Universität zu Köln

Lehmann, Marco M., Wegener, Frederik, Barthel, Matti, Maurino, Veronica G., Siegwolf, Rolf T. W., Buchmann, Nina ORCID: 0000-0003-0826-2980, Werner, Christiane ORCID: 0000-0002-7676-9057 and Werner, Roland A. ORCID: 0000-0002-4117-1346 (2016). Metabolic Fate of the Carboxyl Groups of Malate and Pyruvate and their Influence on delta C-13 of Leaf-Respired CO2 during Light Enhanced Dark Respiration. Front. Plant Sci., 7. LAUSANNE: FRONTIERS MEDIA SA. ISSN 1664-462X

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Abstract

The enhanced CO2 release of illuminated leaves transferred into darkness, termed light enhanced dark respiration (LEDR), is often associated with an increase in the carbon isotope ratio of the respired CO2 (delta(CLEDR)-C-13). The latter has been hypothesized to result from different respiratory substrates and decarboxylation reactions in various metabolic pathways, which are poorly understood so far. To provide a better insight into the underlying metabolic processes of delta(CLEDR)-C-13, we fed position specific C-13-labeled malate and pyruvate via the xylem stream to leaves of species with high and low delta(LEDR)-L-13C values (Halimium halimifolium and Oxalis triangularis, respectively). During respective label application, we determined label-derived leaf (CO2)-C-13 respiration using laser spectroscopy and the C-13 allocation to metabolic fractions during light dark transitions. Our results clearly show that both carboxyl groups (C-1 and C-4 position) of malate similarly influence respiration and metabolic fractions in both species, indicating possible isotope randomization of the carboxyl groups of malate by the fumarase reaction. While C-2 position of pyruvate was only weakly respired, the species-specific difference in natural delta(CLEDR)-C-13 patterns were best reflected by the (CO2)-C-13 respiration patterns of the 0-1 position of pyruvate. Furthermore, 130 label from malate and pyruvate were mainly allocated to amino and organic acid fractions in both species and only little to sugar and lipid fractions. In summary, our results suggest that respiration of both carboxyl groups of malate (via fumarase) by tricarboxylic acid cycle reactions or by NAD-malic enzyme influences delta(LEDR)-L-13C. The latter supplies the pyruvate dehydrogenase reaction, which in turn determines natural delta(LEDR)-L-13C pattern by releasing the C-1 position of pyruvate.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Lehmann, Marco M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wegener, Frederik UNSPECIFIED UNSPECIFIED UNSPECIFIED Barthel, Matti UNSPECIFIED UNSPECIFIED UNSPECIFIED Maurino, Veronica G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Siegwolf, Rolf T. W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Buchmann, Nina UNSPECIFIED orcid.org/0000-0003-0826-2980 UNSPECIFIED Werner, Christiane UNSPECIFIED orcid.org/0000-0002-7676-9057 UNSPECIFIED Werner, Roland A. UNSPECIFIED orcid.org/0000-0002-4117-1346 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-272499
DOI:	10.3389/fpls.2016.00739
Journal or Publication Title:	Front. Plant Sci.
Volume:	7
Date:	2016
Publisher:	FRONTIERS MEDIA SA
Place of Publication:	LAUSANNE
ISSN:	1664-462X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ISOTOPE COMPOSITION; DIURNAL-VARIATION; DEHYDROGENASE COMPLEX; ILLUMINATED LEAVES; MALIC ENZYME; PLANT-CELLS; ARABIDOPSIS; MITOCHONDRIAL; PHOTOSYNTHESIS; INHIBITION Multiple languages Plant Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/27249