title: Phytogenic biosynthesis and emission of methyl acetate.
abstract: Acetylation of plant metabolites fundamentally changes their volatility, solubility and activity as semiochemicals. Here we present a new technique termed dynamic (13) C-pulse chasing to track the fate of C1-3 carbon atoms of pyruvate into the biosynthesis and emission of methyl acetate (MA) and CO2 . (13) C-labelling of MA and CO2 branch emissions respond within minutes to changes in (13) C-positionally labelled pyruvate solutions fed through the transpiration stream. Strong (13) C-labelling of MA emissions occurred only under pyruvate-2-(13) C and pyruvate-2,3-(13) C feeding, but not pyruvate-1-(13) C feeding. In contrast, strong (13) CO2 emissions were only observed under pyruvate-1-(13) C feeding. These results demonstrate that MA (and other volatile and non-volatile metabolites) derive from the C2,3 atoms of pyruvate while the C1 atom undergoes decarboxylation. The latter is a non-mitochondrial source of CO2 in the light generally not considered in studies of CO2 sources and sinks. Within a tropical rainforest mesocosm, we also observed atmospheric concentrations of MA up to 0.6 ppbv that tracked light and temperature conditions. Moreover, signals partially attributed to MA were observed in ambient air within and above a tropical rainforest in the Amazon. Our study highlights the potential importance of acetyl coenzyme A (CoA) biosynthesis as a source of acetate esters and CO2 to the atmosphere.
authors.affiliation: Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors.forename: Kolby
authors.initials: K
authors.lastname: Jardine
authors.forename: Frederik
authors.initials: F
authors.lastname: Wegener
authors.forename: Leif
authors.initials: L
authors.lastname: Abrell
authors.forename: Joost
authors.initials: J
authors.lastname: van Haren
authors.forename: Christiane
authors.initials: C
authors.lastname: Werner
mesh_terms: D000085:Acetates / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D030601:Cistaceae / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D053858:Metabolic Networks and Pathways; D010788:Photosynthesis; D014329:Tropical Climate; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D000085:Acetates; D055549:Volatile Organic Compounds; D002245:Carbon Dioxide; C046923:methyl acetate
keywords: acetyl fragment; dynamic pulse chase; methyl acetate; pyruvate positional labelling; secondary metabolism; stable carbon isotopes; volatile organic compound