Characterization of opaque2 modifier QTLs and candidate genes in recombinant inbred lines derived from the K0326Y quality protein maize inbred

• Published in: Theoretical and applied genetics 2011-03, Vol.122 (4), p.783-794
• Main Authors: Holding, David R, Hunter, Brenda G, Klingler, John P, Wu, Song, Guo, Xiaomei, Gibbon, Bryan C, Wu, Rongling, Schulze, Jan-Michele, Jung, Rudolf, Larkins, Brian A
• Format: Article
• Language: English
• Subjects: Agriculture; Analysis; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Chemical properties; Chromosome Mapping; Chromosomes; Chromosomes, Plant - genetics; Classical genetics, quantitative genetics, hybrids; Corn; DNA-Binding Proteins - genetics; Enzymes; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; Genes, Plant - genetics; Genetic Association Studies; Genetically modified organisms; Genetics of eukaryotes. Biological and molecular evolution; Genomics; Genotype & phenotype; Hardness; Inbreeding; Life Sciences; Molecular Weight; Nuclear Proteins - genetics; Original Paper; Phenotype; Phosphates; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant Proteins - genetics; Proteins; Pteridophyta, spermatophyta; Quantitative Trait Loci - genetics; Quantitative Trait, Heritable; Recombination, Genetic - genetics; Regulation; Transcription Factors - genetics; Vegetals; Zea mays; Zea mays - genetics; Zein - genetics; Zein - metabolism
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-010-1486-3

Quality protein maize (QPM) is a high lysine-containing corn that is based on genetic modification of the opaque2 (o2) mutant. In QPM, modifier genes convert the starchy endosperm of o2 to the vitreous phenotype of wild type maize. There are multiple, unlinked o2 modifier loci (Opm) in QPM and their nature and mode of action are unknown. We previously identified seven Opm QTLs and characterized 16 genes that are differentially up-regulated at a significant level in K0326Y QPM, compared to the starchy endosperm mutant W64Ao2. In order to further characterize these Opm QTLs and the genes up-regulated in K0326Y QPM, we created a population of 314 recombinant inbred lines (RILs) from a cross between K0326Y QPM and W64Ao2. The RILs were characterized for three traits associated with endosperm texture: vitreousness, density and hardness. Genetic linkage analysis of the RIL population confirmed three of the previously identified QTLs associated with o2 endosperm modification in K0326Y QPM. Many of the genes up-regulated in K0326Y QPM showed substantially higher levels of expression in vitreous compared with opaque RILs. These included genes associated with the upstream regulation of the ethylene response pathway, and a gene encoding a regulatory subunit of pyrophosphate-dependent fructose-6-phosphate 1-phosphotransferase, an adaptive enzyme of the glycolytic pathway.