INDUCTION OF RESISTANCE OF AVOCADO FRUIT TO COLLETOTRICHUM GLOEOSPORIOIDES ATTACK BY CO₂ TREATMENT

Postharvest decay by Colletotrichum gloeosporioides is the principal problem encountered during storage of avocado fruits (Prusky et al., 1982). Prusky et al. (1982) have described the presence of a preformed antifungal compound, 1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene, in the peel and the flesh of unripe avocado fruits.
This compound has been suggested as the basis of resistance to decay in unripe fruit (Prusky et al., 1982). The diene was considered to be a pre-infectional, static inhibitor.
However, recent results have indicated that the concentration of the preformed diene can be enhanced by biotic and abiotic elicitors like challenge inoculation with C. gloeosporioides and wounding (Prusky et al., 1991). The regulation of the diene is thought to be due to an effect on epicatechin, a phenol that inhibits the activity of the enzyme lipoxygenase (Prusky et al., 1985). This results in the accumulation of the diene, thus preventing symptom development.

The present work describes the effect of the abiotic elicitor CO₂ on the levels of the preformed diene, epicatechin, and decay development.
The effect of the CO₂ on PAL, a key enzyme leading to the phenylpropanoid pathway, is also reported.

Physiological Basis of Postharvest Technologies

D. Prusky, I. Kobiler, R. Ardi, Y. Fishman

https://doi.org/10.17660/ActaHortic.1993.343.78