Mutant Gene That Changes Protein Composition and Increases Lysine Content of Maize Endosperm

TLDR

Preliminary tests have shown that maize seeds homozygous for the opaque‑2 mutant gene have endosperms with higher lysine content than normal kernels. The authors compared amino‑acid profiles of endosperms from backcross progeny segregating for opaque‑2 versus normal kernels. Opaque‑2 endosperms displayed a distinct amino‑acid pattern, containing 69 % more lysine, due to synthesis of proteins richer in basic amino acids in the acid‑soluble fraction and a lower zein‑to‑glutelin ratio.

Abstract

Preliminary tests have shown that the endosperms of maize seeds homozygous for the opaque-2 mutant gene have a higher lysine content than normal kernels. As a critical test, a backcross progeny was divided into opaque-2 and normal kernels, the endosperms separated, and the amino acids determined. The opaque-2 endosperms had a different amino acid pattern and 69 percent more lysine than the normal seeds. The major reason for these changes is the synthesis of proteins with a greater content of basic amino acids in the acid-soluble fraction of the mutant endosperm. This is accompanied by a reduction in the ratio of zein to glutelin.