Targeting starch granules in potato tubers, using Starch Binding Domain technology

Starch, a naturally abundant nutrient carbohydrate, can be found in almost all agricultural crops. Raw starch does not have most of the characteristics demanded by food and non-food industries, hence it must be modified. To target starch granules during its biosynthesis specifically, we have developed a novel platform technology called Starch Binding Domain technology (SBD). Luciferase reporter gene, Granule Bound Starch synthase I (GBSSI), and important genes involved in starch biosynthesis were fused to the carboxyl (C) as well as the amino (N) terminal part of SBD. All genes were driven by the GBSSI promoter and targeting to the amyloplast was ensured by the GBSSI transit peptide. Two different backgrounds, namely the mutant amf and wild type Kardal were transformed with Agrobactrium-mediated transformation. Luciferase was accumulated inside the granules when it was fused to the SBDs but luciferase alone did not. Expression of different fusion proteins resulted in new starch phenotypes with new functionalities. Depending on the fusion protein, starch properties such as amylose/amylopectin ratio, viscosity behaviour, and DSC characteristics changed. Moreover, in most cases fusion proteins expression resulted in new starch phenotypes. We think that SBD technology can be developed into a true platform technology, in which SBDs can be fused to a large choice of effector proteins to generate potato starches with new or improved functionalities.

کلیدواژه ها:

SBD ، Luciferase ، Starch ، Potat