Dataset Information

Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis.

ABSTRACT: Acyl-CoA: diacylglycerol acyltransferase (DGAT) catalyzes the final committed step in triacylglycerol (TAG) biosynthesis in eukaryotes. In microalgae, the copy number of DGAT genes is extraordinarily expanded and yet the functions of many DGATs remain largely unknown. This study revealed microalgal DGAT can function as lysophosphatidic acyltransferase (LPAAT) both in vitro and in vivo while losing its original function as DGAT. Among the five DGAT encoding genes identified and cloned from the green microalga Haematococcus pluvialis, four encodes HpDGATs that showed TAG synthase activities in yeast for functional complementation analysis, except for one of the type II DGAT encoding genes, i.e., HpDGTT2 gene. The hydrophobic recombinant HpDGTT2 was purified in a soluble form and was revealed to function as a LPAAT via enzymatic assay. Introducing this gene into the green microalga Chlamydomonas reinhardtii led to retarded cellular growth, enlarged cell size and enhanced TAG accumulation, identical to the phenotypes of the transgenic strains with overexpressed CrLPAAT. This study provides a framework for dissecting uncharacterized DGATs, and could pave the way to decrypt the structure-function relationship of this large group of enzymes critical to lipid biosynthesis.

SUBMITTER: Ma H

PROVIDER: S-EPMC7853605 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis.

Ma Haiyan H Wu Xiaoying X Wei Ziwang Z Zhao Liang L Li Zhongze Z Liang Qing Q Zheng Jie J Wang Yu Y Li Yanhua Y Huang Linfei L Hu Qiang Q Han Danxiang D

Journal of experimental botany 20210201 2

Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final committed step in triacylglycerol biosynthesis in eukaryotes. In microalgae, the copy number of DGAT genes is extraordinarily expanded, yet the functions of many DGATs remain largely unknown. This study revealed that microalgal DGAT can function as a lysophosphatidic acyltransferase (LPAAT) both in vitro and in vivo while losing its original function as DGAT. Among the five DGAT-encoding genes identified and cloned from the green ...[more]

PMID: 33005924

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Project description:The unicellular green alga Haematococcus pluvialis has been exploited as a cell factory to produce the high-value antioxidant astaxanthin for over two decades, due to its superior ability to synthesize astaxanthin under adverse culture conditions. However, slow vegetative growth under favorable culture conditions and cell deterioration or death under stress conditions (e.g., high light, nitrogen starvation) has limited the astaxanthin production. In this study, a new paradigm that integrated heterotrophic cultivation, acclimation of heterotrophically grown cells to specific light/nutrient regimes, followed by induction of astaxanthin accumulation under photoautotrophic conditions was developed. First, the environmental conditions such as pH, carbon source, nitrogen regime, and light intensity, were optimized to induce astaxanthin accumulation in the dark-grown cells. Although moderate astaxanthin content (e.g., 1% of dry weight) and astaxanthin productivity (2.5?mg?L(-1) ?day(-1) ) were obtained under the optimized conditions, a considerable number of cells died off when subjected to stress for astaxanthin induction. To minimize the susceptibility of dark-grown cells to light stress, the algal cells were acclimated, prior to light induction of astaxanthin biosynthesis, under moderate illumination in the presence of nitrogen. Introduction of this strategy significantly reduced the cell mortality rate under high-light and resulted in increased cellular astaxanthin content and astaxanthin productivity. The productivity of astaxanthin was further improved to 10.5?mg?L(-1) ?day(-1) by implementation of such a strategy in a bubbling column photobioreactor. Biochemical and physiological analyses suggested that rebuilding of photosynthetic apparatus including D1 protein and PsbO, and recovery of PSII activities, are essential for acclimation of dark-grown cells under photo-induction conditions. Biotechnol. Bioeng. 2016;113: 2088-2099. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.

Dataset Information

Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis.

Publications

Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis.

Similar Datasets

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