Abstract
Heat stress has emerged as a significant abiotic constraint affecting rice yield and grain quality. In recent years, substantial advancements have been achieved in elucidating molecular regulatory mechanisms and breeding applications pertinent to rice heat tolerance. This review offers a comprehensive examination of the fundamental regulatory pathways involved in rice responses to heat stress, encompassing membrane lipid homeostasis, heat signal transduction, transcriptional regulation, RNA stability and translation, epigenetic modifications, hormone signaling, antioxidant defense, and the protection of reproductive organs. Particular emphasis is placed on the functional mechanisms and breeding potential of pivotal thermotolerance-associated genes and quantitative trait loci (QTLs), such as TT1, TT3, and QT12. Additionally, we summarize recent applications of cutting-edge technologies in the enhancement of heat-tolerant rice varieties, including multi-omics integration, CRISPR/Cas9 genome editing, marker-assisted selection (MAS), and rational design breeding. Finally, we address current challenges, including integrating regulatory mechanisms, developing realistic heat simulation systems, validating the functionality of candidate genes, and managing trait trade-offs. This review provides a theoretical foundation for developing heat-tolerant rice cultivars and offers valuable insights to accelerate the breeding of climate-resilient rice varieties for sustainable production.