Functionality of the Paracoccidioides Mating α-Pheromone-Receptor System

Abstract

Recent evidence suggests that Paracoccidioides species have the potential to undergo sexual reproduction, although no sexual cycle has been identified either in nature or under laboratory conditions. In the present work we detected low expression levels of the heterothallic MAT loci genes MAT1-1 and MAT1-2, the α-pheromone (PBα) gene, and the α- and a-pheromone receptor (PREB and PREA) genes in yeast and mycelia forms of several Paracoccidioides isolates. None of the genes were expressed in a mating type dependent manner. Stimulation of P. brasiliensis MAT1-2 strains with the synthetic α-pheromone peptide failed to elicit transcriptional activation of MAT1-2, PREB or STE12, suggesting that the strains tested are insensitive to α-pheromone. In order to further evaluate the biological functionality of the pair α-pheromone and its receptor, we took advantage of the heterologous expression of these Paracoccidioides genes in the corresponding S. cerevisiae null mutants. We show that S. cerevisiae strains heterologously expressing PREB respond to Pbα pheromone either isolated from Paracoccidioides culture supernatants or in its synthetic form, both by shmoo formation and by growth and cell cycle arrests. This allowed us to conclude that Paracoccidioides species secrete an active α-pheromone into the culture medium that is able to activate its cognate receptor. Moreover, expression of PREB or PBα in the corresponding null mutants of S. cerevisiae restored mating in these non-fertile strains. Taken together, our data demonstrate pheromone signaling activation by the Paracoccidioides α-pheromone through its receptor in this yeast model, which provides novel evidence for the existence of a functional mating signaling system in Paracoccidioides.

A modular yeast biosensor for low-cost point-of-care pathogen detection

“…PCM is caused by inhalation of airborne conidia produced by mycelium of the soil ascomycete P. brasiliensis ( 29 ). Recent identification of the genetic components underlying its mating system ( 30 ) enabled us to pursue specific yeast-based detection of P. brasiliensis , which could facilitate detection of its environmental reservoir.…”

“…3E ). The peptide produced by H. capsulatum ( 30 ), the causative agent of histoplasmosis ( 18 ), is identical to that of P. brasiliensis and could be detected using both biosensor strains (fig. S7).…”

Paracoccidioides Species Complex: Ecology, Phylogeny, Sexual Reproduction, and Virulence

“…The biological functionality of α-pheromone and its receptor was elucidated using heterologous expression of these Paracoccidioides genes in the corresponding Saccharomyces cerevisiae null mutants [21]. Features related to sexual reproduction, such as coiled constricted hyphae and knob-like structures, were observed in Paracoccidioides species, indicating the formation of young ascocarps.…”

Identification and characterization of expressed retrotransposons in the genome of the Paracoccidioides species complex

“…In organisms without sexual reproduction, homologous recombination between TEs might be associated with the generation of genetic diversity [ 11 ]. Recent evidence suggests that Paracoccidioides species have the potential to undergo sexual reproduction, although to date a sexual reproduction stage has not been described [ 41 , 42 ]. We identified potentially active retrotransposons in Paracoccidioides genomes and also described potentially active DNA transposons.…”