Abstract
BackgroundMaize (Zea mays ssp. mays) is the most abundantly cultivated and highly valued food commodity in the world. Oil from maize kernels is highly nutritious and important for the diet and health of humans, and it can be used as a source of bioenergy. A better understanding of genetic basis for maize kernel oil can help improve the oil content and quality when applied in breeding.ResultsIn this study, a KUI3/SC55 recombinant inbred line (RIL) population, consisting of 180 individuals was constructed from a cross between inbred lines KUI3 and SC55. We phenotyped 19 oil-related traits and subsequently dissected the genetic architecture of oil-related traits in maize kernels based on a high-density genetic map. In total, 62 quantitative trait loci (QTLs), with 2 to 5 QTLs per trait, were detected in the KUI3/SC55 RIL population. Each QTL accounted for 6.7% (qSTOL1) to 31.02% (qBELI6) of phenotypic variation and the total phenotypic variation explained (PVE) of all detected QTLs for each trait ranged from 12.5% (OIL) to 52.5% (C16:0/C16:1). Of all these identified QTLs, only 5 were major QTLs located in three genomic regions on chromosome 6 and 9. In addition, two pairs of epistatic QTLs with additive effects were detected and they explained 3.3 and 2.4% of the phenotypic variation, respectively. Colocalization with a previous GWAS on oil-related traits, identified 19 genes. Of these genes, two important candidate genes, GRMZM2G101515 and GRMZM2G022558, were further verified to be associated with C20:0/C22:0 and C18:0/C20:0, respectively, according to a gene-based association analysis. The first gene encodes a kinase-related protein with unknown function, while the second gene encodes fatty acid elongase 2 (fae2) and directly participates in the biosynthesis of very long chain fatty acids in Arabidopsis.ConclusionsOur results provide insights on the genetic basis of oil-related traits and a theoretical basis for improving maize quality by marker-assisted selection.
Highlights
Maize (Zea mays ssp. mays) is the most abundantly cultivated and highly valued food commodity in the world
The mean of the KUI3/SC55 recombinant inbred line (RIL) population based on the best linear unbiased prediction (BLUP) values was close to the mid-parent value for almost all measured traits with transgressive segregation (Table 1), suggesting that both parents harbored the alleles responsible for increasing the oil-related traits
In the present study, Quantitative trait locus/loci (QTL) mapping for 19 oil-related traits was conducted with high-density single nucleotide polymorphisms (SNPs) markers in the KUI3/SC55 RIL population
Summary
Maize (Zea mays ssp. mays) is the most abundantly cultivated and highly valued food commodity in the world. Mays) is the most abundantly cultivated and highly valued food commodity in the world. Oil from maize kernels is highly nutritious and important for the diet and health of humans, and it can be used as a source of bioenergy. A better understanding of genetic basis for maize kernel oil can help improve the oil content and quality when applied in breeding. Mays) is one of the most commonly cultivated cereal crops in the world, and a major source of human food, animal feed and bioenergy. Oil is one of the three main components in maize kernels, whose energy is 2.25 times that of starch [3]. The high energy and polyunsaturated fatty acids in maize oil make it a highlyquality edible oil that is healthy for humans. With the increase in oil content in maize kernels, the additional value of maize varieties will certainly increase
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