Question

What is the primary ecological role of fungi, and what are three fungal interactions with humans?

Answer 1

Fungi play vital roles in the biosphere. They are essential to the recycling of nutrients in all terrestrial habitats because they are the dominant decomposers of the complex components of plant debris, such as cellulose and lignin. As opportunistic heterotrophs, they have evolved hyphae to penetrate solid substrates, and spores for long?range dispersal. They cause many diseases of plants and animals, but they also have established mutualistic symbioses with a wide range of organisms: cyanobacteria and green algae (in lichens), bryophytes, pteridophytes, gymnosperms and angiosperms (in mycorrhizae), and coleopteran, dipteran, homopteran, hymenopteran and isopteran insects. As parasites or pathogens they are well equipped to penetrate host organisms and to liberate spores that will effectively transmit them from one host to the next, and many species produce toxic compounds (mycotoxins). Some fungi affect human health in various ways.

Many fungi are opportunistic heterotrophs, disposers of, or recyclers of, organic substrates, especially those of plant origin. Parasitic fungi attack almost all known taxa of plants and animals. Fungi have established mutualistic symbioses with cyanobacteria and chlorophycota (green algae) to form lichens. Fungi often form symbiotic associations with the roots of plants (bryophytes, pteridophytes, gymnosperms and angiosperms) in mycorrhizae. Some fungi live as symbionts with coleoptera, diptera, homoptera and hymenoptera. Some fungi cause diseases (mycoses) in humans or excrete toxic compounds (mycotoxins). Fungal spores can cause severe allergies in humans.

Fungi are ubiquitous within the environment. However, only a few species are routinely found associated with humans and are capable of causing disease

There are various interaction of fungi with human, eg Symbiosis is a type of long-term close biological relationship between two or more species. These relationships can be mutualistic (all organisms benefit), commensalistic (one organism benefits without affecting the other), parasitic (one organism benefits at the expense of the other), or amensalistic (one organism is inhibited or obliterated, while the other is unaffected). For example, most host–pathogen interactions are parasitic with the pathogen causing damage to the host.

Candida albicans, is a commensal which colonises the oral, genital and gastrointestinal tract, but can cause host damage and disease in the context of weakened or uncontrolled immune responses.