Soybean Genes Associated With Low Palmitic and Low Linolenic Acid

It is important to study target genes that control de§novo fatty acid biosynthesis and triacylglycerol in§soybean (Glycine max L. Merr.). At least 5 recessive§alleles condition the low palmitic acid (16:0)§contents of soybean seeds: fap1, fap3, fap , fapnc§and sop1. The fapnc mutation affects the normal§function of the enzyme 16:0-ACP thioesterase encoded§by the gene FATB1. There are four FATB1 isoforms in§soybean: GmFATB1a, GmFATB1b, GmFATB2a, and GmFATB2b. §At least three major loci are responsible for low§linolenic acid (18:3) content in soybean seed oil§(fan, fan2 and fan3). The FAD3 gene encodes an§omega-3 desaturase that converts 18:2 to 18:3. It has§four highly similar microsomal isoforms: GmFAD3A and§GmFAD3B, FAD3-2a and FAD3-2b.§The root and leaf tissue fatty acid composition of§two lines carrying the fapnc, fap1, the fan(PI123440)§(a SNP in intron 2 of GmFAD3A) alleles and Brim a§high yielding line, was examined. It was concluded§that fapnc or fap1 or both mutations have pleiotropic§effects on the leaf fatty acid composition. The fan§mutation has a pleiotropic effects on the leaf and§root fatty acid composition but has not been§negatively correlated with yield.