Fungus Fact Friday

Pleurotus ostreatus 0

#021: Pleurotus ostreatus, The Oyster Mushroom

Pleurotus ostreatus, the “Oyster Mushroom,” is the quintessential pleurotoid mushroom: it is a gilled mushroom with a very short stalk that fruits from the sides of logs. Oyster Mushrooms are some of the best edible wild mushrooms; they are fairly easy to identify, they are meaty, and they appear in large numbers. Additionally, you find them in late fall and winter, when the woods are otherwise boring places for mushroom hunters. Although it grows on hardwood logs in nature, P. ostreatus will decompose pretty much any plant material, which makes it very easy to cultivate. As an added bonus, the Oyster Mushroom attacks nematodes. That’s one cool mushroom, right?

Wheat Leaf Rust, Wheat Stripe Rust, and Wheat Stem Rust 0

#208: Rust Diseases of Wheat

Wheat is the most widely grown crop in the world and is a staple food for billions of people. Diseases affecting wheat are therefore of utmost importance to food security. Some of the most destructive and difficult wheat diseases are the rusts. Wheat rust comes in three varieties: Leaf Rust, Stem Rust, and Stripe Rust, each caused by a different species of fungus. These all look slightly different but all cause rust-colored blemishes on wheat surfaces. The three species are closely related and have nearly identical life cycles. Despite this, managing the diseases is complicated and requires using resistant wheat strains, proper cultural practices, and fungicides.

Fungi in the News Image 0

Winter 2018 Fungal News Update

Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of what we’ve learned about fungi from November 2017 through Early February 2018. Read below to learn about: zombie ants, aflatoxin control, white nose syndrome solutions, using fungi in concrete, and more! Visit the associated links to get the full story.

Sphaerobolus ingoldii 0

#122: Sphaerobolus stellatus, the Artillery Fungus

Sphaerobolus stellatus has one of the most unusual spore dispersal mechanisms: its base pops up and quickly flings a glob of spores into the air. The fungus forms tiny (no more than 3mm across) star-shaped mushrooms in mulch, which can cause problems for homeowners when the spore globs glue themselves to cars, siding, and the like. S. stellatus’s unique spore dispersal strategy has resulted in a variety of common names, including: “Artillery Fungus,” “Cannonball Fungus,” “Cannon Fungus,” “Sphere Thrower” (which is a literal translation of its Latin name), and “Shotgun Fungus.”

Ganoderma applanatum 0

#070: Ganoderma applanatum, The Artist’s Conk

Ganoderma applanatum is unique among fungi in that it is primarily used by humans as an artistic medium. This large, woody bracket fungus features a mostly flat white pore surface that immediately stains brown when handled. Because of this, the mushroom readily becomes a natural canvas for an artist. By lightly scratching the pore surface, an artist can produce beautiful sketches without using a pen, pencil, or paint. The pores stop growing once the mushroom is removed from its substrate, so the stains remain on the pore surface. Conks produced by G. applanatum are woody and therefore decay very slowly. As a result, artwork produced on the Artist’s Conk can last for many years when dried and kept indoors.

207: Ergot Alkaloids 0

207: Ergot Alkaloids

Ergot Alkaloids (EAs) belong to a large class of mycotoxins. They are primarily produced by fungi in the genera Claviceps and Epichloë, although Claviceps purpurea is responsible for most of the impacts on humans. EAs are most common in rye, but can be found in any cereal grain. The toxins were a significant problem in the middle ages, but modern agricultural techniques mean that exposure to enough EAs to cause symptoms is extremely rare.1,2 Sources Many fungi produce ergot alkaloids in many different plant hosts. Humans are impacted most by species of Claviceps, which infect seeds of grasses. The most problematic species is C. purpurea (see FFF#061), which infects rye. A variety of other species infect cereal grains but cause less contamination. Livestock can be sickened by infected grain or by ergot alkaloids produced by endophytes in pasture grasses, most notably by Epichloë coenophiala.1–3 This post focuses on Claviceps and...

Amanita muscaria 0

#069: Amanita muscaria, Part 1: The Type Mushroom

You are undoubtedly familiar with this mushroom, even if you recognize neither its scientific name, Amanita muscaria, nor its common name, “The Fly Agaric.” If the word “mushroom” does not immediately bring this fungus to mind, then the word “toadstool” probably does. You have certainly encountered A. muscaria’s distinctive red cap with white spots in a variety of visual art forms. This toadstool frequently pops up in paintings, cartoons, video games, movies, and decorations. Essentially, A. muscaria is the default mushroom that people (in Western societies, anyway) think of when they hear the word “mushroom” – the type specimen for mushrooms, if you will. This is probably best illustrated by the Wikipedia page for “Mushroom,” which features a prominent picture of the photogenic Fly Agaric. Morphology Amanita muscaria produces large, umbrella-shaped agaric mushrooms with a circular, brightly colored pileus and a central, white stipe. The pileus ranges in size from...

Ochratoxin-producing molds 0

#206: Ochratoxins

Unlike most other mycotoxins found in food, the ochratoxins are primarily produced during food storage. Fungi in the genera Aspergillus and Penicillium are common molds that decompose a variety of foods, from grains to coffee to grapes. In the process, many of those fungi produce ochratoxins, which can damage the kidneys and cause cancer in many animals. Ochratoxins presumably impact humans the same way, but researchers have so far been unable to directly link ochratoxins to any human disease. This is probably because human consumption of ochratoxins is usually very low.

Fusarium molds 0

#205: Zearalenone

Zearalenone is a fascinating mycotoxin produced by Fusarium species. It is the only mycotoxin that mimics the effects of the hormone estrogen. In high doses, it causes sexual organs to develop incorrectly. Pigs are the most susceptible animals and suffer estrogenism and vulvovaginitis when exposed to high levels of zearalenone. The toxin is present in many grain-based foods intended for human consumption, but usually at very low levels. As a result, zearalenone is generally harmless to humans.

Fusarium verticillioides spores 0

#204: Fumonisins

Humans have very little to worry about from fumonisins, mycotoxins produced by Fusarium fungi that cause Fusarium ear rot disease of corn (maize). The toxins are linked with esophageal cancer, but scientists cannot prove that they cause cancer. However, fumonisins are a major problem for horses and pigs. In horses, the toxins cause liquefaction of the brain tissue, while in pigs they cause the lungs to fill with water.