CHARACTERIZATION OF THE VARIABILITY IN LYSINE CONTENT FOR NORMAL AND OPAQUE2 MAIZE ENDOSPERM

Endosperm lysine content is genetically variable in maize (Zea mays L. ) germplasm, but its level is below the minimum dietary standard set b y the FAO. Increasing the content of this essential amino acid in endo sperm proteins depends on understanding the mechanisms regulating the synthesis and accumulation of lysine-rich proteins. In this study, we analyzed the variability for lysine and protein contents in maize endo sperm. Amounts of total protein, zeins, and non-zeins measured by micr oKjeldahl, and lysine content, estimated by aminoacid analysis, were d etermined for 93 maize inbreds. Additionally, an ELISA was used to est imate the relative content of the protein synthesis factor EF-1 alpha in 20 selected genotypes. Considerable differences in lysine content w ere observed among normal and opaque2 genotypes, with the effect of th e mutation being highly dependent on the genetic background. We detect ed a high correlation between the lysine content and the concentration of total non-zein proteins and EF-1 alpha. An assay for EF-1 alpha co ncentration may provide a simple and inexpensive method from breeding programs to select for improved protein quality.