Compartmentation of antifungal compounds in oil cells of avocado fruit mesocarp and its effect on susceptibility to Colletotrichum gloeosporioides

Colletotrichum gloeosporioides decays the mesocarp of unharvested and harvested unripe avocado fruits despite high concentrations of two preformed antifungal compounds within. These compounds, 1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene and 1-acetoxy-2,4-dihydroxy-n-heptadeca-16-ene, a diene and monoene, were found to be largely compartmentalized in specialized oil cells of the avocado mesocarp. The results therefore suggest that a major portion of the antifungal compounds are sequestered in the mesocarp, where they are unavailable to provide resistance to fungal decay. This is in contrast to the case in avocado peel (pericarp), where the antifungal compounds are not sequestered and presumably contact invading fungal hyphae to provide disease resistance.