Resequencing Poplar To Improve Its Use as a Bioenergy Feedstock
The fast-growing black cottonwood (Populus trichocarpa), a fast-growing tree that inhabits stream and river banks across a long north-south range of western North America, has been identified as a promising bioenergy crop. Many genetic and genomic resources for Populus have been developed and are being used to study the molecular basis of desirable traits such as biomass yield, cell wall characteristics, and environmental adaptation. To develop superior Populus cultivars for bioenergy feedstocks, it is necessary to understand the genetic and genomic structure of the Populus population to reliably detect phenotype-genotype associations, which informs suitable breeding approaches. Researchers at the DOE BioEnergy Research Center (BESC), together with the DOE Joint Genome Institute (DOE JGI), sequenced the genomes of 16 different black cottonwood varieties, broadly spanning north to south of the species’ native range, and determined the population structure and genetic variation on a geographic scale. They found that significant genetic differentiation existed and was strongly correlated with latitudinal location of the sampled trees, suggesting that this species may have survived the past glaciation in multiple locations along the northwest of North America. The study demonstrates that advanced population genetics approaches should be more feasible in Populus than previously thought, increasing the potential for genetic improvement of Populus as a biofuel feedstock.
Slavov, G. T., S. P. DiFazio, J. Martin, W. Schackwitz, W. Muchero, E. Rodgers-Melnick, M. F. Lipphardt, C. P. Pennacchio, U. Hellsten, L. A. Pennacchio, T. C. Mockler, M. Freitag, A. Geraldes, Y. A. El-Kassaby, S. D. Mansfield, Q. C. B. Cronk, C. J. Douglas, S. H. Strauss, D. Rokhsar, and G. A. Tuskan. 2012. “Genome Resequencing Reveals Multiscale Geographic Structure and Extensive Linkage Disequilibrium in the Forest Tree Populus trichocarpa,” New Phytologist, DOI: 10.1111/j.1469-8137.2012.04258.x.