Unravelling the effect of control agents on Gnomoniopsis smithogilvyi on a chestnut-based medium by proteomics

BACKGROUND

Gnomoniopsis smithogilvyi is the major chestnut pathogen, responsible for economic losses and recently described as a 3-nitropropionic acid and diplodiatoxin mycotoxin producer. Bacillus amyloliquefaciens QST 713 (Serenade® ASO), B. amyloliquefaciens CIMO-BCA1, and the fungicide Horizon® (tebuconazole) have been shown to reduce the growth of G. smithogilvyi. However, they enhanced mycotoxin production. Proteomics can clarify the mould's physiology and the impact of antifungal agents on the mould's metabolism. Thus, the aim of this study was to assess the impact of Horizon®, Serenade®, and B. amyloliquefaciens CIMO-BCA1 in the proteome of G. smithogilvyi to unveil their modes of action and decipher why the mould responds by increasing the mycotoxin production. For this, the mycelium close to the inhibition zone provoked by antifungals was macroscopically and microscopically observed. Proteins were extracted and analysed using a Q-Exactive plus Orbitrap.

RESULTS

The results did not elucidate specific proteins involved in the mycotoxin biosynthesis, but these agents provoked different kinds of stress on the mould, mainly affecting the cell wall structures and antioxidant response, which points to the mycotoxins overproduction as a defence mechanism. The biocontrol agent CIMO-BCA1 acts similar to tebuconazole. The results revealed different responses on the mould's metabolism when co-cultured with the two B. amyloliquefaciens, showing different modes of action of each bacterium, which opens the possibility of combining both biocontrol strategies.

CONCLUSION

These results unveil different modes of action of the treatments that could help to reduce the use of toxic chemicals to combat plant pathogens worldwide. © 2023 Society of Chemical Industry.

Perspectives on the Probiotic Potential of Indigenous Moulds and Yeasts in Dry-Fermented Sausages

The role of indigenous fungi in the appropriate development of sensory properties and the safety of dry-fermented sausages has been widely established. Nonetheless, their applications as probiotic agents have not been elucidated in such products yet, despite their promising functional features. Thus, it should be interesting to evaluate the probiotic potential of native Debaryomyces hansenii isolates from dry-fermented sausages and their application in the meat industry, because it is the most frequently isolated yeast species from these foodstuffs and its probiotic effects for animals as well as its possible probiotic activity for human beings have been demonstrated. Within the functional ability of foodborne yeasts, anti-inflammatory, antioxidant, antimicrobial, antigenotoxic, and immunomodulatory properties have been reported. Similarly, the use of dry-fermented sausages as vehicles for probiotic moulds remains a challenge because the survival and development of moulds in the gastrointestinal tract are still unknown. Nevertheless, some moulds have been isolated from faeces possibly from their spores as a form of resistance. Additionally, their beneficial effects on animals and humans, such as the decrease in lipid content and the anti-inflammatory activity, have been reported, although they seem to be more related to their postbiotic capacity due to the generated bioactive compounds with profunctional attributes than to their role as probiotics. Therefore, further studies providing knowledge useful for generating dry-fermented sausages with improved functionality are fully necessary.