Transcriptome Analysis of Acer truncatum Seeds Reveals Candidate Genes Related to Oil Biosynthesis and Fatty Acid Metabolism

Abstract

Acer truncatum seeds are an excellent source of beneficial natural compounds, including high levels of unsaturated fatty acids (UFAs), that promote health. Recently, A. truncatum has emerged as an oil crop. Therefore, the transcriptomes of A. truncatum seeds at 70, 85, 100, 115, 145, 180 days after flowering (DAF) were analyzed to gain a better understanding of the transcriptional and translational regulation of seed development and oil biosynthesis. A total of 28,438 genes were identified, and 3069/2636, 3288/3438, 1319/2750, and 5724/5815 upregulated/downregulated genes were identified when comparing different samples with 85 DAF seeds. Sixteen lipid metabolism pathways with 754 differentially expressed genes (DEGs) were identified, including 34 DEGs associated with UFA biosynthesis. A phylogenetic analysis revealed that six putative fatty acid desaturase (FAD) genes clustered into five FAD groups. A quantitative real-time polymerase chain reaction analysis indicated that the temporal expression patterns of oil biosynthesis genes and transcription factors were largely similar to the RNA sequencing results. The results of this study will enhance the current understanding of oil metabolism in A. truncatum seeds and allow new methods of improving oil quality and seed yield in the future.

Ribosome footprint profiling enables elucidating the systemic regulation of fatty acid accumulation in Acer truncatum

“…In a previous study, we found that the oil proportions rapidly increased from 85 to 115 DAF, while the content variation of the components from 115 to 180 DAF was not significant [ 5 ]. in this study, the electron microscopy images of oil bodies were also conducted in seed cells at 85 and 115 DAF, the results showed that no lipid bodies were found at 85 DAF, and the lipid bodies filled the endosperm cells in 115 DAF (Fig.…”

“…5 B). In plants, FA production involves the de novo synthesis and elongation of FAs in plastids and the desaturation of FAs and TAG assembly in the endoplasmic reticulum [ 5 , 31 , 32 ]. However, there have been relatively few studies that examined FA synthesis based on a multi-omics approach (i.e., transcriptomic, translatomic, and proteomic).…”

“…The C18:1 and C18:2 FAs accounted for the largest proportion of the FAs in A. truncatum seeds. Previous studies demonstrated that the accumulation of C18:1 and C18:2 FAs is correlated with the expression of FAD2 and FAD3 , respectively [ 5 , 33 ]. In addition, FAD2 ( Atru.chr3.2406 ) and FAD3 ( Atru.chr3.4197 ) were more highly expressed in the seeds at 115 DAF than at 85 DAF.…”

“…In 2011, seed oil was approved as a New Resource Food by the National Health and Family Planning Commission of the People’s Republic of China, with important implications for various industries (e.g., food and medicine). Acer truncatum seed oil is composed mainly of triacylglycerols (TAGs), with approximately 90% unsaturated fatty acids, including oleic acid (C18:1), linoleic acid (C18:2), α-linolenic acid (C18:3), and nervonic acid (C24:1) [ 3 – 5 ]. The proportions of oleic acid and linoleic acid are higher than those in peanut ( Arachis hypogaea ), sunflower ( Helianthus annuus ), and rapeseed ( Brassica napus ) oils [ 6 ].…”

“…In plants, the general lipid biosynthesis pathway includes the following four steps: de novo FA synthesis in plastids, acyl elongation and editing, TAG assembly in the endoplasmic reticulum, and oil drop formation [ 9 , 12 ]. Some studies demonstrated that ACCase and 3-ketoacyl CoA synthetase (KCS) are the key rate-determining enzymes controlling the synthesis of FAs and very long-chain monounsaturated fatty acids (VLCFAs), respectively [ 5 , 13 ]. Triacylglycerols are stored in oil bodies surrounded by a lipid monolayer.…”