Olive anthracnose, caused by several Colletotrichum species, is the most economically harmful fruit disease of the
olive crop. This work aimed to evaluate the ability of the endophyte Penicillium commune CIMO 14FM009 to
protect the olive tree against Colletotrichum nymphaeae via induction of plant volatile organic compounds (VOCs).
Accordingly, olive tree branches were inoculated with the endophyte and one month later with the pathogen.
After 0, 3, and 24 h of pathogen inoculation, the volatile composition of leaves and fruits was analyzed by HSSPME-
GC/MS, and compared with controls (branches inoculated with buffer, endophyte, or pathogen). The
effect of plant-derived volatiles on C. nymphaeae was also evaluated. Penicillium commune induced the release of
VOCs on the olive trees, with the capacity to reduce significantly the growth (up to 1.4-fold) and sporulation (up
to 1.2-fold) of C. nymphaeae. This effect was most notorious on olives than on leaves, and occurred 3 h after
pathogen-challenge, suggesting the need for a stressful stimulus for the production of antifungal VOCs. The
observed inhibition was associated to a specific set of VOCs released from olives (mostly belonging to the alcohols
and esters chemical classes) and leaves (mostly belonging to the alkenes). Curiously, a set of VOCs
belonging to alkene, alkane and ester classes, were emitted exclusively in olive branches inoculated with
C. nymphaeae. These findings provide new possibilities for controlling olive anthracnose using P. commune and/or
volatiles, which efficacy should be tested in future works.
