| As one of the natural disasters facing human beings,drought seriously affects the growth and development of crops.Wheat is one of the most important rations for humans.According to statistics,about 35% of the world’s population is mainly wheat,and with the increase in population,the demand for wheat is also increasing.However,China’s wheat is mainly grown in arid and semi-arid regions,and drought stress severely restricts the production of wheat in China.Therefore,it is important to study the drought resistance mechanism of wheat and reveal the metabolic regulation network of wheat during drought stress.To this end,two wheat cultivars with significant differences in drought resistance were selected for this experiment: strong drought-tolerant cultivar(Huanxuan 10,HX10);drought-sensitive cultivar(Zhengyin 1,ZY1),which passed 20%PEG-6000(-0.975MPa)at the seedlings stage was used to simulate drought stress,and the differences of transcriptome,metabolome and morphological physiology among different drought-resistant wheat cultivars were systematically studied after water stress.The main test results are as follows:1.After 12 h of water stress,the appearance of two different drought-resistant wheat showed significant changes.Under normal water supply conditions,the growth and appearance of HX10 and ZY1 seedlings were basically the same,but after 12 hours of stress treatment,ZY1 showed more obvious water stress symptoms than HX10,such as leaves yellowing,water loss and wilting were more serious.Secondly,water stress can reduce the leaves water content and leaves osmotic potential of the plant,which will cause the seedling growth to slow down and the biomass to decrease.Compared with HX10,the decreasing trend of ZY1 is more significant.2.Water stress caused root activity,proline content,malondialdehyde content and relative conductivity of wheat seedlings increased.HX10 root activity and proline content were significantly higher than ZY1,while malondialdehyde content(MDA)and relative conductance rate were lower than ZY1.In addition,after water stress,H2O2,O2-content and cell death rate in HX10 tip and root tip were significantly lower than ZY1.3.The results of RNA sequencing showed that in the de nove transcript data analysis,water stress caused 1378 differential expression genes in HX10(up-regulated 756 and down-regulated 622);1570 differentially expressed genes in ZY1(up-regulated 322,down-regulated 1248).There were 214 differentially expressed genes in the two cultivars,of which 188 showed opposite expression trends(168 were up-regulated in HX10,down-regulated in ZY1;22 were down-regulated in HX10,up-regulated in ZY1).Then in the analysis of the transcript data analysis,HX10 identified a total of 4944 differential expressed genes(up-regulated 1740 and down-regulated 3204).A total of 7862 differential expressed genes were detected in ZY1(up-regulated 6441 and down-regulated 2421).There were 1370 differential expressed genes identified in the two cultivars,of which 1289 differential expressed genes were in opposite expression in two cultivars(412 were up-regulated in HX10,down-regulated in ZY1;877 were down-regulated in HX10,up-regulated in ZY1).4.Liquid chromatography-mass spectrometry(LC-MS)was used to detect the changes in the species and quantity of metabolites in two wheat cultivars before and to water stress.The results showed that the number of secondary identifications was met(MS2,through the database).Under the condition that the theoretical secondary fragment search was identified,539 up-regulated differential ions and 486 down-regulated differential ions were obtained in HX10.In ZY1,281 up-regulated differential ions and 312down-regulated differential ions were detected,respectively.In the negative mode,443 differential metabolites were obtained in HX10(up-regulated 215,down-regulated 228),and 460 differential metabolites were detected in ZY1(up-regulated 253,down-regulated207).In addition,in positive mode,HX1 obtained 361 differential metabolites(up-regulated 163,down-regulated197),and ZY1 obtained 358 metabolites(up-regulated180,down-regulated 177).A total of 152 pathways were detected in HX10,and 165 metabolic pathways in ZY1 responded to water stress,such as flavonoid metabolic pathway,carotenoid synthesis pathway and tryptophan metabolism pathway.Combined with the changes of physiological ecology,cells,genes and metabolites of different drought-resistant wheat cultivaes to water stress,the relationship between differential genes,differential metabolites and drought physiological responses of seedlings were analyzed,and the wheat seedlings under water stress was preliminarily constructed to Metabolic regulatory network.Combined with the changes of phenotype,physiology,cell and transcriptional regulatory genes and target metabolites of different genotypes of wheat seedlings to water stress,the relationship between differentially expressed genes,differential metabolites,seedling morphology and physiology were analyzed in Metabolic regulation network. |
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