Can strawberry volatile emissions influence Botrytis cinerea growth?

Many fungal pathogens that infect fruit in the field cause symptomatic disease during storage and marketing as ripening progresses. The development of some diseases is also enhanced by the occurrence of mechanical injuries. As an increase in volatile emissions generally occurs during fruit ripening and following wounding, we hypothesized that volatile organic compounds (VOCs) could be involved in disease development, and have tested this hypothesis in the strawberry-Botrytis cinerea interaction. Thirty-five strawberry VOCs were tested on B. cinerea in vitro and fruit volatile emissions were analyzed in ‘Monterey’ strawberries harvested at four ripening stages by headspace solid-phase microextraction/gas chromatography-mass spectrometry and proton transfer reaction – time of flight – mass spectrometry Results showed that key strawberry aroma compounds stimulated B. cinerea conidial germination at concentrations naturally detected in ripe strawberry, and that some ‘green leaf volatiles’ emitted from wounded fruit also stimulated pathogen’ conidial germination or mycelial growth. These results suggest that B. cinerea may exploit some strawberry volatiles as chemical signals to: i) recognize the ripening stage of the fruit host and resume its growth from the latent phase, and ii) recognize the presence of damaged tissues in the host and increase their colonization by increasing conidial germination or mycelial growth in response to specific VOCs.