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Adaptive differences between Penicillium roqueforti cheese and non-cheese populations
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International audience. Penicillium roqueforti is the emblematic fungus used for blue cheese making. Population genomics analyses revealed five genetic clusters within this species associated with different environments, the clusters being named: “Roquefort cheese”, “non-Roquefort blue cheese”, “Termignon cheese”, “silage”, “lumber/food spoiler”. The existence of these different genetic populations associated with habitats exhibiting contrasting environmental conditions and compositions raises questions about their adaptation to their respective environments. In this context, we compared growth kinetics between the five populations, under various abiotic conditions, carbon sources or fungal growth inhibitors relevant for their environments.To do so, high throughput growth monitoring was performed using laser nephelometry for several strains per population using the following abiotic conditions: pH (2 to 14), temperature (4 to 35°C), salinity (0 to 10% NaCl) and lactic acid concentration (0 to 1.5M). Growth rates were measured for each condition and secondary modeling was used to determine cardinal values. Growth rates were also compared between populations in minimum medium supplemented with different carbon sources (glucose, maltose, starch, cellobiose, pectin, xylose, lactose and galactose). The impact of two inhibitors (tebuconazole and potassium sorbate) on growth rates was also studied.The obtained cardinal growth values differentiated the “non-Roquefort blue cheese” population from the other populations, with a greater tolerance to salt and lactic acid, and a lower optimal growth temperature. These differences in cardinal values are in agreement with an adaptation of the “non-Roquefort blue cheese” population to the typical cheese environment. Our study also showed differences between cheese and non-cheese populations in their ability to use various carbon sources. The results are consistent with a domestication of cheese populations.
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