# Transcriptomic Signature of Lipid Production in Australian Aurantiochytrium sp. TC20

## TL;DR

This study identifies key genes and pathways involved in lipid production in the Australian Aurantiochytrium sp. TC20, offering insights into its role in sustainable fatty acid synthesis.

## Contribution

The study provides a novel transcriptomic signature for lipid production in Aurantiochytrium sp. TC20, highlighting specific genes and pathways involved in fatty acid synthesis.

## Key findings

- Differentially expressed genes related to lipid metabolism effectively distinguish late exponential growth phase samples.
- Significant upregulation of PFAB, TLDP, and PGAM-2 was observed during lipid production.
- KEGG analysis showed enrichment in unsaturated fatty acid biosynthesis and carbon metabolism pathways.

## Abstract

Aurantiochytrium not only excels in producing long-chain polyunsaturated fatty acids such as docosahexaenoic acid for humans, but it is also a source of essential fatty acids with minimal impacts on wild fisheries and is vital in the transfer of atmospheric carbon to oceanic carbon sinks and cycles. This study aims to unveil the systems biology of lipid production in the Australian Aurantiochytrium sp. TC20 by comparing the transcriptomic profiles under optimal growth conditions with increased fatty acid production from the early (Day 1) to late exponential growth phase (Day 3). Particular attention was paid to 227 manually annotated genes involved in lipid metabolism, such as FAS (fatty acid synthetase) and subunits of polyunsaturated fatty acids (PUFA) synthase. PCA analysis showed that differentially expressed genes, related to lipid metabolism, efficiently discriminated Day 3 samples from Day 1, highlighting the key robustness of the developed lipid-biosynthesis signature. Highly significant (pFDR < 0.01) upregulation of polyunsaturated fatty acid synthase subunit B (PFAB) involved in fatty acid synthesis, lipid droplet protein (TLDP) involved in TAG-synthesis, and phosphoglycerate mutase (PGAM-2) involved in glycolysis and gluconeogenesis were observed. KEGG enrichment analysis highlighted significant enrichment of the biosynthesis of unsaturated fatty acids (pFDR < 0.01) and carbon metabolism pathways (pFDR < 0.01). This study provides a comprehensive overview of the transcriptional landscape of Australian Aurantiochytrium sp. TC20 in the process of fatty acid production.

The online version contains supplementary material available at 10.1007/s10126-025-10415-2.