The world’s ten most feared fungi

An account is provided of the world’s ten most feared fungi.Within areas of interest,we have organized the entries in the order of concern.We put four human pathogens first as this is of concern to most people.This is followed by fungi producing mycotoxins that are highly harmful for humans;Aspergillus flavus,the main producer of aflatoxins,was used as an example.Problems due to indoor air fungi may also directly affect our health and we use Stachybotrys chartarum as an example.Not everyone collects and eats edible mushrooms.However,fatalities caused by mushroom intoxications often make news headlines and therefore we include one of the most poisonous of all mushrooms,Amanita phalloides,as an example.We then move on to the fungi that damage our dwellings causing serious anxiety by rotting our timber structures and flooring.Serpula lacrymans,which causes dry rot is an excellent example.The next example serves to represent all plant and forest pathogens.Here we chose Austropuccinia psidii as it is causing devastating effects in Australia and will probably do likewise in New Zealand.Finally,we chose an important amphibian pathogen which is causing serious declines in the numbers of frogs and other amphibians worldwide.Although we target the top ten most feared fungi,numerous others are causing serious concern to human health,plant production,forestry,other animals and our factories and dwellings.By highlighting ten feared fungi as an example,we aim to promote public awareness of the cost and importance of fungi.

A re-evaluation of the Chaetothyriales using criteria of comparative biology

Chaetothyriales is an ascomycetous order within Eurotiomycetes.The order is particularly known through the black yeasts and filamentous relatives that cause opportunistic infections in humans.All species in the order are consistently melanized.Ecology and habitats of species are highly diverse,and often rather extreme in terms of exposition and toxicity.Families are defined on the basis of evolutionary history,which is reconstructed by time of divergence and concepts of comparative biology using stochastical character mapping and a multi-rate Brownian motion model to reconstruct ecological ancestral character states.Ancestry is hypothesized to be with a rock-inhabiting life style.Ecological disparity increased significantly in late Jurassic,probably due to expansion of cytochromes followed by colonization of vacant ecospaces.Dramatic diversification took place subsequently,but at a low level of innovation resulting in strong niche conservatism for extant taxa.Families are ecologically different in degrees of specialization.One of the clades has adapted ant domatia,which are rich in hydrocarbons.In derived families,similar processes have enabled survival in domesticated environments rich in creosote and toxic hydrocarbons,and this ability might also explain the pronounced infectious ability of vertebrate hosts observed in these families.Conventional systems of morphological classification poorly correspond with recent phylogenetic data.Species are hypothesized to have low competitive ability against neighboring microbes,which interferes with their laboratory isolation on routine media.The dataset is unbalanced in that a large part of the extant biodiversity has not been analyzed by molecular methods,novel taxonomic entities being introduced at a regular pace.Our study comprises all available species sequenced to date for LSU and ITS,and a nomenclatural overview is provided.A limited number of species could not be assigned to any extant family.

Fungi between extremotolerance and opportunistic pathogenicity on humans

Numerous agents of infections in humans and other mammals are found among fungi that are able to survive extreme environmental conditions and to quickly adapt to novel habitats.Nevertheless,the relationship between opportunistic potential and polyextremotolerance was not yet studied systematically in fungi.Here,the link between polyextremotolerance and opportunistic pathogenicity is shown in a kingdom-wide phylogenetic analysis as a statistically significant co-occurrence of extremotolerance(e.g.osmotolerance and psychrotolerance)and opportunism at the level of fungal orders.In addition to extremotolerance,fungal opportunists share another characteristic—an apparent lack of specialised virulence traits.This is illustrated by a comparative genomic analysis of 20 dothideomycetous and eurotiomycetous black fungi.While the genomes of specialised fungal plant pathogens were significantly enriched in known virulence-associated genes that encode secreted proteases,carbohydrate active enzyme families,polyketide synthases,and non-ribosomal peptide synthetases,no such signatures were observed in human opportunists.Together the presented results have several implications.If infection of human hosts is a side effect of fungal stress tolerance and adaptability,the human body is most likely neither the preferred habitat of such species,nor important for their evolutionary success.This defines opportunism as opposed to pathogenicity,where infection is advantageous for the species’fitness.Since opportunists are generally incapable of the host-to-host transmission,any host-specific adaptations are likely to be lost with the resolution of the infection,explaining the observed lack of specialised virulence traits.In this scenario opportunistic infections should be seen as an evolutionary dead end and unlikely to lead to true pathogenicity.