scholarly journals Evolution of the Mating Type Locus: Insights Gained from the Dimorphic Primary Fungal Pathogens Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii

2007 ◽  
Vol 6 (4) ◽  
pp. 622-629 ◽  
Author(s):  
James A. Fraser ◽  
Jason E. Stajich ◽  
Eric J. Tarcha ◽  
Garry T. Cole ◽  
Diane O. Inglis ◽  
...  
Keyword(s):  
Mating Type ◽  
Fungal Pathogens ◽  
Histoplasma Capsulatum ◽  
Type Systems ◽  
Coccidioides Immitis ◽  
Coccidioides Posadasii ◽  
Unique Region ◽  
Type Locus ◽  
Evolutionary Forces ◽  
Mating Type Locus

ABSTRACT Sexual reproduction of fungi is governed by the mating type (MAT) locus, a specialized region of the genome encoding key transcriptional regulators that direct regulatory networks to specify cell identity and fate. Knowledge of MAT locus structure and evolution has been considerably advanced in recent years as a result of genomic analyses that enable the definition of MAT locus sequences in many species as well as provide an understanding of the evolutionary plasticity of this unique region of the genome. Here, we extend this analysis to define the mating type locus of three dimorphic primary human fungal pathogens, Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii, using genomic analysis, direct sequencing, and bioinformatics. These studies provide evidence that all three species possess heterothallic bipolar mating type systems, with isolates encoding either a high-mobility-group (HMG) domain or an α-box transcriptional regulator. These genes are intact in all loci examined and have not been subject to loss or decay, providing evidence that the loss of fertility upon passage in H. capsulatum is not attributable to mutations at the MAT locus. These findings also suggest that an extant sexual cycle remains to be defined in both Coccidioides species, in accord with population genetic evidence. Based on these MAT sequences, a facile PCR test was developed that allows the mating type to be rapidly ascertained. Finally, these studies highlight the evolutionary forces shaping the MAT locus, revealing examples in which flanking genes have been inverted or subsumed and incorporated into an expanding MAT locus, allowing us to propose an expanded model for the evolution of the MAT locus in the phylum Ascomycota.

scholarly journals Fungal Sex and Pathogenesis

2010 ◽  
Vol 23 (1) ◽  
pp. 140-159 ◽  
Author(s):  
Geraldine Butler
Keyword(s):  
Genome Sequencing ◽  
Mating Type ◽  
Fungal Pathogens ◽  
Bloodstream Infections ◽  
Morbidity And Mortality ◽  
Sexual Cycle ◽  
Human Pathogens ◽  
Type Locus ◽  
Mating Type Locus ◽  
Skin Colonization

SUMMARYHuman fungal pathogens are associated with diseases ranging from dandruff and skin colonization to invasive bloodstream infections. The major human pathogens belong to theCandida,Aspergillus, andCryptococcusclades, and infections have high and increasing morbidity and mortality. Many human fungal pathogens were originally assumed to be asexual. However, recent advances in genome sequencing, which revealed that many species have retained the genes required for the sexual machinery, have dramatically influenced our understanding of the biology of these organisms. Predictions of a rare or cryptic sexual cycle have been supported experimentally for some species. Here, I examine the evidence that human pathogens reproduce sexually. The evolution of the mating-type locus in ascomycetes (includingCandidaandAspergillusspecies) and basidiomycetes (MalasseziaandCryptococcus) is discussed. I provide an overview of how sex is suppressed in different species and discuss the potential associations with pathogenesis.

scholarly journals Identification of the first oomycete mating-type locus sequence in the grapevine downy mildew pathogen, Plasmopara viticola

2020 ◽  
Author(s):  
Yann Dussert ◽  
Ludovic Legrand ◽  
Isabelle D. Mazet ◽  
Carole Couture ◽  
Marie-Christine Piron ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Mating Type ◽  
Type Systems ◽  
Plasmopara Viticola ◽  
Plant Diseases ◽  
Mating Types ◽  
Type Locus ◽  
Grapevine Downy Mildew ◽  
Mating Type Locus ◽  
A Genome

ABSTRACTMating types are self-incompatibility systems that promote outcrossing in plants, fungi and oomycetes. Mating-type genes have been widely studied in plants and fungi, but have yet to be identified in oomycetes, eukaryotic organisms closely related to brown algae that cause many destructive animal and plant diseases. We identified the mating-type locus of Plasmopara viticola, the oomycete responsible for grapevine downy mildew, one of the most damaging grapevine diseases worldwide. Using a genome-wide association approach, we identified a 570 kb repeat-rich non-recombining region controlling mating types, with two highly divergent alleles. We showed that one mating type was homozygous, whereas the other was heterozygous at this locus. The mating-type locus encompassed 40 genes, including one encoding a putative hormone receptor. Our findings have fundamental implications for our understanding of the evolution of mating types, as they reveal a unique determinism involving an asymmetry of heterozygosity, as in sex chromosomes and unlike other mating-type systems. This identification of the mating-type locus in such an economically important crop pathogen also has applied implications, as outcrossing facilitates rapid evolution and resistance to harsh environmental conditions.

scholarly journals rme1 Mutation of Saccharomyces cerevisiae: map position and bypass of mating type locus control of sporulation.

1981 ◽  
Vol 1 (10) ◽  
pp. 958-960 ◽  
Author(s):  
J Rine ◽  
G F Sprague ◽  
I Herskowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Type Locus ◽  
Mating Type Locus ◽  
Type Information

Sporulation in Saccharomyces cerevisiae normally occurs only in MATa/MAT alpha diploids. We show that mutations in RME1 bypassed the requirements for both a and alpha mating type information in sporulation and therefore allowed MATa/MATa and MAT alpha/MAT alpha diploids to sporulate. RME1 was located on chromosome VII, between LEU1 and ADE6.

Transformation of protoplasted yeast cells is directly associated with cell fusion

1984 ◽  
Vol 4 (4) ◽  
pp. 771-778
Author(s):  
S Harashima ◽  
A Takagi ◽  
Y Oshima
Keyword(s):  
Cell Fusion ◽  
Mating Type ◽  
Nuclear Fusion ◽  
Yeast Cells ◽  
Nuclear Markers ◽  
Type Locus ◽  
Mating Type Locus ◽  
Yeast Protoplasts ◽  
Yeast Plasmids ◽  
Binominal Distribution

The frequency of cell fusion during transformation of yeast protoplasts with various yeast plasmids with a chromosome replicon (YRp or YCp) or 2 mu DNA (YEp) was estimated by two methods. In one method, a mixture of protoplasts of two haploid strains with identical mating type and complementary auxotrophic nuclear markers with or without cytoplasmic markers was transformed. When the number of various phenotypic classes of transformants for the nuclear markers was analyzed by equations derived from binominal distribution theory, the frequency of nuclear fusion among the transformants was 42 to 100% in transformations with the YRp or YCp plasmids and 28 to 39% with the YEp plasmids. In another method, a haploid bearing the sir mutation, which allows a diploid (or polyploid) homozygous for the MAT (mating type) locus to sporulate by the expression of the silent mating-type loci HML and HMR, was transformed with the plasmids. Sporulation ability was found in 43 to 95% of the transformants with the YRp or YCp plasmids, and 26 to 31% of the YEp transformants. When cytoplasmic mixing was included with the nuclear fusion, 96 to 100% of the transformants were found to be cell fusants. Based upon these observations, we concluded that transformation of yeast protoplasts is directly associated with cell fusion.

INTERCONVERSION OF YEAST MATING TYPES II. RESTORATION OF MATING ABILITY TO STERILE MUTANTS IN HOMOTHALLIC AND HETEROTHALLIC STRAINS

Genetics ◽  
1977 ◽  
Vol 85 (3) ◽  
pp. 373A-393
Author(s):  
James B Hicks ◽  
Ira Herskowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Yeast Cells ◽  
Mating Types ◽  
Yeast Saccharomyces Cerevisiae ◽  
Type Locus ◽  
Mating Ability ◽  
Mating Type Locus ◽  
Regulatory Information ◽  
Ho Gene

ABSTRACT The two mating types of the yeast Saccharomyces cerevisiae can be interconverted in both homothallic and heterothallic strains. Previous work indicates that all yeast cells contain the information to be both a and α and that the HO gene (in homothallic strains) promotes a change in mating type by causing a change at the mating type locus itself. In both heterothallic and homothallic strains, a defective α mating type locus can be converted to a functional a locus and subsequently to a functional α locus. In contrast, action of the HO gene does not restore mating ability to a strain defective in another gene for mating which is not at the mating type locus. These observations indicate that a yeast cell contains an additional copy (or copies) of α information, and lead to the "cassette" model for mating type interconversion. In this model, HM  a and hmα loci are blocs of unexpressed α regulatory information, and HMα and hm  a loci are blocs of unexpressed a regulatory information. These blocs are silent because they lack an essential site for expression, and become active upon insertion of this information (or a copy of the information) into the mating type locus by action of the HO gene.

Structure and function of the mating-type locus in the homothallic ascomycete, Didymella zeae-maydis

2013 ◽  
Vol 51 (6) ◽  
pp. 814-820 ◽  
Author(s):  
Sung-Hwan Yun ◽  
Olen C. Yoder ◽  
B. Gillian Turgeon
Keyword(s):  
Mating Type ◽  
Structure And Function ◽  
Type Locus ◽  
Mating Type Locus ◽  
And Function
Sign in / Sign up

Export Citation Format

Share Document