Fungi communicate and engage in more “conversations” after rainfall

Fungi communicate in a way that is still a bit of a mystery to scientists, yet incredibly important to ecosystems. Several species of fungi play an important role in the ecological sustenance of forest trees.

For instance, ectomycorrhizal fungi – commonly found on oak, pine, and birch trees – form a sheath around the outside regions of tree roots, while their mycelial body develops into vast underground networks absorbing crucial nutrients from the soil and transferring them to the trees.

Various studies have examined the possibility of electrical signal transfer between fungi and across trees via these mycelial networks, and hypothesized that fungi generate electrical signals in response to external stimuli to communicate with each other and coordinate growth and other behaviors. Some scientists have argued that these signals can even be used to help transfer nutrients to plants and trees. 

However, the current scientific evidence for these hypotheses remains sparse, and most of the previous studies have been limited to the laboratory, thus failing to properly recreate what happens in the wild.

To address these shortcomings, a team of researchers led by Tohoku University in Japan has conducted a field study in which they examined the behavior of small, tan-colored ectomycorrhizal fungi known as Laccaria bicolor in the wild. By attaching electrodes to six fungi in a cluster, they discovered that the electrical signals emitted by these fungi increased after rainfall.

“In the beginning, the mushrooms exhibited less electrical potential, and we boiled this down to the lack of precipitation,” said study lead author Yu Fukasawa, an assistant professor of Forest Microbial Ecology at Tohoku. “However, the electrical potential began to fluctuate after raining, sometimes going over 100 mV.”

The scientists managed to correlate the way fungi communicate through these electrical fluctuations with precipitation and temperature, and causality analysis revealed that the post-rain electric potential showed signal transport among fungi, which was particularly strong between spatially close mushrooms and exhibited clear directionality.

“Our preliminary results bring a call for studies on fungal electrical potentials in a more ecological context under field conditions,” the authors concluded.

More about how fungi communicate

Fungi, being an incredibly diverse group of organisms, have evolved various methods of communication with each other. Some of the main ways they communicate include chemical signaling, electrical signaling, and through physical connections called mycelial networks.

Chemical signaling

Fungi communicate by releasing chemical signals called pheromones and extracellular signaling molecules. These molecules are used to communicate with other fungi and organisms in their environment. In response to these signals, fungi can change their growth patterns, initiate sexual reproduction, or activate defense mechanisms. Quorum sensing is a common chemical communication strategy used by fungi, where they release and detect signaling molecules to monitor their population density and coordinate collective behaviors.

Fungi communicate through electrical signaling

Recent research has shown that some fungi can generate and transmit electrical signals similar to those found in animal nerve cells. This type of communication is not yet fully understood, but it’s believed to help fungi coordinate their growth, respond to environmental changes, and interact with other organisms.

Mycelial networks

The mycelium is the vegetative part of a fungus, consisting of a network of thread-like structures called hyphae. Mycelial networks can connect individual fungi and act as a communication and resource-sharing system. Through these networks, fungi communicate, exchange nutrients, water, and signaling molecules, allowing them to coordinate their growth, reproduction, and defense strategies.

Mycorrhizal associations, which are symbiotic relationships between fungi and plant roots, provide another example of fungal communication. In these associations, fungi help plants absorb nutrients and water, while plants provide fungi with sugars produced during photosynthesis.

This exchange of resources and signaling molecules helps both organisms to thrive and adapt to their environment.

While research into fungal communication is still in its early stages, the discoveries made so far provide fascinating insights into the complex interactions that govern fungal behavior and ecology.

More about Fungi

Fungi are a diverse group of eukaryotic organisms that include yeasts, molds, and mushrooms. They are distinct from plants, animals, and bacteria, and form their own kingdom, the Fungi kingdom.

Fungi play essential roles in various ecosystems as decomposers, symbionts, and even pathogens. Fungi communicate through a network of chemical and electrical signals. Here are some key features and aspects of fungi:

Structure

Fungal cells have a rigid cell wall made of chitin, a polysaccharide also found in the exoskeletons of insects and crustaceans. Most fungi grow as filamentous structures called hyphae, which together form a larger network called mycelium. Some fungi, like yeasts, grow as single-celled organisms.

Reproduction

Fungi reproduce both sexually and asexually. Asexual reproduction occurs through spore formation, budding, or fragmentation of the mycelium. Sexual reproduction typically involves the fusion of specialized cells called gametes, which can result in the production of genetically diverse spores.

Nutrition

Fungi are heterotrophic organisms, meaning they obtain nutrients by absorbing organic compounds from other organisms. Most fungi are saprophytic decomposers, breaking down dead organic material and recycling nutrients in the ecosystem. Some form symbiotic relationships with other organisms, such as mycorrhizal associations with plant roots or lichens formed between fungi and algae. There are also parasitic fungi that can infect plants, animals, and even humans.

Ecological roles

Fungi are crucial in maintaining ecosystem balance as decomposers, nutrient cyclers, and mutualistic symbionts. They help break down complex organic materials like cellulose and lignin in plant matter, making nutrients available for other organisms. Fungi also form symbiotic relationships with plants, enhancing their nutrient uptake and providing protection from pathogens.

Economic and medical importance

Fungi have numerous applications in food production, medicine, and biotechnology. They are used in the production of bread, beer, cheese, and various fermented foods. Some fungi, like the Penicillium species, produce antibiotics that are critical in treating bacterial infections. However, fungi can also cause diseases in plants, animals, and humans, and spoil food and other products.

Biodiversity

There are an estimated 2.2 to 3.8 million fungal species, but only about 120,000 have been formally described. Fungi can be found in diverse habitats, from terrestrial ecosystems like forests and grasslands to aquatic environments and even extreme environments like deserts and polar regions.

Our understanding of the fungal world is still growing, with new species and their ecological roles being discovered regularly. As research continues, the importance of fungi in maintaining the health and balance of ecosystems becomes increasingly apparent.

The research findings are published in the journal Fungal Ecology.

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By Andrei Ionescu, Earth.com Staff Writer

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