Antagonistic activity of two yeasts against Penicillium expansum in stone fruits.

Background: Stone fruits are vulnerable to contamination by Penicillium expansum (PE), a patulin-producing mould. The use of yeasts as biocontrol agents could be an effective strategy to combat this pathogen. This study evaluated the ability of Metschnikowia pulcherrima L672 (L672) and Pichia kudriavzevii L40 (L40) as biocontrol strategies on peach (Romea), black plum (Black gold), nectarine (Nectavista), and flat peach (Flat Beauty), analysing their impact on incidence and severity of PE damage, patulin production and the expression of the idh gene, a key gene of the patulin biosynthetic pathway.

Results: The results indicate that both yeasts reduced the incidence and severity of PE in the four stone fruit types studied, with a more pronounced effect observed for L672. This yeast reduced the presence of patulin in three of the stone fruits where patulin was produced by PE (nectarine, peach and black plum), while P. kudriavzevii L40 limited patulin production in peach by 90%. Regarding the study of the expression of the idh gene, L40 increased its expression compared to the control, although this effect varied among fruits. In contrast, L672 did not produce changes in gene expression in nectarines and black plums - fruits where patulin was not detected.

Conclusion: The application of the yeasts L672 and L40 as biocontrol agents was shown to be an effective strategy to reduce the incidence and severity of PE and patulin production in stone fruits, with a greater effect of L672 in most cases. Furthermore, differences were observed in the regulation of the idh gene, suggesting that the efficacy of biocontrol in this aspect depends on both the yeast used and the type of fruit. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.