Transcriptomics and Metabolomics Analyses Provide Novel Insights into Glucose-Induced Trophic Transition of the Marine Diatom Nitzschia laevis

Abstract

Diatoms have important ecological roles and are natural sources of bioactive compounds. Nitzschia laevis is a member of marine diatoms that accumulates high-value products including fucoxanthin and eicosapentaenoic acid (EPA). In this study, physiological data showed that comparing to autotrophic growth, mixotrophic cultivation with glucose supplementation led to a decrease of chlorophyll and fucoxanthin content in N. laevis, and an increase of biomass density and EPA yield. To further examine the metabolic barriers for fucoxanthin and EPA biosynthesis, comparative transcriptomic and metabolome analyses were conducted, with a focus on the genes related to carotenoids biosynthesis and fatty acid metabolism. The results indicated that phytoene desaturase (PDS) and zeta-carotene isomerase (ZISO) could be the rate-limiting enzymes in carotenoid biosynthesis. The transcription regulation of 3-ketoacyl-CoA synthase (KCS) and elongation of very long chain fatty acids protein (EVOVL) are important contributors associated with polyunsaturated fatty acids (PUFAs) accumulation. Furthermore, we also investigated the glucose-associated regulatory genes using weighted gene co-expression network analysis, and identified potential hub genes linked with cell cycle, carbohydrate metabolism, purine biosynthesis, and lipid metabolism. This study offers a high-quality transcriptome resource for N. laevis and provides a molecular framework for further metabolic engineering studies on fucoxanthin and EPA production.

Transcriptome and Metabonomics Analysis Revealed the Molecular Mechanism of Differential Metabolite Production of Dendrobium nobile Under Different Epiphytic Patterns

“…In recent years, with the development of science and technology, transcriptome sequencing technology (RNA-Seq) ( Liu H. et al, 2021 ) and other high-throughput sequencing technologies are more widely used, mainly for functional gene mining ( Shovlin and Tropea, 2018 ), gene network analysis ( Pratapa et al, 2020 ), genetic mechanism analysis ( Xu et al, 2020 ), and so on. The combination of transcriptome and metabolome analysis can more comprehensively analyze the regulatory mechanism of secondary metabolite biosynthesis ( Mao et al, 2021 ). At present, the transcriptome of D. nobile has been studied, but there is no study on the determination of secondary metabolites and genetic mechanism of D. nobile under different epiphytic patterns ( Li et al, 2017 ; Wen et al, 2017 ).…”

Towards the usage of Phaeodactylum tricornutum as biofactory for omega-3 fatty acids

“…Several studies have focused on these strain, showing high EPA yields under heterotrophic conditions (Wen and Chen 2000;Wen and Chen 2001). In a recent study, researchers present insights into glucose-induced trophic transition, analyzing N. leavis on transcriptomic and metabolic levels, while glucose was added (Mao et al 2021). In detail, the results suggest that cells cultured with glucose induce upregulation of enzymes associated with e.g., fatty acid elongation, explaining high EPA content (Mao et al 2021).…”

“…In a recent study, researchers present insights into glucose-induced trophic transition, analyzing N. leavis on transcriptomic and metabolic levels, while glucose was added (Mao et al 2021). In detail, the results suggest that cells cultured with glucose induce upregulation of enzymes associated with e.g., fatty acid elongation, explaining high EPA content (Mao et al 2021). It is generally known that plasma membrane transporters are needed for the uptake of external carbon sources (e.g.…”