Engineered composite plants for enhanced carbon fixation through root over-proliferation

Overview

This biotechnology platform addresses the critical challenge of soil carbon sequestration by engineering composite plants with enhanced root systems. The approach harnesses Agrobacterium rhizogenes, a bacterium that naturally induces "Crazy Root" disease, redirecting fixed carbon from shoot and fruit production to extensive root proliferation. By creating auxotrophic mutants of A. rhizogenes, the technology enables field deployment of composite plants that can transfer significantly more carbon to soil through root biomass and exudation of carbon compounds. This solution has potential applications in carbon farming, soil health improvement, and climate change mitigation across multiple crop systems.

Technical specifications

Core technology:

• Auxotrophic A. rhizogenes mutants engineered to require specific carbohydrate or amino acid supplements for survival, enabling containment and eventual bacterial die-off when plants are transferred to soil
• Composite plant system combining wild-type shoots with transgenic "crazy roots" induced by the engineered bacterium
• Multi-crop compatibility validated across soybean, tomato, sweet potato, tobacco, cassava, and citrus systems
• Containment strategy where bacteria lose viability in natural soil conditions due to lack of required nutrients

Key features:

• Overcomes natural plant regulation of shoot-to-root biomass ratios
• Enables field planting of composite plants while preventing environmental release of engineered bacteria
• Supports monitoring of root formation, root exudation, and microbial biomass composition

Technology readiness level

The technology is currently at TRL 3-4 (experimental proof of concept to laboratory validation). The research team has over two decades of experience working with A. rhizogenes and has consistently demonstrated root over-proliferation in multiple plant systems under controlled laboratory conditions. The next phase involves creating and testing single, double, and triple auxotrophic mutants for their ability to induce transgenic roots while maintaining containment. Initial field validation will occur under microplot conditions to monitor root proliferation, carbon fixation potential, and bacterial elimination over growing seasons. Additional assessments of microbial biomass and composition are planned if sufficient funding is secured.