Genome sequencing of four Aureobasidium pullulans varieties: biotechnological potential, stress tolerance, and description of new species.

Background: Aureobasidium pullulans is a black-yeast-like fungus used for production of the polysaccharide pullulan and the antimycotic aureobasidin A, and as a biocontrol agent in agriculture. It can cause opportunistic human infections, and it inhabits various extreme environments. To promote the understanding of these traits, we performed de-novo genome sequencing of the four varieties of A.

Osmoadaptation strategy of the most halophilic fungus, Wallemia ichthyophaga, growing optimally at salinities above 15% NaCl.

Wallemia ichthyophaga is a fungus from the ancient basidiomycetous genus Wallemia (Wallemiales, Wallemiomycetes) that grows only at salinities between 10% (wt/vol) NaCl and saturated NaCl solution. This obligate halophily is unique among fungi. The main goal of this study was to determine the optimal salinity range for growth of the halophilic W.

Morphological response of the halophilic fungal genus Wallemia to high salinity.

The basidiomycetous genus Wallemia is an active inhabitant of hypersaline environments, and it has recently been described as comprising three halophilic and xerophilic species: Wallemia ichthyophaga, Wallemia muriae, and Wallemia sebi. Considering the important protective role the fungal cell wall has under fluctuating physicochemical environments, this study was focused on cell morphology changes, with particular emphasis on the structure of the cell wall, when these fungi were grown in media with low and high salinities. We compared the influence of salinity on the morphological characteristics of Wallemia spp.

Osmotic adaptation of the halophilic fungus Hortaea werneckii: role of osmolytes and melanization.

This study was intended to determine the osmoadaptation strategy of Hortaea werneckii, an extremely salt-tolerant melanized ascomycetous fungus that can grow at 0-5.1 M NaCl. It has been shown previously that glycerol is the major compatible solute in actively growing H.

Hypersaline conditions induce changes in cell-wall melanization and colony structure in a halophilic and a xerophilic black yeast species of the genus Trimmatostroma.

Melanized yeast-like meristematic fungi are characteristic inhabitants of highly stressed environments and are rare eukaryotic extremophiles. Therefore, they are attractive organisms for studies of adaptations. In this study we compared two meristematic species of the genus Trimmatostroma on media of differing water potentials isolated from distinct water-stressed environments: T.

The halophilic fungus Hortaea werneckii and the halotolerant fungus Aureobasidium pullulans maintain low intracellular cation concentrations in hypersaline environments.

Hortaea werneckii and Aureobasidium pullulans, black yeast-like fungi isolated from hypersaline waters of salterns as their natural ecological niche, have been previously defined as halophilic and halotolerant microorganisms, respectively. In the present study we assessed their growth and determined the intracellular cation concentrations of salt-adapted and non-salt-adapted cells of both species at a wide range of salinities (0 to 25% NaCl and 0 to 20% NaCl, respectively). Although 5% NaCl improved the growth of H.

Evidence for 1,8-dihydroxynaphthalene melanin in three halophilic black yeasts grown under saline and non-saline conditions.

The ascomycetous black yeasts Hortaea werneckii, Phaeotheca triangularis, and Trimmatostroma salinum are halophilic fungi that inhabit hypersaline water of solar salterns. They are characterized by slow, meristematic growth and very thick, darkly pigmented cell walls. The dark pigment, generally thought to be melanin, is consistently present in their cell walls when they grow under saline and non-saline conditions.