Translational research progress and challenges for developing drought resilient rice
Dinesh Kumar Saini, Kirti Bardhan, Impa M. Somayanda, Rajeev N. Bahuguna, S. V. Krishna Jagadish
Abstract
• Breakthroughs in breeding for drought-tolerant rice cultivars are explored. • Novel traits aiding rice adaptation to drought stress are identified. • Despite promise, large-scale HTP deployment for rice drought tolerance remains limited. • Tailoring holobionts to enhance drought tolerance remains an underexplored area of research. • A systems biology approach, integrating omics data and predictive modeling, is needed. In this comprehensive review, we highlight the current state and analyze the global impact of drought stress on rice production, explore research progress achieved and offer insights through timely or comparative analyses where applicable. More than half of the world's rice area is affected by drought with Asia being the most severely impacted followed by Sub-Saharan Africa and Latin America. Under limiting freshwater resources and climate change, the traditional rice cultivation witnessed a shift towards water-efficient techniques. Further, integrating under-exploited but potentially valuable traits in modern cultivars, including root architecture, optimized canopy structure, tillering plasticity, and key physiological traits, could help minimize drought-induced damage. Furthermore, although high-throughput phenotyping (HTP) has shown promise for rice drought tolerance breeding, its large-scale deployment has remained limited, despite recent efforts to collect phenotypic data using various HTP platforms under controlled and field conditions. Breakthroughs in drought stress research, including genetic mapping and genomics studies have enabled the identification of important QTLs, genes, and superior alleles/haplotypes. A total of 55 mapping studies are available in rice, which have identified 1452 QTLs involving 263 major QTLs associated with diverse traits contributing to drought stress tolerance. In addition, around 305 cloned and/or characterized genes have been associated with drought-responsive traits in rice. Moreover, 81 important transgenes tested in rice have been shown to enhance drought resilience in transgenic rice plants. Additionally, direct selection for grain yield under drought and utilization of drought-yield QTLs in marker-assisted breeding programs, has resulted in the release of several drought-tolerant rice varieties across South and South–East Asia. Future research direction and the potential of emerging technologies to enhance drought tolerance in rice is emphasized. The holistic approach outlined guides future research and breeding endeavors, fostering sustainable and resilient rice production in the face of changing climatic conditions.