Schizosaccharomyces pombe, the fission yeast, cells alternate between P- and M-mating type, controlled by the alternate alleles of the mating-type locus (mat1). The mat1 switching occurs by replacing mat1 with a copy derived from a silenced "donor locus," mat2P or mat3M. The mechanism of donor choice ensuring that switching occurs primarily and productively to the opposite type, called directio...

The fourth intron of the Euglena gracilis chloroplast photosystem II gene, psbCi4, is a 1,605-bp twintron composed of two group III introns and a coding locus for a 458-aa polypeptide, mat1, located in the internal intron. psbCi4 homologs have been identified in seven euglenoids, including E. myxocylindracea, E. viridis, E. deses, E. pisciformis, Cryptoglena pigra, Eutreptia sp., and Lepocincli...

Epigenetic events allow the inheritance of phenotypic changes that are not caused by an alteration in DNA sequence. Here we characterize an epigenetic phenomenon occurring in the mating-type region of fission yeast. Cells of fission yeast switch between the P and M mating-type by interconverting their expressed mating-type cassette between two allelic forms, mat1-P and mat1-M. The switch result...

Aflatoxins are produced by Aspergillus flavus and A. parasiticus in oil-rich seed and grain crops and are a serious problem in agriculture, with aflatoxin B₁ being the most carcinogenic natural compound known. Sexual reproduction in these species occurs between individuals belonging to different vegetative compatibility groups (VCGs). We examined natural genetic variation in 758 isolates of A. ...

Fusarium wilt caused by Fusarium oxysporum Schltdl. f.sp. phaseoli (Fop), is one of the important diseases of the common bean in Iran and many of the bean growing countries. Incidence of the disease has been reported in tropical and semi-tropical regions of the world. This study was carried out to characterize genetic diversity of F. oxysporum isolates from the common bean by vegetative compati...

Two mating-type genes, designated MAT1-1-1 and MAT1-2-1, were cloned and sequenced from the presumed asexual ascomycete Cladosporium fulvum (syn. Passalora fulva). The encoded products are highly homologous to mating-type proteins from members of the Mycosphaerellaceae, such as Mycosphaerella graminicola and Cercospora beticola. In addition, the two MAT idiomorphs of C. fulvum showed regions of...

Sexual reproduction in fungi is controlled by genes present at the mating type (MAT) locus, which typically harbors transcription factors that influence the expression of many sex-related genes. The MAT locus exists as two alternative idiomorphs in ascomycetous fungi and sexual reproduction is initiated when genes from both idiomorphs are expressed. Thus, the gene content of this locus determin...

Schizosaccharomyces pombe cells can switch between two mating types, plus (P) and minus (M). The change in cell type occurs due to a replication-coupled recombination event that transfers genetic information from one of the silent-donor loci, mat2P or mat3M, into the expressed mating-type determining mat1 locus. The mat1 locus can as a consequence contain DNA encoding either P or M information....

Yeast mating type is determined by the genotype at the mating type locus (MAT). In homothallic (self-fertile) Saccharomycotina such as Saccharomyces cerevisiae and Kluveromyces lactis, high-efficiency switching between a and α mating types enables mating. Two silent mating type cassettes, in addition to an active MAT locus, are essential components of the mating type switching mechanism. In thi...