Research Spotlight: Exploring Fire Blight in Ornamental Apple Trees

By Na Wei, Holden Research Scientist

Crabapple Malus ‘Molten Lava’

Plants are living in a microbial world. They interact not only with microbes in the soil but also the ones living in their flowers. These microbial partners can be beneficial or harmful. One of the most devastating epidemics in ornamental apple trees – fire blight – is caused by bacterial infection initiated during bloom, and can be spread from flower to flower by visiting pollinators. Breakthrough in suppressing this pathogenic microbe is needed.

At Holden, we aim to develop plant probiotics against fire blight using beneficial flower microbes from the resistant cultivars of ornamental apples (crabapples). Holden has established an invaluable resource of crabapple cultivar collection for over 30 years. At Holden’s long-term experiment plot of crabapples, every single tree has been permanently tagged. These cultivars differ in their flowers such as color and smell and disease resistance. We will monitor their flowering and study flower microbes.


Na Wei, Ph.D works in the arboretum’s Long Science Center, home to our team of researchers who conduct nationally recognized research in plant and environmental sciences. Her research seeks to explain the ecological and evolutionary mechanisms that enable adaptation to environmental change in plants. Using crop relatives (wild strawberries and apples), Dr. Wei’s lab addresses eco-evolutionary adaptation through the lenses of functional ecology, genomics and microbiome. Na received her Ph.D. from the University of Michigan, Ecology and Evolutionary Biology (2015).