Heterotrimeric G protein alpha subunit controls growth, stress response, extracellular protease activity, and cyclopiazonic acid production in Penicillium camemberti

- Penicillium camemberti strains expressing a dominant allele of Gαi were obtained.
- Gαi reduces the growth and sporulation rate in the fungus.
- Gαi reduces extracellular proteases and cyclopiazonic acid production.
- Gαi reduces heat and osmotic stress resistance of P. camemberti.
- Gαi stimulates conidial germination in the absence of carbon sources.

The fungus Penicillium camemberti is widely used in the ripening of various bloomy-rind cheeses. Several properties of P. camemberti are important in cheese ripening, including conidiation, growth and enzyme production, among others. However, the production of mycotoxins such as cyclopiazonic acid during the ripening process by P. camemberti has raised concerns among consumers that demand food with minimal contamination. Here we show that overexpressing an α-subunit from the subgroup I of the heterotrimeric G protein (Gαi) influences several of these processes: it negatively affects growth in a media-dependent manner, triggers conidial germination, reduces the rate of sporulation, affects thermal and osmotic stress resistance, and also extracellular protease and cyclopiazonic acid production. Our results contribute to understanding the biological determinants underlying these biological processes in the economically important fungus P. camemberti.