The quorum-sensing molecule 2-phenylethanol impaired conidial germination, hyphal membrane integrity and growth of Penicillium expansum and Penicillium nordicum

Aims The aim of the study was to investigate the antifungal effects of a quorum sensing-molecule, 2-phenylethanol, against the food spoilage moulds Penicillium expansum and Penicillium nordicum. Methods and results Conidial germination of the tested Penicillium spp. (three strains in total) were inhibited by treatments with 2-phenylethanol in a concentration-dependent manner. Germinated conidia was significantly reduced from 4·4-16·7% at 7·5 mmol l-1 and completely inhibited at 15 mmol l-1 2-phenylethanol. Integrity of conidial cell membranes was unaffected by 2-phenylethanol resulting in reversible inhibition pattern of germination. In contrast, membrane permeability of actively growing hyphae was severely compromised, showing 63·5 - 75·7% membrane damage upon treatment with 15 mmol l-1 2-phenylethanol. The overall inhibitory effect of 2-phenylethanol on colony development and growth of P. expansum and P. nordicum was additionally confirmed. Conclusions 2-phenylethanol inhibits conidial germination and growth of P. expansum and P. nordicum in a nonlethal, reversible and concentration-dependent manner. Significance and impact of the study The study indicates that 2-phenylethanol can find potential application as an antifungal agent for biological control of moulds in the food industry.