The Laboratory of Steve DiFazio


















Plant Genomics, Molecular Ecology, Plant Population Genetics, Biotechnology Risk Assessment

My overall research goal is to use the power of genomics to gain enhanced understanding of natural ecosystems.  Trees from the genus Populus are premier model organisms for studies of adaptive molecular variation, because abundant genetic resources are available, including a whole genome sequence, and Populus plays a dominant role in many important ecosystems.  I am actively involved in genome sequencing projects for multiple Populus and Salix species, as well as sequencing projects for other species that are associated with Populus in wild populations.  Thanks to major advances in sequencing and genotyping techniques in recent years, it is now possible to characterize molecular variation in natural populations and map adaptive diversity on a landscape scale. This research is now leading to fundamental insights into the genes that control adaptive variation, and holds out the promise of mechanistic modeling of adaptive responses to climate change.

 I am also interested in functional genomics of Populus and other species with the ultimate goal of enhancing economic and environmental utility. For example, I am currently involved in several aimed at identifying molecular control of cell wall composition, with the ultimate goal of enhancing the utility of trees for biofuels production. I am also working on identifying genes with roles in tolerance of metals like Cd and Al, salt stress, and phosphorous limitation. These eclectic objectives are tractable due to the substantial genomic toolbox that has been accumulated for Populus and, increasingly, Salix. I believe that multiple approaches are required for gene discovery and characterization in forest trees, and that biotechnology will have drastic effects on tree improvement and large-scale silviculture.

 As biotechnological methods continue to develop, and transgenic trees approach commercialization, there will be a great need to devise strategies to assess ecological risks and monitor environmental impacts.  I use a combination of molecular and simulation modeling approaches to help assess potential risks posed by transgenics.  I am also interested in applying similar methods to assessing the threat posed by the introduction and spread of exotic organisms.