To satisfy increasing demands for lignocellulosic biomass as a source of renewable energy, switchgrass, a dedicated bioenergy feedstock in the U.S., should produce as much biomass as possible. This can be achieved by delaying flowering while prolonging the vegetative stage in switchgrass. One key genetic switch that determines production of biomass is regulating the genes that control flowering time.
Hence, Dr. Million Tadege, Associate Professor from OSU’s Plant and Soil Sciences Department, collaborated with Drs. Lifang Niu, Hao Lin, and Tezera Wolabu (Institute of Agricultural Biosciences, OSU), Drs. ChunXiang Fu and Zeng-Yu Wang (Forage Improvement Division, Samuel Roberts Noble Foundation), and Dr. Yanqi Wu (Plant and Soil Sciences, OSU) to conduct a study to increase biomass yield in switchgrass by delaying floral transition.
According to Tadege and coworkers, switchgrass, a perennial grass native to North America, has been a focus on a number of genetic studies to enhance biomass yield because of its ability to produce moderate to high biomass yield on marginal soils.
Using a molecular approach, the research team identified the PvFT1 gene that activates flowering in switchgrass. The team found that overexpression of this gene in switchgrass leads to extremely early flowering, forcing regenerating plants to bloom while still at the tissue culture stage. However, silencing of PvFT1 expression by RNAi technology did not delay flowering time either. With these initial results, the research team suggested that there may be other PvFT genes that are still active in the transgenic switchgrass lines. This initial study was published in the Journal of Plant Cell & Environment.
“Identifying all PvFT genes and testing other molecular approaches in knocking down these PvFT genes in order to produce delayed flowering switchgrass lines with increased biomass yield is underway,” Tadege said. “Our preliminary results lay the foundation for understanding switchgrass flowering time regulation and for the manipulation of biomass yield by genetic engineering and marker-assisted breeding programs,” Tadege added.
Funding of this study was provided by the U.S. Department of Agriculture-National Institute of Food and Agriculture and the Oklahoma NSF EPSCoR.