2023
An Innovative ‘Push-Pull-Protect’ Approach to Improving Protein Quality
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Contributor/Checkoff:
United Soybean Board
Category:
Sustainable Production
Keywords:
Amino acidsSoy protein
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Timothy Durrett, Kansas State University
Co-Principal Investigators:
Project Code:
23-203-S-D-1-A
Contributing Organization (Checkoff):
United Soybean Board
$111,313
Institution Funded:
Kansas State University
$111,313
Brief Project Summary:
We have recently developed specialized methods to accurately measure relevant metabolites, enabling us to study the synthesis and turnover of amino acids in more detail and to target key enzymes. This allows us to emulate strategies for metabolic engineering that have been successful in other systems, by linking enzymes that ‘push’ and ‘pull’ carbon resources to and from amino acids with those that ‘protect’ synthesized protein by suppressing proteases implicated in turnover. This multi-enzyme approach is essential to overcome the internal regulatory mechanisms in seeds that control composition. Initial and ongoing analysis of seed composition indicate changes in levels of sulfur-containing amino acids in the transgenic lines. The proposed in-depth characterization is a necessary first step to accomplishing the end goal of commercial soybean lines with improved amino acid composition and increased protein content.
Information And Results
Project Summary

Project Objectives

Project Deliverables

Progress Of Work

Final Project Results

We developed soybean lines with improved amino acid composition (focusing on the sulfur amino acids methionine and cysteine) by suppressing enzymatic steps affecting the supply and turnover of sulfur amino acids. Gene expression analysis during seed development confirmed a reduction in gene levels. Analysis of oil, protein and amino acid content revealed similar oil content between transgenic lines and wild-type, elevated total protein levels (including increased protein-bound cys and met) in transgenic lines, as well as increased free cys and met. In addition, we also developed soybean lines with increased protein content by targeting two proteases implicated in the degradation of protein late in seed development. Analysis of seed from a subsequent generation revealed similar oil content between transgenic lines and wild-type plants. We also stacked the traits by crossing the different lines, resulting in F1 seed for three genotype combinations. In anticipation of the genotyping needs of the stacked lines, we developed markers to identify each trait.

Benefit To Soybean Farmers

The work generated transgenic lines with increased protein content and improved amino acid composition, without any penalties in oil content. These results confirm the role of target genes in amino acid metabolism, thus identifying loci for future breeding programs or genome editing.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.