Metabolomic response of Euglena gracilis and its bleached mutant strain to light.

Qing Shao,Anping Lei,Lang Hu,Xing Tang,Yerong Liu,Huan Qin,Jiangxin Wang,Haitao Shi

doi:10.1371/journal.pone.0224926

Qing Shao, Anping Lei + Show 6 more

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https://doi.org/10.1371/journal.pone.0224926

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Journal: PloS one	Publication Date: Nov 7, 2019
Citations: 7	License type: CC BY 4.0

Affiliation: Shenzhen University, Hubei Engineering University

Abstract

Euglena, a new superfood on the market, is a nutrient-rich, green single-celled microorganism that features the characteristics of both plant and animal. When cultivated under different conditions, Euglena produces different bioactive nutrients. Interestingly, Euglena is the only known microorganism whose chloroplasts are easy to lose under stress and become permanently bleached. We applied gas chromatography-mass spectrometry (GC-MS) to determine the metabolomes of wild-type (WT) Euglena gracilis and its bleached mutant OflB2 under light stimulation. We found a significant metabolic difference between WT and OflB2 cells in response to light. An increase of membrane components (phospholipids and acylamides) was observed in WT, while a decrease of some stimulant metabolites was detected in OflB2. These metabolomic changes after light stimulation are of great significance to the development of Euglena chloroplasts and their communications with the nucleus.

Highlights

Euglena is a single-celled eukaryotic microalga and shares characteristics of both animals and plants
In the dark WT Euglena cannot photosynthesize and the chloroplasts inside cells may be a burden for cells
The bleached mutants only growing heterotrophically may show benefit for better growth compared to WT under the same condition

Summary

Introduction

Euglena is a single-celled eukaryotic microalga and shares characteristics of both animals and plants. It has no cell wall but contains a photosensitive eyespot structure and a flagellum. Different cultivations of Euglena result in a significant diversity of nutrients inside the cells [1]. The Euglena cells contain fully developed chloroplasts that they can grow both autotrophically under light and heterotrophically by absorbing organic matters from the environment [2]. Unlike the chloroplasts of other microalgae or higher-level plants, the chloroplasts of Euglena have poor stability and are prone to lose part of the chloroplast genome under stress such as antibiotics [2]. The Euglena cells losing part of their photosynthesis-related genes result in bleached mutants that can stably grow and multiply in heterotrophic media

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