Exploring the Impacts of Soil Fungi on the Reintroduction of A. tridentata to the Sagebrush Steppe
Faculty Mentor Information
Dr. Allison Simler-Williamson (Mentor), Boise State University
Abstract
Sagebrush (Artemisia tridentata) steppe ecosystems have declined across their historical range, due to wildfires, invasive species, and anthropogenic disturbances. Restoration seedings aim to reintroduce sagebrush to degraded sites, but their success rates vary. Of the many environmental factors evaluated as obstacles to sagebrush seedings, little is known about what role soil pathogens might play.
We quantified the impacts of fungi on sagebrush seed and seedling survival, as well as how environmental conditions influenced seed-pathogen interactions. We performed Koch’s postulates for 6 fungal isolates cultured from nonviable A. tridentata seeds, which were incubated in a field experiment in winter 2022-23. We inoculated surface-sterilized seeds with fungal spores and incubated seeds in controlled chambers that mimic overwinter conditions in sagebrush steppe for 6-8 weeks, while documenting germination, mortality, and symptom development. To assess weather impacts on disease dynamics, we varied incubation temperatures for one isolate.
In our initial trial, the fungal isolate decreased seed viability and seedling survival by up to 43%, but disease dynamics varied with temperature. Preliminary results from subsequent trials suggest that all isolates generate disease, but with varying severity. Identifying pathogenic fungi in sagebrush steppe soils could contribute to the improvement of A. tridentata reseeding efforts.
Exploring the Impacts of Soil Fungi on the Reintroduction of A. tridentata to the Sagebrush Steppe
Sagebrush (Artemisia tridentata) steppe ecosystems have declined across their historical range, due to wildfires, invasive species, and anthropogenic disturbances. Restoration seedings aim to reintroduce sagebrush to degraded sites, but their success rates vary. Of the many environmental factors evaluated as obstacles to sagebrush seedings, little is known about what role soil pathogens might play.
We quantified the impacts of fungi on sagebrush seed and seedling survival, as well as how environmental conditions influenced seed-pathogen interactions. We performed Koch’s postulates for 6 fungal isolates cultured from nonviable A. tridentata seeds, which were incubated in a field experiment in winter 2022-23. We inoculated surface-sterilized seeds with fungal spores and incubated seeds in controlled chambers that mimic overwinter conditions in sagebrush steppe for 6-8 weeks, while documenting germination, mortality, and symptom development. To assess weather impacts on disease dynamics, we varied incubation temperatures for one isolate.
In our initial trial, the fungal isolate decreased seed viability and seedling survival by up to 43%, but disease dynamics varied with temperature. Preliminary results from subsequent trials suggest that all isolates generate disease, but with varying severity. Identifying pathogenic fungi in sagebrush steppe soils could contribute to the improvement of A. tridentata reseeding efforts.