Scientists from the Department of Plant Sciences, University of Tennessee (United States) report an attempt to increase transient gene expression in switchgrass (Panicum virgatum L., a second generation biofuel crop). Genetic improvement in grass-based biofuel crops has the potential to produce crops which are "tailored" for biofuel processing (for example, varieties with low lignin content). However, grasses are said to be "recalcitrant to genetic transformation). Recently, there have been reports on the genetic transformation of switchgrass, after co-cultivation of the explants with Agrobacterium and biolistics ("gene gun" treated cells) of embryonic calli. The University of Tennessee scientists describe "optimization experiments and wounding treatments that significantly increased transient gene expression of a commercial reporter gene (GUSPlus, a variation of the beta-glucoronidase(GUS) gene) in germinating switchgrass seedlings". They determined the best treatment combination (i.e., type of Agrobacterium strain, acetosyringone concentration, and method of wounding) which increased both transient gene expression, and the likelihood of producing stable transormants. Details of the study are published in the open-access journal, Biotechnology for Biofuels (URL above)..