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Int J Mol Sci

Title:		Integration of C(1) and C(2) Metabolism in Trees
Author(s):		Jardine KJ; Fernandes de Souza V; Oikawa P; Higuchi N; Bill M; Porras R; Niinemets U; Chambers JQ;
Address:		"Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, building 64-241, Berkeley, CA 94720, USA. kjjardine@lbl.gov. National Institute for Amazon Research, Ave. Andre Araujo 2936, Manaus, AM 69060-001, Brazil. viniciusfernandes11@yahoo.com.br. Department of Earth and Environmental Sciences, California State University, East Bay, North Science 329, 25800 Carlos Bee Boulevard, Hayward, CA 94542, USA. patty.oikawa@csueastbay.edu. National Institute for Amazon Research, Ave. Andre Araujo 2936, Manaus, AM 69060-001, Brazil. higuchi.niro@gmail.com. Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, building 64-241, Berkeley, CA 94720, USA. mbill@lbl.gov. Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, building 64-241, Berkeley, CA 94720, USA. rcporras@lbl.gov. Department of Plant Physiology, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia. ylo@emu.ee. Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia. ylo@emu.ee. Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, building 64-241, Berkeley, CA 94720, USA. jchambers@lbl.gov. Department of Geography, University of California Berkeley, 507 McCone Hall #4740, Berkeley, CA 94720, USA. jchambers@lbl.gov"
Journal Title:		Int J Mol Sci
Year:		2017
Volume:		20170923
Issue:		10
Page Number:		-
DOI:		10.3390/ijms18102045
ISSN/ISBN:		1422-0067 (Electronic) 1422-0067 (Linking)
Abstract:		"C(1) metabolism in plants is known to be involved in photorespiration, nitrogen and amino acid metabolism, as well as methylation and biosynthesis of metabolites and biopolymers. Although the flux of carbon through the C(1) pathway is thought to be large, its intermediates are difficult to measure and relatively little is known about this potentially ubiquitous pathway. In this study, we evaluated the C(1) pathway and its integration with the central metabolism using aqueous solutions of (13)C-labeled C(1) and C(2) intermediates delivered to branches of the tropical species Inga edulis via the transpiration stream. Delivery of [(13)C]methanol and [(13)C]formaldehyde rapidly stimulated leaf emissions of [(13)C]methanol, [(13)C]formaldehyde, [(13)C]formic acid, and (13)CO(2), confirming the existence of the C1 pathway and rapid interconversion between methanol and formaldehyde. However, while [(13)C]formate solutions stimulated emissions of (13)CO(2), emissions of [(13)C]methanol or [(13)C]formaldehyde were not detected, suggesting that once oxidation to formate occurs it is rapidly oxidized to CO(2) within chloroplasts. (13)C-labeling of isoprene, a known photosynthetic product, was linearly related to (13)CO(2) across C(1) and C(2) ([(13)C(2)]acetate and [2-(13)C]glycine) substrates, consistent with reassimilation of C(1), respiratory, and photorespiratory CO(2). Moreover, [(13)C]methanol and [(13)C]formaldehyde induced a quantitative labeling of both carbon atoms of acetic acid emissions, possibly through the rapid turnover of the chloroplastic acetyl-CoA pool via glycolate oxidation. The results support a role of the C(1) pathway to provide an alternative carbon source for glycine methylation in photorespiration, enhance CO(2) concentrations within chloroplasts, and produce key C(2) intermediates (e.g., acetyl-CoA) central to anabolic and catabolic metabolism"
Keywords:		Butadienes/metabolism Carbon/chemistry/*metabolism Carbon Isotopes Formaldehyde/chemistry/metabolism Formates/chemistry/metabolism Hemiterpenes/metabolism Isotope Labeling *Metabolic Networks and Pathways Methanol/chemistry/metabolism Pentanes/metabolism;
Notes:		"MedlineJardine, Kolby J Fernandes de Souza, Vinicius Oikawa, Patty Higuchi, Niro Bill, Markus Porras, Rachel Niinemets, Ulo Chambers, Jeffrey Q eng Switzerland 2017/09/28 Int J Mol Sci. 2017 Sep 23; 18(10):2045. doi: 10.3390/ijms18102045"