Heterologous expression of heat-resistant obscure (Hero) proteins enhances thermotolerance in plants.

Improving plant stress tolerance and crop productivity is critical. Membraneless biomolecular condensates formed via liquid-liquid phase separation (LLPS) have been shown to mediate plant responses to various stresses, including heat. While recent advances have elucidated the LLPS role in stress tolerance mechanisms, translating these findings into practical strategies for enhancing plant resilience remains a formidable challenge. In this study, we investigated the effects of two human-derived RNA-binding proteins, Heat-resistant obscure 7 (Hero7) and Hero45, on abiotic stress tolerance in plants. When overexpressed heterologously, these proteins appear to enhance thermotolerance. Under heat stress, Hero7 and Hero45 undergo phase transitions consistent with LLPS, which correlates with the formation of larger processing bodies (PBs) and stress granules (SGs). This may contribute to the protection of mRNAs from heat-induced degradation, potentially improving heat resistance. The present findings demonstrate that LLPS modulation can enhance plant thermotolerance, offering a viable strategy for engineering stress-resistant crops.