USDA-ARS Vegetable Research Crops Unit and Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI53706, USA. Present address: Department of Natural Resources, Northeastern State University, Broken Arrow, OK 74014, USA.
Abstract: The
in vitro development of a whole plant from a single cell is a characteristic feature of plants. Successful embryogenesis and regeneration during
in vitro tissue culture are influenced by different factors including medium components. In this study, we compared two regeneration media (MSIII, B5) and a mixture of these media (MSIII+B5) for the regeneration of plants from putative transgenic carrot calli. Seventeen times more plantlets were regenerated on B5 medium than on either MSIII or MSIII+B5 medium. A total of 432 plantlets were regenerated on B5 medium, compared to only 24 and 28 plantlets on MSIII and MSIII+B5, respectively. Plantlets regenerated on B5 medium were generally healthier and bigger than those regenerated on either MSIII or MSIII+B5 medium. Fifty-two plantlets, 7-9 cm in length, were observed on the B5 regeneration medium, while no plants having 7-9 cm length were observed on either MSIII or MSIII+B5 medium after 4 months. This study demonstrated that B5 is a better medium than MSIII or MSIII+B5 medium for carrot callus regeneration and can be used routinely and efficiently for carrot genetic transformation experiments. The transgenic nature of the regenerated plants was confirmed by both GUS staining assay and Southern hybridization analysis.
