Efficient Agrobacterium-mediated Genetic Transformation Using Cotyledons, Hypocotyls and Roots of ‘duli’ (pyrus Betulifolia Bunge)

The Agrobacterium-mediated transformation assays generate transgenic pear at low efficiencies. For pear gene-function verification and molecular breeding, a fast and effective transformation method is still required. In this study, transgenic 'Duli' (Pyrus betulifolia Bunge) plants marked with EGFP were obtained from cotyledons, hypocotyls and roots using Agrobacterium-mediated transformation systems. The most efficient bud regeneration occurred on MS medium containing 4 mg/L 6-benzylaminopurine (6-BA) and 0.05 mg/L indole-3-butytric acid (IBA) for cotyledons (83%), and on NN69 medium containing 2 mg/L 6-BA and 0.05 mg/L IBA for hypocotyls (63%). However, the transformation efficiencies for cotyledons and hypocotyls were 5% and 2%, respectively. In addition, the infiltration and vacuuming of Agrobacterium rhizogenes were used for root transformation with a transformation efficiency of 52%. Thus, efficient and repeatable transformation systems were established and in combination with the visual marker EGFP, formed a rapid, convenient and highly efficient method to obtain and identify transgenic pear. The results are significant for gene function verification in pear and for the future genetic improvement of pear.