Abstract
An efficient gene transformation is a crucial for complementation test to identify the agronomically important genes. However, significant varietal difference was observed in the efficiency of Agrobacterium-mediated transformation in rice. Gimbozu has become a valuable research material for its highly activated transposable element, mPing. With the use of mPing SCAR markers and mPing tagging system, we have successfully identified several mutant genes induced in Gimbozu. However, the very low transformation efficiency in Gimbozu prevents the complementation test and functional analysis of the candidate genes. Here, we report an effective Agrobacterium-mediated transformation method applicable to Gimbozu. It was very difficult to recover viable calli from Gimbozu after the co-cultivation with Agrobacterium to obtain the transformants, as it is very sensitive to the Agrobacterium infection. To overcome this difficulty, we used a very low density of Agrobacterium (OD600=0.001) for infection and a high amount of meropenem at first screening. It was also important to keep infected calli dry by blotting a callus on paper towel and air drying very carefully at the time of co-cultivation. As a result, we got a sufficient number of transgenic plants in a time (90 plants from 5 resistant calli). Transformation efficiency became 14.3% and the regeneration efficiency was more than 90%.
