title: Identification of Polyketides in the Cuticular Waxes of Triticum aestivum cv. Bethlehem.
abstract: Cuticular waxes are complex mixtures consisting mostly of very-long-chain aliphatics with single, primary functional groups. However, the waxes of many plant species also include aliphatics with one or more functional groups residing on subterminal or mid-chain carbons. In the present work, the cuticular wax mixtures from flag leaf blades and peduncles of Triticum aestivum cv. Bethlehem were analyzed in a search for novel wax constituents with in-chain functionalities, potentially of polyketide origin. The structures of compounds belonging to six different compound classes were elucidated using gas chromatography-mass spectrometry of various derivatives. Among them, a series of 2,4-ketols was identified, with odd carbon numbers ranging from C25to C37and peaking at C33. The analogous C332,4-diketone was identified as well, together with a pair of co-eluting C31mid-chain β-ketol isomers (16-hydroxyhentriacontan-14-one and 14-hydroxyhentriacontan-16-one), a pair of co-eluting C30mid-chain α-ketol isomers (15-hydroxytriacontan-14-one and 14-hydroxytriacontan-15-one), the corresponding C3014,15-diketone, and a pair of co-eluting C31ketones (hentriacontan-14-one and hentriacontan-16-one). All newly discovered structures contain ketone functional groups, with similar C13H27and C15H31alkyl chains on either side of the functionalities, thus resembling the previously reported very-long-chain β-diketones dominating the wheat wax mixtures. Based on these structural characteristics, possible biosynthetic pathways leading to the newly identified polyketide-like compounds are proposed.
authors: Department of Chemistry, The University of British Columbia, Vancouver, BC, V6T 1Z1, Canada.
authors: Radu C
authors: RC
authors: Racovita
authors: Department of Chemistry, The University of British Columbia, Vancouver, BC, V6T 1Z1, Canada. reinhard.jetter@botany.ubc.ca.|Department of Botany, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada. reinhard.jetter@botany.ubc.ca.
authors: Reinhard
authors: R
authors: Jetter
mesh_terms: D053898:Biosynthetic Pathways; D008401:Gas Chromatography-Mass Spectrometry; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D061065:Polyketides / Q000737:chemistry / Q000302:isolation & purification*; D014908:Triticum / Q000737:chemistry* / Q000201:enzymology; D014885:Waxes / Q000032:analysis*
chemical_list: D061065:Polyketides; D014885:Waxes
keywords: Cuticle; Diketones; Fragmentation patterns; Ketols; Ketones; Mass spectrometry; Triticum aestivum; Wax; Wheat