How fungi are similar to and differ from plants and animals:
Witzany, Guenther (ed.) “Introduction: Keylevels of Biocommunication in Fungi.” Biocommunication of Fungi. Springer, 2012. https://doi.org/10.1007/978-94-007-4264-2
“On an evolutionary time scale, the kingdom of fungi emerged approx. 300 million years after the appearance of the first animal species, although they descended from a common ancestor (Lang et al. 2002)” (p. 17).
“Most fungi ... secrete powerful enzymes that enable the cells to digest organic matter from the nearby environment outside their body, in turn breaking this down to smaller molecules that can be absorbed in a dissolved form (Jennings 1995)” (p. 19).
I.e., plants make their own food (photosynthesis); fungi don’t.
“Although plants and animals seem to be descendants of fungi, the relationship between fungi and viruses is different from virus–animal or virus–plant relationships (Villarreal 2005)” (p. 24).
Doesn't this contract the quote from p. 17? [does he mean descendants of viruses?]
“There is new evidence that certain proteins that have been restricted to signalling pathways in animals so far are also common in fungal signalling pathways (Herranz et al. 2005)” (pp. 27-28).
“There is much evidence to suggest that the fungal and animal kingdom share common ancestors, such as protoctists [protists], which have a true nucleus like choano-flagellates (Villarreal 2005). In this sense, fungi and animals are more related to each other than is the case with the plant kingdom. This is further strengthened by the sign-mediated processes, which regulate cellular functions. Yet another indicator of their common ancestry is found in a particular signalling pathway, termed the mitogen-activated protein kinase cascade (MAPK). This plays a crucial role in cell wall stabilisation of fungi and pheromone/mating interactions among mammalian cells. On top of that, MAPK is highly conserved (Lengeler et al. 2000)” (p. 37).
“Today, scientists consider the origin of the plant cell to be the result of the terrestrial activity of mycorrhiza, i.e. settlement on land was a co-evolutionary event that is comparable to that between flowering plants and insects (Villarreal 2005). The mutually beneficial relationship between subterranean fungi and plant roots is a fine-tuned network of sign-mediated interactions developed over millions of years (Besserer et al. 2006), whereby fungi excrete digestive enzymes into the surrounding soil, and convert nutrients into aqueous solutions that in turn can be readily absorbed by the plant. A staggering 80% of all terrestrial plants rely on the activity of mycorrhiza, especially trees (Schwarze et al. 2004)” (p. 38).
Moore, David. Fungal Biology in the Origin and Emergence of Life. Cambridge University Press, 2013.
Evolution: "the first eukaryotes had the nutritional and cell-biological attributes of fungi as well as features that later emerged in plants and animals." Plants then split off. "Opisthokonts [were] ancestors of both animals and fungi." Then animals split off, "leaving their sister ancestral opisthokonts to evolve into fungi." (p. 6)
Plants produce food; animals consume food; fungi recycle or reduce (break down) food - they are saprobes - they decay organic material and digest it, like soil bacteria: saprotrophic nutrition (p. 7).
The Fungi Kingdom includes single-celled yeasts to organisms "that cover hundreds of acres of land." In Oregon, there is a mycelium that covers "2384 acres" and "is estimated to be 1900-8650 years old" (p. 8).
"But mushrooms are not organisms in their own right, they are the fruiting bodies of a much larger and more extensive mycelium growing beneath the ground within the soil." But some live in water, air, on animals. "Fungi are not able to produce their own food directly as plants do; rather, fungi recycle dead organic matter by discharging a full range of digestive enzymes into their surroundings. These enzymes degrade organic material outside the myelium and then the hyphae ingest the soluble nutrients produced by that external digestion" (saprotrophs = decomposers) (p. 9).
That material can be plant or animal, or even inorganic minerals! Coal resulted from pre-fungal times when dead wood piled up and fossilized. Plants' cell walls are made of cellulose and lignin, and "fungi are ... the only organisms capable of breaking down both..." (p. 10).
Symbiosis = mutualism (both partners benefit), e.g., lichen, made of algae and fungi. The algae photosynthesize (use sunlight to make carbohydrates), and the fungi makes the body surrounding the algae, and takes in water and nutrition. This body, lichen, is different from both algae and fungal mycelium. (p. 11).
Seems like an unequal partnership - maybe the fungus not only lives off the algae but also destroys it and only rapid algal reproduction lets it stay ahead of the destruction.
Also, fungi hyphae help plants by increasing "the surface area available for absorbing minerals" (p. 12) and plants share the carbohydrates with the fungi (p. 13). The mycorrhizas extend the plant root surface and help the plant tolerate drought, larger temperature ranges, and acidity. Ruminant mammals have fungi that digest cellulose in their stomachs - the animals don't produce enzymes themselves to do that.
Lincoff, Gary. National Audubon Society Field Guide to North American Mushrooms. Knopf : Random House, 2002.
Fungi "differ from most plants in that they lack chlorophyll...." They get nutrition "in 3 ways: as saprophytes, as parasites, and as mycorrhizae. Saprophytes live on dead organic matter.... Parasites attack living plants or animals. Mycorrhizal mushrooms have a symbiotic relationship with plants...the underground...part...sheaths the roots of the plant, expanding the plant's root system; the mushroom receives necessary carbohyrates from the tree" (pp. 12-13).
Spores are the "reproductive units." When they sprout, they turn into hyphae (plural; hypha = singular), which are "threadlike strands" with cells that have 1 nucleus and "that are collectively known as the mycelium" (singular; mycelia = plural). When 2 or more mycelia meet, they create a mycelium whose cells have 2 nuclei. These are the "vegetative portion of the fungus" and they develop into the fruiting bodies, a.k.a., mushrooms. They produce spores "and the life cycle begins again" (p. 20).
Nice illustrations of caps (p. 14), gills and stalks (pp. 16-18) (rings are the leftovers from veils), the key (p. 35-color plates), and the plates. Also has good descriptions in the text, and a glossary following the text.
