Lung Infections: Common Types and How to Treat Them

Fungi Are Responsible For Life On Land As We Know It

Neither plants nor animals, fungi are the most underappreciated kingdom of the natural world. During a billion years of evolution, they've become masters of survival.

And yet, fungi have also been integral to the development of life on Earth. In fact, neither land plants nor terrestrial animals would exist them. 

WATCH The Kingdom: How Fungi Made Our World

"Fungi are absolutely remarkable chemists," says McMaster University biochemistry professor Gerry Wright.  Fungi produce molecules that humans still can't reproduce in a lab, and we're only beginning to scrape the surface of what we can learn from them.

Here are a few things we found out about the hidden world we pass by every day on The Nature of Things documentary The Kingdom: How Fungi Made Our World.

Fungi drove evolution on land

Fungi were some of the first complex life forms on land, mining rocks for mineral nourishment, slowly turning them into what would become soil. In the Late Ordovician era, they formed a symbiotic relationship with liverworts, the earliest plants.

"Ultimately, fungi helped plants move away from being these marginal tiny little things on the water's edge into large forests and entire ecosystems," explains Katie Field, an associate professor in plant-soil interactions at the University of Leeds.

The fungi provided essential minerals for land plants that allowed them to spread and turn the planet green — changing the composition of the atmosphere. 

Fungi were once the tallest life forms on the plant

Three hundred and sixty million years ago, in the Devonian era, there were no trees yet. The only animals living on land were invertebrates. But enormous fungi towered over the landscape. Prototaxites were megafungi that could be up to eight metres in height.

An artist's rendering of what protoaxites might have looked like based on the fossils they left behind.

For over a hundred years after the discovery of the first Prototaxites fossils, scientists argued about whether they were fungi, trees, lichens or plants.

According to research by Dr. Francis Hueber of the Smithsonian, the Prototaxites met their end at the hands of evolving insects, who started using them as a source of food.

Fungi are part of the reason we exist

Roughly 65 million years ago, an asteroid strike would wipe out 70 percent of all life on Earth. But it wouldn't happen all at once. The lack of sunlight that followed the asteroid impact meant that the plant life that didn't die on impact would start to decay rapidly, creating the conditions for fungi to spread rapidly.

When that happened, mammals had one key advantage over cold-blooded reptiles, then the planet's dominant life forms.

MORE:The Kingdom: How Fungi Made Our WorldFungi Paved The Way For Humans To Evolve In The Aftermath Of A Deadly Asteroid StrikePhotographer Steve Axford Documents The Beauty of Fungi

"They're hot," explains Arturo Casadevall, a professor of public health at Johns Hopkins University. "The reptiles are quite susceptible to fungal diseases, but your typical mammal, which maintains a temperature in the mid 30's or so, creates a thermal exclusionary zone for fungi."

Those surviving mammals are the evolutionary ancestors of every mammal on the planet today, from civet cats to water buffalo to us.

"The warm-bloodedness of mammals, including ourselves, has evolved, in part, as a response to the pressure from fungus," says Rob Dunn, a professor at North Carolina State University. "And so we seem to have cooked out the fungal pathogens."

Fungi are master decomposers that keep our forests alive

Without fungi to aid in decomposition, all life in the forest would soon be buried under a mountain of dead plant matter. 

"[Fungi] are the garbage disposal agents of the natural world," according to Cardiff University biosciences professor Lynne Boddy. "They break down dead, organic matter and by doing that they release nutrients and those nutrients are then made available for plants to carry on growing."

"It's how everything is reborn," says Dunn. "So that this entire web of life is connected and it's connected through the fungi."

In short, fungi eat death, and in doing so, create new life.

Fungi hyphae form mycelium that connects trees and plants in an underground fungal highway — called the wood-wide web — transporting nutrients and sending danger signals.

FROM THE FILM: Fungi form a wood-wide web in forests connecting the entire ecosystem.

Fungi paved the way for human civilization

Otzi, the 45,000-year-old man who was found frozen in the Tyrolean Alps, was carrying ornately strung together fungi with him when he died. Scientists think that these mushrooms were spiritual, but they may also have been medicinal.

"Now we know that [fungi] enhancing your immune system and it will help you also against cancer, against inflammations, antiviral, it's antibacterial, so it has a huge array of medicinal properties," says the University of Innsbruck's Ursula Peintner.

Thousands of years ago, humans brewed beer not to party, but because yeast — a single-celled fungus — made potentially contaminated water safe to drink by killing bacteria.

"In those early gatherings of humans, we pooped on everything," says Dunn. "The danger of getting infected and sick was very high, and it was especially high from the liquids that you would drink. And so in that context fermented drinks might have increased our ability to survive ourselves."

Our species built civilizations around bread and beer made with the help of a single fungus.

FROM THE FILM: One random mutation led to our success as a species and our enjoyment of beer and other alcoholic beverages.

We're only starting to scrape the surface of how much fungus is out there — and what it can do for us

It was only one hundred years ago that Alexander Fleming accidentally discovered penicillin — from a fungus called Penicillium — that we used to combat bacterial epidemics that kept sweeping the planet. Since then, the world's population of humans has tripled.  As our numbers continue to climb, we're turning to fungi for help.

Scientists estimate that there are over 5,000,000 species of fungi on Earth, but we've only discovered about one per cent of them. Professor Rob Dunn says that as we start to dive deeper into the world of fungus, there's no telling what other breakthroughs might be possible.

"We've become really interested recently in trying to figure out how do we find not just any new fungus but fungi that might be useful to people," he says.

New discoveries could be used for anything from breaking down industrial waste to developing new sources of food to making new medicine.  "Most of the coolest stuff nature can do we haven't discovered yet. And so we both systematically look, and we bumble around a little bit."

Fungi have made us who we are — and the most exciting discoveries are yet to come. 

The Plant Doctor: How To Spot Fungal Diseases

Fungi are the most common causal agent of plant disease. Of the more than 2 million species of fungi worldwide, 8,000 are known to be detrimental to plants. These microscopic organisms cause symptoms such as root and crown wilts, leaf spots, rusts, cankers, downy and powdery mildews, and stem and twig blights. Blights cause severe damage to a plant structure, like leaves, flowers or stems; rots are typically caused by soil-borne fungi attacking roots, stems and fruits. Cankers appear as sunken areas or spots where the bark is rough, missing or swollen, and wilts are the result of fungi growing inside a plant's vascular or fluid-conducting tissue, causing these tissues to die.

Because the presence of fungi is not always visible on a plant's surface, they are often identified by their growth patterns, spores or other structures. Fungi absorb nutrients through tiny, thread-like filaments called hyphae. A collection of hyphae on a plant is a key diagnostic sign that can lead to identifying a specific fungus. Examine infected plant tissue with a hand lens, or if further assistance is needed, bring a sample to the Marin Master Help Desk in Novato. The sample can be viewed under a microscope or put onto a petri dish with a nutrient medium to see if identifiable fungi grow out.

Monitor your plants. If a plant appears stressed and symptoms appear, examine the plant for symptoms and signs of injury or disease. Determine the most likely cause by first accurately identifying the host plant: Every species, variety or cultivar has a unique set of characteristics that often provide important clues to identifying the source of the problem. Fungi are often host-specific.

The use of genetically resistant plants, if available, should be the first line of defense for diseases caused by fungi. Good cultural practices in genetically resistant plants can often slow or limit the incidence of fungal disease. Fungicide applications can supplement preventative control measures if/when a fungal disease persists despite the above efforts.

Fungicides are typically more effective when applied preventively but can also be effective when applied after the onset of symptoms. In either case, fungicides must be delivered to the area of the plant where the pathogen is active to be effective. Accurate diagnosis of the fungi is critical to selecting the appropriate fungicide since they vary in their efficacy. Always follow instructions on the fungicide label regarding timing of use and weather conditions.

Controlling plant diseases with cultural practices involves preventing a conducive environment for fungal growth and improving the growing conditions for maximum plant health. Purchase healthy, vigorous plants and carefully inspect the root system before planting. Study the plant's normal growth habits and requirements (soil type, pH, exposure, drainage and exposure) and learn the common problems to which that plant type is vulnerable. Learn from reliable sources how common diseases for that cultivar type are treated.

A Pacific madrone in Inverness with symptoms of foliar blight. (Martha Proctor — Marin Master Gardeners)

Fungal leaf spots and blights (like anthracnose) can be better managed by growing resistant cultivars. Plants with leaf spots, the most prevalent of all plant diseases, or downy mildew fare better by limiting overhead irrigation. Too little water stresses plants, making them more susceptible to disease organisms, like canker fungi; excessive watering results in greater susceptibility to root diseases. Careful watering, sterile pots and uncontaminated, soil-less seedling mixes help reduce the incidence of rots.

Rotate vulnerable plants to a different spot each year to disrupt year-to-year pest cycles. Prune twigs and branches from woody plants infected with blight or fungal canker diseases. Turn the soil after harvest to help break down small roots that may harbor fungi. Removing plant debris and infected plant parts minimizes disease spread and reduces overwintering spores — disinfect tools/machinery with household bleach in a 10% solution of bleach and water.

Prevention is the best approach for most plant diseases.

Sponsored by UC Cooperative Extension, the University of California Marin Master Gardeners provides science- and research-based information for Marin home gardeners. Email questions to helpdesk@marinmg.Org. Attach photos for inquiries about plant pests or diseases. Please call 415-473-4910 to see when a master gardener will be at the office or drop off samples 24/7 in the sample box outside the office. To attend a gardening workshop or subscribe to Leaflet, a free quarterly e-newsletter, go to marinmg.Ucanr.Edu.

Finding Fungus: Scientists Investigate 'Valley Fever' In Southern Utah

SALT LAKE CITY — A lesser-known fungal disease infecting Utahns is getting renewed attention from a team of scientists at the University of Utah.

The school recently received a three-year grant from the Burroughs Wellcome Fund to pay for "Valley Fever" research in Washington County, which is being led by Katharine Walter, an Assistant Professor of Epidemiology at the university.

"Valley Fever is a rapidly emerging fungal disease found in parts of the American West, as well as dry parts of Central and South America," explained Walter.

According to the Centers for Disease Control and Prevention, Valley Fever is an infection that's caused by a fungus that lives in the soil. Both people and animals can contract Valley Fever only if they inhale the microscopic fungal spores from the air. It can't be passed human-to-human, animal-to-human, or vice versa.

Since about 2009, the Utah Department of Health and Human Services has been tracking Valley Fever cases in humans.

"We have seen a pretty steady increase in the number of cases," according to BreAnne Osborn, an epidemiologist with the state agency.

Osborn says most cases have been reported in the Southwestern part of the state but suspects the fungus lives in other parts, too.

"I think our biggest question with Valley Fever is where does the fungus live, and where will the fungus live in the future," she explains.

Those are questions Walter is hoping to answer through her current field research. She says they're starting to sample soil as well as rodents. Subsequently, they'll take the soil back to the lab, and using molecular methods, they'll test to see if the soil has DNA from the fungus present.

"There are a lot of open questions about Valley Fever. It is an understudied pathogen," Walter explains. "The CDC's risk map of where they think Valley Fever exists now is drawn from skin testing studies that were done in the 1940s and 1950s."

She adds that they think the range where the fungus can live in the soil will expand in Utah with climate change as well as rapid development happening in and around the St. George metro area.

As they work to update where the fungus is found, Walter hopes they can raise awareness among people who are at a greater risk of severe illness from the infection including elderly, pregnant, and those with weakened immune systems.

Severe illness is a rarity, though. It's more common for people to either not get sick at all or experience mild symptoms from Valley Fever that typically go away on their own. Those symptoms include rash, fever, fatigue, shortness of breath, and cough. If these symptoms persist for more than a week, the CDC recommends asking a healthcare provider to get a Valley Fever test.

Ultimately, Walter hopes the findings from her research help educate people, and their healthcare providers.

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