Pheromones and pheromone receptors are required for proper sexual development in the homothallic ascomycete Sordaria macrospora.
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 and to G-protein-coupled pheromone receptors of the yeast Saccharomyces cerevisiae. It has been suggested that in S. macrospora, PPG1/PRE2 and PPG2/PRE1 form two cognate pheromone-receptor pairs. To investigate their function, we deleted (delta) pheromone-precursor genes (delta ppg1, delta ppg2) and receptor genes (delta pre1, delta pre2) and generated single- as well as double-knockout strains. No effect on vegetative growth, fruiting-body, and ascospore development was seen in the single pheromone-mutant and receptor-mutant strains, respectively. However, double-knockout strains lacking any compatible pheromone-receptor pair (delta pre2/delta ppg2, delta pre1/delta ppg1) and the double-pheromone mutant (delta ppg1/delta ppg2) displayed a drastically reduced number of perithecia and sexual spores, whereas deletion of both receptor genes (delta pre1/delta pre2) completely eliminated fruiting-body and ascospore formation. The results suggest that pheromones and pheromone receptors are required for optimal sexual reproduction of the homothallic S. macrospora.
Mayrhofer
Severine
S
Department of General and Molecular Botany, Ruhr-University of Bochum, 44780 Bochum, Germany.
Weber
Jan M
JM
Pöggeler
Stefanie
S
D003433:Crosses, Genetic; D017353:Gene Deletion; D049770:Genes, Mating Type, Fungal; D009154:Mutation; D030781:Organisms, Genetically Modified; D043563:Receptors, Pheromone / Q000235:genetics / Q000502:physiology*; D012724:Sex Attractants / Q000235:genetics / Q000502:physiology*; D020037:Sordariales / Q000235:genetics / Q000502:physiology*
D043563:Receptors, Pheromone; D012724:Sex Attractants