ANTIFUNGAL EFFECTS OF COCOA TANNIN ON THE WITCHES BROOM PATHOGEN CRINIPELLIS-PERNICIOSA

Methanol-extractable material from flush shoot tissue of cocoa (Theobroma cacao) inhibited the germination of basidiospores of the witches' broom pathogen Crinipellis perniciosa. In more dilute extracts, abnormally short, swollen germ-tubes emerged from the basidiospores. The anti-fungal factor responsible for these effects was retained by dialysis tubing, and bound to erythrocytes and to protein. These properties were characteristic of the major component of the dialysed extracts, namely polymeric procyanidin (condensed tannin). Highly purified polymeric procyanidin produced effects on C. perniciosa basidiospores that were identical to those produced by crude extracts. The implications of these results for the involvement of procyanidin in host-pathogen interactions are discussed. © 1990.