Life-history strategies and carbon metabolism gene dosage in the Nakaseomyces yeasts
Résumé
The Nakaseomyces clade consists of a group of six hemiascomyceteous yeasts (Candida glabrata, Nakaseomyces delphensis, Candida nivarensis, Candida bracarensis, Candida castelli, Nakaseomyces bacillisporus), phylogenetically close to the yeast Saccharomyces cerevisiae, their representative being the well-known pathogenic yeast Candida glabrata. Four species had been previously examined for their carbon assimilation properties and found to have similar properties to S. cerevisiae (repression of respiration in high glucose- i.e. Crabtree-positivity- and being a facultative anaerobe). We examined here the complete set of the six species for their carbon metabolic gene content. We also measured different metabolic and life-history traits (glucose consumption rate, population growth rate, carrying capacity, cell size, cell and biomass yield). We observed deviations from the glycolytic gene redundancy observed in S. cerevisiae presumed to be an important property for the Crabtree positivity, especially for the two species Candida castelli and Nakaseomyces bacillisporus which frequently have only one gene copy, but different life strategies. Therefore we show that the decrease in carbon metabolic gene copy cannot be simply associated to a reduction of glucose consumption rate and can be counterbalanced by other beneficial genetic variations.