White oak genome reveals genetic markers for climate adaptability and pest resistance

White oak (Quercus alba) is important economically, ecologically, and culturally. However, the species currently faces a major problem: low rates of seedling recruitment, the process by which seeds successfully germinate and grow into new trees.

“Vegetative competition from native and non-native plants, as well as environmental stressors such as drought and disease, are making it increasingly difficult for young white oak trees to establish,” says Meg Staton, assistant professor of bioinformatics and computational genomics in the Department of Entomology and Plant Pathology.

A recent breakthrough Staton and her colleagues have opened up promising new avenues of research. For the first time, they sequenced the complete genome of white oak, which allowed them to better understand its nature. genetic structure and evolution. The achievement will expand understanding of variation within species, helping researchers identify and exploit traits such as pest resistance and climate adaptability that can improve seedling survival.

“While sequencing the genome is a monumental achievement, the next step will be to determine which genetic markers are critical for persistence in challenging environments,” explains Staton. “By identifying these traits, we can support our forest ecosystems, developing new generations that are more resilient.”

Native to Tennessee and much of eastern North America, white oak is used by a wide range of organisms, including mammals, birds, insects and fungi. In addition to playing a key role in maintaining biodiversity, soil health and carbon sequestrationWhite oak is also a highly prized hardwood, used in products such as whiskey barrels at the famous Jack Daniel Distillery in Lynchburg, Tennessee.

Staton led the study with Indiana University's Drew Larson, in collaboration with the University of Kentucky, the U.S. Forest Service, the University of Tennessee and others. However, their recent breakthrough is just one example of how UTIA is promoting forest sustainability.

The other is the Margaret Finley Shackelford Garden Complex, founded in 2001 by the Margaret Finley Shackelford Charitable Foundation, the Hobart Ames Foundation, the Ames Agricultural Research and Education Center in Grand Junction, Tennessee, and the UT Tree Improvement Program. The complex, dedicated to the development of seed orchards for twenty-one species of trees, primarily oaks, occupies more than one hundred acres at the Ames Center. In various floodplain and mountainous areas, researchers are conducting precision forestry experiments that improve both environmental sustainability and timber production, including testing seedlings of a mixture of species in existing ecosystems.

“We plant high-quality, thoroughbred oak seedlings in small forest clearings and leave them to battle vigorous competition from herbaceous plants and trees,” says Allan Houston, research professor in the School of Natural Resources.

“Conventional forestry predicted absolute failure, but some species, like cherry oak, are very competitive. Many of the trees planted flourish, enriching a mature stand, a stand that would not have contained oak. We currently have thousands of trees in these experiments, with the ultimate goal of planting seedlings in other areas where oak species are no longer present.”

Houston is leading projects at the Shackelford Garden Complex with Scott Schlarbaum, professor and director of the UT Tree Improvement Program. The collected seeds are destined for the East Tennessee Forestry State Nursery in Delano, Tennessee, with the exception of small amounts retained for research. Although valuable data was collected on nearly two dozen species, three showed exceptional success: white oak, water oak and the highly competitive cherry oak.

These hardwoods are valued not only for their timber products, but also for their critical role in local ecosystems. Genetic research on white oak first began at the Ames Center in 1973. white oak the seed orchard was established in 1998, and the second generation trial was started in 2001. Orchards of other species, such as Chickasaw plum, began as recently as 2017, with genotypes still being added to increase genetic diversity in the orchard. However, a cherry oak seed orchard has already been established, and seed collection for nursery production is expected to continue in the coming years.

“Sustainable forestry depends on how we manage our resources in the face of a shrinking land base available for forests and a growing population,” says Schlarbaum. “UTIA's advances in DNA sequencing, seed garden development, and precision forestry experiments will strengthen forest ecosystems and ensure their viability for future generations.”