The formation of perylenequinones in etiolated cucumber seedlings infected with Cladosporium cucumerinum

Abstract

Etiolated cucumber seedlings respond to infection by Cladosporium cucumerinum with the synthesis of wine-red pigments. Isolation and purification procedures for these pigments are described. They must be considered as derivatives of 4,9-dihydroxyperylene-3,10-quinone. On the basis of microanalyses, ultraviolet, infrared and nuclear magnetic resonance spectra a more detailed structural formula for the major pigment is tentatively proposed.