Integrated lipidomic and transcriptomic analysis reveals diacylglycerol accumulation in olive of Longnan (China)

PeerJ. 2023 Aug 11:11:e15724. doi: 10.7717/peerj.15724. eCollection 2023.

Abstract

Background: Olive (Olea europaea L.) oil accumulate more diacylglycerols (DAG) than mostly vegetable oils. Unsaturated fatty acids-enriched DAG consumption enhanced wellness in subjects. However, the mechanism of DAG accumulation is not yet fully understood.

Methods: In this study, gene network of DAG accumulation and fatty acid composition in the two olive mesocarps ("Chenggu 32" (CG) and "Koroneiki" (QJ)) were investigated by integrating lipidome and transcriptome techniques.

Results: A total of 1,408 lipid molecules were identified by lipidomic analysis in olive mesocarp, of which DAG (DAG36:3, DAG36:4 and DAG36:5) showed higher content, and triacylglycerols (TAG54:3, TAG54:4) exhibited opposite trend in CG. Specifically, DAG was rich in polyunsaturated fatty acids (especially C18:2) at the sn-2 position, which was inconsistent with TAG at the same positions (Primarily C18:1). Transcriptomic analysis revealed that phospholipase C (NPC, EC 3.1.4.3) were up-regulated relative to QJ, whereas diacylglycerol kinase (ATP) (DGK, EC 2.7.1.107), diacylglycerol acyltransferase (DGAT, EC 2.3.1.20), and phospholipid: diacylglycerol acyltransferase (PDAT, EC 2.3.1.158) were down-regulated.

Conclusion: We speculated that the non-acyl coenzyme A pathway played a significant role in DAG biosynthesis. Additionally, fatty acyl-ACP thioesterase B (FATB, EC 3.1.2.14), stearoyl [acyl-carrier-protein] 9-desaturase (SAD, EC 1.14.19.2) and omega-6 fatty acid desaturase (FAD2, EC 1.14.19.6) were highly expressed in CG and may be involved in regulating fatty acid composition. Meanwhile, phospholipase A1 (LCAT, EC 3.1.1.32) involved in the acyl editing reaction facilitated PUFA linkage at the sn-2 position of DAG. Our findings provide novel insights to increase the DAG content, improve the fatty acid composition of olive oil, and identify candidate genes for the production of DAG-rich oils.

Keywords: Diacylglycerols accumulation; Gene expression; Lipidomics; Transcriptomics; Virgin olive oil.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diacylglycerol O-Acyltransferase / genetics
  • Diglycerides / metabolism
  • Fatty Acids
  • Fatty Acids, Unsaturated
  • Humans
  • Lipidomics
  • Olea* / genetics
  • Transcriptome / genetics

Substances

  • Diacylglycerol O-Acyltransferase
  • Diglycerides
  • Fatty Acids
  • Fatty Acids, Unsaturated

Grants and funding

This research was financially supported by the Basic Research Innovation Group Program Project of Gansu Province (1506RJIA116) and the Major Research Projects Incubation Programme of Northwest Normal University in 2022 (NWNU-LKZD2022-02). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.