NSF Postdoctoral Fellowship in Biology

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2022. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Alayna Mead is "Leveraging genomic and phenotypic data to characterize local adaptation to drought across the range of a model tree species." The host institution for the fellowship is Pennsylvania State University and the sponsoring scientists are Drs. Jill Hamilton, Stephen Keller, and Matthew C. Fitzpatrick.

Trees are ecologically important species that shape ecosystems, and carbon sequestration is among the many benefits they provide to people. The health and persistence of trees is threatened by climate change, particularly by the more frequent and severe droughts that are already occurring in parts of North America and are predicted to increase. Because trees are long-lived and can only shift their range through the movement of seeds and growth of new individuals, their response to changing climates is likely to be slow.

However, not all trees within a species will respond to climate change in the same way: for example, trees that come from drier areas may be naturally more drought-tolerant because they have adapted to the local climate. Identifying genetic variation that makes individual trees more or less drought tolerant will enable us to predict which populations are more at risk, and develop management strategies to conserve them.

This project will focus on Black Cottonwood, or Populus trichocarpa, a tree native to the western United States and Canada that is ecologically, scientifically, and economically important. This project will train the Fellow in a range of skills that will be broadly useful in forest genomics and conservation, including measurement of drought-related traits in the field and analysis of genomic data.

In addition, the Fellow will mentor undergraduate students from multiple universities, with a particular focus on providing training in coding and bioinformatics to students without previous experience in these areas.

Understanding the genetic basis of climate-related traits is important in order to identify genotypes or populations that will be maladapted or well-adapted to future climate, and to devise management plans to conserve species. This project will focus on identifying alleles involved in drought tolerance in Populus trichocarpa, a model tree species. Previous work in P. trichocarpa has been able to identify genes involved in climate adaptation among populations.

However, sampling in the southern part of the range has generally been sparse, despite these populations occurring in drier environments and potentially harboring more genetic variation than the better-studied northern populations. This project will use two whole-genome datasets to identify alleles that likely confer drought adaptation in P. trichocarpa.

First, in conjunction with the PopUp Poplars Project, drought-related traits will be measured in common gardens that include P. trichocarpa and P. balsamifera hybrids, and alleles that are associated with variation in these drought tolerance traits will be identified using a genome-wide association analysis. Second, using a dataset of P. trichocarpa individuals collected across California as part of the California Conservation Genomics Project, this project will use a genotype-environment association analysis to identify alleles that are associated with local water availability in the southern, drier part of the species range.

Additionally, candidate genes will be used to predict how P. trichocarpa will respond to climate change across its range, and to identify genotypes that are likely to be well-adapted to drought and would be ideal for restoration efforts.

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.