RESEARCH-PGR: Genomic and Regulatory Processes Associated with Drought-stress and Environment in Oaks (The Stress Project)

About This Grant

In 2013–2015, 20% of California’s forest cover was lost as a result of drought and wildfire. Because trees are ecologically crucial and economically valuable as timber for construction and furniture, forest management will benefit from knowledge of basic science about the epigenomic basis of tree response to drought. The overarching aims are to utilize natural populations of a widespread California oak, Quercus lobata (valley oak) to compare ecophysiological response to drought in trees adapted to wet, cool versus warm, dry environments to identify candidate genes underlying response to drought stress. This study will provide a unique exploration of the interaction of epigenetic processes with gene expression in response to stress in a foundational oak species endemic to California. Such information will generate valuable genomic resources for the national and international oak scientific communities. The project will have additional broader impacts. It will advance the frontiers of oak research by expanding tools and methods used in crop species and applying them to natural populations of trees. Such information will be impactful by moving us closer to new tools for management of tree populations. This research will benefit society by translating this new knowledge into solutions. Genomic research on oaks will generate foundational knowledge, which can be applied to other species, and inform management strategies in the pursuit of healthy tree populations. In addition, this project will create opportunities to encourage careers in STEM fields for K-12 and college students. Plants are firmly rooted to the ground and cannot escape an environment that becomes unfavorable. Consequently, drought is a major source of stress for all plant species, and exerts strong selective pressure on individual physiological responses that support survival and reproduction. Recent advances have made progress in identifying drought-resistant candidate genes, yet little is known about how epigenetic processes shape their expression. This project will address this significant knowledge gap by elucidating this overlooked biological process associated with proximate response to drought-stress. Utilizing natural populations of a well-studied California endemic oak, Quercus lobata (valley oak), the central aim is to investigate the role of genetics, DNA methylation, and physiological response in trees’ response to drought stress. To do so, a seedling experiment will compare the response of two small groups of differently climate-adapted seedlings exposed to drought stress or well-watered treatments, resulting in two outcomes: 1) the production of methylomes and transcriptomes that will clarify patterns of gene expression in seedlings with different evolutionary histories of adaptation to drought stress; 2) the identification of drought resistant candidate genes. This crucial study will set a foundation for future work looking to the development of gene editing and trait selection, which could include a demonstration of how regulatory mechanisms (such as cis-regulatory elements, accessible chromatin regions, transposable elements, and DNA methylation) differ by genetic architecture and shape expression of drought response genes and physiological phenotypes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.