Identification of the Wax Ester Synthase/Acyl-Coenzyme A:Diacylglycerol Acyltransferase WSD1 Required for Stem Wax Ester Biosynthesis in Arabidopsis    

Abstract

Wax esters are neutral lipids composed of aliphatic alcohols and acids, with both moieties usually long-chain (C 16 and C 18 ) or very-long-chain (C 20 and longer) carbon structures. They have diverse biological functions in bacteria, insects, mammals, and terrestrial plants and are also important substrates for a variety of industrial applications. In plants, wax esters are mostly found in the cuticles coating the primary shoot surfaces, but they also accumulate to high concentrations in the seed oils of a few plant species, including jojoba (Simmondsia chinensis), a desert shrub that is the major commercial source of these compounds. Here, we report the identification and characterization of WSD1, a member of the bifunctional wax ester synthase/diacylglycerol acyltransferase gene family, which plays a key role in wax ester synthesis in Arabidopsis (Arabidopsis thaliana) stems, as first evidenced by severely reduced wax ester levels of in the stem wax of wsd1 mutants. In vitro assays using protein extracts from Escherichia coli expressing WSD1 showed that this enzyme has a high level of wax synthase activity and approximately 10-fold lower level of diacylglycerol acyltransferase activity. Expression of the WSD1 gene in Saccharomyces cerevisiae resulted in the accumulation of wax esters, but not triacylglycerol, indicating that WSD1 predominantly functions as a wax synthase. Analyses of WSD1 expression revealed that this gene is transcribed in flowers, top parts of stems, and leaves. Fully functional yellow fluorescent protein-tagged WSD1 protein was localized to the endoplasmic reticulum, demonstrating that biosynthesis of wax esters, the final products of the alcohol-forming pathway, occurs in this subcellular compartment.

Physical Interaction of Floral Organs Controls Petal Morphogenesis in Arabidopsis

“…Ten genes encode similar proteins in Arabidopsis, and a gene located next to FOP1 on chromosome 5, At5g53380, is the closest homolog of the same family (Supplemental Fig. S3A; Li et al, 2008). The amino acid sequence of FOP1 showed 17.3% identity with that of Acinetobacter spp.…”

“…and plant WS/ DGAT proteins (Supplemental Fig. S3C; Kalscheuer and Steinbüchel, 2003;Li et al, 2008), suggesting that FOP1 is involved in the synthesis of wax esters and triacylglycerols. …”

“…FOP1 corresponds to WSD11, a member of the bifunctional WAX SYNTHASE/DIACYLGLYCEROL ACYLTRANSFERASE (WS/DGAT) family (Kalscheuer and Steinbüchel, 2003;Li et al, 2008). Ten genes encode similar proteins in Arabidopsis, and a gene located next to FOP1 on chromosome 5, At5g53380, is the closest homolog of the same family (Supplemental Fig.…”

Genome of the pitcher plant Cephalotus reveals genetic changes associated with carnivory

“…4). These genes, as well as wax ester synthase orthologues (WSD1) 15 , showed pitcher-predominant expression and are tandemly duplicated in the genome ( Supplementary Fig. 4), suggesting possible co-regulated involvement of the clusters in slippery surface formation.…”

The Potential Anti-Psoriatic Effects of Jojoba Extract

“…Jojoba oil is used in cosmetic, pharmaceutical, dietetic food, animal feeding, lubrication, polishing and bio-diesel fields [16] . Wax esters are neutral lipids which composed mainly of aliphatic alcohols and acids, with both moieties usually longchain (C (16) and C (18)) or very-long-chain (C (20) and longer) carbon structures [17] . Jojoba liquid waxes (JLW) have been demonstrated to possess anti-inflammatory properties.…”