The Hidden Life of Fire-Loving Fungi: How They Thrive in Burned Landscapes
Wildfires, increasingly intense due to climate change, leave behind landscapes of devastation. While most life struggles to recover in the aftermath, a surprising group of organisms not only survives but thrives: fungi. New research from the University of California, Riverside, published in the Proceedings of the National Academy of Sciences, sheds light on the genetic mechanisms that allow certain fungi to flourish in post-fire environments, even consuming charred remains.
For years, scientists have observed that some fungi are remarkably resilient to fire, quickly colonizing burned areas where other organisms have been eliminated. Researchers knew these fungi were often heat-resistant, able to grow rapidly in the absence of competition and capable of extracting nutrients from charcoal. However, the underlying genetic basis for these abilities remained largely unknown until now.
The UCR team, led by Sydney Glassman, associate professor of microbiology and plant pathology, spent five years collecting 18 fungal species from seven different wildfire burn sites across California. They sequenced the genomes of these fungi and exposed them to charcoal, meticulously analyzing how they adapted to this unique food source. Their findings reveal three primary evolutionary strategies employed by these “pyrophilous” (fire-loving) fungi.
One strategy involves gene duplication. Fungi like Aspergillus, commonly known as the green mold found on bread, utilize this method to increase the production of enzymes necessary for digesting charcoal. Essentially, they create multiple copies of the genes responsible for breaking down carbon-rich burned matter, allowing them to produce more enzymes and consume the material more efficiently. This process relies on asexual reproduction.
Another strategy, observed in the large group of mushroom-forming fungi known as Basidiomycota, relies on sexual reproduction. This allows for genetic recombination during mating, enabling rapid evolution and the development of the ability to metabolize char. The ability to quickly adapt through gene mixing provides a significant advantage in the dynamic post-fire environment.
Perhaps the most surprising discovery was the identification of horizontal gene transfer in the fungus Coniochaeta hoffmannii. This fungus appears to have acquired crucial genes from bacteria – a rare occurrence between different kingdoms of life. Horizontal gene transfer, as explained by Glassman, is akin to genetic sharing between individuals, a common practice among bacteria but unusual when crossing kingdom boundaries. “This kind of gene sharing across kingdoms is incredibly rare,” Glassman says, “But it gives this fungus the genes it needs to break down burn scars.”
The research also illuminated how these fungi survive the fire itself. Some produce sclerotia, resilient structures that can remain dormant underground for decades, patiently awaiting favorable conditions for regrowth. Others survive deeper within the soil, emerging to colonize the nutrient-rich, competition-free ground left behind after a fire.
Pyronema, for example, doesn’t possess extensive genetic machinery for charcoal breakdown. Instead, it capitalizes on the reduced competition to quickly form small, orange cup-shaped mushrooms. This opportunistic strategy allows it to thrive in the immediate aftermath of a fire, even without specialized digestive capabilities.
The implications of this research extend beyond understanding ecological recovery. The ability of these fungi to break down charcoal, which shares chemical similarities with many pollutants, suggests potential applications in environmental remediation. Researchers believe that a deeper understanding of fungal digestion processes could lead to innovative solutions for cleaning up oil spills, mining waste, and other forms of industrial contamination.
While much research focuses on plant survival after fires, the role of fungi has been comparatively understudied. “There are a lot of ways these genes can be harnessed to clean up oil spills or break down ores or help restore burned landscapes,” Glassman explains. “It’s a very new area with potentially a lot of beneficial applications.”
This research, conducted over a five-year period and published , represents a significant step forward in understanding the complex interplay between fire, fungi, and ecosystem recovery. As wildfires continue to increase in frequency and intensity, the role of these resilient organisms will become increasingly important in shaping the future of burned landscapes.
