A Three Pronged Approach to understanding the defensive mechanisms in Green Ash (Fraxinus, pennsylvanica) resistant to EAB (Agrilus planipennis)
2018, Jeanne Romero-Severson, PhD, University of Notre Dame
Imagine a tree that protects streambanks, shelters farms from wind and blowing snow, grows rapidly, thrives in urban settings, lives for over 100 years, tolerates cold, heat and salt, has few diseases or insect pests, and displays a beautifully shaped canopy with handsome foliage. These are the ash trees native to America and they are disappearing because of emerald ash borer (EAB), an insect accidently imported from Asia. EAB is spreading rapidly across the United States, killing 98-100% of the ash trees it infests. Dead tree removal and insecticide treatments cost rural and urban communities over 1.7 billion dollars in 2011 alone and the cost continues to increase.
The good news is that a few green and white ash trees (<1%) survive for years after all other local ash trees have died. Scientists working for United States Forest Service and the University of Notre Dame have confirmed that most of these survivors have the ability to fight EAB attack and different trees use different defensive strategies. The grant provided by the Tree Fund has enabled this team of scientists to identify groups of chemical compounds that fight off EAB in individual trees and the genes that produce these compounds. This work allows us to take an important step in identifying the best offspring that will be able to kill the beetle, and survive in our forests and towns.
Although we now have offspring from crosses made with the best lingering ash parents our collaborators have, we need to verify that our set of metabolites does accurately predict which of these offspring are even better than their parents in fighting off the EAB. In developing EAB resistant ash, it is important to remember that that we want the trees to reproduce on their own. This process takes longer than selecting trees for cultivars from healthy populations because we have to produce the healthy populations first! We do not want to disappoint the foresters, the nursery owners or the homeowners with trees that are not what we said they would be. If all goes well, we anticipate that we will have some populations good enough for restoration within five years, and enough seed to release such populations a few years after that. Once these trees begin to grow and thrive, then the development of new cultivars for city streets and parts becomes a reality.
We are working on other initiatives to ensure that enough seed orchards are established to enable release of seed for restoration and cultivar development. Although we have not worked out exactly how the initial seed release will happen, who will get this seed and under what terms, we are confident that this seed release will happen. The impact will be the return of American ash trees to the landscapes where they once grew, shading our rivers, beautifying our neighborhoods and lifting our hearts with the sight of their beautiful green foliage.
Funding Duration: 1.25 years
Grant Program: John Z. Duling Grant
Grant Title: A Three Pronged Approach to understanding the defensive mechanisms in Green Ash (Fraxinus, pennsylvanica) resistant to EAB (Agrilus planipennis)
Researcher: Dr. Jeanne Romero-Severson
Key words: EAB, Emerald Ash Borer
Peer Reviewed Publications from Grant:
General Audience/Trade Publications:
Dr. Jeanne Romero-Severson
2020 – Ready, fire, aim: millions for technology, no impact on forest health. – 30th USDA Interagency Research Forum on Invasive Species – Keynote
Robert Stanley (graduate student)
2020 – Determining the defensive mechanisms in Green Ash (Fraxinus pennsylvanica) resistant to Emerald Ash Borer (Agrilus planipennis) – Plant and Animal Genome, Jan 2020 – Poster
2019 – Determining the defensive mechanisms in Green Ash (Fraxinus pennsylvanica) resistant to Emerald Ash Borer (Agrilus planipennis) – Notre Dame College of Science Joint Annual Meeting, Dec 2019 – Oral
2019 – Determining the defensive mechanisms in Green Ash (Fraxinus pennsylvanica) resistant to Emerald Ash Borer (Agrilus planipennis) – Metabolomics Society of North America, Nov 2019 – Poster
2019 – Determining the defensive mechanisms in Green Ash (Fraxinus pennsylvanica) resistant to Emerald Ash Borer (Agrilus planipennis) – CBBI Symposium Oral Presentation, CBBI Seminar presentation – Oral