Full-length transcriptome revealed the accumulation of polyunsaturated fatty acids in developing seeds of Plukenetia volubilis

Yijun Fu; Kaisen Huo; Xingjie Pei; Chongjun Liang; Xinya Meng; Xiqiang Song; Jia Wang; Jun Niu

doi:10.7717/peerj.13998

Full-length transcriptome revealed the accumulation of polyunsaturated fatty acids in developing seeds of Plukenetia volubilis

PeerJ. 2022 Sep 20:10:e13998. doi: 10.7717/peerj.13998. eCollection 2022.

Authors

Yijun Fu^#¹, Kaisen Huo^#¹, Xingjie Pei¹, Chongjun Liang¹, Xinya Meng¹, Xiqiang Song¹, Jia Wang¹, Jun Niu¹

Affiliation

¹ College of Forestry, Hainan University, Haikou, Hainan, China.

^# Contributed equally.

Abstract

Background: Plukenetia volubilis is cultivated as a valuable oilseed crop, and its mature seeds are rich in polyunsaturated fatty acids (FAs), which are widely used in food and pharmaceutical industries. Recently, next-generation sequencing (NGS) transcriptome studies in P. volubilis indicated that some candidate genes were involved in oil biosynthesis. The NGS were inaccuracies in assembly of some candidate genes, leading to unknown errors in date analyses. However, single molecular real-time (SMRT) sequencing can overcome these assembled errors. Unfortunately, this technique has not been reported in P. volubilis.

Methods: The total oil content of P. volubilis seed (PVS) was determined using Soxhlet extraction system. The FA composition were analyzed by gas chromatography. Combining PacBio SMRT and Illumina technologies, the transcriptome analysis of developing PVS was performed. Functional annotation and differential expression were performed by BLAST software (version 2.2.26) and RSEM software (version 1.2.31), respectively. The lncRNA-targeted transcripts were predicted in developing PVS using LncTar tool.

Results: By Soxhlet extraction system, the oil content of superior plant-type (SPT) was 13.47% higher than that of inferior plant-type (IPT) at mature PVS. The most abundant FAs were C18:2 and C18:3, among which C18:3 content of SPT was 1.11-fold higher than that of IPT. Combined with PacBio and Illumina platform, 68,971 non-redundant genes were obtained, among which 7,823 long non-coding RNAs (lncRNAs) and 7,798 lncRNA-targeted genes were predicted. In developing seed, the expressions of 57 TFs showed a significantly positive correlation with oil contents, including WRI1-like1, LEC1-like1, and MYB44-like. Comparative analysis of expression profiles between SPT and IPT implied that orthologs of FAD3, PDCT, PDAT, and DAGT2 were possibly important for the accumulation of polyunsaturated FAs. Together, these results provide a reference for oil biosynthesis of P. volubilis and genetic improvement of oil plants.

Keywords: Full-length transcriptome; Oil accumulation; Plukenetia volubilis; Polyunsaturated fatty acids; Transcription factors.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Fatty Acids, Unsaturated
Gene Expression Profiling
RNA, Long Noncoding* / metabolism
Seeds / genetics
Transcriptome* / genetics

Substances

RNA, Long Noncoding
Fatty Acids, Unsaturated

Grants and funding

This work was supported by the Hainan University Research Project (KYQD(ZR)-22056 and KYQD(ZR)20055). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.