| Salt is one of the major abiotic stresses affecting plant growth and development,which can lead to reduced yield and quality of grass crops.(Glycine max)is an annual herb of(Glycine spp.)It has the characteristics of high protein content and high hay yield.It is a high-quality legume forage.At present,researches on fodder soybean mainly focus on agronomic characters,nutritional value,planting methods and other aspects,but there are few researches on the molecular mechanism of its salt tolerance.To study and master the growth morphological changes and physiological adaptation mechanism of fodder soybean when salinity changes,and further explore its internal molecular regulation mechanism,will provide theoretical support for the breeding of new breeds of fodder soybean.In this experiment,through the following three aspects of screening fodder soybean breeds with large differences in salt tolerance and physiological characteristics analysis and transcriptomic analysis of the screened fodder soybean breeds with large differences in resistance,the physiological response mechanism and molecular response mechanism of salt tolerance of fodder soybean were preliminically clarified.1.The germination test of 6 breeds of hayseed was conducted by salt solution of different concentrations(CK,100 m M,150 m M,200 m M).Indexes such as germination potential,germination rate and germination index were determined,related indexes of salt resistance were determined for 6 breeds fodder soybean seedlings(growing to the first three-leaf compound),and salt tolerance evaluation system was established for malondialdehyde,soluble protein,soluble sugar,superoxide dismutase and other indexes.After single factor analysis,comprehensive analysis of membership function and correlation analysis,The salt tolerance of six kinds of fodder soybeans was ranked.2.A salt-tolerant cultivar and a salt-sensitive cultivar with a large difference in salt tolerance in experiment 1 were selected for the determination of physiological indexes related to the antioxidant system,osmotic regulation system and ion transport system.3.Fodder soybean breeds with different salt tolerance in experiment 1 were selected for transcriptomic sequencing and bioinformatics analysis.The main research results are as follows:1.There was a positive correlation between the salt tolerance indexes of fodder soybean at germination stage.The salt tolerance of Haydn bean in descending order were Acheng fodder soybean,Gonghe fodder soybean,Muling fodder soybean,Ningcheng fodder soybean,Gongnong535 fodder soybean and Mudanjiang fodder soybean.2.The activities of peroxidase and superoxide dismutase and soluble sugar content of fodder soybean will increase with the increase of salt solution concentration.When salt stress concentration exceeds a certain peak,the increase of salt solution concentration will reduce the activities of peroxidase and superoxide dismutase and soluble sugar content;Salt stress can increase the contents of soluble protein,proline and catalase activity.Salt stress can increase the content of Na~+in aboveground and underground parts,and decrease the content of K~+in aboveground and underground parts.3.Using transcriptomics technology,a c DNA library was constructed using the salt-tolerant Acheng fodder soybean and salt-sensitive Mudanjiang fodder soybean leaves,which were treated with 200mmol·L-1 Na Cl for 12h.A total of 197,901,516 original sequencing data were obtained.There were 441 differentially expressed genes of 91,238 unigenes,Acheng fodder soybean and Mudanjiang fodder soybean,among which 286 were up-regulated and 155 down-regulated.Through GO enrichment analysis,differentially expressed genes were significantly enriched in post-transcriptional gene silencing and RNA3’terminating processes.KEGG enrichment analysis showed that differentially expressed genes were widely involved in metabolic pathways and secondary metabolite biosynthesis pathways.The analysis of transcription factors showed that the transcription factors involved in adapting hayseed beans to salt stress were SET,AP2/ERF-ERF,m TERF,etc.Swissprot analysis was used to screen out differentially expressed genes related to ion transport system such as Na~+/H~+reverse transporter,K~+channel protein and K~+/H~+reverse transporter,and to screen out differentially expressed genes related to glutathione peroxidase pathway,ascorbate peroxidase pathway and catalase pathway. |
