Abstract: Dendrobium ekapol 'Panda 1' was transformed by Agrobacterium tumefaciens. The sensitivity of Dendrobium to hygromycin and transformation effective factors such as different strains of Agrobacterium、bacterium concentration and acetosyringone (AS) were studied by transient gus expression. The results showed that the transformation efficiency of Dendrobium transformed by E1301 (EHA105 equipped with pCAMBIA1301) was 6 times higher than L1301 (LBA4404 equipped with the same vector). Higher concentration of bacterium was more effective to transform Dendrobium (the transformation efficiency at OD₆₀₀ 1.0 or 1.2 was twice as OD₆₀₀ 0.6 or 0.8). When the concentration of bacterium was 0.8 (OD₆₀₀), the transformation efficiency was increased with the addition of AS. At other concentrations (OD₆₀₀ 0.6, 1.0 or 1.2), the transformation efficiencies were reduced with AS. Among all the treatments, the concentration of bacterium of OD₆₀₀ 1.0 without AS gave the highest transformation efficiency of 44.4%. Subjected to GUS histochemical staining, PCR and Southern blot analysis, the hygromycin-resistant shoots were proved to be transformed shoots.

Key words: Dendrobium, GUS, Agrobacterium tumefaciens, transformation, Southern blot