Optimisation of 2-deoxyglucose concentration for identifying the sensitivity level for oil palm embryogenic calli

In this study, the sensitivity of oil palm calli to 2-deoxyglucose (2-DOG) was evaluated to determine the optimal concentration to be used as a selection agent for oil palm embryogenic calli. It was reported earlier that 2-DOG has been used for selecting transformants using the DOGR1 gene which encodes 2-deoxyglucose-6-phosphate (2-DOG-6-P) phosphatase. In plants, 2-DOG is converted into 2-DOG-6-P by endogenous hexokinase which results in the inhibition of cell growth. Therefore, an experiment to determine the optimal concentration of 2-DOG required to fully inhibit the regeneration of untransformed oil palm embryogenic calli was carried out. The untransformed embryogenic calli were cultured on embryogenic callus (EC) medium supplemented with different concentrations of 2-DOG, ranging from 0 to 1000 mg litre-1. Results show that 400 mg litre-1 of 2-DOG led to nearly complete inhibition (>80%) of oil palm embryogenic calli regeneration. This was demonstrated by a reduction in the calli weight and in the ability to form whitish embryoids. This optimal concentration of 2-DOG is recommended to be used for the selection and regeneration of transformed oil palm embryogenic calli after transformation using the DOGR1 gene in future experiments