Abstract
We investigated adaptive genetic variation in Populus trichocarpa, a potential biofuel feedstock crop, to better understand how physiological traits may influence tolerance to water limitation. Our study focused on leaf and stomatal traits, given their roles in plant–water relations and adaptation. Using a diversity panel of over 1300 genotypes, we measured 14 leaf and stomatal traits under control (well-watered) and drought (water-limited) conditions. We conducted genome-wide association studies (GWAS), climate association analyses, and transcriptome (RNA-seq) profiling to identify genetic loci associated with phenotypic variation and adaptation. Stomatal traits, including size and density, were correlated with the climate of origin, with genotypes from more arid regions tending to have smaller but denser stomata. GWAS identified multiple loci associated with trait variation, including a major-effect region on chromosome 10 linked to stomatal size and abaxial contact angle. This locus overlapped with a tandem array of 3-ketoacyl-CoA synthase (KCS) genes and showed strong allele–climate and gene expression associations. Our findings reveal genetic and phenotypic variation consistent with local adaptation and suggest that future climates may favor alleles associated with smaller stomata, particularly under increasing aridity. This work provides insights into climate adaptation and breeding strategies for resilience in perennial crops.
| Original language | English |
|---|---|
| Pages (from-to) | 2647-2664 |
| Number of pages | 18 |
| Journal | New Phytologist |
| Volume | 247 |
| Issue number | 6 |
| DOIs | |
| State | Published - Sep 2025 |
Funding
This material is based on work supported by the Center for Bioenergy Innovation (CBI), U.S. Department of Energy, Office of Science, Biological and Environmental Research Program under Award No. ERKP886. Research in the laboratory of Gail Taylor is supported by the John B. Orr endowment in Environmental Plant Sciences, and this project was supported by the Genomics-Enabled Plant Biology for Determination of Gene Function program by the Office of Biological and Environmental Research in the DOE Office of Science (Award DE-SC0020164). MCK acknowledges the Department of Plant Sciences, UC Davis, for the award of a GSR scholarship funded by endowments, particularly the James Monroe McDonald Endowment, administered by UCANR. We thank all UC Davis interns, graduate students, and postdocs who helped with field collections and lab assistance on this project. This paper is dedicated to the memory of our wonderful colleague and friend, Dr Wellington Muchero, who is much missed. This material is based on work supported by the Center for Bioenergy Innovation (CBI), U.S. Department of Energy, Office of Science, Biological and Environmental Research Program under Award No. ERKP886. Research in the laboratory of Gail Taylor is supported by the John B. Orr endowment in Environmental Plant Sciences, and this project was supported by the Genomics‐Enabled Plant Biology for Determination of Gene Function program by the Office of Biological and Environmental Research in the DOE Office of Science (Award DE‐SC0020164). MCK acknowledges the Department of Plant Sciences, UC Davis, for the award of a GSR scholarship funded by endowments, particularly the James Monroe McDonald Endowment, administered by UCANR. We thank all UC Davis interns, graduate students, and postdocs who helped with field collections and lab assistance on this project. This paper is dedicated to the memory of our wonderful colleague and friend, Dr Wellington Muchero, who is much missed.
Keywords
- Populus trichocarpa
- bioenergy
- climate adaptation
- drought
- leaf
- stomata