Mutations in KASIIB result in increased levels of palmitic acid in soybean seeds

The plasticity of the lipid profile of soybean oil has made the soybean a crop with value in feed, food and industrial uses. Soybean oil typically consists of approximately 10% of the fully saturated palmitic acid, which has value for industrial purposes, however it is generally undesirable in food applications. Two soybean KASII (ketoacyl-ACP synthase II) genes have been previously implicated in the control of seed palmitic acid levels. Using forward genetics, we isolated four novel alleles in the GmKASIIB gene that result in increased levels of palmitic acid, ranging from 13% to 16% of the total fatty acid content, over multiple seasons in the field. Three of the KASIIB mutations result in independent amino acid substitutions at conserved positions in the KASII protein, and one single nucleotide polymorphism is likely to cause aberrant splicing of the KASIIB transcript. These new mutations can be used in breeding applications to increase palmitic acid content and to probe the control of fatty acid biosynthesis in soybean seeds.