Abscisic Acid Improves Linoleic Acid Accumulation Possibly by Promoting Expression of EgFAD2 and Other Fatty Acid Biosynthesis Genes in Oil Palm Mesocarp

Abstract

Abscisic acid plays an important role in fruit development. However, the effect of ABA on fatty acid biosynthesis in oil palm is still unknown. In this study, ABA treatments (CK, A1–A4) were applied to oil palm fruit at 16 WAP (weeks after pollination), and fatty acids in the mesocarp at 24 WAP were analyzed by GC-MS. Results showed that linoleic acid content under treatment A2 (20 μM ABA) was significantly higher (slightly increased by 8.33%) than the control. Therefore, mesocarp samples of A2, and the control at 16, 20, and 24 WAP was sampled for RNA-Seq. KEGG pathway enrichment analysis showed that 43 genes were differentially expressed in the fatty acid biosynthesis pathway, of which expression of EgFAD2 (unigene 105050201) under 20 μM ABA treatment was 1.84-fold higher than in the control at 20 WAP. Further sequence analysis found that unigene 105050201 had more ABA-responsive elements (ABRE), complete conserved domains, and a C-terminal signaling motif among two FAD2 copies. Furthermore, WGCNA and correlation analysis showed co-expression of EgFAD2 (unigene 105050201) with transcription factors (TFs) (WRI1, AP2-EREBP, bZIP, bHLH, C2C2-Dof, MYB, NAC, and WRKY), ABA signaling genes (PYR, PP2C, SnRK, and ABI5), and other genes involved in fatty acid biosynthesis (FATA, FATB, LACS, SAD, Oleosins, and so on). These results indicated that ABA treatment promoted the expression of FAD2 and other genes involved in fatty acid biosynthesis, which possibly resulted in the accumulation of linoleic acid. This study will be helpful for understanding the possible mechanisms through which ABA affects fatty acid biosynthesis and their accumulation in the mesocarp of oil palm.

Comparative transcriptomic and lipidomic analysis of fatty acid accumulation in threeCamellia oleiferavarieties during maturation

“…Studies have shown that spraying exogenous ABA on C. oleifera leaves under shortages of water significantly promotes the activity of genes such as accA , accB , FAD6 , FAD7 , and FAD8 in the leaves (Yang et al, 2024). According to another study, the application of external ABA promoted the transcription of FAD2 within oil palm fruit, which resulted in the accumulation of linoleic acid (Shi et al, 2021). This suggests the involvement of ABA in FA synthesis, with SNRK and PP2C as key elements in ABA signaling.…”

Combined transcriptome and metabolome analysis of sugar and fatty acid of aromatic coconut and non-aromatic coconut in China

“…The genes FatI and FatB are key regulators engaged in the synthesis and accretion of medium-chain fatty acids (C8 to C14) in coconut meat. Their role is crucial in this process ( Shi et al, 2021 ). The expression of CpuFatI and CvFatB1 genes led to the production of capric acid (10:0) in Camelina oil, whereas the expression of CpuFatB4 gene ensued the production of myristic acid (14:0) and increased levels of palmitic acid (16:0) ( Kim et al, 2015 ).…”

Targeted and untargeted metabolomics reveals deep analysis of drought stress responses in needles and roots of Pinus taeda seedlings

“…Previous studies supported our results ( Gu et al., 2020 ). As mentioned above, in needles of WS pine seedlings, ABA levels significantly increased ( Figure 4A ) and (±)-ABA was in positive relation to MAG (18:3) ( Figure S5B and WS_L.vs.WW_L_neg_corr in Table S6 ), suggesting that ABA accumulation might improve unsaturated lipid biosynthesis in WS pine needles and sustain membrane stability and flexibility under drought stress, because ABA improves biosynthesis of some fatty acids in plants ( Norlina et al., 2020 ; Shi et al., 2021 ).…”