Abstract Detail

Mycology

Adams, Catharine [1], Carver, Akiko [2], Stillman, Kyra [3], Bruns, Tom [4].

Using pyrocosms to reveal pyrophilous fungi of forest, meadow, and agricultural soils.

Over the last 25 years, the frequency and severity of wildfires in the Western U.S. have increased significantly. While fire-adapted plants have been the focus of many studies, pyrophilous fungi have been hitherto relatively ignored. Furthermore, the studies that focus on pyrophilous fungi have largely focused on fungi that emerge after forest fires, while potential pyrophilous fungi residing in meadow and agricultural sites remain unidentified.
Here, we used galvanized steel buckets named ‘pyrocosms’ to test how fungi from different soil types respond to fire. Soil was collected from a range of forest sites that were each paired with a nearby meadow site, while agricultural soil was used as a control. To simulate winter, after burning, half of the samples were vernalized by incubating them at 5 degrees for 4 weeks. DNA samples were collected at weeks 1, 2, 4,8, 16 and 32, and the fungal ITS2 region was amplified with Illumina sequencing.
At the community level, PERMANOVA analysis revealed that the biggest driver of community level trends was soil type (forest, meadow, or agricultural), followed by location. The next biggest influence was the week since burning, followed by vernalization, and then whether or not the soil was burned. Shannon diversity was not significantly different between ambient and vernalized samples.
At the species level, the indicator species Pyronema domesticum constituted as much as 90% of the total sequence reads at several sites. Pyronema domesticum was an indicator species both in several forest sites as well as at meadow sites, indicating it may be a widespread, soil type-generalist, pyrophilous fungus, but it tended to be more abundant in forest compared to meadow soils. Vernalization usually delayed the response of P. domesticum by about a week, and dampened the abundance in some samples.
Another indicator species, Lyophyllum anthracophila, only reached high abundance in the vernalized treatments, and this effect occurred in week 16. A third indicator species, OTU1, a Sordariaceae sp, was often more abundant in meadow than forest samples, but was highly abundant in both. This finding implies some important pyrophilous fungi have either not had their ITS regions sequenced and may not yet have been recognized as pyrophilous fungi, possibly because they do not commonly produce macroscopic fruiting bodies.

1 - UC Berkeley, PMB, 341 Koshland Hall, PMB, Berkeley, CA, 94720, United States
2 - UC Berkeley, PMB, 317 Koshland Hall, Plant and Microbial Biology, UC Berkeley, Berkeley, CA, 94720, United States
3 - UC Berkeley, 317 Koshland Hall, Berkeley, CA, 94720, United States
4 - UC Berkeley, 317 Koshland Hall, PMB, Berkeley, California, 94720, United States

Keywords:
Fire
Pyronema
forest
meadow
fungi
Mycology.

Presentation Type: Oral Paper
Session: MY1, Mycology: Ecology and Conservation
Location: /
Date: Monday, July 19th, 2021
Time: 1:00 PM(EDT)
Number: MY1008
Abstract ID:1141
Candidate for Awards:None