Emission patterns of wound volatile compounds following injury of ripe strawberry fruit

Volatile compounds emitted from plants following wounding influence the growth of fungal pathogens, including Botrytis cinerea (grey mould), which causes serious economic loss of strawberry fruit. In the present study the patterns of volatile compound emission from ripe strawberry fruit, comprising store-purchased fruit and two known cultivars, were determined following injury, using solid phase microextraction analysis to sample a stream of air continuously flowing over the fruit. The principal compounds produced from all fruits comprised C₆ aldehydes, alcohols and acetate and butyrate esters derived from the lipoxygenase-hydroperoxide lyase pathway. There was an initial burst of production of aldehydes, including t-2-hexenal, following wounding and then a gradual decline, which in one cultivar continued for 3h. t-2-Hexenal is of special interest, since it has been shown to inhibit or promote Botrytis growth in vitro depending on concentration. The acetate esters t-2-hexenyl acetate, c-3-hexenyl acetate and hexyl acetate were major wound compounds released by the fruit and were produced for 3h after wounding. The production of relatively large quantities of wound-derived esters is markedly different from the patterns observed for most vegetative tissue. Knowledge of the wound compounds produced by strawberry fruit and their profiles of emission after injury provides a basis for studies of the potential roles of these compounds in pathogen development on fruit.