Transcriptomic Analysis Reveals Key Genes Involved in Oil and Linoleic Acid Biosynthesis during Artemisia sphaerocephala Seed Development

Abstract

Artemisia sphaerocephala seeds are rich in polysaccharides and linoleic acid (C18:2), which have been widely used as traditional medicine and to improve food quality. The accumulation patterns and molecular regulatory mechanisms of polysaccharides during A. sphaerocephala seed development have been studied. However, the related research on seed oil and C18:2 remain unclear. For this study, A. sphaerocephala seeds at seven different development stages at 10, 20, 30, 40, 50, 60, and 70 days after flowering (designated as S1~S7), respectively, were employed as experimental samples, the accumulation patterns of oil and fatty acids (FA) and the underlying molecular regulatory mechanisms were analyzed. The results revealed that oil content increased from 10.1% to 20.0% in the early stages of seed development (S1~S2), and up to 32.0% in mature seeds, of which C18:2 accounted for 80.6% of the total FA. FA and triacylglycerol biosynthesis-related genes jointly involved in the rapid accumulation of oil in S1~S2. Weighted gene co-expression network analysis showed that transcription factors FUS3 and bHLH played a critical role in the seed oil biosynthesis. The perfect harmonization of the high expression of FAD2 with the extremely low expression of FAD3 regulated the accumulation of C18:2. This study uncovered the gene involved in oil biosynthesis and molecular regulatory mechanisms of high C18:2 accumulation in A. sphaerocephala seeds; thus, advancing research into unsaturated fatty acid metabolism in plants while generating valuable genetic resources for optimal C18:2 breeding.

Transcriptomic and Metabolomic Analysis Unravels the Molecular Regulatory Mechanism of Fatty Acid Biosynthesis in Styrax tonkinensis Seeds under Methyl Jasmonate Treatment

“…Further analysis showed that Fusca 3 ( FUS3 ) and a basic helix–loop–helix ( bHLH ) in MEblack were co-expressed with biotin carboxyl carrier protein ( BCCP ), 3-hydroxyacyl-ACP dehydratase ( HAD ), EAR and FATB as well as other genes that regulate FA biosynthesis. As such, FUS3 and bHLH were found to be the core genes in the FA accumulation of A. sphaerocephala seeds [ 5 ]. In our experiment, eight modules were obtained through WGCNA, among which the bZIP gene in the MEturquoise module was identified as one of the core genes that is involved in the regulation of FA biosynthesis.…”

“…Then, Mal-CoA:ACP S-malonyltransferase (MAT), the principal substrate for the subsequent elongation, transfers Mal-CoA to the malonyl group. Next, the carbon chain is extended by the FA synthases system through condensation, reduction and dehydration [ 5 ]. FAs have practical values in chemical and pharmaceutical industries and could be utilized as crucial raw materials for food processing [ 6 , 7 ].…”

24-Epibrassinolide Promotes Fatty Acid Accumulation and the Expression of Related Genes in Styrax tonkinensis Seeds

“…Then, malonyl-CoA:ACP S-malonyltransferase (MAT), the principal substrate for the subsequent elongation, transferred malonyl-CoA to the malonyl group. Next, KAR, EAR, 3-hydroxyacyl-ACP dehydratase (HAD), and 3-ketoacyl-ACP synthase I (KASI) resulted in carbon chain extension [ 30 ]. During this process, FAS could add two additional carbon units to malonyl-ACP to produce either 16:0-ACP or 18:0-ACP after six of seven cycles, respectively [ 18 , 31 ].…”

“…The positive correlation between FAD2 and C18:2 was confirmed in our experiment. Additionally, the high expression of FAD2 led to more C18:2 accumulation in Artemisia sphaerocephala and Gossypium hirsutum seeds [ 30 , 41 ]. ACCase in plants included heterogeneous and homogenous forms, and heterogeneous ACCase was an indispensable speed-limiting enzyme in FA biosynthesis, consisting of four subunits: BC, BCCP, α-CT, and β-CT [ 42 , 43 ].…”

“…As described in Figure 11 , MYB (213), C2H2 (141), AP2/ERF (130), bHLH (108), GRAS (106), bZIP (99), C2C2 (94), and WRKY (75) dominated in the FA biosynthesis of S. tonkinensis seeds. Thus, the basilic TFs regulating oil biosynthesis varied by species [ 30 ]. bZIP could bind to the FAD3 promoter and activate its expression to synthesize α-linolenic polyunsaturated FAs in A. thaliana seeds [ 47 ].…”