Meta-topolin enhances regeneration and Agrobacterium-mediated genetic transformation in radish (Raphanus sativus L.)

초록

Meta-topolin (mT) is a novel aromatic cytokinin that stimulates morphogenesis and is an alternative source of cytokinins frequently employed in regeneration systems. Hence, the present research explored the prospect of mT for improving regeneration and genetic transformation efficiency. Cotyledonary node explants were cultured on optimum plant growth regulator medium incorporated with mT for enhanced shoot induction (93.6%, 2.0 mg l(-1) BA and 0.9 mg l(-1) mT), elongation (89.3%, 2.0 mg l(-1) GA(3) and 0.9 mg l(-1) mT), and rooting (90.3%, 0.9 mg l(-1) IBA and 0.9 mg l(-1) mT) respectively. The plant transformation study was carried out through Agrobacterium-mediated transformation using the pCAMBIA1301 vector containing the LB4404 strain for standardizing transformation strategies. Transformed shoots and rooting were determined in two stages using 10 and 6 mg l(-1) hygromycin B for exterminating chimeric explants. After co-cultivation, explants were cultured at the optimal concentration of 0.9 mg l(1)(- )mT, 2.0 mg l(-1) BA, 2.0 mg l(-1) GA(3), and 0.9 mg l(-1) IBA for enhanced transformation efficiency (27.3%), corresponding to transformed regeneration without mT (18.6%) occurring with less efficiency. The existence of transgenes in the radish genome was ascertained by the GUS assay, PCR, RT-PCR, and qRT-PCR. Overall, our investigation demonstrated that including mT increases regeneration and enhances transformation efficiency in radish. Therefore, diverse radish varieties could use a designed transformation strategy to acquire essential traits.

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