| Oats are used as both food and feed.They have rich nutritional value and can adapt to various harsh growth environments.It is a dominant crop in Inner Mongolia.It is mostly planted in arid and saline soils and plays an important role in agricultural production practices and sustainable development.However,the current research on drought resistance and salt tolerance of oats mainly focuses on stress resistance screening,growth and physiological and biochemical indicators.However,the molecular mechanism of oats response to drought and salt stress has not been clearly reported,and further research is necessary.Based on the research on the physiological mechanism of stress resistance in oats in the early stage of the research group,this thesis selects drought-resistant and sensitive varieties to compare and analyze the differentially expressed genes and proteins of oat roots after drought stress,and screen through multi-omics association analysis and network interaction mapping.Identify the key cor-DEGs-DEPs;in addition,select salt-tolerant and salt-sensitive varieties,compare and analyze the differentially expressed genes in oat roots after salt stress,screen differential metabolites,and perform functional enrichment and metabolic pathway analysis on them.Horizontal analysis of the response of oats to different degrees of salt stress,after the joint analysis of the two levels,the results of different levels are mapped to the KEGG database to obtain its integrated pathway graphics to screen and identify oats salt tolerance genes to explore key metabolic pathways.The q RT-PCR technology was used to verify the key differentially expressed genes,and to dig out related genes involved in the regulation of oats drought resistance and salt tolerance,provide a theoretical basis for revealing the mechanism of oat response to drought and salt stress,and for the selection of drought-resistant and salt-tolerant oat germplasm resources and Lay the foundation for high-yield cultivation technology research.The main findings are as follows:(1)Transcriptomics analysis of oats in response to drought stressDrought-resistant variety JIA2 detected 1086 up-regulated genes and 2919down-regulated genes under moderate drought stress,1792 up-regulated genes and 4729down-regulated genes were detected under severe drought stress;drought-sensitive variety Bayou 9 under moderate drought stress 395 up-regulated genes and 669 down-regulated genes were detected,and 886 up-regulated genes and 439 down-regulated genes were detected under severe drought stress.Drought-resistant cultivar JIA2 under moderate and severe drought stress specifically expresses most of the differentially expressed genes down-regulated,mainly involved in redox reaction,carbohydrate metabolism,plant growth hormone signal regulation and secondary metabolism and other functions.(2)Proteomics analysis of oats in response to drought stressUnder moderate drought stress,the drought-resistant variety JIA2 had 489up-regulated and 394 down-regulated differentially expressed proteins.Under severe drought stress,there were 493 up-regulated and 701 down-regulated differentially expressed proteins;under moderate drought stress,BA9 had 590 differentially expressed proteins.Up-regulated and 397 down-regulated differentially expressed proteins,and under severe drought stress,126 up-regulated and 75 down-regulated differentially expressed proteins.Under drought stress,a total of 314 specifically expressed differential proteins were detected in the drought-resistant variety JIA2,and the number of up-regulated and down-regulated expressed proteins was similar,mainly involving ribosome structure,protein binding,redox process,metabolic process,membrane components,catalytic activity,Carbohydrate metabolism process and so on.(3)Association analysis of transcriptomics and proteomics reveals the drought resistance mechanism of oatsTranscriptomics and proteomics correlation analysis results showed that the drought-resistant variety JIA2 under severe drought stress and normal water supply treatments detected four types of interacting differentially expressed proteins in the differential gene protein interaction network analysis of the drought-resistant variety JIA2.These four types of proteins mainly involve plant hormones.Signal transduction,biosynthesis of secondary metabolites,carbohydrate metabolism process and metabolic pathways.The q RT-PCR technology was used to verify the 13 key cor-DEGs-DEPs screened and identified from the 4 key pathways.The expression trend of these genes is the same as the expression trend of their corresponding proteins,indicating that these 13 key cor-DEGs-DEPs play a key role in the strong drought resistance of JIA2.(4)Transcriptomics analysis of oats in response to salt stressBY2 detected 3915 and up-regulated genes and 13,492 down-regulated genes under moderate salt stress,and 16076 up-regulated genes and 23707 and down-regulated genes under severe salt stress.In BY5,4898 up-regulated genes and 3414 down-regulated genes were detected under moderate salt stress,and 34040 up-regulated genes and 14757down-regulated genes were detected under severe salt stress.Most of the differentially expressed genes of BY2 in salt-tolerant varieties under salt stress are up-regulated,mainly involving peroxidase,phenylalanine ammonia lyase,ABC transport,heat shock protein,?-amylase,glutamate decarboxylase,etc..(5)Metabonomics analysis of oats in response to salt stressA total of 201 metabolites were identified.In BY2 under moderate salt stress,34differential metabolites were significantly up-regulated,5 were significantly down-regulated,18 metabolites were significantly up-regulated,and 9 were significantly down-regulated under severe salt stress;Baiyan Under No.5 moderate salt stress,35different metabolites were significantly up-regulated,5 were significantly down-regulated,21 metabolites were significantly up-regulated,and 14 were down-regulated under severe salt stress.The response of BY2 varieties to Na Cl resulted in the increase of a large number of metabolites.Under salt stress,especially BY5 in 300 m M Na Cl,the content of sugars,amino acids and polyols was inhibited.(6)Association analysis of transcriptomics and metabolomics reveals the salt tolerance mechanism of oatsUnder salt stress,the Na~+/K~+transporter gene expression difference between BY2 and BY5.BY2 has a lower Na~+concentration,while the K~+concentration is higher than BY5.The higher salt tolerance in BY2 is mainly low Na~+and elevated K~+levels.Under salt stress conditions,the differentially expressed genes and metabolites of BY2 and BY5 are mainly enriched in metabolic pathways such as starch and sucrose metabolism,galactose metabolism and glycolysis/gluconeogenesis.Under salt stress,BY2 and important genes related to starch and sucrose metabolism are up-regulated,which leads to the increase of sucrose and trehalose levels in BY2 under salt stress,which provides sufficient energy for plants.Differentially expressed genes related to galactose metabolism were up-regulated in BY2 and down-regulated in BY5.In 300 m M Na Cl,the up-regulated expression of genes in BY2 reflects that glycolysis is activated,while under salt stress,most genes in the glycolytic pathway of BY5 are down-regulated.The q RT-PCR technology was used to verify the 12 key differentially expressed genes screened and identified from the 3 key pathways,laying a theoretical foundation for further verification of oat salt tolerance genes.The above results preliminarily revealed the differences in response to salt stress and drought stress and molecular regulation mechanisms of oats with different tolerances,and screened and identified some candidate genes for drought resistance and salt tolerance,which will be used for future breeding of drought-resistant,salt-tolerant oat germplasm resources and high yield.Cultivation technology research has laid a theoretical foundation. |
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