Submitted to: Plant Cell Tissue And Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 30, 2005
Publication Date: January 11, 2006
Citation: Vogel, J.P., Garvin, D.F., Leong, O.M., Hayden, D.M. 2006. Agrobacterium-mediated transformation and inbred line development in the model grass brachypodium distachyon. Plant Cell Tissue And Organ Culture. 84:199-211. Interpretive Summary: Model systems are proven, powerful discovery tools for modern biology. However, it is crucial that the appropriate model system be chosen to answer the questions being asked. For example, while Arabidopsis is a very powerful system with tremendous resources, it is not useful for answering questions about temperate grasses (i.e. forage grasses and cereals) where the biology of dicots and monocots diverge (i.e. cell wall structure and composition). At present, there are no established model systems suitable to study the unique features of temperate grasses. Brachypodium distachyon is a strong candidate to fill this void. This paper describes the development of characterized inbred lines and a high-efficiency Agrobacterium-mediated transformation system, two tools necessary for Brachypodium to become a useful model system.
Technical Abstract: Brachypodium distachyon has been proposed as a model temperate grass because its physical and genetic attributes (small stature, simple growth requirements, small genome size, availability of diploid ecotypes, annual lifecycle and self fertility) are suitable for a modern model plant. Two additional requirements that are necessary before Brachypodium can be widely accepted as a model system are an efficient transformation system and readily available and homogeneous reference genotypes. Here we describe the development and characterization of inbred lines from 27 accessions of Brachypodium. Determination of c-values indicated that five of the source accessions were diploid with a genome size approximately 3 times the size of Arabidopsis. An Agrobacterium-mediated transformation protocol was developed and used to successfully transform 10 of the 19 lines tested with efficiencies ranging from 0.4% to 15%. The diploid accession Bd21 was readily transformed. Segregation of transgenes in the T2 generation indicated that most of the lines contained an insertion at a single genetic locus.