The expression of AtRKD4 transgene during induction of somatic embryogenesis in transgenic dendrobium phalaenopsis Orchid Carrying 35S::GR::AtRKD4

Abstract

Dendrobium phalaenopsis Fitzg. is an ekndemic orchid from Larat island (Maluku) Eastern Indonesia which is classified as an endangered plant. Therefore, mass propagation to conserve this plant needs to be conducted. For rapid propagation, Arabidopsis AtRKD4 gene has been introduced into protocorm of D. phalaenopsis by using Agrobacterium-mediated transformation with T-DNA containing 35S::GR::AtRKD4 construct. Dexamethasone (DEX) was used to activate the transgene AtRKD4. The leaf of one year-old plantlets were cut and cultivated in New Phalaenopsis (NP) medium added with either 15 µM DEX, or 3 mg.L-1 thidiazuron (TDZ), and NP0 as control. We analyzed the expression of the transgene in developmental stages of 1-, 3-, 5-, and 7-days after induction by either DEX or TDZ. RT-PCR experiment by using AtRKD4 specific primer was used for detection the expression of transgenes. The result showed that 382 bp AtRKD4 cDNA fragment can be amplified by using AtRKD4 specific primer, indicating that transgene expressed in transformant plants at 1-, 3-, 5-, and 7-days after induction by either DEX or TDZ.