Genetic Analysis of opaque 2 Modifier Loci in Quality Protein Maize

Quality Protein Maize (QPM) was created by selecting for genetic modifiers that convert the starchy endosperm of an opaque2 (o2) mutant to a hard, vitreous phenotype. Genetic analysis has shown there are multiple, unlinked o2 modifiers (Opm), but their identity and mode of action are unknown. A microarray hybridization performed with RNA obtained from true breeding o2 progeny with vitreous and opaque kernel phenotypes identified a small group of differentially expressed genes, some of which map at or near the Opm QTLs. Keywords: Genetic modification Compared 18 days after pollination endosperm transcript profiles in true breeding modified (vitreous; V) and non-modified (opaque; O) opaque 2 kernels. Used four vitreous biological reps (V1-V4) and four opaque biological reps (O1-O4). Each biological rep is a pool of 25 kernels representing 5 kernels form each of 5 uniform phenotype ears (vitreous or opaque). Four arrays used: Array 1= V1 vs O1, Array 2 = V2 vs O2, Array 3 = V3 vs O3, Array 4 = V4 vs O4