Regeneration and Agrobacterium-mediated transformation of mature woody species Photinia x fraseri "Red Robin"

An efficient regeneration protocol for genetic transformation was developed from the leaves of an 11-year-old Phtinia x fraseri "Red Robin" tree. A high frequency of adventitious buds (88.63 +/- A 1.38%) and the highest maximum mean number of adventitious buds per explant (4.65 +/- A 0.48) were obtained in light conditions on Murashige-Skoog (MS) medium containing 2 mg l(-1) benzyladenine (BA) and 0.2 mg l(-1) alpha-Naphthaleneacetic acid (NAA). After preculturing for 6 days, over 95% of the shoots successfully rooted on 1/2 MS medium supplemented with 0.3 mg l(-1) indole-3-butyric acid (IBA) within 3 weeks. For genetic transformation, two crucial parameters (30 mg l(-1) kanamycin for selection and 30-min suspension time) were optimized. Taken together, a reliable transformation system with an efficiency of more than 5% was established. This genetic transformation protocol can be utilized for further genetic manipulation of the Photinia tree.