Decoding Phosphorus Metabolism in Black Rice: Molecular Pathways and Nutritional Implications

Phosphorus (P) is an essential macronutrient crucial for rice growth and productivity, yet its limited availability in soils significantly restricts yield potential. Black rice ( Oryza sativa L.), a pigmented landrace enriched in anthocyanins and micronutrients, thrives in P-deficient and low-input ecosystems. This makes it a unique genetic resource for exploring how nutrient signaling intersects with secondary metabolism to enhance both stress adaptation and nutritional quality. This review summarizes recent advances in understanding the molecular and physiological mechanisms underlying phosphorus acquisition, transport, and utilization in black rice. It focuses on key allelic variations in phosphorus transporters ( OsPHT1;2 , OsPHT1;8 , OsPHO1;2 ), transcription factors ( OsPHR2 , OsWRKY74) , and regulatory modules such as SPX-domain proteins and the miR399–PHO2–IPS1 signaling pathway. The review also highlights the integration of these phosphorus-regulatory networks with anthocyanin biosynthesis genes (DFR, LDOX, OsC1), and discusses the genomic loci (Pup1 and others) influencing root architecture and ionome traits that enhance phosphorus-use efficiency.Black rice demonstrates superior phosphorus uptake, redistribution, and stress signaling efficiency due to its unique genetic and regulatory features. Phosphorus deficiency not only activates adaptive nutrient acquisition pathways but also enhances the accumulation of anthocyanins, thereby improving the crop’s antioxidant capacity and nutraceutical value. The convergence of nutrient signaling with secondary metabolism underscores black rice’s dual potential as a functional food and a breeding reservoir for developing P-efficient, stress-resilient rice varieties. Future research should focus on integrating multi-omics data, validating candidate genes, and translating laboratory insights into field-level applications for sustainable rice improvement.