Switchgrass Chromosome Structure Revealed
Switchgrass is considered to be a promising biofuel feedstock because of its ability to produce high biomass yields on marginal lands with minimal inputs. Several efforts to improve switchgrass as a dedicated bioenergy crop have been initiated, but breeding efforts are hampered by the outbred, tetraploid nature of this species and by limited knowledge of its chromosome architecture. Researchers at the USDA-Agricultural Research Service have used sophisticated molecular, cytological, and imaging techniques to tease apart and unambiguously identify the nine relatively small and otherwise undistinguishable base chromosomes of a dihaploid switchgrass line, producing the first karyotype (systematized arrangement of the total chromosome complement) of this bioenergy crop. The scientists were able to distinguish the two switchgrass ecotypes as well as the two basic subgenomes using this resource. This new capability will greatly facilitate identification of specific gene pools (e.g., regionally adapted cultivars) for switchgrass improvement toward the goal of making it a productive biomass crop. The research was supported in part by the joint USDA-DOE Plant Feedstocks Genomics for Bioenergy Program.
Young, H. A., G. Sarath, and C. M. Tobias. 2012. “Karyotype Variation Is Indicative of Subgenomic and Ecotypic Differentiation in Switchgrass,” BMC Plant Biology 12, 117. DOI: 10.1186/1471-2229-12-117.