The Aleurone Layer of Cereal grains: Development, Genetic Regulation, and Breeding Applications

Cereal aleurone cells are differentiated from triploid endosperm cells and exhibit distinct cytological, physiological, and biochemical characteristics that distinguish them from the starchy endosperm cells of cereals. Aleurone cells retain viability throughout seed development, whereas the starchy endosperm is composed of dead cells that undergo programmed cell death during the maturation process. Despite the variation observed among cereal species with respect to aleurone-related traits, the aleurone plays an indispensable role in regulating many aspects of seed development, including the accumulation of storage reserves, the acquisition of dormancy, and germination. Given the fact that many nutrients, such as lipids, dietary fibers, vitamins, and some minerals like iron and zinc, are predominantly accumulated in the aleurone cells of cereal grains, the aleurone layer has attracted much attention with the aim of improving the nutritional value of cereals. This review provides a comprehensive introduction to the developmental, genetic, and molecular basis of aleurone cell differentiation and proliferation, with a particular focus on the improvement of aleurone-related traits through the application of knowledge regarding the molecular network that governs aleurone development. It also presents a detailed discussion of the challenges associated with cereal improvement through the manipulation of aleurone-related traits, along with potential solutions to these challenges.