Stimulation of fungal spore germination and inhibition of sporulation in fungal vegetative thalli by fatty acids and their volatile peroxidation products

Abstract

As little as 200 parts per billion of 2,4-hexadienal in aerial solution stimulated germination of Alternaria alternata conidiospores in soil-imposed stasis. This compound, as well as trans-2-hexene-1-ol, and palmitic acid, stimulated germination of Fusarium solani f. sp. pisi conidiospores. Other 5- to 10-carbon aldehydes, ketones, and alcohols, as well as some 16- to 18-carbon aldehydes and fatty acids, stimulated germination of these spores at 10- or 100-fold higher concentrations. Chlamydospores of F. solanif. sp. pisi were stimulated to germinate by heptanal, octanal, nonanal,trans,trans-2,4-nonadienal, decanal, and undecanal at 20 000 or 20 0000 parts per billion in air, but not by any compound at lower concentrations. Compounds similar to those stimulating germination of conidiospores or chlamydospores inhibited sporulation of vegetative A. alternata thalli at concentrations as low as 800 parts per billion.