@article {2658, title = {Composition of secondary alcohols, ketones, alkanediols, and ketols in Arabidopsis thaliana cuticular waxes}, journal = {Journal of Experimental Botany}, volume = {60}, number = {6}, year = {2009}, note = {ISI Document Delivery No.: 437ZCTimes Cited: 0Cited Reference Count: 25Wen, Miao Jetter, Reinhard}, month = {Apr}, pages = {1811-1821}, type = {Article}, abstract = {Arabidopsis wax components containing secondary functional groups were examined (i) to test the biosynthetic relationship between secondary alcohols and ketols and (ii) to determine the regiospecificity and substrate preference of the enzyme involved in ketol biosynthesis. The stem wax of Arabidopsis wild type contained homologous series of C-27 to C-31 secondary alcohols (2.4 mu g cm(-2)) and C-28 to C-30 ketones (6.0 mu g cm(-2)) dominated by C-29 homologues. In addition, compound classes containing two secondary functional groups were identified as C-29 diols (similar to 0.05 mu g cm(-2)) and ketols (similar to 0.16 mu g cm(-2)). All four compound classes showed characteristic isomer distributions, with functional groups located between C-14 and C-16. In the mah1 mutant stem wax, diols and ketols could not be detected, while the amounts of secondary alcohols and ketones were drastically reduced. In two MAH1-overexpressing lines, equal amounts of C-29 and C-31 secondary alcohols were detected. Based on the comparison of homologue and isomer compositions between the different genotypes, it can be concluded that biosynthetic pathways lead from alkanes to secondary alcohols, and via ketones or diols to ketols. It seems plausible that MAH1 is the hydroxylase enzyme involved in all these conversions in Arabidopsis thaliana.}, keywords = {BRASSICA-OLERACEA, chain lengths, CHROMATOGRAPHY, cytochrome P450, ECERIFERUM MUTANTS, EPICUTICULAR WAXES, fatty acid derivatives, GAS, HYDROXYLATION, LEAF WAXES, LEAVES, MAH1, MASS SPECTROMETRY, neutral lipids, plant surface composition, RESISTANT, ULTRASTRUCTURE, wax}, isbn = {0022-0957}, url = {://000265524400023}, author = {Wen, M. and Jetter, R.} } @article {1531, title = {CER4 encodes an alcohol-forming fatty acyl-coenzyme A reductase involved in cuticular wax production in Arabidopsis}, journal = {Plant Physiology}, volume = {142}, number = {3}, year = {2006}, note = {ISI Document Delivery No.: 103NGTimes Cited: 40Cited Reference Count: 64Rowland, Owen Zheng, Huanquan Hepworth, Shelley R. Lam, Patricia Jetter, Reinhard Kunst, Ljerka}, month = {Nov}, pages = {866-877}, type = {Article}, abstract = {A waxy cuticle that serves as a protective barrier against uncontrolled water loss and environmental damage coats the aerial surfaces of land plants. It is composed of a cutin polymer matrix and waxes. Cuticular waxes are complex mixtures of very-long-chain fatty acids and their derivatives. We report here the molecular cloning and characterization of CER4, a wax biosynthetic gene from Arabidopsis (Arabidopsis thaliana). Arabidopsis cer4 mutants exhibit major decreases in stem primary alcohols and wax esters, and slightly elevated levels of aldehydes, alkanes, secondary alcohols, and ketones. This phenotype suggested that CER4 encoded an alcohol-forming fatty acyl-coenzyme A reductase (FAR). We identified eight FAR-like genes in Arabidopsis that are highly related to an alcohol-forming FAR expressed in seeds of jojoba (Simmondsia chinensis). Molecular characterization of CER4 alleles and genomic complementation revealed that one of these eight genes, At4g33790, encoded the FAR required for cuticular wax production. Expression of CER4 cDNA in yeast (Saccharomyces cerevisiae) resulted in the accumulation of C24: 0 and C26: 0 primary alcohols. Fully functional green fluorescent protein-tagged CER4 protein was localized to the endoplasmic reticulum in yeast cells by confocal microscopy. Analysis of gene expression by reverse transcription-PCR indicated that CER4 was expressed in leaves, stems, flowers, siliques, and roots. Expression of a beta-glucuronidase reporter gene driven by the CER4 promoter in transgenic plants was detected in epidermal cells of leaves and stems, consistent with a dedicated role for CER4 in cuticular wax biosynthesis. CER4 was also expressed in all cell types in the elongation zone of young roots. These data indicate that CER4 is an alcohol-forming FAR that has specificity for very-long-chain fatty acids and is responsible for the synthesis of primary alcohols in the epidermal cells of aerial tissues and in roots.}, keywords = {ACID ELONGASE, CELL-DIFFERENTIATION, CUTICLE DEVELOPMENT, ECERIFERUM MUTANTS, EPICUTICULAR WAXES, GENE-EXPRESSION MAP, NORMAL ACCUMULATION, PISUM-SATIVUM, POLLEN FERTILITY, TRANSCRIPTIONAL ACTIVITY}, isbn = {0032-0889}, url = {://000241892900007}, author = {Rowland, O. and Zheng, H. Q. and Hepworth, S. R. and Lam, P. and Jetter, R. and Kunst, L.} } @article {1625, title = {Very-long-chain secondary alcohols and alkanediols in cuticular waxes of Pisum sativum leaves}, journal = {Phytochemistry}, volume = {67}, number = {22}, year = {2006}, note = {ISI Document Delivery No.: 108TITimes Cited: 4Cited Reference Count: 18Wen, Miao Au, Jason Gniwotta, Franka Jetter, Reinhard}, month = {Nov}, pages = {2494-2502}, type = {Article}, abstract = {In cuticular waxes from leaves of Pisum sativum, 19 secondary alcohols, 10 primary/secondary alkanediols and three secondary/secondary alkanediols were identified by various chemical transformations with product assignment employing GC-MS. The homologous series Of C-29-C-33 secondary alcohols (1.1 mu g/cm(2)) was dominated by hentriacontanol isomers (94\%). Only octacosanediols and trace amounts of hexacosanediols (< 1\%) were detected in the primary/secondary alkanediol faction (0.7 mu g/cm(2)). The secondary/secondary alkanediols (0.12 mu g/cm(2)) contained a single homologue with chain length C-31. All three compound classes showed characteristic isomer distributions with secondary functional groups predominantly located between C-14 and C-16. Based on the isomer compositions, the sequence of biosynthetic steps introducing the hydroxyl functions is discussed. (c) 2006 Elsevier Ltd. All rights reserved.}, keywords = {biosymbetic pathways, chain length, CHEMICAL-COMPOSITION, EPICUTICULAR WAXES, GC-MS, leaf surface, pea}, isbn = {0031-9422}, url = {://000242261700010}, author = {Wen, M. and Au, J. and Gniwotta, F. and Jetter, R.} } @article {1026, title = {Tomato fruit cuticular waxes and their effects on transpiration barrier properties: functional characterization of a mutant deficient in a very-long-chain fatty acid beta-ketoacyl-CoA synthase}, journal = {Journal of Experimental Botany}, volume = {55}, number = {401}, year = {2004}, note = {ISI Document Delivery No.: 829GETimes Cited: 49Cited Reference Count: 44}, month = {Jun}, pages = {1401-1410}, type = {Article}, abstract = {Cuticular waxes play a pivotal role in limiting transpirational water loss across the plant surface. The correlation between the chemical composition of the cuticular waxes and their function as a transpiration barrier is still unclear. In the present study, intact tomato fruits (Lycopersicon esculentum) are used, due to their astomatous surface, as a novel integrative approach to investigate this composition-function relationship: wax amounts and compositions of tomato were manipulated before measuring unbiased cuticular transpiration. First, successive mechanical and extractive wax-removal steps allowed the selective modification of epi- and intracuticular wax layers. The epicuticular film consisted exclusively of very-long-chain aliphatics, while the intracuticular compartment contained large quantities of pentacyclic triterpenoids as well. Second, applying reverse genetic techniques, a loss-of-function mutation with a transposon insertion in a very-long-chain fatty acid elongase beta-ketoacyl-CoA synthase was isolated and characterized. Mutant leaf and fruit waxes were deficient in n-alkanes and aldehydes with chain lengths beyond C-30, while shorter chains and branched hydrocarbons were not affected. The mutant fruit wax also showed a significant increase in intracuticular triterpenoids. Removal of the epicuticular wax layer, accounting for one-third of the total wax coverage on wild-type fruits, had only moderate effects on transpiration. By contrast, reduction of the intracuticular aliphatics in the mutant to approximately 50\% caused a 4-fold increase in permeability. Hence, the main portion of the transpiration barrier is located in the intracuticular wax layer, largely determined by the aliphatic constituents, but modified by the presence of triterpenoids, whereas epicuticular aliphatics play a minor role.}, keywords = {ARABIDOPSIS-THALIANA, BARRIER, BICOLOR L MOENCH, CITRUS LEAF CUTICLES, CONDENSING ENZYME, CONDUCTANCE, cuticle, ECERIFERUM CER MUTANTS, EPICUTICULAR WAX, EPICUTICULAR WAXES, EPIDERMAL, intracuticular wax, PRUNUS-LAUROCERASUS L, tomato, transpiration, TRANSPORT-PROPERTIES, WATER PERMEABILITY}, isbn = {0022-0957}, url = {://000222034600015}, author = {Vogg, G. and Fischer, S. and Leide, J. and Emmanuel, E. and Jetter, R. and Levy, A. A. and Riederer, M.} }