The influence of plant pyruvate, orthophosphate dikinase on a C3 plant with respect to the intracellular location of the enzyme

We produced transgenic tobacco plants expressing the plastidic pyruvate, orthophosphate dikinase (PPDK) from the facultative Crassulacean acid metabolism plant Mesembryanthemum crystallinum. These transgenic plants had increased PPDK amounts in leaves and seeds. They produced more seeds per seed capsule and heavier seed capsules than the wildtype. When the enzyme was expressed in the cytosol by deleting the plastid signal sequence the transgenic tobacco plants produced less seeds than the wildtype and the transgenic line with the strongest phenotype produced nearly no seeds at all. All transgenic tobaccos were different than the wildtype with respect to the pattern of free amino acids in seeds and sink- and source leaves but not in roots. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.