Volatile organic compounds (VOC) as biomarkers for detection ofCeratocystis platani

Ceratocystis platanicauses canker stain of plane trees, and it represents a serious disease ofPlatanusspp. both in the United States and Europe. Current chemical or biological controls do not effectively manageC. platani, so new preventive methods need to be developed in order to limit this pathogen spreading. In this work, we have characterized the main volatile organic compounds (VOC) emitted in vitro from pure cultures ofC. plataniand other common pathogenic fungal species of hosts plants growing in the same ecosystems as plane trees. We found thatC. plataniemitted a similar blend of VOC compared with phylogenetically similar speciesC. populicola. In particular,C. plataniwas characterized by emission of isoamyl acetate and isobutyl acetate whileC. populicolaby ethyl acetate and isobutyl acetate, which were not released by any of the other out-group fungal species grown on the same medium. Moreover, following a targeted approach based on the main VOC found in vitro, we have successfully validated in vivo that VOC uniquely emitted byC. platani(i.e. isobutyl acetate along with isoamyl alcohol) were released from the bark of plane trees followingC. plataniinoculation. Our results highlight the possibility to exploit VOC emitted specifically byC. platanias biomarkers to recognizePlatanus x acerifoliaplants infected by this pathogen.