A First Draft of the Core Fungal Microbiome of Schedonorus arundinaceus with and without Its Fungal Mutualist Epichloë coenophiala .

Tall fescue ( Schedonorus arundinaceus ) is a cool-season grass which is commonly infected with the fungal endophyte Epichloë coenophiala . Although the relationship between tall fescue and E. coenophiala is well-studied, less is known about its broader fungal communities. We used next-generation sequencing of the ITS2 region to describe the complete foliar fungal microbiomes in a set of field-grown tall fescue plants over two years, and whether these fungal communities were affected by the presence of Epichloë . We used the Georgia 5 cultivar of tall fescue, grown in the field for six years prior to sampling. Plants were either uninfected with E. coenophiala , or they were infected with one of two E. coenophiala strains: The common toxic strain or the AR542 strain (sold commerically as MaxQ). We observed 3487 amplicon sequence variants (ASVs) across all plants and identified 43 ASVs which may make up a potential core microbiome. Fungal communities did not differ strongly between Epichloë treatments, but did show a great deal of variation between the two years. Plant fitness also changed over time but was not influenced by E. coenophiala infection.