Starch is a major component of many plant-based foods, accounting for about 30-60% of total calorie intake in the diet of most cultures. It is also the major component of the most common cereal crops, such as rice, wheat, and maize. Starch is synthesized in plastids by the orchestration of several enzymes and starch-binding proteins, which shapes polyglucan chains into complex starch granules. We have studied how this orchestration occurs by using several new breeding techniques to monitor the localization and actions of the individual enzymes and factors in starch biosynthesis, such as starch synthases, glucan kinases, starch-binding proteins, and starch-branching enzymes. With insights into the role of the individual components of starch biosynthesis, it is possible to create tailor-made starch types for new functionalities. As an example, we have created starches with an exceptionally high degree of resistance towards amylolysis, by targeting selected enzymes specifically with precision breeding. Acute clinical trials have been conducted to demonstrate how crops created with such techniques can be used to make tailor-made foods with reduced postprandial glucose response in humans with and without type 2 diabetes (T2D).
Our work demonstrates how new breeding technology can be used for the precision breeding of healthier starches, which has profound perspectives for improving the quality of plant-based foods with potential in the prevention and management of T2D.