A Single Nucleotide Insertion in a FatB Gene Is Responsible for Reducing Saturated Fatty Acids in Maize Seed Oil

Vegetable oils with reduced saturated fatty acids have signficant human health benefits. SRS72NE, a Dow AgroSciences maize inbred has been shown to contain signficantly lower levels of saturated fatty acids in seed oil. QTL mapping in an F2 population demonstrates that the reduced fatty acid trait in this inbred is largely controlled by a major QTL on chromosome 9 that explains 79.1% of palmitic acid and 79.6% total saturated fatty acid variations. Map-based cloning further identifies a G-nucleotide insertion in the 6^th exon of a type B fatty acyl-ACP thioesterase (FatB) gene in the SRS72NE allele. The insertion is predicted to create a frame-shift in SRS72NE fatB that results in a truncated, non-functional enzyme. A high throughput functional marker capable of differentiating the wild type and the mutant FatB alleles has been developed for molecular breeding.