In most heterothallic mushroom species, inbreeding is avoided by an incompatibility system determined by two loci each with multiple alleles (the A and B mating-type loci). In this study we investigated the genetic structure of the mating-type loci in the tropical oyster mushroom Pleurotus djamor using both positional cloning and degenerate PCR methods. DNA sequences from genomic regions cosegr...

Cell type specification is a fundamental process that all cells must carry out to ensure appropriate behaviors in response to environmental stimuli. In fungi, cell identity is critical for defining "sexes" known as mating types and is controlled by components of mating type (MAT) loci. MAT-encoded genes function to define sexes via two distinct paradigms: 1) by controlling transcription of comp...

About 15,000 species of ascomycete fungi lack a known sexual state. For fungi with asexual states in the anamorph genera Embellisia, Ulocladium, and Alternaria, six species have known sexual states but more than 50 species do not. In sexual filamentous ascomycetes, opposite mating type information at the MAT1 locus regulates mating and the opposite mating type genes each have a clonal, non-reco...

Agaricomycetes, the mushrooms, are considered to have a promiscuous mating system, because most populations have a large number of mating types. This diversity of mating types ensures a high outcrossing efficiency, the probability of encountering a compatible mate when mating at random, because nearly every homokaryotic genotype is compatible with every other. Here I summarize the data frommati...

INTRODUCTION Within the Cryptococcus neoformans species complex, two species and five serotypes are recognized: C. neoformans (var. grubii, serotype A; var. neoformans, serotype D and a hybrid, serotype AD) and C. gattii (serotypes B and C). Mating types a and alpha are designated by a single locus, with the mating type alpha being most prevalent in serotype A and D strains. OBJECTIVE To eval...

Diploids of the yeast Hansenula wingei are nonagglutinative and do not form zygotes in mixed cultures with either sexually agglutinative haploid mating type. However, a low frequency of diploid x haploid cell fusions (about 10(-3)) is detectable by prototrophic selection. This frequency of rare diploid x haploid matings is not increased after the diploid culture is induced for sexual agglutinat...

Discovery of sexual development in the ascomycete Trichoderma reesei (Hypocrea jecorina) as well as detection of a novel class of peptide pheromone precursors in this fungus indicates promising insights into its physiology and lifestyle. Here we investigated the role of the two pheromone receptors HPR1 and HPR2 in the H. jecorina pheromone-system. We found that these pheromone receptors show an...

Blastomyces dermatitidis is a dimorphic fungal pathogen that primarily causes blastomycosis in the midwestern and northern United States and Canada. While the genes controlling sexual development have been known for a long time, the genes controlling sexual reproduction of B. dermatitidis (teleomorph, Ajellomyces dermatitidis) are unknown. We identified the mating-type (MAT) locus in the B. der...

A method to determine the mating competence of Chlamydomonas eugametos was developed. The contribution of each mating type in the pair formation was investigated using asymmetric gamete mixtures. It was established that pair formation is not mediated by a pheromonal attraction mechanism between partner gametes, but depends on collision chances. On the other hand, it was demonstrated that during...

Cell surface carbohydrates, detected by fluorescein isothiocyanate/concanavalin A (FITC-ConA), were identified at four locations on gametes of Chlamydomonas reinhardtii. (1) The cell wall: uniform labelling with FITC-ConA was observed; a substantial number of sites were localized in the sodium dodecyl sulphate-insoluble inner wall, which contains the flagellar collars. (2) The periplasm: a cres...