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United States Department of Agriculture

Agricultural Research Service

Research Project: Modification of Soybeans for Food, Feed, and Industrial Applications

Location: Plant Genetics Research

Title: Identification of the molecular genetic basis of the low palmitic acid seed oil trait in soybean mutant line RG3 and association analysis of molecular markers with elevated seed stearic acid and reduced seed palmitic acid

item Gillman, Jason
item Tetlow, Ashley -
item Hagely, Katherine -
item Boersma, Jeffery -
item Cardinal, Andrea -
item Rajcan, Istvan -
item Bilyeu, Kristin

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2014
Publication Date: N/A

Interpretive Summary: Soybean is one of the world’s most important oilseed crops. The fatty acid profile of the oil determines its functionality for food and industrial purposes. Understanding the interaction of different alleles of genes controlling the fatty acid profile of soybean seeds is a necessary step to directed manipulation of the fatty acid profile. The objective of this research was to characterize a soybean population at the molecular and phenotypic fatty acid profile level for changes in the saturated fatty acids, palmitic acid and stearic acid. The results demonstrated a clear effect of novel alleles of previously characterized genes controlling the fatty acid profile of the oil in this soybean population. The impact of the research is the establishment of accurate genotyping platforms to rationally create new soybean germplasm with improved fatty acid profiles in the oil.

Technical Abstract: The fatty acid composition of vegetable oil is becoming increasingly critical for the ultimate functionality and utilization in foods and industrial products. Partial chemical hydrogenation of soybean oil increases oxidative stability and shelf life but also results in the introduction of trans fats as an unavoidable byproduct. Due to mandatory labeling of consumer products containing trans fats, conventional soybean oil has lost the ability to deliver the most appropriate economical functionality and oxidative stability, particularly for baking applications. Genetic improvement of the fatty acid profile of soybean oil is one method to meet requirements for oil feedstocks. In this report, we characterize three mutant genetic loci controlling the saturated fatty acid content of soybean oil: two genes additively reduce palmitic acid content (fap1 and fap3-ug), and one gene independently elevates stearic acid content (fas). We identified a new null allele of fap3-ug/GmFATB1A (derived from line ELLP2), as well as a splicing defect mutation in a beta-ketoacyl-[acyl-carrier-protein] synthase III (KASIII) candidate gene located in the region mapped to fap1, derived originally from EMS mutant line C1726 (Cardinal et al. 2013). Molecular marker assays have been developed to track these causative mutations in a recombinant inbred line population segregating for fap1, fap3-ug, and a novel fas allele. We also report evidence for an additional unidentified minor gene enhancing the stearic acid content in lines derived from RG7.

Last Modified: 7/31/2014
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