Plant & Animal Genomes XVI Conference

January 12-16, 2008
Town & Country Convention Center
San Diego, CA

Association Genetics Of 100 Candidate Genes Involved In Adaptation-Related Cold Tolerance In Douglas-Fir

Barnaly Pande¹ , Andrew, J. Eckert² , Brandon, R. Tearse¹ , Jill, L. Wegrzyn¹ , Jennifer, M. Lee² , Konstantin, V. Krutovsky³ , Brad, J. St. Clair⁴ , David, B. Neale¹

¹  Department of Plant Sciences, University of California, Davis, CA, USA

²  Department of Evolution and Ecology, University of California, Davis, CA, USA

³  Department of Forest Science, Texas A&M University, 2135 TAMU, College Station, TX

⁴  USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR, USA

Understanding and pinpointing the sources of natural variation that result in the adaptation of populations of individuals, has been a long-standing major goal of molecular, population and evolutionary genetics. Now, with the rapid advances in sequencing technologies, the possibility of understanding the differences within and between populations, is much closer at hand.
We have studied adaptation-related traits and genes in the conifer Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), that is adapted to the highly heterogeneous environments of the US Pacific Northwest and cataloged genetic changes over a ~300 million year evolution. It has been shown that winter temperatures and frost dates are most important for influencing the adaptation of Douglas-fir to these environments, and our previous studies have identified QTL for adaptation-related traits such as bud flush and cold hardiness in spring and fall seasons.
In this study, we have resequenced differentially cold-regulated candidate genes emerging from studies of gene expression using Douglas-fir EST libraries. From the analysis of 100 genes using a diverse panel of trees, we have been able to estimate the level of nucleotide diversity as well as identify genes that show evidence of selection using standard tests of neutrality. In addition, we have genotyped a subset of the identified SNPs in ~700 unrelated trees that range across the natural Douglas-fir forests of Washington and Oregon. Tests of association reveal 11 SNPs that individually account for up to 5% of the variation in adaptation-related traits, such as growth, cold-damage resistance and bud flush, even after multiple testing correction. These findings pave the way for making more informed decisions regarding the conservation of genetic resources and management of Douglas-fir breeding programs, and for predicting, and possibly mitigating effects of climate change.