Biosynthesis and Applications of Natural Insecticides

The discovery and utilisation of natural insecticides derived from biological sources have advanced significantly over recent decades. These compounds, often complex secondary metabolites, are synthesised via specialised enzymatic pathways in plants, fungi and bacteria. Polyketide and non-ribosomal peptide backbones are assembled by modular enzyme complexes and further modified by oxidation, methylation and glycosylation to yield diverse structures such as the spinosyns, pyrethrins and azadirachtins. The spinosyn class typifies a macrolide tetracycle decorated with unique sugar moieties that confer high potency and environmental safety. Genetic and metabolic engineering strategies have been employed to enhance titres, involving pathway refactoring, overexpression of key methyltransferases and heterologous expression in optimised microbial hosts. Parallel efforts in structural biology have elucidated the catalytic mechanisms of glycosyltransferases and polyketide synthases, enabling rational design of enzyme variants with altered substrate specificity. Beyond spinosyns, botanical insecticides such as pyrethrum and neem extract remain important, with rigorous fractionation and semisynthetic modification yielding new analogues with improved stability. Synthetic biologists are now exploring genome mining in understudied microorganisms for novel biosynthetic gene clusters, while integrated bioprocess design addresses scale-up challenges. Applications extend from crop protection to vector control, with formulations tailored for controlled release, low non-target effects and biodegradability. The global significance of these agents lies in reducing reliance on broad-spectrum synthetic pesticides, mitigating resistance development and safeguarding ecosystems. Continual interplay between fundamental enzymology, strain engineering and formulation science underpins the trajectory of natural insecticide research, promising both enhanced efficacy and sustainability.

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Biosynthesis and Applications of Natural Insecticides publication trend

The graph below shows the total number of articles in biosynthesis and applications of natural insecticides across all publications each year (not limited to Nature Index journals).

Technical terms

Polyketide synthase (PKS): A multi-enzyme complex that assembles polyketide backbones through sequential condensation of acyl-CoA precursors.

Glycosyltransferase: An enzyme that catalyses the transfer of sugar moieties to aglycone scaffolds, crucial for biological activity and solubility.

Heterologous expression: Production of biosynthetic genes in a non-native microbial host to optimise yield or facilitate genetic manipulation.

Macrolide: A class of natural products characterised by large lactone rings, often exhibiting antibiotic or insecticidal properties.

Secondary metabolite: A bioactive compound not essential for primary growth, typically involved in organismal defence or communication.

Rhamnosyltransferase: A subclass of glycosyltransferases responsible for attaching rhamnose sugars, as in the final maturation of spinosyns.

References

1. Improving spinosad production by tuning expressions of the forosamine methyltransferase and the forosaminyl transferase to reduce undesired less active byproducts in the heterologous host Streptomyces albus J1074. Microbial Cell Factories (2023).
2. Mechanistic insight for improving butenyl-spinosyn production through combined ARTP/UV mutagenesis and ribosome engineering in Saccharopolyspora pogona. Frontiers in Bioengineering and Biotechnology (2024).
3. Functional Characterization and Substrate Specificity of Spinosyn Rhamnosyltransferase by in Vitro Reconstitution of Spinosyn Biosynthetic Enzymes*. Journal of Biological Chemistry (2009).