Gene discovery to improve maize grain quality traits

Maize is one of the most important agronomic crops in the world. The kernel provides feed, food, and a resource for many unique industrial and commercial products. By utilizing genetic variation, the composition of the kernel can be altered for both the quantity and quality (structure and chemical diversity) of starch, protein, and oil throughout kernel development. The ability of future generations of plant breeders/plant scientists to use existing genetic variation and to identify and manipulate commercially important genes will open new avenues for designing novel variation in grain composition. This will provide the basis for the development of the next generation of specialty maize and of new products to meet future needs. Developing plants with improved grain quality traits involves overcoming a variety of technical challenges inherent in metabolic engineering programs. Advances in plant genetics and in technologies for genome-wide studies and for large-scale gene expression analysis are contributing to the acceleration of gene discovery for product development. In this article information is presented on the genetic variation known to affect the composition, development, and structure of the maize kernel with particular emphasis on pathways relevant to differentiation of starch-filled cells, starches, storage proteins, lipids, and carotenoid biosynthesis. A brief description of the potential that the new technologies of cell and molecular biology will provide for the creation of new variation in the future are indicated and discussed.