Gene discovery to improve quality-related traits in maize ¶

Maize is one of the most important agronomic crops in the world. Its grain provides feed, food and a resource for many unique industrial and commercial products. For example, 57% of the EU’s non-food starch market and 71% of food starches are accounted for by maize. 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 reviewed on the genetic variation known to affect the composition, development and structure of the maize kernel with particular emphasis on pathways relevant to the differentiation of starch-filled cells, starches, storage proteins, lipids and carotenoid biosynthesis. Finally, 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.