Universität zu Köln

Rademacher, Nadine, Kern, Ramona, Fujiwara, Takayuki, Mettler-Altmann, Tabea, Miyagishima, Shin-ya ORCID: 0000-0002-9111-0832, Hagemann, Martin, Eisenhut, Marion ORCID: 0000-0002-2743-8630 and Weber, Andreas P. M. (2016). Photorespiratory glycolate oxidase is essential for the survival of the red alga Cyanidioschyzon merolae under ambient CO2 conditions. J. Exp. Bot., 67 (10). S. 3165 - 3176. OXFORD: OXFORD UNIV PRESS. ISSN 1460-2431

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Abstract

Glycolate oxidase knockouts in Cyanidioschyzon reveal that red algae harbour a plant-like photorespiratory pathway. This suggests that a photorespiratory pathway employing peroxisomal glycolate oxidase is ancient and not recently evolved.Photorespiration is essential for all organisms performing oxygenic photosynthesis. The evolution of photorespiratory metabolism began among cyanobacteria and led to a highly compartmented pathway in plants. A molecular understanding of photorespiration in eukaryotic algae, such as glaucophytes, rhodophytes, and chlorophytes, is essential to unravel the evolution of this pathway. However, mechanistic detail of the photorespiratory pathway in red algae is scarce. The unicellular red alga Cyanidioschyzon merolae represents a model for the red lineage. Its genome is fully sequenced, and tools for targeted gene engineering are available. To study the function and importance of photorespiration in red algae, we chose glycolate oxidase (GOX) as the target. GOX catalyses the conversion of glycolate into glyoxylate, while hydrogen peroxide is generated as a side-product. The function of the candidate GOX from C. merolae was verified by the fact that recombinant GOX preferred glycolate over L-lactate as a substrate. Yellow fluorescent protein-GOX fusion proteins showed that GOX is targeted to peroxisomes in C. merolae. The GOX knockout mutant lines showed a high-carbon-requiring phenotype with decreased growth and reduced photosynthetic activity compared to the wild type under ambient air conditions. Metabolite analyses revealed glycolate and glycine accumulation in the mutant cells after a shift from high CO2 conditions to ambient air. In summary, or results demonstrate that photorespiratory metabolism is essential for red algae. The use of a peroxisomal GOX points to a high photorespiratory flux as an ancestral feature of all photosynthetic eukaryotes.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Rademacher, Nadine UNSPECIFIED UNSPECIFIED UNSPECIFIED Kern, Ramona UNSPECIFIED UNSPECIFIED UNSPECIFIED Fujiwara, Takayuki UNSPECIFIED UNSPECIFIED UNSPECIFIED Mettler-Altmann, Tabea UNSPECIFIED UNSPECIFIED UNSPECIFIED Miyagishima, Shin-ya UNSPECIFIED orcid.org/0000-0002-9111-0832 UNSPECIFIED Hagemann, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Eisenhut, Marion UNSPECIFIED orcid.org/0000-0002-2743-8630 UNSPECIFIED Weber, Andreas P. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-277787
DOI:	10.1093/jxb/erw118
Journal or Publication Title:	J. Exp. Bot.
Volume:	67
Number:	10
Page Range:	S. 3165 - 3176
Date:	2016
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1460-2431
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CHLAMYDOMONAS-REINHARDTII; CONCENTRATING MECHANISMS; GENE-EXPRESSION; CARBON; ARABIDOPSIS; METABOLISM; MUTANT; PHOTOSYNTHESIS; EVOLUTION; PATHWAY Multiple languages Plant Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/27778