Database Research Summaries2018 Network Guided Modification of Soybean Meal Composition
Research Focus
The focus of this project is to increase soybean value for the entire value chain, selection of soybean germplasm and identification of soybean genes controlling protein synthesis and storage along with the development of markers for those genes, provide the opportunity to create soybeans with higher protein levels and will aid in the development of commercial soybean varieties with an improved nutritional bundle.
Objectives
- Use CRISPR/Cas9 approaches to develop soybean seeds that are deregulated for methionine biosynthesis and contain gene sequences enriched in methionine codons.
- Utilize co-expression network analysis to identify key regulatory networks operable during soybean seed development that impact amino acid and protein biosynthesis.
- Utilize available soybean mutant populations and modern gene editing methodologies to create mutations in these key regulatory pathways and then evaluate their impact on seed amino acid composition and protein concentrations.
Results
- We completed the design and cloning of CRISPR/Cas9 vector containing four (4) gRNA and targeting five (5) Glycinin (11S) genes. The efficacy of the selected targets to knockout 11S genes was confirmed in soybean hairy roots.
- We now have T1 seeds harboring deletions in Methionine γ-Lyase (MGL) However, transformations to knockout other Met catabolism genes, in combination with 7S, have been unsuccessful so far.
- Using gene-modeling softwares, we designed two versions of Gly1 gene with increased Met codons. Gly1(Ins) and Gly1(Mod1) encode 4.3% and 2% Met codons, respectively, compared to 1.4% Met codons in wild-type Gy1. The Met-enhanced Gly1 genes were synthesized and cloned in front of Gly1 promoter. Stable transformation to express Gly1(Mod1) in soybean seeds is on-going.
- We identified a fast neutron (FN) mutant with increased seed protein content. This mutant is deleted for a Met catabolism gene, S-adenosyl methionine synthase1 (SAMS1). Using the HPLC/UV-based method we developed, our analysis showed that this mutant contained 28.8% higher seed Met (bound and free) compared to WT Williams 82.
Importance
- Soybean growers look to gain more value from the constituents of the seed, it is critical to ensure that protein levels are maintained at or above current levels. This project uses gene editing techniques to alter a few, well chosen targets that have the potential for large impact both on protein quantity and quality.
For more information about this research project, please visit the National Soybean Checkoff Research Database.
Funded in part by the soybean checkoff.
