Meiotic pairing in homothallic S. cerevisiae was studied by tetrad analysis, using strains that were trisomic or tetrasomic for chromosomes. I. The disomic segregants of these strains produce tetrasomic spore colonies that can be distinguished by their phenotype. Results indicated the existence of preferential pairing and nonrandom assortment of chromosomes at meisosis I. The frequency of cross...

The homothallic, filamentous ascomycete Sordaria macrospora is self-fertile and produces sexual fruiting bodies (perithecia) without a mating partner. Even so, S. macrospora transcriptionally expresses two pheromone-precursor genes (ppg1 and ppg2) and two pheromone-receptor genes (pre1 and pre2). The proteins encoded by these genes are similar to alpha-factor-like and a-factor-like pheromones a...

During large-scale surveys for soilborne Phytophthora species in forests and semi-natural stands and nurseries in Europe during the last decade, homothallic Phytophthora isolates with paragynous antheridia, semipapillate persistent sporangia and a growth optimum around 25 degrees C which did not form catenulate hyphal swellings, were recovered from 39 host species in 16 families. Based on their...

Mating-type genes in fungi encode regulators of mating and sexual development. Heterothallic ascomycete species require different sets of mating-type genes to control nonself-recognition and mating of compatible partners of different mating types. Homothallic (self-fertile) species also carry mating-type genes in their genome that are essential for sexual development. To analyze the molecular b...