Penicillium phytopathogenic species provoke severe postharvest disease and economic
losses. Penicillium expansum is the main pome fruit phytopathogen while Penicillium
digitatum and Penicillium italicum cause citrus green and blue mold, respectively.
Control strategies rely on the use of synthetic fungicides, but the appearance of
resistant strains and safety concerns have led to the search for new antifungals.
Here, the potential application of different antifungal proteins (AFPs) including
the three Penicillium chrysogenum proteins (PAF, PAFB and PAFC), as well as the Neosartorya
fischeri NFAP2 protein to control Penicillium decay, has been evaluated. PAFB was
the most potent AFP against P. digitatum, P. italicum and P. expansum, PAFC and NFAP2
showed moderate antifungal activity, whereas PAF was the least active protein. In
fruit protection assays, PAFB provoked a reduction of the incidence of infections
caused by P. digitatum and P. italicum in oranges and by P. expansum in apples. A
combination of AFPs did not result in an increase in the efficacy of disease control.
In conclusion, this study expands the antifungal inhibition spectrum of the AFPs evaluated,
and demonstrates that AFPs act in a species-specific manner. PAFB is a promising alternative
compound to control Penicillium postharvest fruit decay.