Identification of quantitative trait loci (QTLs) for key cheese making phenotypes in the blue-cheese mold Penicillium roqueforti

Understanding the genetic determinants underlying quantitative traits is crucial for our understanding of adaptation and for improving varieties in domesticated organisms. Penicillium roqueforti is the mold used worldwide for blue cheese making. The two domesticated cheese populations in P. roqueforti each display very little genetic diversity, but are highly differentiated. We therefore generated progenies between these populations despite reduced fertility. As expected, offspring displayed high variation in multiple traits important for cheese making, involved in aspect, flavor or food security, such as color, lipolysis, proteolysis and extrolite production. We detected genetic determinants for most of these traits, paving the way for generating new varieties. Several genomic regions impacted multiple traits, as often found in domesticated organisms. These findings further contribute to our understanding of the genetic mechanisms underlying rapid adaptation to new environments, likely involving master gene regulation impacting multiple genes.