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Γ-Zeins Are Essential For Endosperm Modification In Quality Protein Maize, Yongrui Wu, David R. Holding, Joachim Messing

Center for Plant Science Innovation: Faculty and Staff Publications

Essential amino acids like lysine and tryptophan are deficient in corn meal because of the abundance of zein storage proteins that lack these amino acids. A naturalmutant, opaque 2 (o2) causes reduction of zeins,anincreaseofnonzeinproteins,andas a consequence, adoubling of lysine levels.However, o2’s soft inferior kernels precluded its commercial use. Breeders subsequently overcame kernel softness, selectingseveral quantitative loci (QTLs), called o2modifiers,without losing the high-lysine trait. These maize lines are known as “quality protein maize” (QPM). One of the QTLs is linked to the 27-kDa γ-zein locus on chromosome 7S. Moreover, QPM lines have 2- to 3-fold higher levels of the 27-kDa γ-zein, …