Plant Disease: A Pressing Global Challenge
Plant diseases threaten global food systems. According to data from the Food and Agriculture Organization (FAO) of the United Nations, up to 40% of global crop yield losses are directly attributed to plant diseases and pests.
Chemical Pesticide Predicament: Heavy Ecological Costs
The extensive use of chemical pesticides not only leads to their persistence and migration in soil and water bodies, causing environmental pollution, but also enters the food chain through bioaccumulation and biomagnification, threatening aquatic organisms and ultimately posing risks to human health[1]. Moreover, chemical pesticides have negative impacts on non-target organisms, disrupting biological control . Additionally, the long-term of chemical pesticides is causing a widespread and rapid increase in resistance in both target and non-target populations[2].
Cyclic lipopeptides: Proming Alternative
Cyclic lipopeptides (CLPs) produced by Bacillus strains are recognized as promising "green pesticide substitutes." They offer broad-spectrum antifungal and antibacterial activity, high safety profiles for plant and animal hosts, and are naturally biodegradable—making them ideal candidates for sustainable agriculture[3].
The Central Bottleneck: The "Yield Lock" in CLP Industrialization
However, their extremely low production levels in wild-type strains form a critical bottleneck that severely restricts large-scale application. Current research indicates that CLP yields in wild-type Bacillus are typically in the milligram-range.
Fengycin production usually remains below 500 mg/L, and Iturin A production in wild strains often falls below 100 mg/L. Even with preliminary optimization, most engineered strains struggle to exceed 3 g/L—far below the economic threshold of over 5 g/L required for viable industrial-scale production.
The HBUT-China team is addressing this challenge head-on. By four Design-Build-Test-Learn (DBTL) cycles, we are engineering Bacillus velezensis to become high-yield factories for CLPs.
ARTP mutagenesis
We employ ARTP mutagenesis combined with high-throughput screening to rapidly obtain high-yield mutant strains, effectively breaking through the low production of wild-type strains.
Targeted genetic engineering
We implemented a targeted genetic mutation strategy using CRISPR-Cas9 system to reconstruct key beneficial mutations, directly addressing the instability inherent in random mutagenesis.
Metabolic Reconstruction
We utilize a dual-gRNA CRISPR system to eliminate substrate competition between parallel CLP pathways to redirect metabolic flux toward the industrial target product-fengycin biosynthesis.
NRPS reprogramming
We developed a computational tool to predict the pairs and function of non-ribosomal peptide synthetase (NRPS) communication domain. This tool will guide the rational reprogramming of biosynthetic gene clusters, establishing a versatile platform for developing novel lipopeptide variants with enhanced antimicrobial properties.
Our mission is to empower farmers with sustainable tools, turning the tide against plant diseases and steering agriculture toward an environmentally friendly future.
References
[1]Rafiei, B., & Kioumarsi, H. (2024). Adverse effects of pesticides on environment and non-target organisms. Journal of Environmental Research and Technology, *9*(16), 1–18.
[2]Delnat, V., Tran, T. T., Janssens, L., & Stoks, R. (2019). Resistance to a chemical pesticide increases vulnerability to a biopesticide: Effects on direct mortality and mortality by predation. Aquatic Toxicology, *219*, 105310.
[3]Vahidinasab, M., Adiek, I., Hosseini, B., Akintayo, S. O., Abrishamchi, B., Pfannstiel, J., Henkel, M., Lilge, L., Voegele, R. T., & Hausmann, R. (2022). Characterization of Bacillus velezensis UTB96, demonstrating improved lipopeptide production compared to the strain B. velezensis FZB42. Microorganisms, *10*(11), 2225.
[4]Zhou, W., Zheng, W., & Tao, S. M. (2015). Advances in cyclic lipopeptide substances from Bacillus subtilis. Journal of Microbiology, *35*(4), 80–86.