Abstract
Recently, several approaches have been adopted to improve Agrobacterium-mediated transformation of rice in order to generate a large number of transformants needed for gene targeting studies. We have succeeded in establishing a highly efficient transformation system in rice by co-cultivating suspension-cultured small calli with Agrobacterium on a filter paper moistened with N6 media containing the extract of the calli. The calli were subcultured by transferring 0.2 ml (packed cell volume) of the calli into 15 ml fresh media in 100 ml Erlenmeyer flasks every three days. After 3 weeks, the calli were used for transformation. The bacteria were collected and suspended in AA medium containing the extract of calli. For Agrobacterium infection, the density of the bacteria was adjusted and the calli were washed with N6 media containing the extract of calli, immersed in a bacterial suspension. The calli were transferred on a filter paper moistened with N6 media containing the extract of calli. Efficiency of transformation was about 60 times higher than that of calli co-cultured in N6 co-cultivation medium without the extract of calli.
