Identification of a Potential Gene for Elevation ω-3 Concentration and its Efficiency for Improving ω-6/ω-3 Ratio in Soybean

This present study was to identify a novel candidate gene that contribute to the elevated α-linolenic acid (ALA, ω-3) concentration in PE2166 from mutagenesis of Pungsannamul. Major loci qALA5_1 and qALA5_2 were detected on chromosome 5 of soybean through quantitative trait loci mapping analyses of recombinant inbred lines. With next generation sequencing of parental lines and Pungsannamul, and recombinant analyses, a potential gene, Glyma. 05g221500 (HD) controlling elevated ALA concentration was identified. HD is a homeodomain-like transcriptional regulator that may regulate the expression level of microsomal ω-3 fatty acid desaturase (FAD3) genes responsible for the conversion of linoleic acid into ALA in the fatty acid biosynthetic pathway. In addition, we hypothesized that combination of mutant alleles, HD and either of microsomal delta-12 fatty acid desaturase 2-1 (FAD2-1\ could reduce the ω-6/ω-3 ratio. In populations where HD, and FAD2-1A and FAD2-1B genes were segregated, combination of a hd allele from PE2166 and either of the variant FAD2-1 alleles were sufficient to reduce the ω-6/ω-3 ratio in seeds.