Reprogramming of carbon metabolism drives fatty acid biosynthesis during avocado mesocarp development

Avocado mesocarp is a unique non-seed tissue capable of accumulating high levels of oil, yet the metabolic regulation underlying this process during fruit development remains poorly understood. We investigated how central carbon metabolism is coordinated with fatty acid biosynthesis in two avocado cultivars with contrasting oil accumulation patterns, 'Hass' and 'Fuerte', using integrated metabolomic and proteomic analyses. Fatty acid profiling revealed cultivar-dependent differences in timing and rate of lipid accumulation, with 'Fuerte' exhibiting earlier fatty acid synthesis and 'Hass' showing a delayed but prolonged accumulation phase. Metabolite profiling indicated a developmental shift in carbon partitioning, characterized by declining soluble sugars and polyols alongside increasing organic acids and amino acids. Proteomic analyses revealed extensive reprogramming of glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle, closely associated with the induction of fatty acid biosynthetic enzymes. Integration of protein abundance with fatty acid content using partial least squares regression identified acetyl-CoA carboxylase, β-ketoacyl-ACP synthase, and stearoyl-ACP desaturase as key metabolic steps linking carbon sources to lipid accumulation. Pathway reconstructions further highlighted cultivar-specific temporal strategies coordinating carbon metabolism with triacylglycerol biosynthesis. Together, these findings demonstrate that oil accumulation in avocado mesocarp is driven by a tightly regulated developmental reprogramming of carbon metabolism.