Wallemia mellicola

Last updated

Wallemia mellicola
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Wallemiomycetes
Order: Wallemiales
Family: Wallemiaceae
Genus: Wallemia
Species:
W. mellicola
Binomial name
Wallemia mellicola
S. Jančič, H.D.T. Nguyen, Seifert & Gunde-Cim. 2015

Wallemia mellicola is a xerophilic fungus of the phylum Basidiomycota, described in 2015 upon taxonomic revision of the species Wallemia sebi . [1] A large amount of published research referring to W. sebi was likely actually performed on W. mellicola. An example of this is the sequencing of the W. mellicola genome, which was published under the name of W. sebi. [2]

It has a worldwide distribution and is often found in habitats with low accessibility of water, from food preserved with high concentrations of sugar, salt or with drying, to dried straw and house dust. It has rarely been reported as the cause of human infections. [3]

Like other species of the same genus, W. mellicola grows at low water activity, however it is not obligately xerophilic and can grow without additional solute in the growth medium. It grows at salt concentrations up to 24% NaCl, 13% MgCl2 and at temperatures between 10 °C and 34 °C. [1]

W. mellicola has a compact genome of 9.8 Mb with few repeats, which is one of the smallest genomes in Basidiomycota and in Agaricomycota. [2] Three gene family expansions that were observed in W. mellicola were considered significant, including heat shock protein, stress responsive alpha-beta barrel, and amino acid transporter, and they may be responsible for the survival W. mellicola at low water activity. Genes involved in High Osmolarity Glycerol signalling pathway were also found and were suggested to play an important role in the adaptation to osmotic stress. Wallemia mellicola also have a large number of transporters that allow it to survive in hyperosmotic conditions. [2] After sequencing the genomes of additional 25 strains of W. mellicola, these was found to form a relatively homogeneous and widespread population. [4] According to population genomic data the species is at least occasionally recombining. Two versions of a putative mating-type locus have been found in the sequenced genomes, each present in approximately half of the strains. [4]

Related Research Articles

A halophile is an extremophile that thrives in high salt concentrations. In chemical terms, halophile refers to a Lewis acidic species that has some ability to extract halides from other chemical species.

Halotolerance is the adaptation of living organisms to conditions of high salinity. Halotolerant species tend to live in areas such as hypersaline lakes, coastal dunes, saline deserts, salt marshes, and inland salt seas and springs. Halophiles are organisms that live in highly saline environments, and require the salinity to survive, while halotolerant organisms can grow under saline conditions, but do not require elevated concentrations of salt for growth. Halophytes are salt-tolerant higher plants. Halotolerant microorganisms are of considerable biotechnological interest.

<span class="mw-page-title-main">Basidiomycota</span> Division of fungi

Basidiomycota is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basidiomycota includes these groups: agarics, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, chanterelles, earth stars, smuts, bunts, rusts, mirror yeasts, and Cryptococcus, the human pathogenic yeast.

<i>Aureobasidium pullulans</i> Species of fungus

Aureobasidium pullulans is a ubiquitous and generalistic black, yeast-like fungus that can be found in different environments. It is well known as a naturally occurring epiphyte or endophyte of a wide range of plant species without causing any symptoms of disease. A. pullulans has a high importance in biotechnology for the production of different enzymes, siderophores and pullulan. Furthermore, A. pullulans is used in biological control of plant diseases, especially storage diseases.

<span class="mw-page-title-main">Sodium/myo-inositol cotransporter</span> Protein-coding gene in the species Homo sapiens

Sodium/myo-inositol cotransporter is a protein that in humans is encoded by the SLC5A3 gene.

Population genomics is the large-scale comparison of DNA sequences of populations. Population genomics is a neologism that is associated with population genetics. Population genomics studies genome-wide effects to improve our understanding of microevolution so that we may learn the phylogenetic history and demography of a population.

<i>Hortaea werneckii</i> Species of fungus

Hortaea werneckii is a species of yeast in the family Teratosphaeriaceae. It is a black yeast that is investigated for its remarkable halotolerance. While the addition of salt to the medium is not required for its cultivation, H. werneckii can grow in close to saturated NaCl solutions. To emphasize this unusually wide adaptability, and to distinguish H. werneckii from other halotolerant fungi, which have lower maximum salinity limits, some authors describe H. werneckii as "extremely halotolerant".

Pathogenomics is a field which uses high-throughput screening technology and bioinformatics to study encoded microbe resistance, as well as virulence factors (VFs), which enable a microorganism to infect a host and possibly cause disease. This includes studying genomes of pathogens which cannot be cultured outside of a host. In the past, researchers and medical professionals found it difficult to study and understand pathogenic traits of infectious organisms. With newer technology, pathogen genomes can be identified and sequenced in a much shorter time and at a lower cost, thus improving the ability to diagnose, treat, and even predict and prevent pathogenic infections and disease. It has also allowed researchers to better understand genome evolution events - gene loss, gain, duplication, rearrangement - and how those events impact pathogen resistance and ability to cause disease. This influx of information has created a need for bioinformatics tools and databases to analyze and make the vast amounts of data accessible to researchers, and it has raised ethical questions about the wisdom of reconstructing previously extinct and deadly pathogens in order to better understand virulence.

<span class="mw-page-title-main">Wallemiomycetes</span> Class of fungi

The Wallemiomycetes are a class of fungi in the division Basidiomycota. It consists of the single order Wallemiales, containing the single family Wallemiaceae, which in turn contains the single genus Wallemia. The phylogenetic origin of the lineage was placed to various parts of Basidiomycota, but according to the analysis of a larger dataset it is a sister group of Agaricomycotina. The genus contains species of xerophilic molds that are found worldwide. The seven described species are distinguished by conidial size, xerotolerance, halotolerance, chaotolerance, growth temperature regimes, extracellular enzyme activity profiles, and secondary metabolite patterns. They are typically isolated from low-moisture foods, indoor air dust, salterns and soil. W. sebi is thought to be one of the causes of the hypersensitivity pneumonitis known as the farmer's lung disease, but since the other species were recognised and separated from W. sebi only recently, their role in the disease cannot be excluded.

Black yeasts, sometimes also black fungi, dematiaceous fungi, microcolonial fungi or meristematic fungi is a diverse group of slow-growing microfungi which reproduce mostly asexually. Only few genera reproduce by budding cells, while in others hyphal or meristematic (isodiametric) reproduction is preponderant. Black yeasts share some distinctive characteristics, in particular a dark colouration (melanisation) of their cell wall. Morphological plasticity, incrustation of the cell wall with melanins and presence of other protective substances like carotenoids and mycosporines represent passive physiological adaptations which enable black fungi to be highly resistant against environmental stresses. The term "polyextremotolerance" has been introduced to describe this phenotype, an example of which is the species Aureobasidium pullulans. Presence of 1,8-dihydroxynaphthalene melanin in the cell wall confers to the microfungi their characteristic olivaceous to dark brown/black colour.

<i>Wallemia sebi</i> Species of fungus

Wallemia sebi is a xerophilic fungus of the phylum Basidiomycota.

<i>Wallemia ichthyophaga</i> Species of fungus

Wallemia ichthyophaga is one of the three species of fungi in the genus Wallemia, which in turn is the only genus of the class Wallemiomycetes. The phylogenetic origin of the lineage was placed to various parts of Basidiomycota, but according to the analysis of larger datasets it is a (495-million-years-old) sister group of Agaricomycotina. Although initially believed to be asexual, population genomics found evidence of recombination between strains and a mating type locus was identified in all sequenced genomes of the species.

Previously classified under the species complex Aureobasidium pullulans, Aureobasidium subglaciale is a black yeast-like, extremophile, ascomycete fungus that is found in extreme cold habitats. The species was originally isolated from subglacial ice of arctic glaciers. The first isolate of this species was obtained from subglacial ice of the Norwegian island Spitsbergen, one of the coldest places inhabited by humans. of Genomic data collected from specimens in the Aureobasidium pullulans complex justified distinction of four different species

Aspergillus restrictus is a species of fungus in the genus Aspergillus. It is from the Restricti section. The species was first described in 1931. It is xerophilic, frequently found in house dust. Studies have suggested that it is an allergen implicated in asthma. In 2016, the genome of A. restrictus was sequenced as a part of the Aspergillus whole-genome sequencing project - a project dedicated to performing whole-genome sequencing of all members of the genus Aspergillus. The genome assembly size was 23.26 Mbp.

Aureobasidium melanogenum, formerly known as Aureobasidium pullulans var. melanogenum is a ubiquitous black, yeast-like fungus that is found mainly in freshwater habitats. The species also includes strains causing human infections, which were previously classified as A. pullulans. It was named due to abundant melanin production and accumulation in the cell walls, which leads to dark green, brown or black appearance of the cells and colonies The species was established when the genomes of the four former varieties of Aureobasidium pullulans were sequenced and the large differences between them were discovered.

Aureobasidium namibiae, formerly known as Aureobasidium pullulans var. namibiae is a ubiquitous black, yeast-like fungus. It was described on the basis of only one strain isolated from dolomitic marble in Namibia. The species was established when the genomes of the four former varieties of Aureobasidium pullulans were sequenced and the large differences between them were discovered.

Penicillium nordicum is an anamorph species of fungus in the genus Penicillium which produces ochratoxin A. Penicillium nordicum contaminates protein rich foods and foods with high NaCl-konzentration. It is mostly found on dry-cured meat products and cheese products

Aerobic fermentation or aerobic glycolysis is a metabolic process by which cells metabolize sugars via fermentation in the presence of oxygen and occurs through the repression of normal respiratory metabolism. Preference of aerobic fermentation over aerobic respiration is referred to as the Crabtree effect in yeast, and is part of the Warburg effect in tumor cells. While aerobic fermentation does not produce adenosine triphosphate (ATP) in high yield, it allows proliferating cells to convert nutrients such as glucose and glutamine more efficiently into biomass by avoiding unnecessary catabolic oxidation of such nutrients into carbon dioxide, preserving carbon-carbon bonds and promoting anabolism.

Fungal genomes are among the smallest genomes of eukaryotes. The sizes of fungal genomes range from less than 10 Mbp to hundreds of Mbp. The average genome size is approximately 37 Mbp in Ascomycota, 47 Mbp in Basidiomycota and 75 Mbp in Oomycota. The sizes and gene numbers of the smallest genomes of free-living fungi such as those of Wallemia ichthyophaga, Wallemia mellicola or Malassezia restricta are comparable to bacterial genomes. The genome of the extensively researched yeast Saccharomyces cerevisiae contains approximately 12 Mbp and was the first completely sequenced eukaryotic genome. Due to their compact size fungal genomes can be sequenced with less resources than most other eukaryotic genomes and are thus important models for research. Some fungi exist as stable haploid, diploid, or polyploid cells, others change ploidy in response to environmental conditions and aneuploidy is also observed in novel environments or during periods of stress.

References

  1. 1 2 Jančič, Sašo; Nguyen, Hai D. T.; Frisvad, Jens C.; Zalar, Polona; Schroers, Hans-Josef; Seifert, Keith A.; Gunde-Cimerman, Nina (2015). "A Taxonomic Revision of the Wallemia sebi Species Complex". PLOS ONE. 10 (5): e0125933. Bibcode:2015PLoSO..1025933J. doi: 10.1371/journal.pone.0125933 . ISSN   1932-6203. PMC   4446336 . PMID   26017053.
  2. 1 2 3 Padamsee, Mahajabeen; Kumar, T. K. Arun; Riley, Robert; Binder, Manfred; Boyd, Alex; Calvo, Ana M.; Furukawa, Kentaro; Hesse, Cedar; Hohmann, Stefan; James, Tim Y.; LaButti, Kurt (March 2012). "The genome of the xerotolerant mold Wallemia sebi reveals adaptations to osmotic stress and suggests cryptic sexual reproduction". Fungal Genetics and Biology. 49 (3): 217–226. doi:10.1016/j.fgb.2012.01.007. ISSN   1096-0937. OSTI   1165588. PMID   22326418.
  3. Guarro, Josep; Gugnani, Harish C.; Sood, Neelam; Batra, Rashmi; Mayayo, Emilio; Gené, Josepa; Kakkar, Shalini (March 2008). "Subcutaneous phaeohyphomycosis caused by Wallemia sebi in an immunocompetent host". Journal of Clinical Microbiology. 46 (3): 1129–1131. doi:10.1128/JCM.01920-07. ISSN   1098-660X. PMC   2268330 . PMID   18174296.
  4. 1 2 Sun, Xiaohuan; Gostinčar, Cene; Fang, Chao; Zajc, Janja; Hou, Yong; Song, Zewei; Gunde-Cimerman, Nina (6 April 2019). "Genomic Evidence of Recombination in the Basidiomycete Wallemia mellicola". Genes. 10 (6): 427. doi: 10.3390/genes10060427 . ISSN   2073-4425. PMC   6628117 . PMID   31167502.