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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Disease and Pest Management Research Unit » Research » Publications at this Location » Publication #409823
Research Project: Disease Management in Small Fruit and Nursery Crops Based on Knowledge of Pathogen Diversity, Biology, and Environmental Effects

Location: Horticultural Crops Disease and Pest Management Research Unit

Title: Cultivars and production environments shape shoot endophyte profiles of boxwood with different blight resistance

Author
item LI, XIAOPING - Virginia Tech
item Weiland, Gerald - Jerry
item OHKURA, MANA - Oregon State University
item Luster, Douglas - Doug
item DAUGHTREY, MARGERY - Cornell University
item Gouker, Fred
item CHEN, GLORIA - Virginia Tech
item KONG, PING - Virginia Tech
item HONG, CHAUNXUE - Virginia Tech

Submitted to: PhytoFrontiers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/26/2024
Publication Date: 5/9/2024
Citation: Li, X., Weiland, J.E., Ohkura, M., Luster, D.G., Daughtrey, M.L., Gouker, F.E., Chen, G., Kong, P., Hong, C. 2024. Cultivars and production environments shape shoot endophyte profiles of boxwood with different blight resistance. PhytoFrontiers. https://doi.org/10.1094/PHYTOFR-03-24-0023-R.
DOI: https://doi.org/10.1094/PHYTOFR-03-24-0023-R

Interpretive Summary: Boxwood blight is a serious disease affecting the leaves and stems of boxwood plants. Naturally-occurring microbes live inside the leaves as endophytes and could serve as potential biocontrol agents for reducing boxwood blight disease. However, it is unknown which microbes are present inside the leaves. We sampled leaf microbes from four different boxwood varieties in Virginia and Oregon during the spring, summer, and fall. Then, we identified bacteria and fungi associated with the leaves using DNA sequencing. Although many different microbes were identified, three bacterial and seven fungal genera were common to all four varieties at both locations. The bacterial genera were generally associated with growth- or health-promoting species, while many of the fungal genera are considered to be plant pathogens or saprophytes. These results improve our understanding of the microbes associated with boxwood plants and may be useful for identifying biocontrol agents.

Technical Abstract: Boxwood is a renowned landscape plant and a major evergreen shrub in the U.S. green industry. Its phyllosphere endophytic microbiota play an important role in the plant’s health and productivity. However, it remains unknown whether their geographic location, cultivars, and growth conditions may impact the boxwood phyllosphere endophytes. Here, shoot samples were collected from four boxwood cultivars in two distinct climatic regions of the U.S., Oregon and Virginia, and in three sampling months: May, August, and November of 2021. DNA from the surface-sterilized shoots was amplified for bacterial 16S rRNA V5-V7 and fungal ITS1 regions, and the amplicons were sequenced for endophytic metagenomics. We found that boxwood growing region and cultivar had a stronger effect on the fungal than bacterial community diversity, structure, and composition. Divergent microbial compositional were associated with the three levels of boxwood blight resistance among the four cultivars. Comparison between the most susceptible and tolerant cultivars identified distinct microbial signatures linked to specific resistant levels, including dissimilarity in community structure, taxa with differential abundance, and microbial indicators. Moreover, we identified three bacterial and seven fungal genera that were prevalent and abundant across the regions and sampling times as core microbiome, and many of the bacterial cores are known to have strains beneficial to plant growth and health while the fungal cores contain a wealth of plant pathogens and saprophytes. These results advanced our understanding of boxwood-associated microbiomes and are fundamental for leveraging the microbiome for better boxwood protection and production.