Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2006
Publication Date: 7/25/2006
Citation: Bilyeu, K.D., Palavalli, L., Sleper, D.A., Beuselinck, P.R. 2006. Molecular genetic resources for development of 1 percent linolenic acid soybeans. Crop Science. 46:1913-1918. Interpretive Summary: Reducing linolenic acid, an unstable component of vegetable oil, in soybeans has become a primary objective in crop science research because of the health concerns surrounding the intake of trans fatty acids in the human diet. Conventional elimination of linolenic acid in soybean oil is through chemical hydrogenation, which creates trans fatty acids. Plant breeding efforts have centered on the desire to generate soybean varieties that produce good yields of stable oil which contain no trans fatty acids through genetic reductions in linolenic acid. In the work desribed in this manuscript, soybean breeding lines containing only 1 percent linolenic acid were characterized at the molecular level in an effort to improve breeding efforts for low linolenic acid content in soybean oil. We identified three genes that controlled the trait in the low linolenic acid lines. Molecular marker assays were developed to allow soybean breeders to efficiently capture the trait when developing new soybean varieties. The results expand the molecular tools available to breeders that are trying to incorporate the low linolenic acid trait into other elite lines and to develop new varieties that will offer improved oil characteristics for the U.S. soybean products market.
Technical Abstract: Advanced plant breeding will incorporate the most efficient methods available to introgress new traits and develop improved crops. Molecular markers that are specifically targeted to desirable alleles are important molecular genetic resources for selection of traits. Reducing the amount of linolenic acid in soybeans is a desired breeding objective so that oxidatively stable soybean oil can be produced without the production of trans fatty acids. The objective of this work was to determine the molecular genetic basis for soybeans containing 1 percent (10g kg) linolenic acid in the seed oil fraction and to develop molecular markers specific for identified alleles. Utilizing the soybean homologues of Arabidopsis FAD3 as candidate genes, mutations were discovered in all three GmFAD3 genes in the soybean line A29. The mutations were associated with the linolenic acid phenotype. Novel combinations of different mutant alleles at the three GmFAD3 loci allowed the development of new germplasm containing 1 percent linolenic acid in the seed oil along with the ability to use SNP-based molecular markers in a backcross breeding strategy.