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Transcriptomic and lipidomic analysis of the differential pathway contribution for the incorporation of erucic acid to triacylglycerol during pennycress seed maturation

ABSTRACT: Thlaspi arvense (Pennycress) is an emerging feedstock for biofuel production because of its high seed oil content enriched in erucic acid. A transcriptomic and a lipidomic study were performed to analyze the dynamics of gene expression, glycerolipid content and acyl-group distribution during seed maturation. Genes involved in fatty acid biosynthesis were expressed at the early stages of seed maturation. Genes encoding enzymes of the Kennedy pathway like TaDGAT1, TaLPAT or TaGPAT increased their expression with maturation, coinciding with the increase in TAG species containing 22:1. Positional analysis showed that the most abundant TAG species contained 18:2 at sn-2 position in all maturation stages, suggesting no specificity of the TaLPAT for VLCFAs. TaDGAT2 mRNA was more abundant at the initial maturation stages, coincident with the rapid incorporation of 22:1 to TAG, suggesting a coordination between DGAT enzymes for TAG biosynthesis. Genes encoding TaPDAT1, TaLPCAT or TaPDCT, involved in acyl-editing or PC-derived DAG/TAG biosynthesis showed also higher expression at the early maturation stages, coinciding with a higher proportion of TAG species containing C18 fatty acids. These results suggested a higher contribution of these two pathways at the early stages of seed maturation. LC-MS analysis of the content and acyl-group distribution of DAG and PC pools was compatible with the acyl content in TAG at the different maturation stages. Our data point to a model in which a strong temporal coordination between pathways and isoforms in each pathway, both at the expression and acyl-group incorporation, contributes to high erucic TAG accumulation in Pennycress.

ORGANISM(S): Thlaspi arvense

PROVIDER: GSE256460 | GEO | 2024/04/25

REPOSITORIES: GEO

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Project description:Jatropha curcas, a tropical shrub, is an attractive biofuel crop, which produces seeds with a high content of oil and protein. Most J. curcas accessions contain a range of toxins and anti-nutritional compounds, which are unfavorable for human consumption and animal feed. With the goal of better understanding the development of its seeds and to improve Jatropha`s agronomic performance, a two-step approach was performed: 1) generation of the entire transcriptome of six different developmental stages of J. curcas seeds using 454-Roche sequencing of a cDNA library, 2) comparison of transcriptional expression levels in six different developmental stages of seeds using a custom Agilent 8x60K oligonucleotide gene expression microarray. A total of 793,875 high quality reads with an average length of 358 bp were generated and assembled into 19,841 unique full-length contigs, of which 13,705 could be annotated with GO terms. Microarray data analysis identified a total of 9,111 contigs which were differentially expressed between the six developmental stages (based on P-value of < 1e-8). The microarray-based differential expression results were validated for 192 putative genes using high-throughput quantitative real-time PCR. Results from Gene Ontology (GO) and pathway enrichment analysis showed that the upstream biosynthesis pathways were relatively active among differentially expressed sequences (DESs) during seed development, such as starch and sucrose metabolism, glycolysis/gluconeogenesis, glycerophospholipid metabolism, amino sugar and nucleotide sugar metabolism. Further, DESs related to hormone and seed development, flavonoid biosynthesis-related pathways were over-represented. A pairwise comparison was used to discover particular seed maturation dependent patterns of gene expression. Genes related to fatty acid biosynthesis were over represented in early stage, while flavonoid biosynthesis in the late stage. The data provide a useful resources and references for the seed transcriptome of J. curcas and other related species with oil producing seeds. The identified transcripts related to seed development provide a starting point for further investigation into the molecular mechanisms underlying this process.

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Transcriptomic and lipidomic analysis of the differential pathway contribution for the incorporation of erucic acid to triacylglycerol during pennycress seed maturation

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