Abstract text: Phytophagous pests are becoming an increasingly important challenge due to climate change, the growing demand for food, and rising production costs. Their control is limited not only by the environmental impact of chemical pesticides but also by the rapid development of resistance in pest populations. Therefore, it is essential to explore more sustainable strategies that are effective without negatively affecting crop performance.

The plant cell wall plays a dual role in defence: it acts as a physical barrier against attackers and also serves as a source of damage-associated molecular patterns (DAMPs), which can activate plant immune responses. Although plant–pathogen interactions have been widely studied, much less is known about how plant cell walls respond to pests. In this work, the interaction Tetranychus urticae-Arabidopsis thaliana was used as a model to study defence mechanisms related to cell wall modifications and DAMP release.

Transcriptomic analyses showed enrichment of genes associated with cell wall processes including cellulose, hemicellulose, pectin, lignin, and callose related genes. Complementary FTIR analyses indicated significant changes in cell wall composition at early stages of infestation. Monosaccharide analysis revealed an increase in glucose content. Further experiments confirmed callose accumulation and detected cellodextrins in the water-soluble extract. Finally, the application of external DAMPs coming from cellulose improved resistance without fitness cost. Overall, these findings provide new insights into plant–pest interactions and support the use of DAMPs as a sustainable approach for pest control.