Fungus Fact Friday

Tagged: life cycle

#014: Characteristics of Phylum Chytridiomycota 1

Fungus Fact

#014: Characteristics of Phylum Chytridiomycota

Phylum chytridiomycota is the oldest phylum of fungi, with a fossil record dating back to the Vendian period (around 500 million years ago). It is no surprise, then, that chytrids are the simplest fungi.  Hyphae produced by chytrids can be unicellular, diminutive rhizoids or multicellular and as large as those produced by species in the other fungal phyla.  Chytrids are unique among the fungi in that they produce motile spores.  Each spore is equipped with one whiplash flagellum at its posterior.  Other fungus-like organisms which produce motile spores (often with multiple flagella) but have cellulose cell walls are no longer classified as fungi (chytrids, like all other fungi, have chitin in their cell walls).  Asexual zoospores are formed in a zoosporangium and are released through a pore.  The simplest chytrids form a very small network of rhizoids and produce only one zoosporangium per thallus.  However, more complex chytrids may form...

#013: Characteristics of Phylum Basidiomycota [Archived] 19

Archived

#013: Characteristics of Phylum Basidiomycota [Archived]

Note: This is an archived post. You can find the current version of this post here. Phylum Basidiomycota accounts for about 35% of all described fungal species.* This phylum contains the fungi that people are most familiar with. The classic “Mario mushroom” (based on Amanita muscaria), the grocery store button mushroom and other varieties of Agaricus bisporus, shiitakes, oyster mushrooms, and even the major “magic mushrooms” are all basidiomycetes.  However, basidiomycota also includes rusts and smuts, which are economically important plant pathogens, some yeasts, and a few lichenized fungi.  Like the ascomycota, the basidiomycota fill a variety of different ecological roles.  Many form mycorrhizae with plants (amanitas, chanterelles, russulas, etc.), others parasitize plants (rusts, smuts, honey mushrooms, etc.), a lot decompose organic material (cultivated mushrooms, yeasts, etc.), and some live in a variety of symbioses with insects (this includes some interesting mutualisms with leaf cutter ants and termites).

#012: Characteristics of Phylum Ascomycota 16

Fungus Fact

#012: Characteristics of Phylum Ascomycota

Phylum Ascomycota includes about 75% of described fungal species.*  It includes the baker’s yeast, Saccharomyces ceriviciae, scientifically important fungi such as Neurospora crassa and Penicillium chrysogenum, a number of desirable edible mushrooms, most notably morels and truffles, most lichenized fungi, and many important plant pathogens, such as the causal agent of chestnut blight.  As you can tell from this list, the ascomycetes have a variety of life history strategies and ecological roles.  Many ascomycetes grow as hyphae, others grow as yeasts, and some can even switch between the two.  Some ascomycota only reproduce sexually, others only reproduce asexually, and many do both.  Ascomycetes can be saprophytic (they decompose non-living matter), parasitic (on plants, bugs, humans, etc.), or mutualistic (with algae, plants, or even beetles).  Ascomycota have provided us with penicillin and have helped scientists understand the cell cycle, meiosis, and heredity.  Despite this diversity, Ascomycota is a monophyletic group (it...

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Fungus Fact

#009: Overview of the Fungal Life Cycle

Filamentous fungi begin their lives as sexual spores. Each spore has a haploid (only one copy of each chromosome) nucleus, which is designated “n.” When the spore lands in a favorable environment, it germinates and produces a mycelium. There are two ways that this mycelium can grow vegetatively: through growth of the mycelium or through asexual reproduction. The fungus can produce asexual mitospores (n) which are dispersed and grow a new mycelium that is genetically identical to the parent. When this mycelium encounters another fungus with a compatible mating type they fuse together (plasmogamy). However, their nuclei remain separate and the cells become dikaryotic (meaning “two nuclei,” designated “n+n”). This gives rise to a dikaryotic mycelium. In ascomycetes and some other fungi, the dikaryotic mycelium only results in the production of fruiting bodies. In basidiomycetes, the dikaryotic mycelium grows vegetatively and produces fruiting bodies. Some basidiomycetes form clamp connections to...