The apple rootstock M26 (Malus domestica) was infected with a binary vector system of Agrobacterium tumefaciens carrying the neomycin phosphotransferase II and Arabidopsis phyB genes. Thirteen transformed clones were obtained from 329 infected leaves. Five of the clones had a single copy integration, six clones had two copies, one clone had five copies and one of the clones had eight copies of the phyB gene integrated. No differences in rooting were found between transformed and untransformed plants. The stem length was reduced in nine of the 13 transgenic clones, and shoot, root and plant dry weights were reduced in all transformed clones compared with untransformed control plants. Northern analysis showed that the Arabidopsis phyB gene was expressed in the transformed clones.
Keywords: AbbreviationsBAP: Benzylaminopurine; Apple rootstock; GA: Gibberillic acid; Genetic transformation; IAA: Indole acetic acid; IBA: Indole butyric acid; Key words Agrobacterium; PCR: Polymerase chain reaction; Phytochrome B gene; T-DNA: Transfer DNA; Transgene expression; nptII: Neomycin phosphotransferase II gene; phy: Phytochrome; rbcS: Ribulose-1,5-bisphosphate carboxylase small subunit gene.