Loss and fragmentation of chromosome 5 are major events linked to the adaptation of rad52-ΔΔ strains of Candida albicans to sorbose

Candida albicans can adapt and grow on sorbose plates by losing one copy of Chr5. Since rad52 mutants of Saccharomyces cerevisiae lose chromosomes at a high rate, we have investigated the ability of C. albicans rad52 to adapt to sorbose. Carad52-ΔΔ mutants generate Sou+ strains earlier than wild-type but the final yield is lower, probably because they die at a higher rate in sorbose. As other strains of C. albicans, CAF2 and rad52-ΔΔ derivatives generate Sou+ strains by a loss of one copy of Chr5 about 75% of the time. In addition, rad52 strains were able to produce Sou+ strains by a fragmentation/deletion event in one copy of Chr5, consisting of loss of a region adjacent to the right telomere. Finally, both CAF2 and rad52-ΔΔ produced Sou+ strains with two apparent full copies of Chr5, suggesting that additional genomic changes may also regulate adaptation to sorbose.