Characterization of the Soil Bacterial Community from Selected Boxwood Gardens across the United States.

In a recent study, we observed a rapid decline of the boxwood blight pathogen () soil population in all surveyed gardens across the United States, and we speculated that these garden soils might be suppressive to . This study aimed to characterize the soil bacterial community in these boxwood gardens. Soil samples were taken from one garden in California, Illinois, South Carolina, and Virginia and two in New York in early summer and late fall of 2017 and 2018. Soil DNA was extracted and its 16S rRNA amplicons were sequenced using the Nanopore MinION platform. These garden soils were consistently dominated by and , regardless of garden location and sampling time. These two orders contain many species or strains capable of pathogen suppression and plant fitness improvement. Overall, 66 bacterial taxa were identified in this study that are known to have strains with biological control activity (BCA) against plant pathogens. Among the most abundant were spp. and spp., which may have contributed to the decline in these garden soils. This study highlights the importance of soil microorganisms in plant health and provides a new perspective on garden disease management using the soil microbiome.