Transcriptome sequencing and identification of key genes in the oil content accumulation and unsaturated fatty acid biosynthesis pathway of Hibiseu manihot seeds

Abstract

Abstract Background Hibiseu manihot of various tissues has a high application value, accumulating more than 65% of unsaturated fatty acids in the seeds as well as high levels of oleic acid. Performing transcriptome analysis is beneficial to reveal the molecular mechanism of fatty acid biosynthesis during the development of Hibiseu manihot seeds.Results Transcriptome analysis was performed using seeds of Hibiseu manihot at 5, 15 and 30 days after flowering. There were 3338 (1320down, 2018up), 6657 (3408down, 3249up), 3851 (2001down, 1850up) differentially expressed genes in 5 DAF vs 15 DAF, 5 DAF vs 30 DAF, 15 DAF vs 30 DAF. GO functional analysis showed that differentially expressed genes were mainly involved in three functional categories bioengineering, molecular function and cellular component. KEGG enrichment analysis showed that the differentially expressed genes were mainly involved in environmental information processes, genetic information processing, metabolism and other metabolic pathways. Nine genes related to fatty acid biosynthesis and oleic acid metabolic pathways were validated by qRT-PCR, and the results showed that the qRT-PCR were consistent with the transcriptome sequencing results. The analysis of fatty acid content in Hibiseu manihot seeds at different stages showed that oleic acid increased and then decreased with seed development, at the same time, linoleic acid decreased first and then increased. and stearic acid content was more stable. It was hypothesized that KASII, SAD, FATA, PDAT and FAD2 might be closely related to the high content of oleic acid in Hibiseu manihot seeds, which laid a molecular foundation for further study on the functions of KASII, SAD, FATA, PDAT and FAD2.Conclusions This study has important significance and reference value for regulating the lipid metabolism pathway of Hibiseu manihot and mining the key genes involved in the lipid synthesis and accumulation of Hibiseu manihot.