Molecular physiology of aluminum toxicity and tolerance in rice

Aluminum (Al 3+ ) toxicity in rice plants is a significant concern in acidic soils, particularly in Southeast Asia, where large areas of arable land are affected. This is an environmental and agricultural hazard that severely reduces rice yields, leading to food scarcity, as rice is the dietary food of half of the world’s population. The study highlights current knowledge of Al 3+ interactions with growth-restricting factors, adaptive mechanisms in rice, and progress in identifying Al 3+ tolerance genes. Al 3+ -induced organic acid exudation, such as citrate and malate mediated by OsFRDL4 , involves complex signaling cascade with phytohormones, yet transmembrane signaling remains poorly understood. We describe the regulation of novel genes such as ART1, Nrat1, STAR1 and STAR2 at transcriptional level to reveal their role in Al 3+ tolerance. Additionally, microbial interactions in acidic soils and the contribution of root border cells to Al 3+ tolerance are discussed. While many QTLs associated with Al 3+ tolerance have been mapped across rice populations, candidate gene identification and functional validation are still lacking. Integrating genomic, physiological, and microbial insights will be critical for advancing rice breeding programs aimed at enhancing Al 3+ tolerance and ensuring sustainable production in acidic soils.