Agrobactenum tumefaciens-Mediated Genetic Transformation of Sugar Beet (Beta vulgaris L.)

Genetic transformation of sugar beet (Beta vulgaris L.) cv Bella (2n = 3x = 27) cv Dippie Ero (2n = 2x = 18) and accession SVP31–188 (2n = 2x = 18) was investigated by infecting in vitro-derived shoot base segments with Agrobactenum tumefaciens strain LBA 4404 carrying either pBin 19 or pBI 121 plasmid. MS media supplemented with 0.5 mg.I⁻¹ naphthalene acetic acid, 0.25 mg.l⁻¹ 6-benzylaminopurine and 100 μg.ml⁻¹ kanamycin were effective for the production of callus and shoots from Agrobactenum infected expiants irrespective of the method of infection. Most of pBin 19- and all of pBI 121-mediated transformants failed to root on selective rooting media. Only 11.1% of pBin 19-mediated Bella transformants rooted on media containing 0.5 mg.l⁻¹ kinetin and 100 μg.ml⁻¹ kanamycin and all of them were the product of co-cultivation in the presence of acetosyringone. In the case of pBI 121-mediated transformants as many as 40–50 copies of the GUS gene was determined to be integrated with tandem repeats into at least six different sites of cv Bella genome. Fluorometric assay also demonstrated the transformed nature of a number of sugar beet shoots.