Arabidopsis thaliana wax synthase gene homologues show diverse expression patterns that suggest a specialized role for these genes in reproductive organs

Abstract

Wax esters perform a wide variety of important functions in bacteria, plants, and animals. In plants, wax esters are integral components of the protective cuticles and also serve as primary carbon and energy storage compounds in the seeds of some species such as Simmondsia chinensis. Wax synthases catalyze wax ester formation from fatty acids and alcohols. While wax synthase activity has only been demonstrated for a few proteins, many putative wax synthases have been identified in sequence databases based on homology to known wax synthases. Twelve wax synthase homologues were previously identified in the Arabidopsis thaliana genome sequence. Establishing function(s) for these genes has proven difficult since prior studies failed to detect expression of any of these genes. Here we present results from reverse transcriptase PCR experiments and analysis of publicly available gene expression databases which show that eleven of these twelve homologues are expressed in Arabidopsis, with a bias toward expression in reproductive organs, and that one of the putative homologues is likely to be a pseudogene. These results are discussed relative to other previously described wax synthases as well as numerous new homologues that are being discovered as sequence databases expand.