Engineered fhb7 enzyme for fusarium head blight resistance in transgenic crops

Overview

Fusarium head blight (FHB) is one of the most destructive diseases of wheat and barley worldwide, driven by Fusarium graminearum and related fungi. Beyond yield loss, these pathogens produce trichothecene mycotoxins such as deoxynivalenol (DON), which contaminate grain and pose serious risks to human and animal health. The Fhb7 gene, originally identified in wheat, encodes a glutathione S-transferase that detoxifies trichothecenes through de-epoxidation, conferring broad resistance to multiple Fusarium species.

This offering centers on an engineered version of Fhb7 designed to deliver stronger and broader catalytic activity against DON and related mycotoxins. The solution is intended for integration into transgenic cereal crops, including wheat, rice, and corn, to reduce FHB damage, lower mycotoxin contamination, and protect food and feed supply chains.

Technical specifications

• Target pathway: detoxification of trichothecene mycotoxins (including DON) via enzymatic de-epoxidation
• Enzyme class: glutathione S-transferase (Fhb7) with confirmed role in broad-spectrum Fusarium resistance
• Structural basis: first high-resolution crystal structure of Fhb7 solved at approximately 2.4 Å by X-ray crystallography, enabling structure-guided engineering
• Engineering approach: identification of key catalytic amino acid residues, with candidate sites already confirmed for mutagenesis to enhance degradation activity
• Application: development of transgenic wheat, rice, and corn lines expressing engineered Fhb7 for improved FHB resistance and reduced mycotoxin accumulation
• Differentiator: combines a structurally characterized enzyme with targeted protein engineering to move beyond the natural resistance level observed in Fhb7-containing wheat

Technology readiness level

The program is at an early-to-mid stage of translational development. The natural Fhb7 gene has been validated in wheat (published in Science, 2020) as conferring strong FHB resistance, and preliminary results from the team confirm that Fhb7 is a viable starting point for protein engineering. A high-resolution crystal structure has been obtained, and candidate catalytic residues for enzyme improvement have been identified.

Planned next steps include solving the co-crystal structure of Fhb7 with its substrate, applying structure-guided protein engineering combined with directed enzyme evolution to enhance catalytic activity and broaden substrate scope, and ultimately producing transgenic crop lines carrying the engineered Fhb7 for resistance testing. The technology is not yet commercially deployed and represents an opportunity for collaborative development toward field-ready transgenic cultivars.