Photodynamic herbicide synergist targeting GSTF1 to reverse grass weed herbicide resistance

Overview

Grass weeds including black-grass, rye-grass, and wild oat have developed resistance to widely used herbicides, creating a major challenge for crop protection. This research targets glutathione-s-transferase phi 1 (GSTF1), a protein identified as a key molecular driver of herbicide resistance in these species. The proposed solution uses photodynamic therapy (PDT) to deliver a precision herbicide synergist: a photosensitizer coupled to a natural GSTF1 inhibitor. When activated by UV light, the photosensitizer enables targeted inhibition of GSTF1, reversing herbicide resistance in grass weeds without the broad environmental toxicity associated with conventional chemical inhibitors such as 4-chloro-7-nitrobenzofurazan.

Technical specifications

• Target: GSTF1 protein, the primary molecular mediator of herbicide resistance in grass weeds
• Mechanism: Photodynamic therapy couples a photosensitizer compound to a natural GSTF1 inhibitor (such as flavone glycosides), enabling UV-light-activated precision targeting
• Validation evidence: In black-grass cell suspension cultures, photosensitizer treatment with UV activation reduced cell viability by 50% or more compared to controls (one-way ANOVA, p ≤ 0.05). In seedling assays, 10 µM photosensitizer treatment significantly reduced biomass at 14 days post-treatment (p ≤ 0.05)
• Application modes: Designed for use as a herbicide synergist (herbicide buster) to restore efficacy of existing herbicides on resistant populations; planned foliage spray delivery for field-relevant uptake assessment
• Species scope: Black-grass, rye-grass, and wild oat, all of which carry the GSTF1 orthologue

Technology readiness level

The technology is at early-to-mid stage development. Proof-of-concept has been demonstrated in cell culture and seedling assays confirming photosensitizer activity and GSTF1 inhibition. Future validation will assess the herbicide-busting effect of the photosensitizer-coupled natural inhibitor in both herbicide-sensitive and herbicide-resistant black-grass populations through imaging and phenotyping, with extension to rye-grass and wild oat. The team is actively seeking funding and support for foliage spray uptake studies to advance the technology toward field application.