Elucidating the influence of resident seed and soil microbiota on the developing creeping bentgrass microbiome

Authors: DOHERTY, JOSEPH - University Of Maryland; Crouch, Jo Anne; ROBERTS, JOSEPH - University Of Maryland

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2020
Publication Date: 4/22/2020
Publication URL: https://handle.nal.usda.gov/10113/7019779
Citation: Doherty, J.R., Crouch, J., Roberts, J.A. 2020. Elucidating the influence of resident seed and soil microbiota on the developing creeping bentgrass microbiome. Agrosystems, Geosciences & Environment. 3(1):3:e20038. https://doi.org/10.1002/agg2.20038.
DOI: https://doi.org/10.1002/agg2.20038

Interpretive Summary: The microscopic organisms that live inside plants have a tremendous impact on the health of their host, in both good and bad ways. As a plant grows from seed, a unique set of microorganisms, collectively known as the microbiome, simultaneously grows inside the plant. For turfgrass, such as creeping bentgrass, the origin of the microbiome during seed germination and plant development is unknown. By generating a series of microbiome DNA barcodes over time, we determined that as a creeping bentgrass seed grows into a young plant, the majority of its microbiome originates from the soil it grows in, not from the seed itself. These findings suggest that plant health would likely be enhanced by the supplementing the soil with beneficial microorganisms when the seeds are planted.

Technical Abstract: Characterization of the entire plant microbiome may allow for the development of new diagnostic tools or ways of improving plant health. To that end, this project sought to determine the influence that resident seed and soil microbiota exert on the developing creeping bentgrass (Agrostis stolonifera L. cv. “007”) microbiome. A sterile growth environment was created in a laminar flow hood. Sterile 50 mL conical tubes were filled with autoclaved or non-autoclaved soil (85% sand and 15% peat) and seeded with “007” creeping bentgrass. Foliage and rhizosphere samples were taken at emergence, two, four, and six weeks post-emergence, while soil samples were taken at the conclusion of the experiment. Amplicon sequencing libraries were generated from extracted environmental DNA, sequenced using an Illumina MiSeq, and analyzed in R. After quality control 3.32 x 107 sequences were grouped into 2,273 bacterial and 303 fungal amplicon sequence variants (ASVs). Bacterial and fungal ASVs were predominantly members of the Proteobacteria and Eurotiomycetes, respectively. Ordination of Bray-Curtis distance matrices revealed significant differences in community centroids between grass planted in autoclaved and non-autoclaved soil. However, taxonomic profiling showed these differences were due to shifts in taxa present at very low relative abundances (<0.5%). These data show that the microbiota originating from the seed exerts only a minimal influence over the microbiome of developing creeping bentgrass. Instead, the majority of the microbiome associated with the developing grass plant appears to come from the soil.