Fungus Fact Friday

Tagged: ecology

#019: Apiosporina morbosa, Black Knot of Cherry [Archived] 0

Archived

#019: Apiosporina morbosa, Black Knot of Cherry [Archived]

Note: this is an archived post.  You can view the current version of this post here. And now for something completely different: identifying trees from a long way away. If you’ve ever tried to identify deciduous trees in the winter, you know how hard it is to identify a tree based on its bark.  However, thanks to the fungus Apiosporina morbosa, identifying cherry trees in winter becomes a walk in the park.  Apiosporina morbosa is an ascomycete that parasitizes cherry and plum trees.  Commonly known as “black knot,” the fungus forms black, dry, cracked, irregular swellings on branches which grow to surround the branch.  According to Michael Kuo, these knots look like “dried cat poop on a stick.”*  Although this is not the most attractive-looking fungus, it is very helpful for identifying cherry trees from hundreds of feet away, especially in winter when the knots are not hidden by leaves.

#018: Characteristics of the Phyla Blastocladiomycota and Neocallimastigomycota 1

Fungus Fact

#018: Characteristics of the Phyla Blastocladiomycota and Neocallimastigomycota

These two groups of fungi were recently taken out of the Chytridiomycota and elevated to the rank of phylum. Not surprisingly, both of these phyla produce motile spores (zoospores).  The blastocladiomycota inhabit fresh water and soil and fill similar ecological roles to the core chytrids.  Many of the blastocladiomycota are pathogens of small, aquatic animals (such as nematodes or water bears), algae, or semi-aquatic plants.  The genus Allomyces contains saprobic species often used in experiments.  In Allomyces the female gametes secrete the pheromone sirenin to attract the male gametes.  The main difference between the blastocladiomycota and the chytridiomycota is that the blastocladiomycota produce an extensive mycelium.  Furthermore, only certain cells at the tips of the hyphae produce sexual (male and female, haploid) or asexual (diploid) zoospores.  In the core chytrids, the entire thallus is used to produce zoospores.

#017: Characteristics of Phylum Microspora 1

Fungus Fact

#017: Characteristics of Phylum Microspora

Phylum microspora (not to be confused with the green algae genus Microspora) contains some of the most unusual fungi: the microsporidia. There are over 1200 described species in this phylum (and that is only a fraction of their biodiversity), divided into about 150 genera (plural of genus).  These organisms were originally thought to be protozoans, but recent DNA studies have demonstrated that they belong with the fungi.  The microsporidia are all obligate parasites of animals and have an extremely reduced cell structure.  They do not have mitochondria, so they can only grow and reproduce within the cells of their host.  Their very resistant spores persist in the environment for a long time and allow them to spread from one animal to another.  The spores are 1 to 40 micrometers long, making them the smallest eukaryotes.  The spores are rougly oval and have a cell wall made of chitin that is...

#015: Characteristics of Phylum Glomeromycota [Archived] 1

Archived

#015: Characteristics of Phylum Glomeromycota [Archived]

Note: This is an archived post. You can find the current version of this post here. The Glomeromycota are all fungi which form arbuscular mycorrhizae (AM). Mycorrhizae are a type of mutualism with plants where the fungus gets sugars and gives up hard-to-extract nutrients (especially phosphorous).  AM fungi accomplish this by forming structures within the plant’s root cells while not causing a disease reaction.  Most land plant species form AM, and only a few families are considered non-mycorrhizal.  AM fungi tend to be generalists, colonizing a variety of different plant species.  Each plant is usually colonized by multiple AM species.  This mycorrhizal network has a variety of different roles in an ecosystem.  It supplies nutrients to plants, determines what species make up an ecosystem’s plant community, and allows other plants (like orchids and Indian pipe) to parasitize larger plants via the network.  A recent study has also suggested that plants...

#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...

#010: Fungal Fossils 0

Fungus Fact

#010: Fungal Fossils

It may surprise you to learn that fungi are reasonably well represented in the fossil record. Most of these fossil fungi are microscopic and lack reproductive structures. Additionally, it is often difficult to infer their ecology, making positive identification difficult, if not impossible.  Fossil fungi are often found inside fossilized plant tissue.  This includes fossils of mycorrhizae, plant pathogens, and wood decomposers.  Many of these finds come from Rhynie Chert in Scotland, which dates to the Devonian period (around 400 million years ago, characterized by small land plants and the first forests).  This is around the same time of the first fossilized land plants.  The fact that mycorrhizae were already well-established by this time suggests that fungi were instrumental in helping plants colonize the land.  The best-preserved fossil fungi are found in amber, often growing on insects.  A mosquito trapped in Baltic amber (from the Eocene period, around 47 million...