Autophagy Deficiency Promotes β-Lactam Production inPenicillium chrysogenum

Abstract

ABSTRACTWe have investigated the significance of autophagy in the production of the β-lactam antibiotic penicillin (PEN) by the filamentous fungusPenicillium chrysogenum. In this fungus PEN production is compartmentalized in the cytosol and in peroxisomes. We demonstrate that under PEN-producing conditions significant amounts of cytosolic and peroxisomal proteins are degraded via autophagy. Morphological analysis, based on electron and fluorescence microscopy, revealed that this phenomenon might contribute to progressive deterioration of late subapical cells. We show that deletion of theP. chrysogenumortholog ofSaccharomyces cerevisiaeserine-threonine kinaseatg1results in impairment of autophagy. InP. chrysogenum atg1cells, a distinct delay in cell degeneration is observed relative to wild-type cells. This phenomenon is associated with an increase in the enzyme levels of the PEN biosynthetic pathway and enhanced production levels of this antibacterial compound.