Inhibitory effect and action mechanism of perillaldehyde on the Fusarium graminearum in postharvest fresh ginger

Abstract

Perillaldehyde, the predominant antimicrobial compound found in Perilla, offers a safe and highly efficient solution for the preservation of fruits and vegetables. This study delved into the inhibitory potential of perillaldehyde against Fusarium graminearum, the primary postharvest pathogen affecting ginger. The current research encompassed both in vitro and in vivo investigations. Our results revealed that the minimum inhibitory concentration of perillaldehyde required to combat F. graminearum was 240 µL·L−1. At this concentration, perillaldehyde exhibited remarkable efficacy in reducing ginger disease rates, with a staggering 99.9% inhibition in mycelium growth. Furthermore, perillaldehyde disrupted the integrity of the fungal cell membrane, hence elevated outer membrane permeability. This resulted in the leakage of proteins, sugars, nucleic acids, and an increase in electrical conductivity within F. graminearum. Notably, perillaldehyde treatment led to a substantial increase in malondialdehyde content in F. graminearum, which was 2.5 times higher than the control group. It also significantly reduced ergosterol content and ATPase activity by 87% and 85%, respectively. The presence of reactive oxygen species (ROS) increased, exacerbating membrane peroxidation damage. Electron microscopy unveiled the transformative impact of perillaldehyde on F. graminearum. Perillaldehyde induced extensive shrinkage, morphological thinning, spatial structure folding, and the leakage of essential cell nutrients, cell wall membranes, and organelle damage. In summary, perillaldehyde's mode of action disrupts the energy supply and metabolism of mycelia, ultimately inducing apoptosis and proving to be a potent inhibitor of F. graminearum. Its application in preserving fresh ginger effectively extended the nutritional quality of the product, demonstrating its potential as an efficient preservative. This biological preservation technique offers convenience over traditional physical methods and addresses concerns related to chemical residue, thereby opening new avenues for ginger green preservation technology.