Genomics of Adaptation in Switchgrass: A Candidate Bioenergy Crop

Our research is focused on the genetics and genomics of environmental stress response and adaptation in switchgrass, which will be important for future crop improvement and switchgrass’ viability as an energy source. To link whole genome expression, physiological change, and metabolomic response to drought stress we have conducted a series of drydown experiments.  These systems biological experiments will help to better understand the organismal response of switchgrass to drought. To determine the genetic architecture of drought stress response in switchgrass, we are conducting genetic mapping under a large rainout shelter in central Texas.  We have mapped many loci (QTLs) involved in phenotypic variation within switchgrass and have created novel mapping populations through crosses of accessions across divergent ecoregions. However, three of the main challenges for genetic research in switchgrass are its long generation time, large physical size, and polyploid genome.  To circumvent these difficulties, we are developing a small rapid cycling diploid perennial relative of switchgrass (Panicum hallii) as a genomic system for bioenergy research. In collaboration with the Joint Genome Institute, we have sequenced over a dozen accessions of P. hallii from across the steep soil moisture gradient of Texas to Arizona.  This has paved the way for landscape genomics and the genetic mapping of divergence between P. hallii accessions that are locally adapted to wet and dry habitats. Overall, our efforts have opened up new possibilities for genetic analysis and breeding in switchgrass.