Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/1998
Publication Date: N/A
Interpretive Summary: Many traits in plants including the nutritional quality of the seeds are controlled by several genes, each contributing an effect. The relative effect of each gene is often strongly influenced by the particular growth conditions of the crop in a given year in a given place. Identifying the important genes for such traits so that plant breeders can select for favorable variations in them thus becomes a challenging task. Oil content in the cereal oat is a trait that is under such complex genetic control. A high oil content would provide more energy when oat is used for livestock feed, but low oil content is favored for human diets. We used techniques involving analysis of variations of specific segments of the oats' genetic material or DNA, data from multiple growth environments, and special statistical methods to identify regions of the oat DNA that have an influence on the oat grain oil content. Furthermore, in the process of locating the DNA sequence or gene coding for a protein that is thought to play a key role in the synthesis of oat grain oil we discovered that the gene was located at one of the DNA sites we previously found to control oat grain oil content. This result shows that by modifying the structure of this particular gene or manipulating its inheritance oat breeders will have the opportunity to breed oat types for particular uses, higher oil as desired by livestock producers for oat use in animal feed or lower oil oats for oat grain millers to use in human foods.
Technical Abstract: Oat groats are unique among cereals for the high level and the embryo-plus- endosperm localization of lipids. Genetic manipulation of groat quality traits such as oil is desired for optimizing the value of oat in human and livestock diets. A locus having a major effect on oil content in oat groats was located on linkage group 11 by single factor analysis of variance, simple interval mapping, and simplified composite interval mapping. A partial oat cDNA clone for plastidic acetyl-CoA carboxylase (ACCase), which catalyzes the first committed step in de novo fatty acid synthesis, identified a polymorphism linked to this major QTL. Similar QTL and ACCase locus placements were obtained with two recombinant inbred populations, 'Kanota' x 'Ogle' (KO) and 'Kanota' x 'Marion' (KM), containing 137 and 139 individual lines, respectively. By having a common parent these populations provide biological replication of the results in that significant genomic regions should be evident in analyses of multiple cross combinations. The KO population was mapped with 150 RFLP loci distributed over the genome and was grown in five diverse environments (locations and years) for measurement of groat oil content. The KM population was mapped with 60 RFLP loci and grown in three environments. The QTL linked to AccaseA on linkage group 11 accounted for up to 48% of the phenotypic variance for groat oil content. These results provide strong support for the hypothesis that ACCase has a major role in determining groat oil content. Other QTLs were identified in both populations and accounted for an additional 10 to 20% of the phenotypic variance.