Traditionally, the kingdom Fungi consists of four phyla known as Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota, though the classification of the fungi has shifted tremendously in recent decades to include Glomeromycota as a new phylum for the arbuscular mycorrhizal fungi, as well as the elimination of the oomycetes, plasmodiophorids and slime molds from the fungal into the christen and protist kingdoms (Voigt & Kirk, 2011). This paper aims to demonstrate that all fungi are not the same by differentiating among three fungal phyla (Zygomycota, Ascomycota, and Basidiomycota) in terms of their reproduction methods, means of obtaining nutrients, and importance to humans.
In Zygomycota, existing literature demonstrates that there are in excess of 1000 species of Zygomycetes that reproduce asexually or sexually (Tortora, Funke, & Case, 2012). The dimorphic zygomycetous (Benjaminiella poitrasii) and Gilbertella persicaria fungi, for instance, reproduce asexually by uni-to-multispored sporangia charged with the responsibility of producing nonmotile, single-celled sporangiospores. The common black bread mold (Rhizopus stolonifer), which is an example of a zygomycete species in Zygomycota phyla, reproduces sexually when hyphae of two dissimilar mating strains get together, create gametangia, blend, and consequently breed a diploid zygosporangium and zygospore which eventually goes through meiosis to produce haploid sporangia (Voigt & Kirk, 2011).
Ascomycota (sac fungi) have around 65,000 described species and reproduce either sexually through the production of ascosphores (by meiosis and mitosis) in sac-like asci, or asexually through projecting conidiophores which creates conidia spores. They include cup fungi, powdery mildew, morels, black knot, Morchella, yeast, penicillium, and conidiophores. In contrast, Basidiomycota comprise around 25,000 species that reproduce sexually by forming elaborate fruiting bodies referred to as basidiocarps; these bodies hold millions of tiny, club-shaped cells (basidia) that produce four sexual spores each. Basidomycetes come in all shapes, sizes and colors, and include mushrooms, coral fungus, conch fungus, puffballs, jelly fungi, bracket fungi, gills, and the human pathogenic yeast Cryptococcus (Tortora et al., 2012; Voigt & Kirk, 2011).
Zygomycota, Ascomycota and Basidiomycota obtain their nutrients through parasitic means and establishing symbiotic relationships with hosts. All of these fungi develop on or inside their host and obtain nutrients via absorptive, heterotrophic nutrition, which is made possible by secreting potent digestive enzymes that break down organic materials into minute fragments which are then absorbed into the cell. In symbiotic relationships, all the three fungi are known to gain nutrients from the host while providing essential sterols and vitamins. In parasitic relationships, the fungi are known to account for most of the animal and plant pathogens by mostly compromising the immune systems of their main source of nutrients. For example, an ascomycete known as Pneumocystis carinii is responsible for deadly pneumonia in human beings by compromising the immune system as it seeks nutrients inside the host (Tortora et al., 2012; Voigt & Kirk, 2011).
Lastly, there is compelling evidence indicating that all the three fungi discussed in this paper have varied levels of importance to humans. Some species of Zygomycota are not only used to ferment various food items, hence contributing substantially to their nutritional value, but also to decompose dead plant matter and to produce important industrial products including lactic acid, amylases, rennin and organic acids. Although most zygomycetes are generally harmful to human beings by virtue of their association with disease-causing pathogens, some are being tapped for use in the biological control of specific insect pests due to their parasitic nature (Tortora et al., 2012). Ascomycetes have many beneficial outcomes for humans, including serving as choice edibles (e.g., morels, truffles and lobster mushrooms), production of antibiotics (Penicillium chrysogenum) to kill bacteria and immunosuppressant agents (Tolypocladium niveum) to prevent rejection of vital organs during transplantation, development of useful proteins such as insulin and human growth hormone, and in making of bread, beer and wine (Saccaromyces cerevisiae).Basidiomycota are useful to human beings in terms of decomposing dead plant matter, including wood and leaf litter, and also for serving as important sources of food (e.g., mushrooms) and other bioactive compounds used in traditional and alternative medicine (Voigt & Kirk, 2011).
References
Tortora, G.J., Funke, B.R., & Case, C.L. (2012). Microbiology: An introduction (11th ed.). San Francisco, CA: Benjamin Cummings.
Voigt, K., & Kirk, P.M. (2011). Recent developments in the taxonomic affiliation and phylogenetic positioning of fungi: Impact in applied microbiology and environmental biotechnology. Applied Microbiology & Biotechnology, 90(1), 41-47.