Glandular Trichome Metabolites in Pest Resistance Mechanisms

Glandular trichomes are specialised epidermal structures that secrete a diverse arsenal of metabolites, including acylsugars, terpenoids and flavonoids, which confer resistance to herbivorous insects and mites. These secretions operate through multiple modes of action: direct toxicity, feeding deterrence, disruption of oviposition and interference with pest development. Chemical diversity arises from lineage-specific duplications and functional divergence of core metabolic enzymes, yielding a rich array of acyl chain lengths, branching patterns and sugar backbones. Trichome density and spatial distribution across leaf surfaces further modulate pest behaviour, often forcing insects to settle on less favourable sites. Recent advances in analytical chemistry and genomics have mapped the biosynthetic pathways governing these specialised metabolites, uncovering molecular switches that control acyl donor supply, enzyme specificity and subcellular localisation. Exploiting natural genetic variation in wild relatives has demonstrated the feasibility of breeding or engineering crops with enhanced, endogenous defence traits. Such strategies promise sustainable pest management by reducing reliance on synthetic pesticides, thereby supporting environmental health and global food security.

Research from Nature Portfolio

Recent studies have revealed how subtle changes in BAHD acyltransferase enzymes drive metabolic innovation in glandular trichomes. In wild tomato species, a few amino acid substitutions in key acyltransferases invert the order of acylation reactions on sucrose, resulting in novel acylsugar structures with distinct defensive properties. This work illuminates the evolutionary mechanisms underpinning chemical diversity in trichome exudates and identifies precise molecular targets for metabolic engineering of pest-resistant cultivars.

Glandular Trichome Metabolites in Pest Resistance Mechanisms publication trend

The graph below shows the total number of articles in glandular trichome metabolites in pest resistance mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Glandular trichome: A specialised hair-like epidermal appendage that produces and stores secondary metabolites for defence.

Acylsugars: Esterified sugar molecules bearing fatty acid chains, synthesised in trichomes to deter or intoxicate herbivores.

Specialised metabolite: A compound produced by plants beyond primary metabolism, often mediating interactions with pests or pollinators.

BAHD acyltransferase: A plant enzyme family that catalyses the transfer of acyl groups onto acceptor molecules, crucial for assembling diverse defence compounds.

Oviposition: The process by which female insects deposit eggs onto or into a substrate, often influenced by chemical cues.

References

1. Sticky business: the intricacies of acylsugar biosynthesis in the Solanaceae. Phytochemistry Reviews (2024).
2. Evolution of a flipped pathway creates metabolic innovation in tomato trichomes through BAHD enzyme promiscuity. Nature Communications (2017).
3. Differential and Synergistic Functionality of Acylsugars in Suppressing Oviposition by Insect Herbivores. PLOS ONE (2016).
4. Trichomes and Allelochemicals in Tomato Genotypes Have Antagonistic Effects Upon Behavior and Biology of Tetranychus urticae. Frontiers in Plant Science (2018).