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

Genetic transformation of sugar beet (Beta vulgaris L.) cv Bella (2n = 3x = 27) cv Dipple Ero (2n = 2x = 18) and accession SVP31-188 (2n = 2x = 18) was investigated by Infecting in vitro-derived shoot base segments with Agrobacterium tumefaciens strain LBA 4404 carrying either pBin 19 or pSI 121 plasmid. MS media supplemented with 0.5 mg.l^-1 naphthalene acetic acid, 0.25 mg.l^-1 6-benzylaminopurine and 100 βg.ml^-l kanamycin were effective for the production of callus and shoots from Agrobacterium Infected explants irrespective of the method of infection. Most of pSin 19- and all of pSI 121-medlated transformants failed to root on selective rooting media. Only 11.1% of pSin 19-mediated Sella transformants rooted on media containing 0.5 mg.l^-1 kinetin and 100 βg.ml^-1 kanamycin and all of them were the product of co-cultivation In the presence of acetosyringone. In the case of pSI 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 Sella genome. Fluorometrlc assay also demonstrated the transformed nature of a number of sugar beet shoots.