Agrobacterium-mediated sorghum transformation

Agrobacterium tumefaciens was used to genetically transform sorghum. Immatu re embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a 'Super-binary' vector with a bar gene as a selectable marker fo r herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable transforma tion experiments. A number of different transformation conditions were test ed and a total of 131 stably transformed events were produced from 6175 emb ryos in these two sorghum lines. Statistical analysis showed that the sourc e of the embryos had a very significant impact on transformation efficiency , with field-grown embryos producing a higher transformation frequency than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T-0 plants confirmed the integration of the T-DNA into the sorghum genom e. Mendelian segregation in the T-1 generation was confirmed by herbicide r esistance screening. This is the first report of successful use of Agrobact erium for production of stably transformed sorghum plants. The Agrobacteriu m method we used yields a higher frequency of stable transformation that ot her methods reported previously.