Optimization of genetic transformation of orchid (Dendrobium Sonia) mediated by Agrobacterium tumefaciens

Abstract

Dendrobium Sonia is a popular orchid and used for many purposes in Vietnam. In this study, the transformation is set on protocorm like bodies (PLBs) mediated by Agrobacterium tumefaciens containing vector with GUS gene and kanamycin resistance gene. The main factors influencing the transformation including medium for regeneration and growth of PLBs, acetosyringone (AS) concentration, the co-cultivation time, Agrobacterium strain, bactericidal antibiotic concentrations and screening of transformed PLBs were surveyed. Results showed that MS medium supplemented with 1.0 mg/l NAA in combination with 0.5 mg/l or 0.3 mg/l BA was suitable for PLBs regeneration from stem tissue slices. The highest transformation efficiency (percentage of PLBs with GUS gene expression) was obtained when PLBs were infected and co-cultivated with Agrobacterium on the medium containing 100 µM AS for 3 days (with strain EHA105 and C58) or 4 days (with strain LBA4404). Medium containing 300 mg/l cefotaxime and 7-15 mg/l hygromycin was suitable for the disinfection and screening of transformed PLBs.