sentence: Interestingly , while the genus appears to be heterothallic , based on the presence of either the MAT1-1 or MAT1-2 idiomorph in all strains examined , all three fully sequenced isolates ( Pb01 , Pb03 and Pb18 ) encode both the receptors for the mating a-pheromone ( PreA ) and the α - pheromone ( PreB ) .