Overexpressing GmCGS2 Improves Total Amino Acid and Protein Content in Soybean Seed

Abstract

Soybean (Glycine max (L.) Merr.) is an important source of plant protein, the nutritional quality of which is considerably affected by the content of the sulfur-containing amino acid, methionine (Met). To improve the quality of soybean protein and increase the Met content in seeds, soybean cystathionine γ-synthase 2 (GmCGS2), the first unique enzyme in Met biosynthesis, was overexpressed in the soybean cultivar “Jack”, producing three transgenic lines (OE3, OE4, and OE10). We detected a considerable increase in the content of free Met and other free amino acids in the developing seeds of the three transgenic lines at the 15th and 75th days after flowering (15D and 75D). In addition, transcriptome analysis showed that the expression of genes related to Met biosynthesis from the aspartate-family pathway and S-methyl Met cycle was promoted in developing green seeds of OE10. Ultimately, the accumulation of total amino acids and soluble proteins in transgenic mature seeds was promoted. Altogether, these results indicated that GmCGS2 plays an important role in Met biosynthesis, by providing a basis for improving the nutritional quality of soybean seeds.

Integrating Genome-Wide Association Study, Transcriptome and Metabolome Reveal Novel QTL and Candidate Genes That Control Protein Content in Soybean

“…Among them, a total of 12,712 DEGs and 315 DAMs were identified [ 17 ]. Previous studies have demonstrated that overexpression of GmCGS2 leads to the upregulation of genes associated with the aspartic acid pathway, resulting in a substantial enhancement of total amino acid content and soluble protein levels within transgenic mature seeds [ 18 ]. In soybean, GmST05 may bind to GmSWEET10a in order to regulate seed size and protein content [ 19 ].…”

Identification of Quantitative Trait Loci (QTL) for Sucrose and Protein Content in Soybean Seed

“…Despite the high quality of soy protein, there has been a significant effort to improve the overall quality of protein content in soybean seed further. One example of progress in this area is the overexpression of the GmCGS2 gene in soybean seed to improve total protein content, including Met, a limiting amino acid in soybean [ 3 ]. Such breeding efforts will further enhance soybeans’ viability as a complete source of indispensable amino acids [ 4 ].…”