| Rapeseed is one of the three major oil crops in China.During its growth,it often suffers from abiotic stresses such as drought,high temperature,and salt damage,among which salt damage is the most serious.The germination period is a period when rape is very sensitive to salt stress.Therefore,it is of great significance to carry out genetic research on salt tolerance of rape during germination.In this study,two Brassica napus varieties Huayouza 62(H62)and Zhongshuang 11(ZS11)with different salt tolerances were selected as the test materials.Experiments of setting different salinity in the germination period.The main results of transcriptome and metabonomic analysis are as follows.(1)Transcriptome data analysis results.According to the transcriptome analysis of Huayouza 62 and Zhongshuang11,there are 1379 genes with high expression in H62,1737 genes with low expression in H62,1233 genes with high expression in ZS11 and 1833 genes with low expression in ZS11.Through gene ontology(GO)and KEGG functional enrichment analysis of the above differential genes,it was found that the low-expression genes in H62 were mainly enriched in related metabolic pathways such as plant hormone signal transduction,phenylpropane biosynthesis and plant MAPK signaling pathways,and high expression Genes are significantly enriched in biosynthesis-related metabolic pathways such as amino sugar and nucleotide sugar metabolism,amino acid biosynthesis and cutin;genes with low expression in ZS11 are significantly enriched in metabolic pathways related to phenylpropane biosynthesis and plant signal transduction,Highly expressed genes are significantly enriched in metabolic pathways related to starch and sucrose metabolism and amino acid biosynthesis.Combined with the expression analysis,103 candidate genes related to salt tolerance were screened out.(2)Metabolic data analysis results.There are 97 different metabolites(VIP ? 2)in variety H62,71 of which decrease,26 increase.Compared with the control,the content of citric acid and isocitrate in Huayouza 62 under salt stress increased significantly.There are 91 kinds of different metabolites(VIP ? 2.5)in ZS11,among which 55 kinds of different metabolites such as coumarin acetate,N-acetyl-L-aspartic acid,betaine aldehyde show a downward trend,36 kinds of different metabolites such as ferulic acid,ADP mannose,N-formyl-L-aspartic acid show an upward trend.By analyzing the different metabolites(VIP ? 2)between each salt concentration of the two varieties and the control,it was found that the contents of glucose,fructose,maltose,mannose,galactose,inositol and other sugars and inositol metabolites increased at 150 m M and 200 mMNaCl concentrations.These results suggest that Huayouza 62 may be able to adapt to salt stress by promoting TCA cycle to produce more ATP,while Zhongshuang11 may be able to adapt to salt stress by accumulating carbohydrate and inositol metabolites.(3)Analysis and verification of salt tolerant candidate genes.Based on the results of transcriptome analysis,six differentially expressed genes were randomly selected and validated by q RT-PCR.The results were consistent with RNA-seq,indicating the credibility of RNA-seq data.Among the 103 candidate genes discovered by transcriptome,26 gene expression vectors were constructed and transformed into rape and Arabidopsis,96 positive plantlets were obtained from Bn LTP3 gene.The results showed that the expression of Bn LTP3 was the highest in the transgenic plants treated with 200 mMNa Cl,and was significantly higher in the 150 m M salt concentration than in the non transgenic plants.Based on transcriptome and metabonomics,some differentially expressed genes related to metabolites such as citric acid,ferulic acid and myristic acid were found. |
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