Establishment of Agrobacterium tumefaciens-mediated transformation of Onobrychis viciifiolia

Sainfoin (Onobrychis viciifolia) is a forage legume crop with resurgent popularity due to its anti-bloating and anthelmintic properties attributed to its relatively high content of condensed tannins. Although this property of sainfoin is desirable, sainfoin lags behind other popular forage crops in attributes, such as biomass yield, waterlogging tolerance, and stand persistence. Traditional breeding efforts to improve sainfoin have been constrained by its tetraploid genome and obligatory outcrossing nature. To accelerate the development of competitive cultivars using molecular-based approaches, a method for stable genetic transformation was needed. Here we describe a method for Agrobacterium tumefaciens-mediated transformation of sainfoin Mountainview cotyledons using A. tumefaciens strain GV3101 that produces an average transformation efficiency of 10%. We used the FB_35S::RUBY binary vector for transformation which harbors the RUBY reporter gene to enable quick and easy identification of transformation events early in the tissue culturing process. This research establishes the foundation for future advances in sainfoin through molecular-based improvement.