A Culture-independent Approach to Understanding the Role of Soil Fungal
Communities in Bromus tectorum Stand Failure
Abstract
Bromus tectorum (cheatgrass) is an invasive annual grass that has
colonized large portions of the Intermountain Western United States.
Cheatgrass stand failures have been observed throughout the invaded
region, the cause of which may be related to the presence of several
species of pathogenic fungi in the soil or surface litter. In this
metagenomic study, we compared the fungal communities between sites that
have and have not experienced stand failure. Samples were taken from the
soil and surface litter near Winnemucca, Nevada and in Skull Valley,
Utah. Our results show distinct fungal communities associated with stand
failure based on both geography and sample type. In both the Winnemucca
and Skull Valley surface litter, there was an elevated abundance of the
endophyte Ramimonilia apicalis in samples that had experienced a stand
failure. Winnemucca surface litter stand failure samples had increased
abundance of a potential pathogen in the genus Comoclathris. Skull
Valley surface litter stand failure samples had increased abundance of
the known cheatgrass pathogen Clarireedia capillus-albis while the soils
had increased abundance of potential pathogens in the genera Olpidium
and Monosporascus.