High-throughput Agrobacterium-mediated barley transformation

Background: Plant transformation is an invaluable tool for basic plant research, as well as a useful technique for the direct improvement of commercial crops. Barley (Hordeum vulgare) is the fourth most abundant cereal crop in the world. It also provides a useful model for the study of wheat, which has a larger and more complex genome. Most existing barley transformation methodologies are either complex or have low (< 10%) transformation efficiencies. Results: A robust, simple and reproducible barley transformation protocol has been developed that yields average transformation efficiencies of 25%. This protocol is based on the infection of immature barley embryos with Agrobacterium strain AGL1, carrying vectors from the pBract series that contain the hpt gene (conferring hygromycin resistance) as a selectable marker. Results of large scale experiments utilising the luc (firefly luciferase) gene as a reporter are described. The method presented here has been used to produce hundreds of independent, transgenic plant lines and we show that a large proportion of these lines contain single copies of the luc gene. Conclusion: This protocol demonstrates significant improvements in both efficiency and ease of use over existing barley transformation methods. This opens up opportunities for the development of functional genomics resources in barley.