CAPSIDIOL ACCUMULATION IN CAPSICUM-ANNUUM STEMS DURING THE HYPERSENSITIVE REACTION TO PHYTOPHTHORA-CAPSICI

Inoculation of the seems of the three varieties of C. annuum (L.), wit h different sensitivities to the pepper pathogen, P. capsici, resulted in a hypersensitive reaction of different length along the stems and the accumulation of capsidiol. This suggests that all the pepper culti vars analyzed contain a mechanism for recognizing this pathogen and th e genetic information for initiating the defense response. The differe nces lie in the inhibitory capacity towards the fungal hyphae, which i s only really effective in Smith-5, the sole variety in which pathogen ic attack is stopped totally. Capsidiol accumulates in the stems of al l the pepper cultivars when inoculated with P. capsici, although there are significant differences depending on the cultivar and on the hist ological zone of the stem studied. The greatest accumulation of capsid iol corresponds to the 6th day of infection in the necrotic zone of th e resistant variety (Smith-5), suggesting that this variety alone has the ability to accumulate sufficiently high phytoalexin levels to inhi bit fungal development.