Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2015
Publication Date: 3/11/2016
Citation: Thapa, R., Carrero-Colon, M., Hudson, K.A. 2016. New alleles of FATB-1A to reduce palmitic acid levels in soybean. Crop Science. 56:1-5.
Interpretive Summary: Soybean oil is predominantly composed of five fatty acids, including the saturated fatty acid palmitic acid, which makes up approximately ten percent of the total fatty acids in normal commodity soybeans. It is desirable to reduce levels of saturated fats in soybean oil intended for human consumption, as in salad dressings or cooking oil. Genetic variation is a safe and economical way to improve the profile of soybean oil. We identified soybean plants that produced seed with less than the normal levels of palmitic acid. Two lines were identified that had 30% or greater reductions in levels of palmitic acid. To make these lines useful for soybean breeding, we identified the changes in the FATB1A gene that are responsible for the improved oil phenotype. We created molecular markers that allow breeders and geneticists to follow the genes in plant populations. These new soybean lines could prove useful in the development of healthier soybean oils.
Technical Abstract: In wild-type soybeans, palmitic acid typically constitutes 10% of the total seed oil. Palmitic acid is a saturated fat linked to increased cholesterol levels, and reducing levels of saturated fats in soybean oil has been a breeding target. To identify novel and useful variation that could help in reducing palmitic acid levels in soybean, we screened a chemically mutagenized population. Two lines with reduced levels of seed palmitic acid were identified, and each line had a 30% reduction in palmitic acid. Both lines carried distinct mutations in the FATB1A (Glyma.05G012300) gene that co-segregated with the reduced palmitic acid phenotype. One line carried a single base change that disrupted the splicing of the FATB1A mRNA, and the second contained a missense mutation (aspartic acid substituted for glycine) in a conserved domain of the FATB1 enzyme. Molecular markers were designed that will enable breeders to follow these new FATB1A mutant alleles in plant populations to facilitate gene stacking for oil improvement.