Isolation and Testing of Endophytes from Big Bluestem (Andropogon gerardii) for Plant Growth Promotion

Abstract

Rising global populations are causing persistent strain on agricultural systems. One sustainable alternative involves using plant species containing endophytes that can improve plant performance. Big bluestem (Andropogon gerardii) is a perennial grass known to host endophytes, but the functions of its endophytes are ambiguous. I hypothesized that endophytes present within a plant influences plant growth, therefore I investigated plant growth-promoting endophytes isolated from big bluestem. I isolated 68 bacterial and 17 yeast strains from seeds of 24 big bluestem plants grown in a low-input system. I performed DNA-based taxonomic identification, screened the strains for beneficial properties, selected the best-performing endophytes, and experimentally inoculated them into big bluestem and switchgrass (Panicum virgatum). Bacterial endophyte inoculation slightly increased big bluestem plant height, but no other benefits were observed. Future studies can explore if endophyte benefits to the plant host may be more likely if the plant is experiencing abiotic or biotic stressors.