A full length cDNA has been cloned encoding nicotinamide adenine dinucleotide phosphate specific glutamate dehydrogenase (NADP-GDH) from Chlorella sorokiniana with the RT-PCR method. The complete nucleotide sequence of NADP-GDHgene had 94% homology to the previously reported one . The NADP-GDHgene was constructed into a vector highly expressed in plants. The specific activity of NADP-GDH in transformants was detected, but not in the control plants. All transformed shoots on MS medium containing lower concentration of nitrogen and the transformed seedlings grown in lower concentration of nitrogen vermiculite had higher growth rate and more leaves than the control plants. Transformed leaf discs cultured on MS medium containing different nitrogen concentrations had more chlorophyll contents compared to the controls. These results suggested that exogenous NADP-GDH may enhance the absorption and utilization to ammonium in plants. The increased weight of transformed leaf discs cultured on medium supplemented with different concentrations of phosphinothricin (PPT) was more than that of control discs.0.5 μg/mL PPT could be used as a selecting drug instead of kanamycin to develop the transformants. These results suggested that the NADP-GDH gene might besed as a new selecting gene in the future research of plant gene engineering.
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