Ethylene-jasmonate interplay involving ERF regulons modulates acute heat stress response in rice seedlings.

Rice (Oryza sativa), a staple cereal crop, is significantly threatened by rising temperatures, which impact all stages of growth, including the crucial early seedling establishment phase. Despite being critical in determining overall growth and productivity, response to acute (short-term intense) heat stress during the early seedling stage remains understudied. Here, by using gradients of heat stress duration and intensity, we identified a critical threshold, beyond which acute heat stress significantly impedes seedling growth. Transcriptome analysis of seedlings exposed to growth-inhibiting temperature revealed (i) shared and distinct responses in shoots and roots, and (ii) transcription factor (TF)-target modules that co-regulate key biological processes, uncovering core molecular mechanisms of the acute heat stress response. Notably, TF-target and functional interactome analysis, along with hormone inhibitor assays, revealed ethylene-response factors (ERFs) as prime regulators of the heat stress response involving ethylene and jasmonic acid as upstream regulators. Pre-treatment with ethylene precursor and jasmonic acid mitigated the impact of acute heat stress on the growth of rice seedlings by activating ERFs. These findings suggest that identifying and targeting master regulators presents a novel strategy to coordinate multiple transcription factors to enhance stress resilience, an approach with significant implications for global food security in the context of challenging climatic conditions.