A new thermophilic species of Myceliophthora from China

Fungal-fungal co-culture: a primer for generating chemical diversity

Covering: 2002 to 2020In their natural environment, fungi must compete for resources. It has been hypothesized that this competition likely induces the biosynthesis of secondary metabolites for defence. In a quest to discover new chemical diversity from fungal cultures, a growing trend has been to recapitulate this competitive environment in the laboratory, essentially growing fungi in co-culture. This review covers fungal-fungal co-culture studies beginning with the first literature report in 2002. Since then, there has been a growing number of new secondary metabolites reported as a result of fungal co-culture studies. Specifically, this review discusses and provides insights into (1) rationale for pairing fungal strains, (2) ways to grow fungi for co-culture, (3) different approaches to screening fungal co-cultures for chemical diversity, (4) determining the secondary metabolite-producing strain, and (5) final thoughts regarding the fungal-fungal co-culture approach. Our goal is to provide a set of practical strategies for fungal co-culture studies to generate unique chemical diversity that the natural products research community can utilize.

Halophilic and thermotolerant Gymnoascus species from several special environments, China

This study introduces three new Gymnoascus species (Gymnoascaceae, Onygenales), G. halophilus, G. stercorarius and G. thermotolerans, isolated from sediments in Chaka Salt Lake, compost and cornfield soil, respectively, in China, based on a polyphasic characterization including morphology, physiology and molecular phylogeny. Phylogenetic relationships were assessed based on the nuclear internal transcribed spacer (ITS = ITS1 + 5.8S + ITS2) region and a combined multilocus alignment of the ITS, 18S subunit rRNA gene and 28S subunit rRNA genes. Our study identified phylogenetic and phenotypic characters that differentiated the three new species from known species in the genus. Salinity and temperature tolerance tests revealed that G. halophilus was an obligate halophile while G. stercorarius and G. thermotolerans were halotolerant and thermotolerant. A key to accepted species of Gymnoascus is provided.

Thermophilic fungi in the new age of fungal taxonomy

Thermophilic fungi are of wide interest due to their potential to produce heat-tolerant enzymes for biotechnological processes. However, the taxonomy of such organisms remains obscure, especially given new developments in the nomenclature of fungi. Here, we examine the taxonomy of the thermophilic fungi most commonly used in industry in light of the recent taxonomic changes following the adoption of the International Code of Nomenclature for Algae, Fungi and Plants and also based on the movement One Fungus = One Name. Despite the widespread use of these fungi in applied research, several thermotolerant fungi still remain classified as thermophiles. Furthermore, we found that while some thermophilic fungi have had their genomes sequenced, many taxa still do not have barcode sequences of reference strains available in public databases. This lack of basic information is a limiting factor for the species identification of thermophilic fungi and for metagenomic studies in this field. Based on next-generation sequencing, such studies generate large amounts of data, which may reveal new species of thermophilic fungi in different substrates (composting systems, geothermal areas, piles of plant material). As discussed in this study, there are intrinsic problems associated with this method, considering the actual state of the taxonomy of thermophilic fungi. To overcome such difficulties, the taxonomic classification of this group should move towards standardizing the commonly used species names in industry and to assess the possibility of including new systems for describing species based on environmental sequences.