Advertisement

Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Starch biosynthesis from triose-phosphate in transgenic potato tubers expressing plastidic fructose-1,6-bisphosphatase

  • 91 Accesses

  • 9 Citations

Abstract.

A full length cDNA clone encoding plastidic fructose-1,6-bisphosphatase (cp-FBPase), together with a transit peptide, was isolated from a potato (Solanum tuberosum L.) leaf cDNA library. Potato plants were transformed with the isolated cp-FBPase sequence behind a patatin class I promoter to ensure tuber-specific expression of the enzyme. Plant lines were selected which expressed up to 250 mU (g FW)–1 in the developing tubers, which is 10- to 20-fold the activity found in wild-type tubers. Intact amyloplasts were isolated from in vitro-grown minitubers developed in darkness. Comparison with marker enzymes showed that cp-FBPase activity in transgenic tubers, as well as the low FBPase activity in the wild-type tubers, was localised inside the amyloplasts. The intact amyloplasts isolated from both wild-type and transgenic tubers synthesised starch from [U-14C]glucose-6-phosphate. Conversely, only the transgenic tubers expressing cp-FBPase showed appreciable synthesis of starch from [U-14C]dihydroxyacetone phosphate, and this synthesis rate was correlated to the activity of cp-FBPase. Thus, the expression of cp-FBPase in tubers allows for a new route of starch biosynthesis from triose-phosphates imported from the cytosol. The transgenic tubers did not differ from wild-type tubers with respect to starch content, or the levels of neutral sugars and phosphorylated hexoses.

This is a preview of subscription content, log in to check access.

We’re sorry, something doesn't seem to be working properly.

Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.

Author information

Additional information

Electronic Publication

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Thorbjørnsen, T., Asp, T., Jørgensen, K. et al. Starch biosynthesis from triose-phosphate in transgenic potato tubers expressing plastidic fructose-1,6-bisphosphatase. Planta 214, 616–624 (2002). https://doi.org/10.1007/s004250100647

Download citation

  • Amyloplast Carbohydrate metabolism Plastidic fructose-1,6-bisphosphatase Solanum (starch biosynthesis) Starch biosynthesis Transgenic potato tubers