Composition of cuticular waxes coating flag leaf blades and peduncles of Triticum aestivum cv. Bethlehem.
The work herein presents comprehensive analyses of the cuticular wax mixtures covering the flag leaf blade and peduncle of bread wheat (Triticum aestivum) cv. Bethlehem. Overall, Gas Chromatography-Mass Spectrometry and Flame Ionization Detection revealed a wax coverage of flag leaf blades (16 μg/cm(2)) a third that of peduncles (49 μg/cm(2)). Flag leaf blade wax was dominated by 1-alkanols, while peduncle wax contained primarily β-diketone and hydroxy-β-diketones, thus suggesting differential regulation of the acyl reduction and β-diketone biosynthetic pathways in the two analyzed organs. The characteristic chain length distributions of the various wax compound classes are discussed in light of their individual biosynthetic pathways and biosynthetic relationships between classes. Along with previously reported wheat wax compound classes (fatty acids, 1-alkanols, 1-alkanol esters, aldehydes, alkanes, β-diketone, hydroxy-β-diketones, alkylresorcinols and methyl alkylresorcinols), esters of 2-alkanols and three types of aromatic esters (benzyl, phenethyl and p-hydroxyphenethyl) are also reported. In particular, 2-heptanol esters were identified. Detailed analyses of the isomer distributions within 1-alkanol and 2-alkanol ester homologs revealed distinct patterns of esterified acids and alcohols, suggesting several wax ester synthases with very different substrate preferences in both wheat organs. Terpenoids, including two terpenoid esters, were present only in peduncle wax.
Department of Chemistry, The University of British Columbia, Vancouver, BC, V6T 1Z1, Canada.
Radu C
RC
Racovita
Department of Plant Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel.
Shelly
S
Hen-Avivi
Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Universidad Politécnica de Valencia, Valencia, 46022, Spain.
Josefina-Patricia
JP
Fernandez-Moreno
Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Universidad Politécnica de Valencia, Valencia, 46022, Spain.
Antonio
A
Granell
Department of Plant Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel.
Asaph
A
Aharoni
Department of Chemistry, The University of British Columbia, Vancouver, BC, V6T 1Z1, Canada; Department of Botany, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada. Electronic address: reinhard.jetter@botany.ubc.ca.
Reinhard
R
Jetter
D000438:Alcohols / Q000737:chemistry; D004952:Esters / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D007659:Ketones / Q000032:analysis; D019441:Plant Epidermis / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry*; D013729:Terpenes / Q000032:analysis / Q000737:chemistry; D014908:Triticum / Q000737:chemistry*; D014885:Waxes / Q000737:chemistry*
D000438:Alcohols; D004952:Esters; D007659:Ketones; D013729:Terpenes; D014885:Waxes
2-Alkanol esters; Benzyl esters; Bread wheat; Chain length profiling; Cuticular wax; Phenethyl esters; Poaceae; Primary alcohols; Triticum aestivum; Wax ester metamers; p-Hydroxy-phenethyl esters; β-Diketones