Marked for protection: ac4C guides mRNAs into stress granules during heat stress.

Rising global temperatures and increasingly frequent heat events pose a major threat to crop productivity and food security. Heat stress disrupts plant physiological and metabolic processes, compromising growth, development, and ultimately yield (Lesk et al. 2021). Understanding the molecular mechanisms that allow plants to withstand elevated temperatures is therefore increasingly important for improving crop resilience. Post-transcriptional regulation provides plants with a rapid means of reshaping gene expression during stress. RNA modifications can influence mRNA stability, translation, and localization, including partitioning into stress granules (SGs) - dynamic biomolecular condensates that rapidly assemble when cells experience adverse conditions (Arango et al. 2018; Kudrin et al. 2024; Kearly et al. 2024; Shen 2025). Recent work showed that N4-acetylcytidine (ac4C)-modified RNAs are preferentially enriched in SGs, raising the intriguing possibility that RNA modifications contribute to determining SG composition (Kudrin et al. 2024). Zhang et al. (Zhang et al. 2026) now provide a mechanistic and physiological framework for this idea in plants, connecting RNA acetylation, selective mRNA partitioning into SGs, transcript protection, and heat-stress tolerance.