Regeneration and Possibility for Genetic Transformation of Rose

The important stage of genetic transformation is development effective and successful system for plant regeneration. As a major cut flower crop, it have been focused the attention according to this problems of many research groups from all over the world during the last 10 years. The research investigation concerns a development of new varieties to satisfy the continuously changeable requirements of numerous clients and admirers of this flower crop, and varieties more resistant to biotic and abiotic stress. In our study were used leaf explants from Bulgarian novel selected c.v. Anny (Rosa hybrida L.), using two pathways for plant regeneration- somatic embryogenesis and adventituos organogenesis. Several variants were tested for somatic embryogenesis. Some of the best results were achieved in liquid induction medium B5IV (Denchev P. et al., 1991) for a period of 2 weeks, induced explants were replaced on solidified medium for development B53MT (basal B5 supplemented with TDZ-0.2 mg/l and 3 % maltose) for 5 days. The maturation of somatic embryos was carried out on B5reg (B5 basal medium with 0.5 mg/l BAP and 0.01 mg/l NAA) resulting with around 50 % regeneration. This study attempted to achieve regeneration via adventituos organogenesis from leaf explants. The best results were showed on solidified MSN nutrient medium (basal MS supplemented with BAP-5 mg/l, TDz-1mg/1 and NAA-1 mg/l), cultivated first two weeks on dark, after that in conditions of growth room for 30 days. These results were reliable to carry out experiments of direct gene transformation with leaf disks and emryogenic mass (c.v. Anny). As a plasmid DNA was used binary vector pBECKS BIN400, containing selective mark genes GUS (under promoter 35S) and NPT II gene with promoter NOS for kanamycin resistance. Transient transformation was confirmed by glucuronidase activity of plant tissue using a fluorometric analysis of Jefferson et al., (1987) and putative stable-transformed rose embryogenic mass has been isolated. Several factors that have a significant affect on transformation efficiency were examined in an effort to optimize the biolistic process for gene transfer in roses. Some of the best results were achieved with leaf disks experiments.