Growth and phenotype of potato plants expressing an antisense gene of P-protein of glycine decarboxylase under control of a promoter with preference for the mesophyll

A cDNA encoding P-protein of glycine decarboxylase was expressed in antisen se orientation in leaves of potato (Solanum tuberosum cv. Solara) under con trol of the promoter of a P-protein gene of glycine decarboxylase from Flav eria pringlei. This promoter targets gene expression preferentially to the leaf mesophyll cells. In two of the transgenic lines, mitochondria oxidise glycine only with extremely low rates. Phenotypically, these transgenic lin es were only marginally different from wild type plants under ambient carbo n dioxide concentrations and indistinguishable from wild type plants when g rown under 800 ppm carbon dioxide. When grown in ambient carbon dioxide, tr ansgenic plants accumulated high amounts of glycine during the light period followed by nearly complete degradation in the following night.