Plant Seed Protein Composition Through CGS Feedback Removal
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Solution Overview
Problem
Human and monogastric mammals, including humans, are unable to synthesize essential amino acids like methionine, leading to protein-energy malnutrition (PEM) due to dietary deficiencies, which can cause health issues such as lowered resistance to diseases and retarded development.
Innovation Solution
Genomic modifications in plants to inhibit feedback regulation of cystathionine γ-synthase (CGS) and reduce low methionine storage proteins, promoting the production of high methionine content storage proteins through proteome rebalancing, using techniques like CRISPR/Cas9 to introduce deletions, insertions, or substitutions in the CGS and low methionine storage protein genes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feedback regulation of cystathionine γ-synthase (CGS) is maintained, then plant growth and development are normally regulated, but methionine content in seeds remains low
Solution Approach 1:
The patent extracts and removes the feedback regulation mechanism (MTO1 region) from the CGS enzyme system. By introducing genomic modifications that delete or disrupt the MTO1 region, the feedback inhibition is completely removed, allowing CGS to operate at maximum capacity for methionine production without being constrained by normal regulatory controls.
Solution Approach 2:
The patent changes the regulatory parameter of CGS activity by modifying the MTO1 region sequence. This genetic modification alters the enzyme's responsiveness to feedback inhibition, transforming it from a regulated state to an constitutively active state that continuously produces methionine at elevated levels.
2Quantity of substance
If low methionine storage proteins are highly expressed, then plant growth is supported, but overall protein quality and methionine content decrease
Solution Approach 1:
The patent applies local quality changes by specifically targeting and modifying the expression profiles of particular storage protein genes (7S and 11S proteins). Instead of uniformly affecting all proteins, the genomic modifications selectively alter the composition of seed storage proteins to enrich methionine content while maintaining overall protein production.
Solution Approach 2:
The patent inverts the natural protein expression hierarchy by suppressing the typically dominant low-methionine storage proteins (7S and 11S) and allowing high-methionine proteins to become more prominent. This inversion of the normal protein composition ratio achieves superior methionine content in the seed proteome.
3Quantity of substance
If genomic modifications are introduced to increase methionine content, then nutritional quality improves, but genetic stability and plant robustness may be compromised
Solution Approach 1:
The patent applies partial action by introducing targeted genomic modifications at specific loci (MTO1 region and storage protein genes) rather than comprehensive genome-wide changes. This localized approach achieves the desired methionine enrichment while minimizing potential disruptions to overall genetic stability and plant physiology.
Data Source
AI summary
Plant seeds with increased protein and methionine content and having a modified expression of a cystathionine γ-synthase (CGS) polypeptide, modified expression of a low methionine content (< about 1.0% methionine) storage protein polypeptide, or modified expression of both are provided. Methods for modifying expression of CGS polypeptides and polynucleotides and low methionine content seed storage polypeptides and polynucleotides include genome editing to modify the MTO1 regulatory region of CGS to create feedback insensitive methionine production and low methionine content polypeptides to create proteome rebalancing toward high methionine content storage protein production, and transformation with recombinant DNA constructs to enhance or suppress expression are disclosed herein.