Improving Nutritional Quality of Maize Proteins by Expressing Sense and Antisense Zein Genes

• Published in: Journal of agricultural and food chemistry Vol. 52; no. 7; pp. 1958 - 1964
• Main Authors: Huang, Shihshieh, Adams, Whitney R, Zhou, Qing, Malloy, Kathleen P, Voyles, Dale A, Anthony, Jan, Kriz, Alan L, Luethy, Michael H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 07.04.2004
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; DNA, Antisense - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression; Genetics and breeding of economic plants; Mutation; Nutritive Value; Plants, Genetically Modified - chemistry; Plants, Genetically Modified - genetics; Seeds - chemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Varietal selection. Specialized plant breeding, plant breeding aims; Yield, quality, earliness, varia; Zea mays; Zea mays - chemistry; Zea mays - genetics; Zein - genetics; Monocotyledones; Zein reduction; high tryptophan; Gramineae; Quality; Angiospermae; Chemical composition; Zein; nutritional quality; Zea mays; high lysine; quality trait; Nutritive value; Corn; Tryptophan; maize; Lysine; Aminoacid; Genetic improvement; Plant protein; Cereal; Spermatophyta; Mutation; Prolamin; antisense
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0342223

The predominant proteins in maize grain are a family of alcohol-soluble prolamin storage proteins called zeins. They account for >50% of total seed proteins but are deficient in several essential amino acids. As a result, the corn grain is considered to be nutritionally poor for monogastric animals with respect to key essential amino acids, most notably lysine, tryptophan, and methionine. Thus, corn mutants with reduced levels of zeins, such as opaque-2 (o2), have been demonstrated to possess grain with improved nutritional quality characteristics. The o2 mutant has a superior amino acid composition and has been used through conventional breeding to develop Quality Protein Maize (QPM) for human and animal consumption in developing countries. With the understanding of molecular genetics of zeins and progress in biotechnology, an alternative approach to zein reduction is explored here. Through the targeted reduction of the 19-kDa α-zeins, increased levels of lysine, tryptophan, and methionine have been engineered in grain of transgenic hybrids. Currently, the agronomic properties and nutritional values of these transgenic lines are being evaluated. Keywords: Zein reduction; high lysine; high tryptophan; quality trait; antisense; maize; nutritional quality