Moulded by humans: The domestication of blue-veined cheese fungi.

It is hard to imagine a world without food-associated microbes. The production of bread, wine, beer, salami, coffee, chocolate, cheese and many other foods and beverages all rely on specific microbes. In cheese, myriad microbial species collaborate to yield the complex organoleptic properties that are appreciated by millions of people worldwide. In the early days of cheese making, these complex communities emerged spontaneously from the natural flora associated with the raw materials, the equipment, the production environment or craftsmen involved in the production process. However, in some cases, the microbes shifted their natural habitat to the new cheese-associated environment. The most obvious cause of this is backslopping, where part of a fermented product is used to inoculate the next batch. In addition, some microbes may simply adhere to the tools used in the production process. These microbial communities gradually adapted to the novel man-made niches, a process referred to as "domestication." Domestication is associated with specific genomic and phenotypic changes and ultimately leads to lineages that are genetically and phenotypically distinct from their wild ancestors. In this issue of Molecular Ecology, Dumas et al. have investigated a prime example of cheese-associated microbes, the fungus Penicillium roqueforti. The authors identified several hallmarks of domestication in the genome and phenome of this species, allowing them to hypothesize about the origin of blue-veined cheese fungi domestication, and the specific evolutionary processes involved in adaptation to the cheese matrix.