High spatial resolution imaging of the dynamics of cuticular lipid deposition during Arabidopsis flower development.

The extensive collection of () and () mutants of maize and Arabidopsis have proven invaluable in dissecting the branched metabolic pathways that support cuticular lipid deposition. This bifurcated pathway integrates a fatty acid elongation-decarbonylative branch and a fatty acid elongation-reductive branch, which collectively has the capacity to generate hundreds of cuticular lipid metabolites. In this study, a combined transgenic and biochemical strategy was implemented to explore and compare the physiological function of three homologous genes, , , and , in the context of this branched pathway. These biochemical characterizations integrated new extraction chromatographic procedures with high spatial resolution mass spectrometric imaging methods to profile the cuticular lipids on developing floral tissues transgenically expressing these transgenes in wild-type or mutant lines of Arabidopsis. Collectively, these datasets establish that both the maize and genes are functional homologs of the Arabidopsis gene. In addition, the dynamic distribution of cuticular lipid deposition follows distinct floral organ localization patterns indicating that the fatty acid elongation-decarbonylative branch of the pathway is differentially localized from the fatty acid elongation-reductive branch of the pathway.