| According to the survey,there are about 40 million hectares of saline soil in China,accounting for a quarter of the total area of cultivated land in China.The continuous expansion of the area of saline soil has caused great challenges to China’s agricultural development.Therefore,breeding and screening wheat varieties(lines)with strong salt tolerance is of great practical significance in making full use of saline land and solving current food problems.In this study experiment,141 synthetic artificial hexaploid wheat were used as materials to cultivate wheat seedlings by using the hydroponic method,and water was used as a control.Four salt stress treatments for different salt concentrations to control the salt concentration(Na Cl: 0,100mmol/L,150mmol/L,200mmol/L)were carried out under salt stress treatment.One is to obtain the materials with strong salt tolerance by evaluating,To determine the phenotypic and physiological indexes of wheat germination stage and seedling stage,to comprehensively evaluate the salt tolerance of the experimental materials,to select the wheat varieties with strong salt tolerance,the other is to predict and mine the new salt-tolerance genes by transcriptome analysis under and to carry out the seedling root system after 200mmol/L Na Cl salt stress.Transcriptome analysis provides a theoretical reference to the mining of wheat salt-tolerance genes and the breeding of varieties.The main results were as follows:1.Through the determination of phenotypic and physiological indexes at the malt stage and seedling stage,it was found that the dry weight,fresh weight,and root shoot ratio of dry weight were greatly affected when wheat was under salt stress,and the response to salt stress was also very sensitive.Principal component analysis(PCA)divided 15 indexes into 5comprehensive indexes,among which 13 indexes had higher proportion,including germination rate,seedling height,coleoptile length,root length,underground fresh weight,dry weight root shoot ratio,fresh weight root shoot ratio,above-ground dry weight,above-ground fresh weight,above groundwater content,soluble sugar,underground dry weight,malondialdehyde and so on indicators of sex screening.2.The comprehensive value of the membership function(D value)of each wheat variety was systematically clustered,and 17 highly salt-tolerant varieties were found selected,accounting for 12.06% of the tested materials;61 salt-tolerant varieties were identified with,accounting for 43.26%;48 were moderately salt-tolerant varieties,accounting for 34.04% of the tested materials;15 were salt-sensitive varieties,accounting for 10.64% of the tested materials.3.Through high-throughput sequence(RNA-Seq),a total of 1009677180 totals reads were obtained;GO functional classification accounted for the higher molecular function,catalytic activity,transferase activity,and biofilm.KEGG enrichment analysis found that the number of genes enriched in the Phenylpropane biosynthesis pathway was significantly higher than that of other pathways,and the degree of enrichment was the most significant.The other pathway included The effects of the pigment P450 and cytochrome P450 on the metabolism of foreign substances,MAPK signaling pathways-plant,and plant hormone signal transduction.It can be seen that the response of plants to salt stress wais,not a simple process.When plants are exposed to salt stress,they will mobilize multiple pathways to deal with salt stress.Among the 16 pathways related to salt tolerance,150 differential genes were found selected to be expressed only in the salt-tolerant variety GJP 18,and were expressed at all periods after salt stress.of which,and on this basis,10 candidate genes for salt tolerance were selected for subsequent research. |
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