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Title: Hexokinase is necessary for glucose-mediated photosynthesis repression and lipid accumulation in a green alga

Abstract

Global primary production is driven largely by oxygenic photosynthesis, with algae as major contributors. The green alga Chromochloris zofingiensisreversibly switches off photosynthesis in the presence of glucose in the light and augments production of biofuel precursors(triacylglycerols) and the high-value antioxidant astaxanthin. Here we used forward genetics to reveal that this photosynthetic and metabolic switch is mediated by the glycolytic enzyme hexokinase (CzHXK1). In contrast to wild-type, glucose-treated hxk1 mutants do not shut off photosynthesis or accumulate astaxanthin, triacylglycerols, or cytoplasmic lipid droplets. We show that CzHXK1 is critical for the regulation of genes related to photosynthesis, ketocarotenoid synthesis and fatty acid biosynthesis. Sugars play fundamental regulatory roles in gene expression, physiology, metabolism, and growth in plants and animals, and we introduce a relatively simple, emerging model system to investigate conserved eukaryotic sugar sensing and signaling at the base of the green lineage.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Univ. of California, Berkeley, CA (United States). Howard Hughes Medical Inst., Dept. of Plant and Microbial Biology; Lawrence Berkeley National Lab., Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging Division
Publication Date:
Research Org.:
Univ. of California, Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23). Biological Systems Science Division
OSTI Identifier:
1562686
Grant/Contract Number:  
SC0018301
Resource Type:
Accepted Manuscript
Journal Name:
Communications Biology
Additional Journal Information:
Journal Volume: 2; Journal Issue: 1; Journal ID: ISSN 2399-3642
Publisher:
Springer Nature
Country of Publication:
United States
Language:
English

Citation Formats

Roth, Melissa S., Westcott, Daniel J., Iwai, Masakazu, and Niyogi, Krishna K. Hexokinase is necessary for glucose-mediated photosynthesis repression and lipid accumulation in a green alga. United States: N. p., 2019. Web. doi:10.1038/s42003-019-0577-1.
Roth, Melissa S., Westcott, Daniel J., Iwai, Masakazu, & Niyogi, Krishna K. Hexokinase is necessary for glucose-mediated photosynthesis repression and lipid accumulation in a green alga. United States. doi:10.1038/s42003-019-0577-1.
Roth, Melissa S., Westcott, Daniel J., Iwai, Masakazu, and Niyogi, Krishna K. Thu . "Hexokinase is necessary for glucose-mediated photosynthesis repression and lipid accumulation in a green alga". United States. doi:10.1038/s42003-019-0577-1. https://www.osti.gov/servlets/purl/1562686.
@article{osti_1562686,
title = {Hexokinase is necessary for glucose-mediated photosynthesis repression and lipid accumulation in a green alga},
author = {Roth, Melissa S. and Westcott, Daniel J. and Iwai, Masakazu and Niyogi, Krishna K.},
abstractNote = {Global primary production is driven largely by oxygenic photosynthesis, with algae as major contributors. The green alga Chromochloris zofingiensisreversibly switches off photosynthesis in the presence of glucose in the light and augments production of biofuel precursors(triacylglycerols) and the high-value antioxidant astaxanthin. Here we used forward genetics to reveal that this photosynthetic and metabolic switch is mediated by the glycolytic enzyme hexokinase (CzHXK1). In contrast to wild-type, glucose-treated hxk1 mutants do not shut off photosynthesis or accumulate astaxanthin, triacylglycerols, or cytoplasmic lipid droplets. We show that CzHXK1 is critical for the regulation of genes related to photosynthesis, ketocarotenoid synthesis and fatty acid biosynthesis. Sugars play fundamental regulatory roles in gene expression, physiology, metabolism, and growth in plants and animals, and we introduce a relatively simple, emerging model system to investigate conserved eukaryotic sugar sensing and signaling at the base of the green lineage.},
doi = {10.1038/s42003-019-0577-1},
journal = {Communications Biology},
number = 1,
volume = 2,
place = {United States},
year = {2019},
month = {9}
}

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Works referenced in this record:

The Chlamydomonas Genome Reveals the Evolution of Key Animal and Plant Functions
journal, October 2007

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