TuATG1 ‐mediated autophagy confers thermotolerance in Tetranychus urticae and provides an RNAi target for pest management

BACKGROUND: Tetranychus urticae is a globally distributed agricultural pest with exceptional thermotolerance, enabling rapid outbreaks under hot conditions, particularly in glasshouses. Antioxidant enzymes contribute to heat resistance, yet the molecular mechanisms underlying long-term thermotolerance remain unclear. Our transcriptome analysis identified several autophagy-related genes (ATGs) as being significantly responsive to heat stress, making them strong candidates for functional investigation in T. urticae, where their roles have not yet been examined. This study combined transcriptomics, reference gene validation, expression profiling and RNA interference (RNAi) to investigate autophagy-mediated heat tolerance. RESULTS: Comparative RNA-seq analysis (25 °C versus 39 °C) revealed broad transcriptional reprogramming, with significant enrichment of lysosomal, antigen processing and presentation, apoptosis, metabolic, immune and autophagy pathways. Lysosome was the most significantly enriched pathway, and additional changes were observed in PI3K-Akt and mTOR signaling, suggesting coordinated regulation of stress, immunity and metabolism under heat exposure. GAPDH and α-tubulin were validated as stable reference genes under heat stress. Expression profiling showed temperature- and time-dependent induction of TuATG1. RNAi silencing of TuATG1 achieved 76.36% knockdown, causing 31.47% mortality at 25 °C, and high lethality under 42 °C, with complete mortality after 5 h exposure. These results confirm that TuATG1 is critical for both basal homeostasis and heat adaptation in T. urticae. CONCLUSION: This study provides the first functional evidence that autophagy mediates thermotolerance in T. urticae and identifies TuATG1 as a promising RNAi target. Manipulating autophagy-related pathways may enable sustainable, climate-resilient control strategies for T. urticae, reducing reliance on chemical acaricides. © 2026 Society of Chemical Industry.