The responses and adaptations of rice (Oryza sativa L.) to drought stress: A review

Abstract

The rise in global temperature due to human activities poses a threat to the survival and productivity of plants. As sessile organisms, plants are frequently exposed to abiotic stressors, among which drought is the most critical factor limiting rice (Oryza sativa L.) yield worldwide. Understanding the mechanisms underlying drought adaptation in rice is essential for breeding drought-resilient genotypes. Advancements in molecular biology, genomics, and high-throughput phenotyping have uncovered complex networks of genetic, biochemical, and physiological responses that enable rice to withstand drought stress. This study examines the adverse effects of drought on rice and the mechanisms employed by rice to adapt to drought, utilizing an integrated molecular, biochemical, and physiological approach. It highlights the multifaceted nature of drought tolerance and its implications for developing resilient cultivars. Key mechanisms identified include osmotic adjustment, morphological changes, the expression of drought-responsive genes, the secretion of stress-related phytohormones, and the activation of antioxidant enzymes, all of which contribute to maintaining cellular homeostasis. Transcriptome and proteome analyses have expanded the catalogue of stress-responsive genes and proteins, particularly those involved in abscisic acid signalling, aquaporins, and late embryogenesis abundant proteins. The regulatory roles of transcription factors such as DREB, NAC, and MYB in modulating these stress-response pathways are emphasized. Furthermore, genome-wide association studies and quantitative trait locus (QTL) mapping have identified genomic regions associated with drought tolerance, providing valuable targets for marker-assisted selection in breeding programs. The integration of these findings offers a roadmap for improving rice varieties with enhanced drought tolerance. Future research should focus on validating candidate genes, proteins, and QTLs across diverse genetic backgrounds to ensure stable productivity under water-limited conditions.