Characterization of New Allelic Combinations for High-Oleic Soybeans

A soybean line with elevated levels of oleic acid was identified in a forward genetic screen. The causative mutation was identified and the line contained a C to T transition mutation causing a novel amino acid substitution in FAD2-1B, a gene that encodes an enzyme critical for soybean fatty acid biosynthesis. Alone, this fad2-1b mutation resulted in a 30% increase in seed oleic acid levels. Double mutant combinations with four previously isolated mutant alleles of the FAD2-1A gene were produced to determine the synergistic effects of mutation in both genes on oleic acid levels in seeds. In all instances, mutant alleles of FAD2-1A and FAD2-1B combined to produce seed containing over 70% oleic acid in the oil fraction. These lines provide a new germplasm resource that could be used to create high oleic soybeans through conventional breeding approaches.