A complementation analysis by parasexual recombination of Candida albicans morphological mutants

Area of Science:

• Mycology
• Cell Biology
• Genetics

Background:

• Candida albicans exhibits dimorphism, switching between yeast and filamentous forms.
• This morphological transition is crucial for its pathogenicity and survival.
• Understanding the genetic control of dimorphism is vital for developing targeted therapies.

Purpose of the Study:

• To investigate the effects of benomyl on Candida albicans morphogenesis.
• To identify and genetically characterize mutants with altered dimorphic transitions.
• To elucidate the genes involved in regulating Candida albicans dimorphism.

Main Methods:

• Benomyl treatment of Candida albicans strains to induce morphological mutants.
• Isolation and characterization of yeast (Y) and rough colony (R) phenotypes.
• Genetic complementation analysis using protoplast fusion with nutritional and conditional lethal markers.

Main Results:

• Benomyl induced stable morphological mutants with altered morphogenesis, unable to bud or form blastospores (Y-phenotype) and growing as filaments (R-phenotype).
• Genetic complementation analysis revealed two distinct complementation groups, indicating mutations in two relevant genes.
• Protoplast fusion crosses between complementing mutants restored wild-type morphology (oval yeast cells, smooth colonies), while non-complementing crosses retained mutant phenotypes.

Conclusions:

• Benomyl is a potent inducer of heritable morphological changes in Candida albicans.
• Two genes have been identified as critical for regulating the dimorphic transition from blastospores to mycelium.
• These findings provide insights into the genetic basis of Candida albicans dimorphism and potential therapeutic targets.