Photo-Oxidative Stress-Driven Mutagenesis and Adaptive Evolution on the Marine Diatom Phaeodactylum tricornutum for Enhanced Carotenoid Accumulation.

Zhiqian Yi,Sigurdur Brynjolfsson,Yuetuan Zhang,Manuela Magnusdottir,Maonian Xu,Weiqi Fu

doi:10.3390/md13106138

Zhiqian Yi, Sigurdur Brynjolfsson + Show 4 more

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https://doi.org/10.3390/md13106138

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Journal: Marine Drugs	Publication Date: Sep 29, 2015
Citations: 88	License type: CC BY 4.0

Affiliation: University of Iceland

Abstract

Marine diatoms have recently gained much attention as they are expected to be a promising resource for sustainable production of bioactive compounds such as carotenoids and biofuels as a future clean energy solution. To develop photosynthetic cell factories, it is important to improve diatoms for value-added products. In this study, we utilized UVC radiation to induce mutations in the marine diatom Phaeodactylum tricornutum and screened strains with enhanced accumulation of neutral lipids and carotenoids. Adaptive laboratory evolution (ALE) was also used in parallel to develop altered phenotypic and biological functions in P. tricornutum and it was reported for the first time that ALE was successfully applied on diatoms for the enhancement of growth performance and productivity of value-added carotenoids to date. Liquid chromatography-mass spectrometry (LC-MS) was utilized to study the composition of major pigments in the wild type P. tricornutum, UV mutants and ALE strains. UVC radiated strains exhibited higher accumulation of fucoxanthin as well as neutral lipids compared to their wild type counterpart. In addition to UV mutagenesis, P. tricornutum strains developed by ALE also yielded enhanced biomass production and fucoxanthin accumulation under combined red and blue light. In short, both UV mutagenesis and ALE appeared as an effective approach to developing desired phenotypes in the marine diatoms via electromagnetic radiation-induced oxidative stress.

Highlights

Diatoms form a major lineage of unicellular algae and play an essential role in marine ecosystems [1].Diatoms account for the production of a large portion of the total energy of the oceans and are responsible for the global silicon cycle [2]
The lethality effect of UV exposure time was studied by subjecting P. tricornutum to ultraviolet C (UVC) radiation for different time periods
The survival rate was dependent on the UV exposure time, and the prolonged exposure time led to lower survival rate (Figure 2a), which was consistent with previous publications [14,16,20]

Summary

Introduction

Diatoms form a major lineage of unicellular algae and play an essential role in marine ecosystems [1].Diatoms account for the production of a large portion of the total energy of the oceans and are responsible for the global silicon cycle [2]. The marine pennate diatom Phaeodactylum tricornutum is a model species to study diatom physiology and diatom-based biotechnological applications as its genome has been sequenced, annotated and published [1] This particular diatom, i.e., P. tricornutum, usually exists in three different morphotypes in liquid cultures: fusiform, oval, and triradiate, making it an ideal model to study cellular mechanisms involved in morphological transformation [3]. It grows rapidly and accumulates a large amount of neutral lipids, which can be converted to biodiesel, accounting for as much as 20% of its total dry weight in normal non-stress growth conditions [4]

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