An efficient and reproducible Agrobacterium-mediated transformation method for hexaploid wheat (Triticum aestivum L.)

Background: Despite wheat being a worldwide staple, it is still considered the most difficult to transform out of themain cereal crops. Therefore, for the wheat research community, a freely available and effective wheat transformationsystem is still greatly needed.Results: We have developed and optimised a reproducible Agrobacterium-mediated transformation system for thespring wheat cv ‘Fielder’ that yields transformation efficiencies of up to 25%. We report on some of the importantfactors that influence transformation efficiencies. In particular, these include donor plant health, stage of the donormaterial, pre-treatment by centrifugation, vector type and selection cassette. Transgene copy number data for independentplants regenerated from the same original immature embryo suggests that multiple transgenic events arisefrom single immature embryos, therefore, actual efficiencies might be even higher than those reported.Conclusion: We reported here a high-throughput, highly efficient and repeatable transformation system for wheatand this system has been used successfully to introduce genes of interest, for RNAi, over-expression and for CRISPR–Cas9 based genome editing.