Molecular Analysis of Soybean Lines with Low Palmitic Acid Content in the Seed Oil

摘要

Palmitic acid is the major saturated fatty acid found in soybean [Glycine max (L.) Merr.] oil, accounting for approximately 11% of the seed oil content. Reducing the palmitic acid levels of the oil is desirable because of the negative health effects specifically associated with this fatty acid. One of the genetic loci known to reduce the seed palmitate content in soybean is fap_(nc). Previous studies indicated that fap_(nc) is associated with a deletion in a gene (designated FATB) encoding 16:0-ACP thioesterase activity. In this report, we isolated full length cDNAs of three of the four unique FATB genes expressed in soybean and show that the isoform designated GmFATBla represents the specific gene deleted in lines possessing the fap_(nc) locus. Allele specific primers corresponding to GmFATBla were used to genotype plants from two F4-derived populations that were segregating for fap_(nc). The GmFATB1a-specific markers were effective in accounting for 62 to 70% of the genotypic variation in palmitate content in the two populations studied. Because the markers developed in this study are 100% linked to the locus of interest, they should be particularly useful in marker-assisted selection programs designed to lower the palmitic acid levels of soybean oil.