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Title: Introgression of leginsulin, a cysteine-rich protein, and high-protein trait from an Asian soybean plant introduction genotype into a North American experimental soybean line

Author
item Krishnan, Hari
item KIM, WON-SEOK - University Of Missouri
item Oehrle, Nathan
item ALASWAD, ALAA - University Of Missouri
item Baxter, Ivan
item WIEBOLD, WILLIAM - University Of Missouri
item Nelson, Randall

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2015
Publication Date: 3/10/2015
Publication URL: https://handle.nal.usda.gov/10113/61169
Citation: Krishnan, H.B., Kim, W., Oehrle, N.W., Alaswad, A.A., Baxter, I.R., Wiebold, W.J., Nelson, R.L. 2015. Introgression of leginsulin, a cysteine-rich protein, and high-protein trait from an Asian soybean plant introduction genotype into a North American experimental soybean line. Journal of Agricultural and Food Chemistry. 63:2862-2869.

Interpretive Summary: Soybean is widely used as the major ingredient for protein in animal feeds. However, the nutritive value of soybeans can be further enhanced if the concentration of sulfur-containing amino acids, methionine and cysteine, can be increased. The methionine and cysteine content of soybean is about 2-3%, which falls short of the desired levels required for the optimum growth of poultry and swine. Increasing the content of native soybean proteins rich in sulfur-containing amino acids should enhance the nutritive value of soybean meal. In this study, we have examined the effect of introducing leginsulin, a sulfur amino acid rich protein, into a North American soybean cultivar on the protein content and quality. Our study demonstrates that introduction of leginsulin significantly improves the protein content and quality of North American soybean cultivar. The information from this study will be valuable for the soybean breeders and genetics to develop North American soybean cultivars with proteins rich in sulfur-containing amino acids.

Technical Abstract: Soybean is an important protein source for both humans and animals. However, soybean proteins are relatively poor in the sulfur-containing amino acids, cysteine and methionine. Improving the content of endogenous proteins rich in sulfur containing amino acids could enhance the nutritive value of soybean meal. Leginsulin, a cysteine-rich peptide, predominantly accumulates in Asian soybean accessions but not in North American cultivars. By screening a diverse soybean accessions from the USDA Soybean Germplasm Collection we were able to identify one plant introduction (PI) 427138, as a high protein line with relatively high amounts of elemental sulfur that also has high amounts of leginsulin. We have introgressed these desirable traits from PI 427138 into experimental lines with the aim of improving the overall protein content and quality of seed proteins. Biochemical characterization of inbred progenies from the cross of LD00-3309 by PI 427138 grown in six locations reveal stable ingression of high-protein, high elemental sulfur, and high leginsulin accumulation traits. Comparison of soybean seed proteins resolved by high resolution 2-D gel electrophoresis in combination with Delta2D image analysis software revealed the preferential accumulation of a few glycinin subunits contributed to the increased protein content in the introgressed lines. Amino acid analysis revealed that even though the leginsulin introgressed lines had higher protein content, leginsulin accumulation and elemental sulfur, the overall concentration of sulfur containing amino acids was not significantly altered when compared with the parental lines. The soybean experimental lines developed during this study (Leg-3, Leg-7 and Leg-8) lack A5, A4 and B3 glycinin subunits and could be utilized in breeding programs to develop high-quality tofu cultivars.