The use of mannose selection system for gene transfer in tobacco plants (Nicotiana tabacum l.), a model plant for oil palm transformation

A mannose selection system was evaluated for its potential application as a selectable marker in tobacco using biolistic transformation. The above system uses pmi gene isolated from Escherichia coli that helps transgenic plants expressing it to convert mannose-6-phosphate (from mannose) into a metabolisable carbon source, fructose-6-phosphate. The ability to utilise mannose allows the transformed cells to survive on the medium containing mannose as compared to the untransformed cells. This was achieved by transforming the tobacco leaf discs using a construct carrying the pmi and ?-glucuronidase (gusA) genes which were driven by 35S cauliflower mosaic virus (CaMV35S) promoter. The tobacco leaf discs were cultured on medium supplemented with 30 g litre-1 mannose for callus induction, proliferation and regeneration. The presence of the pmi gene was proven by PCR analysis and ?-glucuronidase (gusA) activity confirmed the expression of gusA gene. Results showed that this procedure might be efficient in tobacco and other plants. The transformation procedure presented here, PMI/mannose system for selection of transgenic plants, represents an alternative for the production of transgenic plants under conditions that are safe for human health and the environment