Synthetic antimicrobial peptides control Penicillium digitatum infection in orange fruits

Area of Science:

• Food Science
• Microbiology
• Biotechnology

Background:

• Fungal contamination, particularly by Penicillium digitatum, significantly contributes to food spoilage, impacting food safety and economic stability.
• Effective control of Penicillium digitatum is crucial for preserving food quality and preventing economic losses.

Purpose of the Study:

• To evaluate the in vitro antifungal activity of synthetic antimicrobial peptides against Penicillium digitatum.
• To investigate the mechanisms of action employed by these peptides against the fungus.
• To assess the efficacy of selected peptides in controlling Penicillium digitatum colonization on orange fruits.

Main Methods:

• In vitro assessment of eight synthetic antimicrobial peptides against Penicillium digitatum.
• Microscopic analysis (atomic force and fluorescence) to elucidate peptide-fungal membrane interactions.
• Evaluation of reactive oxygen species (ROS) induction.
• In vivo fruit challenge assays to determine efficacy against fungal colonization.

Main Results:

• All tested peptides demonstrated in vitro inhibition of Penicillium digitatum growth.
• Peptides were observed to target the fungal membrane, causing pore formation, leakage of cellular contents, and cell death.
• Some peptides induced significant levels of reactive oxygen species (ROS).
• Three peptides (PepGAT, PepKAA, and Mo-CBP3-PepI) effectively controlled Penicillium digitatum on orange fruits at a concentration 20-fold lower than sodium propionate.

Conclusions:

• Synthetic antimicrobial peptides exhibit potent antifungal activity against Penicillium digitatum.
• The primary mechanism involves disruption of the fungal cell membrane and induction of ROS.
• PepGAT, PepKAA, and Mo-CBP3-PepI show significant potential as novel, effective food preservatives against Penicillium digitatum infections.