Identification and characterization of the part of the bacterial community associated with field-grown tall fescue ( Festuca arundinacea ) cv. SFRO Don Tomás in Uruguay

The aims of this study were to isolate, characterize and identify the native culturable putative endophytic bacterial community associated with tall fescue (Festuca arundinacea) cv. SFRO Don Tomas, cultivated in Uruguay, and to study the effects of inoculation on cv. SFRO Don Tomas and the commercial cv. Tacuabe. A total of 342 isolates were collected from surface-sterilized roots, stems and seeds of healthy cv. SFRO Don Tomas. The functional ability of the isolates to produce indole, to solubilize minerals (P, Fe, K) and to biologically fix molecular nitrogen (N2) was determined. Several infection traits, such as the ability to produce proteases, peroxidases, cellulases and hemicellulases, were identified in the isolates. Selected bacterial isolates were identified by 16S rRNA sequencing and shown to belong to a broad spectrum of genera, including Bacillus, Microbacterium, Curtobacterium, Streptomyces, Acidovorax, Variovorax, Acinetobacter, Pseudomonas, Pantoea, Rhanella and Xanthomonas. Plant growth promotion assays shown that ten isolates were able to promote the growth of cv. SFRO Don Tomas under gnotobiotic conditions, thereby highlighting the potential of these isolates in biotechnological applications as inoculant for this cultivar which is highly adapted to dry and cold seasons.