Bactobio Milestones: New bio-derived compounds protect wheat plants from Septoria
26 August 2025
Bactobio Milestones: New bio-derived compounds protect wheat plants from Septoria
Bactobio has discovered two new bio-derived compounds that protect wheat plants against Zymoseptoria tritici, the fungal pathogen responsible for Septoria wheat blotch, under greenhouse conditions and without observed phytotoxicity.
Both compounds showed robust activity against Z. tritici in vitro which, crucially, has successfully translated to effective in planta disease control. This activity has been validated externally, where the compounds also showed activity against other plant pathogens, including pathogens affecting wheat.
Importantly, the compounds retained activity against strains resistant to major wheat fungicides. Initial in vitro and in silico toxicology assessments across human, animal and environmental indicators are also encouraging.
Together, these results represent one of the most important applied milestones for Bactobio’s crop protection pipeline: two new bio-derived compounds that have moved from laboratory activity to protection in living plants.
Septoria wheat blotch: a persistent threat to wheat production
Wheat is one of the UK’s most important crops. In 2024, the UK wheat harvest was estimated at 11 million tonnes, produced across 1.5 million hectares.
Septoria wheat blotch remains one of the most damaging diseases affecting UK winter wheat. It reduces green leaf area, limits photosynthesis and can cause severe yield losses of up to 50% when disease pressure is high. AHDB estimates that Septoria causes annual UK yield losses worth £110–220 million, despite fungicide applications.
Control already depends on an integrated approach: choosing more resistant wheat varieties, adjusting agronomy to reduce disease pressure and using fungicides carefully to protect yield. Varietal resistance is an important foundation, but it is not a complete solution. Resistant varieties can still be affected under high disease pressure, and disease resistance can change over time.
For growers, the challenge is practical and persistent: protecting yield while managing input costs, resistance pressure and the shift toward lower-impact crop protection.
A shrinking toolbox for wheat growers
Fungicides remain an important part of Septoria control, but the available toolbox is under pressure.
Z. tritici has developed reduced sensitivity or resistance to several important fungicide groups. Some older chemistries are no longer effective against Septoria, while others must be used carefully to protect their remaining value.
Regulatory change is also reshaping crop protection. The withdrawal of chlorothalonil in 2020 removed an important anti-resistance tool for Septoria management. Wider changes in pesticide regulation are reinforcing the need for new products that can support effective disease control while fitting a more sustainable, resistance-conscious future for farming.
The direction of travel is clear: wheat growers need new tools that work in the plant, support resistance management and fit within integrated pest management.
Building a broader crop protection pipeline
The biologicals sector is growing quickly, with many products built around well-characterised microbial strains or defined natural-product classes.
Bactobio’s approach starts further upstream. We culture previously inaccessible microbes and screen their chemistry directly, expanding the biological diversity available for crop protection discovery.
This gives us the potential to build a broader pipeline of bio-derived candidates and follow the product path that best fits the disease, crop and compound profile. In some cases, that may mean a purified bio-derived active. In others, it may mean a biological product.
For Septoria, the priority is clear: identify compounds that are active against the pathogen, retain activity against resistant strains, show a promising safety profile and work in plants.
These new compounds are an encouraging example of that approach in action.
From greenhouse activity to field readiness
Our next steps include formulation and scale-up, further human, animal and environmental safety testing, resistance and mechanism-of-action studies, and small plot field trials.
Septoria wheat blotch is a long-standing challenge for growers. These results are a meaningful step toward a new generation of crop protection tools: bio-derived, active in plants and designed for the realities facing wheat production today.