Storage Proteins and their Metabolism

Abstract

The identification and cloning of storage protein genes over the last 20 years has provided new tools to improve grain and forage crops. To date, storage protein biotechnology has been used to address deficiencies of essential amino acids in important crop species, improve the digestibility of forage crops for ruminant animals and improve quality traits such as the bread making quality of wheat dough. High lysine maize is already available through the breeding of storage protein mutants, whilst transgenic crops containing storage proteins that impart a nutritional benefit are currently undergoing field trials. However, despite recent advances in this area, a number of limitations remain. In some cases, the rate of synthesis of particular amino acids limits protein accumulation. In other cases, the introduction of a new storage protein has altered the expression levels of endogenous proteins, potentially affecting desirable traits. In addition, some of the storage proteins targeted for use in transgenic plants have been identified as allergens.