VIEW ARTICLE

Postinfectional Fungus Inhibitors from Plants: Fungal Oxidation of Capsidiol in Pepper Fruit. A. Stoessl, Agricultural Research Institute, Canada Department of Agriculture University Sub Post Office, London, Ontario, N6A 3KO; C. H. Unwin(2), and E. W. B. Ward(3). (2)(3)Agricultural Research Institute, Canada Department of Agriculture University Sub Post Office, London, Ontario, N6A 3KO. Phytopathology 63:1225-1231. Accepted for publication 19 March 1973. DOI: 10.1094/Phyto-63-1225.

Capsidiol, the antifungal sesquiterpene induced in pepper fruit by several fungi, was rapidly oxidized in shake cultures of Botrytis cinerea and Fusarium oxysporum f. vasinfectum to the less toxic ketone, capsenone. This was further degraded by B. cinerea to undetermined minor products. In pepper fruit, four of six Fusarium spp. oxidized capsidiol to capsenone. Increases in capsidiol levels occurred between 6 and 12 hr after inoculation with F. oxysporum f. pisi or F. oxysporum f. vasinfectum. Capsidiol was oxidized by the latter almost as rapidly as it was formed. The extent of the capsidiol-capsenone conversion by Fusarium spp. was sufficient to eliminate inhibition of spore germination but not of mycelial growth. The ability to perform the oxidation does not appear to be specifically associated with the pathogenicity of the Fusaria for pepper fruit.