Modified Antimicrobial Peptides for Cation-Stable Pathogen Resistance
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Solution Overview
Problem
Existing plant defensins lose antifungal activity at elevated concentrations of mono- and bivalent cations, limiting their effectiveness in transgenic crops, and there is a need for broad-spectrum antimicrobial agents that can combat multiple pathogens without promoting resistance.
Innovation Solution
Recombinant and edited polynucleotides encoding antimicrobial peptides with modified amino acid sequences, operably linked to heterologous promoters, are introduced into plant genomes to enhance resistance to plant pathogens, including fungi and oomycetes, by stabilizing the peptides' activity in the presence of high cation concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plant defensins are used to inhibit plant pathogens, then antifungal activity is achieved, but activity is lost at elevated concentrations of mono- and bivalent cations
Solution Approach 1:
The patent modifies the amino acid sequence of plant defensins by substituting specific residues (e.g., Cys to Ser, Cys to Ala, or other conservative substitutions) to change the peptide's chemical properties. These parameter changes in amino acid composition allow the defensin to maintain antifungal activity while being resistant to inhibition by mono- and bivalent cations, directly resolving the contradiction between maintaining antifungal activity and tolerating elevated cation concentrations
Solution Approach 2:
The patent creates a composite antimicrobial peptide system by combining modified defensin peptides with other functional elements. The modified defensin sequence is integrated into a broader protein context or combined with adjuvant substances that enhance cation resistance while preserving antifungal activity, thereby achieving both reliability under cation stress and maintained pathogen inhibition
2Reliability
If existing antimicrobial agents are used to control plant pathogens, then pathogen inhibition is achieved, but microbial resistance develops
Solution Approach 1:
The patent employs a multi-peptide approach where multiple defensin sequences (e.g., ComDef1, ComDef2, ComDef3 with different amino acid compositions) are used simultaneously or in combination with other antimicrobial agents. This segmentation of the antimicrobial strategy into distinct peptide components with different modes of action prevents microbial resistance by ensuring that not all pathogens are susceptible to a single agent, thereby maintaining long-term pathogen control reliability
Solution Approach 2:
The modified defensin peptides are designed to exhibit broad-spectrum activity against multiple plant pathogen types (fungi, oomycetes, bacteria) through conserved structural motifs and cationic charge characteristics. This multi-functionality allows a single peptide or peptide combination to control diverse pathogens, reducing the need for multiple specialized agents and minimizing selective pressure for resistance development
Data Source
AI summary
Antimicrobial SbDef1-type peptides and proteins are disclosed along with compositions comprising the SbDef1-type peptides and proteins and transgenic or genetically edited plants or microorganisms that express the SbDef1-type peptides and proteins to inhibit growth of pathogenic microbes. Such SbDef1-type peptides and proteins, compositions, plants, and microorganisms can provide for inhibition of microbial growth.