A study led by UC Berkeley postdoctoral researcher Monika Fischer aims to explain the function of Pyronema, a genus of “fire-loving” fungus, in a post-fire environment.
According to Matt Traxler, campus assistant professor of plant and microbial biology and corresponding author, Fischer initiated the study in 2019 in an attempt to explain the role of Pyronema after a wildfire. He added that graduate student Frances Stark and colleagues at the University of Wisconsin-Madison were also involved in the study.
The research was based on a previous study on the Rim Fire in 2013, conducted by campus professor emeritus of plant and microbial studies Tom Bruns.
“We really wanted to know how Pyronema is responding to the post-fire environment in a barren, burned landscape,” Fischer said. “We were curious to know if it might be able to use charcoal as food because that is the only thing that is there right after a fire.”
During a wildfire, the top layer of soil will burn and organic matter will either turn into charcoal or leave as carbon dioxide, Traxler said. He added that the bottom layer of the soil will become a layer of dead, but not burnt, organic material, or necromass.
In order to determine whether Pyronema was consuming the charcoal or necromass, Fischer grew the fungus in a lab on four different carbon sources: charcoal, burned soil, a necromass substitute and pure water. Fischer noted that RNA was then extracted from the fungus after growing on these surfaces and sequenced to determine which genes were turned on during fungal growth.
“The first big trend that really jumped out to me was that a lot of metabolic genes were turned on,” Fischer said. “That was our first hint that it might be actually eating this charcoal and not purely persisting on it.”
Pyronema is a “first responder” to recovery after wildfire, according to Fischer. Traxler said her study has demonstrated that Pyronmea can thrive off both necromass and charred material, which also has implications for how rapidly ecosystems and organisms can recover after a fire.
While the recovery of plants after a fire is known, much of the recovery that occurs within the microbial community underground is still a “black box,” according to Bruns. However, Fischer hopes that further study of Pyronema will allow researchers to better understand ecosystems and find ways that people can more efficiently help the recovery process.
“We think Pyronema might be a way to immediately take some of that charred material and bring it back into the ecosystem in a way that a lot of organisms can use,” Traxler said. “It’s a way of recycling back some of this char in a short time frame.”