Cell-penetrating peptide platform for sustainable organic agriculture

Overview

This solution introduces a cell-penetrating peptide platform that enables the direct delivery of protein-based defense activators and biostimulants into plant cells. Built around the engineered 90-amino acid peptide MTD4, the platform addresses a long-standing challenge in agriculture: efficiently transporting bioactive proteins and peptides across the plant cell wall and membrane. When MTD4 is fused with the harpin protein HrpZ, the resulting MTD4-HrpZ construct activates plant immunity and stimulates growth, offering a sustainable, protein-based approach to crop protection that is well suited for organic agriculture systems.

In greenhouse validation trials, spraying tomato plants with 1 µM MTD4-HrpZ significantly reduced infection by bacterial speck and spot pathogens. A separate seedling treatment with 0.5 µM MTD4-HrpZ increased plant height and fresh weight by approximately 20%. These dual benefits—disease suppression and growth promotion—make the platform attractive for growers seeking to reduce reliance on synthetic agrochemicals while maintaining or improving yields.

Technical specifications

Core technology:

• MTD4 is a 90-amino acid engineered cell-penetrating peptide that enhances intracellular delivery of cargo proteins via endocytosis
• The platform can be fused with a range of defense activators, biostimulants, or short peptides for targeted plant applications
• Validated fusion construct MTD4-HrpZ combines the delivery capability of MTD4 with the immune-activating properties of the harpin protein HrpZ

Demonstrated performance:

• MTD4-Rh enters the cytosol of Nicotiana benthamiana leaf cells with substantially higher efficiency than the parental FN3-Rh control protein
• Spraying 4-week-old tomato plants with 1 µM MTD4-HrpZ significantly reduces infection by bacterial speck and spot pathogens
• Two applications of 0.5 µM MTD4-HrpZ on tomato seedlings increased plant height and fresh weight by approximately 20%
• Application method is foliar spraying, enabling straightforward integration into existing crop management practices

Technology readiness level

The MTD4 delivery platform has been validated at the laboratory and controlled-environment level, with demonstrated efficacy in reducing bacterial disease and promoting growth in tomato. Current development objectives include optimizing the system for short peptide delivery, expanding efficacy testing in controlled environments, conducting field trials on tomato immunity and growth, and developing cost-effective production methods for large-scale agricultural deployment. The technology is positioned for transition from controlled-environment validation toward field-scale trials and commercial production scale-up.