An Improved Tissue Culture System for Embryogenic Callus Production and Plant Regeneration in Switchgrass (Panicum virgatum L.)

The increased emphasis on research of dedicated biomass and biofuel crops begs for biotechnology method improvements. For switchgrass (Panicum virgatum L.), one limitation is inefficient tissue culture and transformation systems. The objectives of this study were to investigate the utility of a new medium described here, LP9, for the production and maintenance of switchgrass callus and its regeneration, which also enables genetic transformation. LP9 medium is not based on Murashige and Skoog (MS) medium, the basal medium that all published switchgrass transformation has been performed. We demonstrate an efficient tissue culture system for switchgrass Alamo 2, which yields increased viability of callus and the ability to maintain callus for a duration of over 6 months. This longevity gives a greater useful callus lifetime than for published switchgrass MS-based media. This increased longevity enables greater potential efficiency and throughput for a transformation pipeline. Callus produced on LP9 is categorized as type II callus, which is more friable and easier to multiply, maintain and transfer than type I callus obtained from previously described tissue culture systems.