The Chemical Landscape of the Date Palm ( Phoenix dactylifera ) Cuticle: A Comprehensive Repertoire of Cutin and Wax Compositions

Fruit cuticles are key determinants of water retention, mechanical integrity, and postharvest quality, particularly in fruits cultivated under hot and arid conditions. Despite the global importance of date palm ( Phoenix dactylifera ) fruits, the structure and chemical composition of their cuticles remain poorly understood. Here, we present the first comprehensive characterization of the date palm fruit cuticle by integrating high-resolution microscopy and GC-MS analyses across 11 cultivars representing major production regions. Pronounced cultivar-dependent variation was observed in exocarp anatomy, cuticle thickness, and cuticular wax deposition, including the first report of epicuticular wax crystalloids on date palm fruits. Chemical profiling revealed a diverse cutin polymer comprising 19 monomers, unexpectedly enriched in very-long-chain fatty acids and alcohols. Cuticular waxes comprised 32 lipid compounds spanning multiple chemical classes. Cutin and wax compositions varied independently among cultivars, highlighting the chemical complexity of the date palm fruit cuticle and its relevance to fruit quality and postharvest.