Study On Transcriptome And Molecular Regulation Of Lipid Metabolism Of Suaeda Salsa

Suaeda salsa(Suaeda salsa L.)seeds have high oil content and abundant unsaturated fatty acids,they have extremely high development and utilization value to be a potential special oil crop.Therefore,they become an important biological resource for exploiting and improving the key genes related to oil synthesis.The regulation mode of their lipid metabolism pathway needs to be comprehensively and deeply studied.This study used wild Suaeda salsa at the saline-alkali experimental site of Heilongjiang Bayi Agricultural University as the research material,the leaves and roots at 6 weeks after emergence and the developmental seeds at 2 weeks after flowering were sampled.Using high-throughput transcriptome sequencing and lipidomic assays,the metabolic regulation of lipids and gene expression in Suaeda salsa were studied at the molecular biological level.The key genes involved in oil synthesis and related lipid metabolism pathways in Suaeda salsa were explored,which provided basis for further study on the regulatory rules and gene function of genes related to oil metabolism in Suaeda salsa,laying a theoretical foundation for the development and utilization of Suaeda salsaa as a special oil crop.Below were key research findings:1.transcriptome analysis of Suaeda salsaIn this study,the Suaeda salsa c DNA library was sequenced using the Illumina Hi Seq4000 high-throughput sequencing platform.A total of 28 Gb Clean Data were obtained from 9samples(leaves,developing seeds and root).The result of sequencing analysis showed that the number of differentially expressed genes was the most among the comparison group of roots Vs developing seeds,but the number of differentially expressed genes was the least among the comparison group of leaves Vs developing seeds.The differentially expressed genes(Log2FC?1.5)in the leaves Vs roots comparison group were annotated,and 1817 genes were annotated in the KEGG pathway,among which the most differentially expressed genes were annotated in the carbon metabolism category;the leaves Vs developing seeds alignment group shared 669 differentially expressed genes which were annotated in the KEGG pathway,where the most differentially expressed genes were annotated in the phytohormones signal transduction category;a total of 881 differentially expressed genes were annotated to KEGG in the comparison group of the roots Vs developing seeds,among the carbon metabolism categories,the most differentially expressed genes were annotated.2.Analysis of differential expression of lipid-related genes in the transcriptome of Suaeda salsaA total of 358 lipid-related differentially expressed genes were screened in the leaves Vs roots group using the obtained Suaeda salsa transcriptome data,the DEGs in this group were mainly enriched in "alpha-linolenic acid metabolism";in the leaves Vs develoing seeds group,the lipid-related differentially expressed genes were 142,the DEGs in this group were mainly enriched in "linoleic acid metabolism";the lipid-related differentially expressed genes screened in the group of the roots Vs developming seeds were identified,A total of 347 DEGs in this group were mainly enriched in the "biosynthesis of keratin,berberine and wax" category.3.Lipidomics analysis of Suaeda salsaIn this study,six major phospholipids,two major galactolipids,and three major lysophospholipids were detected using lipidomics analysis techniques.The proportion of galactolipid MGDG in Suaeda salsa was the highest,followed by phospholipid PC.The molar percentage of DGDG and MGDG in the leaves is higher than in other tissues.The PG in the phospholipids is also the main plastid glyceride,its molar percentage is highest in the developing seeds,and the other main phospholipids all have higher molar percentage in the root.At the same time,the content of lysophospholipids in Suaeda salsa is relatively low,mainly appeared in developing seeds.The contents of galactolipids MGDG and DGDG were highest in36:6 molecular species in Suaeda salsa,indicating that Suaeda salsa is a typical 18:3 plant,and MGDG and DGDG are mainly derived from the endoplasmic reticulum eukaryotic pathway.4.Construction of an interaction network of lipid-related genes and metabolitesIn this study,the transcriptome and lipidomics data were analyzed jointly to constract the network of differentially expressed genes and metabolites,and the main lipid metabolism regulatory network was established.Genes regulating oil synthesis pathways are mainly up-regulated in developing seeds,such as ACCase,KASIII,SAD,and EAR,which were involved in fatty acid synthesis,and GPAT and DGAT which has role in regulating triacylglycerol synthesis;genes that regulate phospholipid metabolism pathways are mainly up-regulated in roots,such as PIS which catalytic reaction to produce PI,LPAAT and PLD involved in PA synthesis,and equimolar percentages of PI,PA,and PS were significantlyincreased in roots;genes involved in galactolipid metabolism were mainly up-regulated in leaves,in leaves the molar percentages of MGDG and DGDG were significantly higher than those of other tissues.