Biotechnological tools for improving the quality of seed legume crops

The structure of legume seed protein is considered in relation to the poor nutritional quality of legume seeds. Various biotechnological applications to improve seed nutritional quality are reviewed, such as the construction of modified and hybrid genes containing new methionine codons or the identification and utilization of plant genes coding for protein of high nutritional value. Plant proteins are an important component of the human diet and in some countries they represent the major part of food protein available to the population. Legume seeds contain a high level of proteins, which unfortunately has an unbalanced amino acid composition. Although they are rich in lysine and other essential amino acids, sulphurated amino acids, such as cystine and methionine, are present in very low amounts, thus affecting the biological value of the seeds. It is known that seed amino acid content is related to the structure of seed proteins, which represent the major constituents of the seed.