Novel Allele of FAD2-1A from an EMS-Induced Mutant Soybean Line (PE529) Produces Elevated Levels of Oleic Acid in Soybean Oil

Soybean seed oils contain approximately 23% oleic acid, and elevated amounts of oleic acid help prevent cardiovascular diseases and improve the quality of the oil. Chemically, it helps maintain the oxidative stability of oil; hence, soybean breeders primarily seek to increase its concentration for improved oil quality. As soybean seeds with mutant alleles of FAD2-1A and FAD2-1B genes have been reported to produce approximately 80% of oleic acid, a mutant population was developed from an ethyl methanesulfonate (EMS)-induced soybean cultivar (Pungsannamul). From this, a new mutant allele of FAD2-1A was identified using mutant lines with elevated oleic acid levels and the pooled-DNA sequencing method. This study identified PE529 as the allele with >40% oleic acid carrying the novel allele of the FAD2-1A gene. The single nucleotide polymorphism (SNP) in PE529 also induced the conversion from tryptophan to a premature stop codon at position 293 in the amino acid sequence (W293STOP). The inheritance analysis showed that the elevated oleic acids in PE529 were attributed to the fad2-1a W293STOP allele. In this study, seeds capable of producing approximately 80.0% oleic acid were identified from F-2 populations where fad2-1a W293STOP and fad2-1b alleles were segregated. Hence, soybeans with novel alleles are useful genetic resources to improve soybean oil quality in breeding programs.

Automated summary

Soybean breeders are focused on increasing the concentration of oleic acid in soybean seed oils to improve oil quality. This study identified a new mutant allele of the FAD2-1A gene, PE529, which produces soybean seeds with over 40% oleic acid. This discovery provides valuable genetic resources for improving soybean oil quality in breeding programs.