Increased Virulence and Competitive Advantage of a/α Over a/a or α/α Offspring Conserves the Mating System of Candida albicans

Academic Article


  • Abstract The majority of Candida albicans strains in nature are a/α and must undergo homozygosis to a/a or α/α to mate. Here we have used a mouse model for systemic infection to test the hypothesis that a/α strains predominate in nature because they have a competitive advantage over a/a and α/α offspring in colonizing hosts. Single-strain injection experiments revealed that a/α strains were far more virulent than either their a/a or α/α offspring. When equal numbers of parent a/α and offspring a/a or α/α cells were co-injected, a/α always exhibited a competitive advantage at the time of extreme host morbidity or death. When equal numbers of an engineered a/a/α2 strain and its isogenic a/a parent strain were co-injected, the a/a/α2 strain exhibited a competitive advantage at the time of host morbidity or death, suggesting that the genotype of the mating-type (MTL) locus, not associated genes on chromosome 5, provides a competitive advantage. We therefore propose that heterozygosity at the MTL locus not only represses white-opaque switching and genes involved in the mating process, but also affects virulence, providing a competitive advantage to the a/α genotype that conserves the mating system of C. albicans in nature.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Lockhart SR; Wu W; Radke JB; Zhao R; Soll DR
  • Start Page

  • 1883
  • End Page

  • 1890
  • Volume

  • 169
  • Issue

  • 4