Comparative analysis of nutritional composition of seeds of wild-type soybean and lines overexpressing GmWRI1a

Abstract

ABSTRACT Context. With the widespread use of transgenic soybeans (Glycine max (L. ) Merr.), their nutritional assessment for human food and animal feed is an important aspect of safety evaluation. WRINKLED 1 (WRI1) is a transcriptional activator of genes involved in fatty acid synthesis. Aims. We aimed to evaluate the effect of overexpression of GmWRI1a in soybean on the nutritional profile of soybean seeds. Methods. Using molecular biology techniques, we identified three transgenic soybean lines stably overexpressing GmWRI1a (GmWRI1a-OE). We quantified the nutritional and anti-nutritional components in seeds of GmWRI1a-OE and wild-type (DN50) soybean, and compared them on the basis of the principle of substantial equivalence. Key results. The GmWRI1a and Bar genes were stably inherited in the three GmWRI1a-OE lines, and GmWRI1a protein content was higher in transgenic soybean seeds than in wild-type seeds. Overexpression of GmWRI1a resulted in changes in fatty acid composition, a significant increase in oil content, and a significant decrease in stachyose content in seeds. Contents of other nutritional components (proximates, amino acids and isoflavones) and anti-nutritional factors (phytic acid, trypsin inhibitors and raffinose) in seeds were not significantly different between the wild-type and GmWRI1a-OE lines. Conclusions. Contents of nutritional and anti-nutritional components of GmWRI1a-OE seeds were all within the reference ranges reported for commercially available soybeans and, therefore, are substantially equivalent to those of wild-type seeds. Implications. GmWRI1a-OE soybean seeds are a high-quality product for health-conscious consumers.