A culture‐independent approach to understanding the role of soil fungal communities in Bromus tectorum stand failure

Abstract

Cheatgrass (Bromus tectorum L.) is an invasive annual grass (Poaceae) that has colonized large portions of the Intermountain West. 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 metabarcoding 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 an increased abundance of a potential pathogen in the genus Comoclathris. Skull Valley surface litter stand failure samples had an increased abundance of an undescribed new species in the Rustroemiaceae family which is responsible for the so‐called bleach blonde syndrome in cheatgrass, while the soils had an increased abundance of potential pathogens in the genera Olpidium and Monosporascus.

Multiomics Reveals Mechanisms of Alternaria oxytropis Inhibiting Pathogenic Fungi in Oxytropis ochrocephala

“…10 It has been speculated that Comoclathris may be an important pathogenic fungus causing Bromus tectorum stand failure. 12 Our results stated that these three pathogenic fungi, Leptosphaeria, Colletotrichum, and Comoclathris, were significantly upregulated in the EF group, indicating that O. ochrocephala without endophytic fungi was susceptible to disease. The presence of endophytic A. oxytropis would significantly reduce the risk of plant infection with these three pathogenic fungi, thus improving plant disease resistance In our study, the significantly enriched differential metabolic pathways between the EF and EI groups were identified by the KEGG pathway enrichment analysis, according to differential metabolites.…”

“…ochrocephala being infected with fungal diseases of the Ascomycota phylum in this study. Leptosphaeria , Colletotrichum , and Comoclathris are well-known plant pathogens. Leptosphaeria can induce diseases of rape and other plants, causing serious economic losses, and many toxic secondary metabolites have been isolated from Leptosphaeria- infected plants.…”

“…Because of its wide range of parasitism, Colletotrichum is widely distributed and can infect crops and medicinal plants . It has been speculated that Comoclathris may be an important pathogenic fungus causing Bromus tectorum stand failure . Our results stated that these three pathogenic fungi, Leptosphaeria , Colletotrichum , and Comoclathris , were significantly upregulated in the EF group, indicating that O.…”

“…11 Comoclathris may play an essential role as a pathogenic fungus in causing Bromus tectorum stand failure. 12 In recent years, integrative analysis of microbiomes and metabolomes has become increasingly extensive in studies of human health, plant disease resistance, and nutrition of cash crops. 13 Previous studies confirmed that Epichloëspecies can enhance salt tolerance by improving metabolite contents 14 of Achnatherum inebrians.…”