Transcriptome Analysis Of Chelidonium Majus Elaiosomes And Seeds Provide Insights Into Fatty Acid Biosynthesis

Elaiosomes are specialized fleshy and edible seed appendages dispersed by ants.Lipids are the primary components of elaiosomes.Chelidonium majus is a well-known plant,the seeds of which are dispersed by ants.Previous studies have identified the presence of primary fatty acids in its elaiosomes and seeds.However,the molecular mechanisms underlying fatty acid biosynthesis in elaiosomes remain unknown.In order to gain a comprehensive transcriptional profile of the elaiosomes and seeds of C.majus,and understand the expression patterns of genes associated with fatty acid biosynthesis,four different developmental stages,including the flower-bud(Ch01),flowering(Ch02),young seed(Ch03),and mature seed(Ch04)stages,were chosen to perform whole-transcriptome profiling through the RNA-seq technology(Illumina NGS sequencing).(1)A total of63,064 unigenes were generated from 12 libraries.Of these,7,323,258,and 11,540 unigenes were annotated with 25 clusters of orthologous groups(COGs),43 gene ontology(GO)terms,and 373 Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways,respectively.(2)In addition,322 genes were involved in lipid transport and metabolism,and 508 genes were involved in the lipid metabolism pathways,cause in elaiosomes there are almost full of fatty acids.(3)Forty-one significantly differentially expressed genes(DEGs)involved in the lipid metabolism pathways were identified,most of which were upregulated in Ch03 compared to Ch02,indicating that fatty acid biosynthesis primarily occurs during the flowering to the young seed stages.(4)Of the DEGs involved in fatty acid biosynthesis metabolic pathway and biosynthesis of unsaturated fatty acid metabolic pathway,FatA/B,DESA1,SCD,FAD2 and fabG are all significant upregulated.FatA/B,DESA1 and fabG were involved in palmitic acid synthesis;SCD and DESA1 were involved in oleic acid synthesis,and FAD was involved in linoleic acid synthesis,and the three fatty acid are mainly in elaisomes in C.majus.(5)qRT-PCR results of the selected genes ACSL,DESA1,fabG and FatB were generally consistent with the RNA sequencing results,indicating that the RNA-seq results were reliable.