Changes in soluble endosperm proteins associated with selection of quality protein maize lines

Comparisons of endosperm albumins, globulins, glutelins and zeins, as defined by differential solubility, were made for four maize triads. Each triad consisted of a normal inbred line, an opaque-2 (o2) version of the same inbred, and a quality protein maize (QPM) line derived from the o2 line. Data from the 12 entries were collected from duplicate trials, one grown in College Station, Texas in 1993 and the other at Homestead, Florida in 1995. Both the o2 and QPM endosperms showed a shift from zein to non-zeins. QPM endosperm had higher amounts of glutelin (expressed as mg/g dry flour) than normal endosperm in all triads. Glutelins were the most prevalent non-zein proteins, and endosperm glutelin content was significantly correlated to lysine level. Glutelins and zeins were subjected to SDS-polyacrylamide gel electrophoresis to identify changes associated with selection of the QPM lines. Consistent enhancement of 48 and 90 kD glutelin bands in the QPM version of each triad suggests that proteins in these bands contribute to the quality improvement made during selection for QPM lines. Increases in -zeins were highly correlated with increased density in QPM lines, and there was also indication that the increased glutelins might also contribute to seed density.

Changes in soluble endosperm proteins associated with selection of quality protein maize lines Academic Article