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Abstract A transient heat stress occurring during early seed development in rice (Oryza sativa) reduces seed size by altering endosperm development. However, the relationship between the timing of the stress and specific developmental stage on heat sensitivity is not well‐understood. To address this, we imposed a series of non‐overlapping heat stress treatments and found that young seeds are most sensitive during the first two days after flowering. Temporal transcriptome analysis of developing, heat stressed (35°C) seeds during this window shows thatInositol‐requiring enzyme 1 (IRE1)‐mediated endoplasmic reticulum (ER) stress response and jasmonic acid (JA) pathways are the early (1–3 h) drivers of heat stress response. We propose that increased JA levels under heat stress may precede ER stress response as JA application promotes the spliced form ofOsbZIP50,an ER response marker gene linked to IRE1‐specific pathway. This study presents temporal and mechanistic insights into the role of JA and ER stress signalling during early heat stress response of rice seeds that impact both grain size and quality. Modulating the heat sensitivity of the early sensing pathways and downstream endosperm development genes can enhance rice resilience to transient heat stress events.
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This content will become publicly available on January 3, 2026
Reducing Cofilin dosage makes embryos resilient to heat stress
Abstract In addition to regulating the actin cytoskeleton, Cofilin also senses and responds to environmental stress. Cofilin can promote cell survival or death depending on context. Yet, many aspects of Cofilin’s role in survival need clarification. Here, we show that exposing earlyDrosophilaembryos to mild heat stress (32°C) induces a Cofilin-mediated Actin Stress Response and upregulation of heat- and ER-stress response genes. However, these responses do not alleviate the negative impacts of heat exposure. Instead, heat stressed embryos show downregulation of hundreds of developmental genes, including determinants of the embryonic body plan, and are less likely to hatch as larvae and adults. Remarkably, reducing Cofilin dosage blunts induction of all stress response pathways, mitigates downregulation of developmental genes, and completely rescues survival. Thus, Cofilin intersects with multiple stress response pathways, and modulates the transcriptomic response to heat stress. Strikingly, Cofilin knockdown emerges as a potent pro-survival manipulation for embryos.
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- Award ID(s):
- 2243257
- PAR ID:
- 10595351
- Publisher / Repository:
- bioRxiv
- Date Published:
- Format(s):
- Medium: X
- Institution:
- bioRxiv
- Sponsoring Org:
- National Science Foundation
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