Diversity of Endophytic Fungi and Bacteria Inhabiting the Roots of the Woodland Grass, Festuca gigantea (Poaceae)

Abstract

We studied the occurrence of endophytic fungi and bacteria in the roots of F. gigantea, a woodland perennial grass common throughout Europe and temperate Asia. The taxonomic assignment was carried out according to the isolate’s colony and cytological species morphotype characteristics and confirmed by the assessment of the standard DNA sequences, ITS, RPB2, SSU, and TEF1-a for fungi and 16S rDNA for bacteria. Our study has shown that F. gigantea roots are the habitat to a wide range of fungi and bacteria. The occurrence of fungal structures was determined in ~40% of the roots examined by Trypan Blue staining. In a surface-sterile root-cutting culture on PDA medium, we obtained isolates of six endophytic fungi species: four members of Ascomycota—Alternaria alternata, Cadophora fastigiata, Chaetomium funicola, and Microdochium bolleyi—and two of Basidiomycota—Coprinellus sp. and Sistotrema brinkmannii. In addition, we report bacteria co-occurring endophytically in the roots of this grass. The Firmicutes group was the most prevalent, consisting of four Gram-positive, endospore-forming bacteria taxa. The isolates were identified as Bacillus pumilus, Bacillus sp., Lysinibacillus sp., and Priestia aryabhattai. Moreover, two Gram-negative bacteria were detected—Kosakonia sp. (Proteobacteria) and Pedobacter sp. (Bacteroidetes). Thus, applying the isolate-culture approach, we identified a set of microorganisms in the roots of a typical grass native to the deciduous forest floor. The functional roles of these endophytes are diverse, and many of them, saprotrophs and decomposers of wood and plant debris, are linked to the decomposition of organic matter. This is the first detailed report on fungal and bacterial endophytes inhabiting the roots of F. gigantea. This study fills in a research gap on endophytes associated with the below-ground parts of Festuca spp., hitherto extensively studied for Epichloë/Neotyphodium associations in their foliar parts.