Negative regulators that mitigate abiotic stress sensitivity of rice: insights and future perspectives

Abiotic stresses such as drought, extreme temperatures, salinity, heavy metals, and ultraviolet radiation have severely reduced rice productivity by disrupting cellular balance and physiological processes. Rice plants perceive environmental stress through the complex signaling networks that include phytohormone-mediated pathways, transcriptional regulation, reactive oxygen species, ion transport systems, and post-translational modifications. While numerous studies have been focused on positive regulators that enhance stress tolerance, but emerging evidence also suggest that negative regulators have an equally important role in modulating stress responses and balancing stress tolerance. These regulators have been shown to function at multiple molecular levels, including TFs, protein phosphatases, ubiquitin-proteasome components, signaling repressors, and chromatin-associated modifiers that modulate ABA-dependent and independent stress signaling pathways. This review provides a comprehensive study of negative regulators identified in rice and discusses their physiological impacts on the stomatal regulation, ROS scavenging, ion homeostasis, photosynthetic efficiency, and developmental adaptation. We have further summarized the strategies that are used for the identification of negative regulators through transcriptomic, genetic, and functional genomics approaches. Finally, we highlight emerging opportunities for the manipulation of negative regulatory networks to combat stress tolerance without compromising overall yield, offering future perspectives for developing climate-resilient rice cultivars.