Investigation of Agrobacterium-mediated transient GFP expression in leaf explants of plum

In the present study, the susceptibility of leaf explants of European plum cultivars ‘Startovaya’ and ‘Improved French’, and plum rootstock ‘Elita’ for Agrobacterium-mediated gene delivery have been evaluated. In vitro leaves were infected with A. tumefaciens strains CBE21 and AGLO harboring the plasmid pCamGFP containing the gfp gene and the hpt gene driven by the Cauliflower mosaic virus promoter. The first GFP fluorescence was detected at the second day after agrobacterial infection, the maximum number of cells with transient expression was observed on the 10^th day of culture. Noticeable stimulatory effect of AGL0 on the T-DNA delivery was found in European plums ‘Startovaya’ and ‘Improved French’. In general leaf explants of rootstock ‘Elita’ displayed lower susceptibility to the Agrobacterium-mediated transformation. The presence of acetosyringone in the co-cultivation medium was shown to decrease the efficiency of T-DNA delivery into cells of ‘Elita’ irrespective of the agrobacterial strain used. In contrast, the combination of acetosyringone with AGL0 and CBE21 increased the transient expression in ‘Startovaya’ and ‘Improved French’, respectively.