甘露糖 D-MANNOSE

 most plants are incapable of surviving on a synthetic medium -containing mannose as energy source, because these plants miss the enzyme phosphomannose isomerase (pmi). -this leads to an accumulation of -mannose 6-phosphate which depletes intracellular stores of inorganic -phosphate. in the presence of pmi, mannose 6-phosphate is converted into fructose 6-phosphate to enter the glycolytic pathway. a new selection system has been developed by genetically transforming plant cells with the gene mana, coding for pmi, as marker. cells containing this gene are able to grow on mannose.