used as experimental materials to study the differences of physiological,biochemical and metabolic responses of Different Wheat Seedlings under drought stress.GC-MS was used to determine the metabolites and metabolic path differences between different varieties,which is of great significance for the selection and cultivation of drought resistant wheat varieties in the future.The main results are as follows:1.Through the physiological and biochemical analysis of the two varieties under the drought stress,it was found that the stomatal conductance and net photosynthetic rate of Yanzhan 4110 and Jiaomai 266 had the same change trend under the drought stress,which decreased gradually with the extension of stress time.The stomatal conductance and net photosynthetic rate of Yanzhan 4110 were higher than those of Jiaomai 266.From the perspective of membrane ion permeability,the membrane ion permeability of Jiaomai 266 under stress is higher than that of Yanzhan 4110,indicating that Jiaomai 266 has higher membrane oxidation degree and more serious injury degree.The activities of cat and pod in roots increased under drought stress,and in Yanzhan 4110 were significantly higher than Jiaomai 266.2.Through GC-MS analysis of wheat leaf metabolomics,it was found that under drought stress,the contents of organic acids and lipids in the two wheat varieties decreased significantly,and the metabolites of sugars and amino acids were significantly different between the two wheat varieties.In Yanzhan 4110,most of the oligosaccharides,including pine disaccharide,fructose,maltose,l-glucan,gentian disaccharide and 1-bagasse trisaccharide,increased,but in Jiaomai 266,the content did not change significantly.In Yanzhan 4110,the content of most amino acids increased.In Jiaomai 266,only valine and N-carbamoyl L-aspartic acid increased,while other metabolites decreased..3.Through the analysis of the metabolic pathway after stress,we found that there were differences in metabolic pathway between Yanzhan 4110 and Jiaomai 266 under severe drought stress.In order to maintain the function and stability of cell membrane structure,the synthesis of sheath amine alcohol was strengthened.However,Yan Zhan 4110 also enhanced the catabolism of starch and cellulose,transforming macromolecular polysaccharides into oligosaccharides,so as to reduce the osmotic potential of cells.In addition,the metabolism of vitamin B6 and ascorbic acid in Yanzhan 4110 was strengthened,and the antioxidant function was maintained.In contrast,most of the metabolic pathways of Jiaomai 266 decreased and some of the metabolic responses remained unchanged.This indicated that the energy of Yan Zhan 4110 was mainly used for the protection of cytoplasm and functional enzymes during the stress period.During the stress period,the protective function of Jiaomai 266 was poor and the stress damage was serious.