Transcription analysis of pheromone receptor genes hpr1 and hpr2 in Δblr1, Δblr2, Δblr1 Δblr2 and Δenv1 strains compared to the wild type. Strains were cultivated in daylight at 22°C on malt-agar plates, i.e., conditions corresponding to mating assays. At indicated time points of 3, 4, and 6 days, confronted wild-type strains of opposite mating types undergo stages of precontact (P), initial contact between the colonies (C), and the macroscopically visible start of fruiting body formation (F), respectively. RNA was isolated at these time points after inoculation of the indicated strain from mycelia harvested from the growth front of the hyphae.