Improvement of the aluminum borate whisker-mediated method of DNA delivery into rice callus

We improved the aluminum borate whisker-mediated method of DNA delivery into rice callus (Oryza saliva L., cv. Notohikari). The following factors were examined: amount of whiskers, the kind of apparatus for agitation, the type of whiskers, duration of agitation, and agitation speed. Twenty callused scutellar tissues were agitated in a 1.5 ml microtube containing aluminum borate whiskers (ABW), liquid medium, and the plasmid pAct1-F carrying the β-glucuronidase (GUS) gene. After the agitation, the scutellar tissues were subjected to transient GUS expression assay, which visualizes GUS-expressing cells as blue spots. Efficiencies of DNA delivery were evaluated as the number of blue spots resulting from the assay. In the present study, we succeeded in improving the efficiency of DNA delivery by changing the apparatus for agitation from rotary (Vortex Genie 2) to multidirectional (MT-360), and the type of ABW from Alborex Y to an aminosilane-coated Alborex (Alborex YS3A).