Potential of Antifungal Proteins (AFPs) to Control Penicillium Postharvest Fruit Decay

Abstract

<i>Penicillium</i> phytopathogenic species provoke severe postharvest disease and economic losses. <i>Penicillium expansum</i> is the main pome fruit phytopathogen while <i>Penicillium digitatum</i> and <i>Penicillium italicum</i> 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 <i>Penicillium chrysogenum</i> proteins (PAF, PAFB and PAFC), as well as the <i>Neosartorya fischeri</i> NFAP2 protein to control <i>Penicillium</i> decay, has been evaluated. PAFB was the most potent AFP against <i>P. digitatum</i>, <i>P. italicum</i> and <i>P. expansum</i>, 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 <i>P. digitatum</i> and <i>P. italicum</i> in oranges and by <i>P. expansum</i> 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 <i>Penicillium</i> postharvest fruit decay.