Functionality of the Paracoccidioides mating α-pheromone-receptor system.

Area of Science:

• Mycology
• Fungal Genetics
• Molecular Biology

Background:

• Paracoccidioides species are known fungal pathogens.
• Evidence suggests Paracoccidioides may possess a sexual cycle, but it has not been observed.
• Key genes involved in sexual reproduction, including mating type (MAT) loci and pheromone signaling, have been identified but their function remains unclear.

Purpose of the Study:

• To investigate the expression and functionality of mating-related genes in Paracoccidioides.
• To determine if Paracoccidioides produces active pheromones and if these can signal through their cognate receptors.
• To provide evidence for a functional mating signaling system in Paracoccidioides.

Main Methods:

• Analyzed the expression of MAT1-1, MAT1-2, PBα, PREB, and PREA genes in different Paracoccidioides forms.
• Tested the response of P. brasiliensis strains to synthetic alpha-pheromone.
• Utilized heterologous expression of Paracoccidioides pheromone and receptor genes in Saccharomyces cerevisiae null mutants.

Main Results:

• Low expression levels of mating and pheromone genes were detected in Paracoccidioides, not dependent on mating type.
• Paracoccidioides strains showed insensitivity to synthetic alpha-pheromone.
• Heterologous expression in S. cerevisiae demonstrated that Paracoccidioides alpha-pheromone activates its receptor, leading to mating responses.
• Restoration of mating in S. cerevisiae null mutants by expressing Paracoccidioides pheromone genes.

Conclusions:

• Paracoccidioides species secrete a functional alpha-pheromone that activates its cognate receptor.
• A functional pheromone signaling pathway exists in Paracoccidioides.
• These findings provide novel evidence supporting the existence of a sexual cycle and mating system in Paracoccidioides.