Chen, Qiang. Seed-associated bacterial endophytes from turf grasses promote seedling growth and defend plants from disease. Retrieved from https://doi.org/doi:10.7282/t3-0s2c-hb27
DescriptionAnimals and plants harbor microbiomes providing benefits to hosts. In plants, both prokaryotic and eukaryotic microbiomes have been universally found and shown to promote plant growth, enhance disease resistance and abiotic stress tolerance. Fungal endophytes from grasses have been well characterized, but bacterial endophytes were rarely studied. This dissertation will present research that was conducted to test the hypothesis that cool-season turfgrass seeds bear bacterial endophytes providing beneficial effects on host, such as seed germination, growth promotion, and antifungal effects. Bacteria were isolated from seeds of different turfgrass species. Among them, Bacillus amyloliquefaciens, Bacillus pumilus, and Pantoea agglomerans were demonstrated to promote seed germination and seedling growth, and alter root architecture on host. B. amyloliquefaciens strains were shown to produce antifungal lipopeptides that suppress the growth of several fungal pathogens. Metagenomic analysis on the bacterial community associated with turfgrass seeds from low and high moisture climate revealed that moisture level influenced the community structure of the bacteria on/in turf seeds. The abundance of several bacterial groups at different taxonomy ranks on/in the seeds was either positively or negatively correlated with the seed germination rate. Overall, data supported that bacterial endophytes inhabiting turfgrass seeds benefited host by promoting seed germination and seedling development, as well as providing antifungal compounds. Moreover, moisture level was found to affect the structure of bacterial community on/in turfgrass seed, which further influenced the seed germination.