Novel alleles of FAD2-1A induce high levels of oleic acid in soybean oil

Authors: COMBS, RACHEL - University Of Missouri; Bilyeu, Kristin

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2019
Publication Date: 6/16/2019
Citation: Combs, R., Bilyeu, K.D. 2019. Novel alleles of FAD2-1A induce high levels of oleic acid in soybean oil. Molecular Breeding. 39:79. https://doi.org/10.1007/s11032-019-0972-9.
DOI: https://doi.org/10.1007/s11032-019-0972-9

Interpretive Summary: Commodity soybeans are undergoing a change to meet the demands for healthier and sustainable foods. Major shifts in market expectations for the nutritional and functional qualities of the oil are driving the commodity soybean to embrace new seed compositional qualities. We identified novel mutations in an enzyme that can create enhanced value seed oils. Using conventional soybean breeding and molecular marker assisted selection, new soybean germplasm was developed that contained fatty acid profiles that improve the nutritional and functional qualities of the seed oil. The impact of this research is the availability of technology to create soybean varieties that can meet the expectations of the new commodity oil market.

Technical Abstract: Soybean plays an important role in seed oil production for foods and industrial products in the United States. Chemical hydrogenation of commodity soybean oil increased functionality but unavoidably created trans-fat which is linked to many health issues in humans. An alternative to using hydrogenation of the oil to enhance oxidative stability is to genetically increase the level of oleic acid in the seed oil. Our goal was to develop soybean germplasm as a source for more functional soybean oil with a high oleic acid, increased stearic acid, and low linolenic acid profile utilizing new and existing variant alleles of key fatty acid desaturase genes. Using forward genetics, novel alleles of FAD2-1A were discovered and characterized from a mutant soybean population already containing elevated seed stearic acid content. One of the two new FAD2-1A alleles combined with existing mutant alleles of FAD2-1B created a high oleic acid seed oil phenotype in soybean germplasm lines. Seed stearic acid increased to ~10-11% in lines containing combinations of FAD2-1A and FAD2-1B mutant alleles plus the SACPD-C missense mutant alleles; however, the increase in stearic acid was associated with a decrease in the oleic acid content and did not meet the target of at least 20% stearic acid in the seed oil. In addition, existing FAD3 mutant alleles were incorporated into the novel high oleic acid and high oleic/elevated stearic acid soybean lines with four or five targeted alleles combined to create soybean germplasm with more functional soybean oil. This study is beneficial for improving the quality of soybean oil based on nutritional value and oxidative stability.