A modified method for routine Agrobacterium-mediated transformation of in vitro grown potato microtubers.

In vitro-grown potato (Solanum tuberosum L.) microtubers were used as an explant source in the production of transgenic plants by Agrobacterium-mediated gene transfer. In this study we tested four diverse potato cultivars, Lemhi Russet, Russet Burbank, Wauseon, and Yankee Chipper on various levels of zeatin riboside and 3-indoleacetyl-DL-aspartic acid for their ability to regenerate transgenic plants after infection with Agrobacterium tumefaciens. Culturing microtuber blocks from the medullary area separately from cortex and epidermal tissue containing the eyes resulted in fewer transgenic plants, with transgenic shoots arising only from the tissue with the eyes. Lemhi and Russet Burbank microtuber discs were also transformed with a chimeric gene, CLaSP, designed to increase resistance to blackspot bruise in the tuber. This method resulted in transformed plants in every experiment, with an efficiency that appeared to be genotype dependent.