Exploring natural pesticides: metabolomic insights into wheat and barley response to scopoletin and umbelliferone

Incorporating a natural, eco-friendly approach – allelopathy – into integrated pest management can significantly reduce reliance on hazardous pesticides. This study examines the metabolic and physiological responses of wheat (Triticum aestivum) and barley (Hordeum vulgare) to the allelochemicals umbelliferone (UMB) and scopoletin (SCOP), evaluating their potential as biopesticides. Despite their demonstrated bioactivity, commercialization is hindered by limited understanding of their mechanisms of action, impact on non-target organisms, and cost-effectiveness. To address these challenges, a metabolomic approach was used to assess the effects of UMB and SCOP on important worldwide cereal crops and identify key metabolites involved in their responses. A metabolomic approach was used to compare their effects with conventional pesticides: 2,4-dichlorophenoxyacetic acid (2,4-D) and tebuconazole (1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol, TBC). Non-target LC-ESI-MS/MS and LC-Full-MS/ddMS² analyses identified significant metabolite changes, while chemometric tools ensured robust data interpretation, which were validated by cross-validation and permutation testing, confirming the stability and predictive accuracy of the results. The findings showed that UMB minimally disrupts plant metabolism while activating key defense pathways, as evidenced by increased levels of fatty acids, auxins, and phytoalexins. In contrast, SCOP induced metabolic changes similar to those of the synthetic fungicide TBC, suggesting its potential as a natural fungicide alternative. These outcomes establish a robust framework for assessing the broader applicability of natural biopesticides, offering innovative and environmentally benign alternatives to synthetic pesticides while addressing pressing challenges in food security and environmental sustainability.