Reference Report for SoyBase12402909
Title: | Effect of alleles governing 16:0 concentration on glycerolipid composition in developing soybeans |
Authors: | Wilson, R.F., Marquardt, T.C., Novitzky, W.P., Burton, J.W., Wilcox, J.R., Dewey, R.E. |
Source: | J. Am. Oil Chem. Soc. 2001, 78(4):329-334 |
Abstract: | Soybean (Glycine max (L.) Merr.) oil typically contains 11% palmitic acid, but germplasm with recessive alleles at Fap gene loci exhibit from less than 4% to about 35% 16:0. Although these alleles are used to develop new cultivars, little is known about how they influence palmitic acid concentration. One theory suggests that fap alleles may mediate differences in triacylglycerol composition through genetic effects on the activity or substrate specificity of acyltransferases, such as diacylglycerol acyltransferase (EC 2.3.1.20). Based on logistic function analysis of developing seed, differences in fap allele expression are evident in the rate of palmitic acid accumulation in triacylglycerol, with peak deposition near mid-seed fill. Acetate saturation kinetics also reveal a strong positive relation between the relative amount of de novo palmitic acid synthesis and the indigenous palmitic acid concentration in triacylglycerol among fap genotypes. However, no differences appear in the kinetics of palmitoyl-CoA metabolism in developing seed of these genotypes. Therefore, the fap alleles apparently do not encode or regulate the activities of glycerolipid acyltransferase enzymes. Rather, major genetic effects on triacylglycerol composition accrue through regulation of palmitic acid production in the plastids of developing soybean cotyledons. |