In vivo CRISPR-Cas9 expression in Candida glabrata, Candida bracarensis, and Candida nivariensis: A versatile tool to study chromosomal break repair.

The CRISPR-Cas9 system is extremely useful for genome editing in many species, including the model yeast Saccharomyces cerevisiae, and other yeast species. We have previously reported the use of an inducible CRISPR-Cas9 system in Candida glabrata, which allows genome editing but also the study of double-strand break (DSB) repair. We report, in this study, a comparable system for C.

Lessons from the Nakaseomyces: mating-type switching, DSB repair and evolution of Ho.

This short paper aims to review what our recent studies in the Nakaseomyces yeasts, principally Candida glabrata, reveal about the evolution of the mating-type switching system and its components, as well as about the repair of chromosomal double-strand breaks in this clade. In the model yeast Saccharomyces cerevisiae, the study of mating-type switching has, over the years, led to major discoveries in how cells process chromosomal breaks. Indeed, in this species, switching, which allows every haploid cell to produce cells of opposite mating types that can mate together, is initiated by the Ho endonuclease, linking sexual reproduction to a programmed chromosomal cut.

Functional networks of co-expressed genes to explore iron homeostasis processes in the pathogenic yeast .

is a cause of life-threatening invasive infections especially in elderly and immunocompromised patients. Part of human digestive and urogenital microbiota, faces varying iron availability, low during infection or high in digestive and urogenital tracts. To maintain its homeostasis, must get enough iron for essential cellular processes and resist toxic iron excess.

A single Ho-induced double-strand break at the MAT locus is lethal in Candida glabrata.

Mating-type switching is a complex mechanism that promotes sexual reproduction in Saccharomycotina. In the model species Saccharomyces cerevisiae, mating-type switching is initiated by the Ho endonuclease that performs a site-specific double-strand break (DSB) at MAT, repaired by homologous recombination (HR) using one of the two silent mating-type loci, HMLalpha and HMRa. The reasons why all the elements of the mating-type switching system have been conserved in some Saccharomycotina, that do not show a sexual cycle nor mating-type switching, remain unknown.

Genome editing in the yeast Nakaseomyces delphensis and description of its complete sexual cycle.

The environmental yeast Nakaseomyces delphensis is, phylogenetically, the closest known species to Candida glabrata, a major fungal pathogen of humans. C. glabrata is haploid and described as asexual, while N.

A new inducible CRISPR-Cas9 system useful for genome editing and study of double-strand break repair in Candida glabrata.

In recent years, the CRISPR-Cas9 system has proven extremely useful for genome editing in many species, including the model yeast Saccharomyces cerevisiae and other yeast species such as Candida glabrata. Inducible CRISPR-Cas9 systems have the additional advantage of allowing to separate the transformation step of the organism by the CRISPR-Cas9 system, from the cutting and repair steps. This has indeed been developed in S.

Genome Comparisons of Serial Clinical Isolates Reveal Patterns of Genetic Variation in Infecting Clonal Populations.

is an opportunistic fungal pathogen that currently ranks as the second most common cause of candidiasis. Although the mechanisms underlying virulence and drug resistance in are now starting to be elucidated, we still lack a good understanding of how this yeast adapts during the course of an infection. Outstanding questions are whether the observed genomic plasticity of plays a role during infection, or what levels of genetic variation exist within an infecting clonal population.

André Goffeau's imprinting on second generation yeast "genomologists".

All authors of the present paper have worked in labs that participated to the sequencing effort of the Saccharomyces cerevisiae reference genome, and we owe to this the fact that we have all chosen to work on genomics of yeasts. S. cerevisiae has been a popular model species for genetics since the 20th century as well as being a model for general eukaryotic cellular processes.

Genomes shed light on the secret life of Candida glabrata: not so asexual, not so commensal.

Candida glabrata is an opportunistic yeast pathogen, whose incidence has increased over the last decades. Despite its genus name, this species is actually more closely related to the budding yeast Saccharomyces cerevisiae than to other Candida pathogens, such as Candida albicans. Hence, C.

Patterns of Genomic Variation in the Opportunistic Pathogen Candida glabrata Suggest the Existence of Mating and a Secondary Association with Humans.

Candida glabrata is an opportunistic fungal pathogen that ranks as the second most common cause of systemic candidiasis. Despite its genus name, this yeast is more closely related to the model yeast Saccharomyces cerevisiae than to other Candida pathogens, and hence its ability to infect humans is thought to have emerged independently. Moreover, C.

Life-history strategies and carbon metabolism gene dosage in the Nakaseomyces yeasts.

The Nakaseomyces clade consists of a group of six hemiascomyceteous yeasts (Candida glabrata, Nakaseomyces delphensis, C. nivarensis, C. bracarensis, C.

Efficient Mating-Type Switching in Candida glabrata Induces Cell Death.

Candida glabrata is an apparently asexual haploid yeast that is phylogenetically closer to Saccharomyces cerevisiae than to Candida albicans. Its genome contains three MAT-like cassettes, MAT, which encodes either MATa or MATalpha information in different strains, and the additional loci, HML and HMR. The genome also contains an HO gene homolog, but this yeast has never been shown to switch mating-types spontaneously, as S.

Trends in IT Innovation to Build a Next Generation Bioinformatics Solution to Manage and Analyse Biological Big Data Produced by NGS Technologies.

Sequencing the human genome began in 1994, and 10 years of work were necessary in order to provide a nearly complete sequence. Nowadays, NGS technologies allow sequencing of a whole human genome in a few days. This deluge of data challenges scientists in many ways, as they are faced with data management issues and analysis and visualization drawbacks due to the limitations of current bioinformatics tools.

Chaos of Rearrangements in the Mating-Type Chromosomes of the Anther-Smut Fungus Microbotryum lychnidis-dioicae.

Sex chromosomes in plants and animals and fungal mating-type chromosomes often show exceptional genome features, with extensive suppression of homologous recombination and cytological differentiation between members of the diploid chromosome pair. Despite strong interest in the genetics of these chromosomes, their large regions of suppressed recombination often are enriched in transposable elements and therefore can be challenging to assemble. Here we show that the latest improvements of the PacBio sequencing yield assembly of the whole genome of the anther-smut fungus, Microbotryum lychnidis-dioicae (the pathogenic fungus causing anther-smut disease of Silene latifolia), into finished chromosomes or chromosome arms, even for the repeat-rich mating-type chromosomes and centromeres.

Candida glabrata: a deadly companion?

The yeast Candida glabrata has become a major fungal opportunistic pathogen of humans since the 1980s. Contrary to what its name suggests, it is much closer, phylogenetically, to the model yeast Saccharomyces cerevisiae than to the most prevalent human fungal pathogen, Candida albicans. Its similarity to S.

The complete genome of Blastobotrys (Arxula) adeninivorans LS3 - a yeast of biotechnological interest.

Background: The industrially important yeast Blastobotrys (Arxula) adeninivorans is an asexual hemiascomycete phylogenetically very distant from Saccharomyces cerevisiae. Its unusual metabolic flexibility allows it to use a wide range of carbon and nitrogen sources, while being thermotolerant, xerotolerant and osmotolerant.

Results: The sequencing of strain LS3 revealed that the nuclear genome of A.

Comparative genomics of emerging pathogens in the Candida glabrata clade.

Background: Candida glabrata follows C. albicans as the second or third most prevalent cause of candidemia worldwide. These two pathogenic yeasts are distantly related, C.

A mouse model for Candida glabrata hematogenous disseminated infection starting from the gut: evaluation of strains with different adhesion properties.

Adhesion to digestive mucosa is considered a crucial first step in the pathogenicity of invasive Candida infections. Candida glabrata disseminated infections predominantly start from the gut. A mouse model of disseminated infection starting from the gut was set up.

Pichia sorbitophila, an Interspecies Yeast Hybrid, Reveals Early Steps of Genome Resolution After Polyploidization.

Polyploidization is an important process in the evolution of eukaryotic genomes, but ensuing molecular mechanisms remain to be clarified. Autopolyploidization or whole-genome duplication events frequently are resolved in resulting lineages by the loss of single genes from most duplicated pairs, causing transient gene dosage imbalance and accelerating speciation through meiotic infertility. Allopolyploidization or formation of interspecies hybrids raises the problem of genetic incompatibility (Bateson-Dobzhansky-Muller effect) and may be resolved by the accumulation of mutational changes in resulting lineages.

Insertion site preference of Mu, Tn5, and Tn7 transposons.

Background: Transposons, segments of DNA that can mobilize to other locations in a genome, are often used for insertion mutagenesis or to generate priming sites for sequencing of large DNA molecules. For both of these uses, a transposon with minimal insertion bias is desired to allow complete coverage with minimal oversampling.

Findings: Three transposons, Mu, Tn5, and Tn7, were used to generate insertions in the same set of fosmids containing Candida glabrata genomic DNA.

Having sex, yes, but with whom? Inferences from fungi on the evolution of anisogamy and mating types.

The advantage of sex has been among the most debated issues in biology. Surprisingly, the question of why sexual reproduction generally requires the combination of distinct gamete classes, such as small and large gametes, or gametes with different mating types, has been much less investigated. Why do systems with alternative gamete classes (i.

Unraveling the genomic diversity of small eukaryotes.

A report of the meeting Comparative Genomics of Eukaryotic Microorganisms, 17-22 October 2009, San Feliu de Guixols, Spain.

Complete mitochondrial genome sequences of three Nakaseomyces species reveal invasion by palindromic GC clusters and considerable size expansion.

Here we report the sequence of three mitochondrial genomes from yeasts of the Nakaseomyces clade that includes the pathogenic yeast Candida glabrata, namely, that of Kluyveromyces delphensis, Candida castellii and Kluyveromyces bacillisporus. The gene content is equivalent to that of C. glabrata, but reveals the existence of new group I introns in COX1 and CYTB and new potential intronic endonucleases.