High frequency transformation ofKalanchoe laciniata.

Leaf explants ofKalanchoe laciniata were cocultivated for different days (2, 4, 6 and 8 days) with disarmedAgrobacterium tumefaciens strains A208SE, GV3111SE and EHA101 carring a binary vector pROA93. The vector contains a cauliflower mosaic virus 35S promotor which drives the coding sequence of neomycin phosphotransferase II (NPT-II) in one direction and β-glucuronidase (GUS) in the opposite direction. Prolonged cocultivation (6 days) resulted in a marked increase of GUS gene transient expression, in terms of, the number of explants with transformed cells (up to 100%) and the percent area of transformed tissue (∼ 50%). Explants cocultivated for 6-7 days showed a dramatic increase in the frequency of stable transformation and 75-80% of the inoculated explants produced transgenic plants. Cocultivation with the nopaline strain A208SE for 7 days gave as high as 10 transgenic plants per explant.