Towards the rational design of cereal starches

A major challenge in cereal biotechnology is to achieve the rational design of renewable polymers to meet specific requirements for improving human health, nutrition, and food quality, to increase the energy supply, and to provide safer and more profitable industrial inputs. The field of starch synthesis research has advanced at a rapid pace over the past decade, and many core observations about the pathway are well established over a range of species. Owing to the complexity of the starch-synthesis process, in which suites of enzymes act at the interface between soluble and insoluble phases, the rational design of starch granules with specific functionality is still in its infancy. Our fundamental biochemical knowledge of starch biosynthesis has recently advanced, and this new information could be exploited to create novel variability in carbohydrate polymers in cereal grains, We propose two strategies for moving more rapidly towards truly rational design of starch. First, the focusing of fundamental research on processes that are involved in the regulation of starch synthesis and granule assembly. Second, the development of iterative strategies, exploiting new molecular genetics tools, to screen for desired properties in highthroughput systems.