Rice Science

Rice Science

• Review • Previous Articles     Next Articles

NRAMPs: Versatile Transporters Involved in Metal Ion Homeostasis and Their Applications in Rice Breeding

  1. China National Rice Research Institute, Hangzhou 310006, China; Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA; Crop Germplasm Innovation and Genetic Improvement Key Laboratory of Sichuan Province / Crop Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China; #These authors contributed equally to this work
  • Contact: HUANG Qina; LIANG Yan
  • Supported by:

    This study was supported by the National Key R&D program (Grant No. 2022YFD1201505), the Sichuan Financial Special Project, China (Grant No. 2021ZYGG-002), the Central Public-Interest Scientific Institution Basal Research Fund, China (Grant No. CPSIBRF-CNRRI-202306), and the Sichuan Provincial Financial Independent Innovation Project, China (Grant No. 2022ZZCX001). We thank the Public Laboratory of China National Rice Research Institute for their technical support in an experiment.

PDF

Supplement

1

Abstract: The NRAMP (natural resistance-associated macrophage protein) family plays a pivotal role in metal ion transport, regulating both essential micronutrient uptake (e.g., Fe, Mn, Zn) and toxic heavy metal accumulation (e.g., Cd, As, Pb) in plants. In rice (Oryza sativa), OsNRAMP transporters critically influence metal homeostasis, stress adaptation, and grain safety. Among them, OsNRAMP5 serves as a major entry point for Cd and Mn uptake, making it a prime target for low-Cd rice breeding. However, knockout of OsNRAMP5 leads to severe Mn deficiency, highlighting the need for precise genetic modifications (e.g. OsNRAMP5-Q337K) that reduce Cd accumulation while maintaining Mn nutrition. Additionally, OsNRAMP1 and OsNRAMP2 contribute to Cd translocation and plant immunity, whereas OsNRAMP3/4/6/7 participate in Mn, Fe, and Zn distribution and stress responses. This review systematically summarizes the structural, functional, and regulatory mechanisms of OsNRAMPs, emphasizing their roles in metal transport, pathogen resistance, and abiotic stress adaptation. Furthermore, we discuss strategies for developing low-Cd rice varieties, including QTL-based breeding, CRISPR/Cas9-mediated gene editing, and multi-gene stacking approaches. Finally, we outline future research directions, such as structural engineering of metal-binding sites and field validation of engineered rice lines, to ensure sustainable rice production in heavy metal-contaminated soils.

Key words: NRAMP transporter, metal homeostasis, cadmium regulatory network, low-Cd rice breeding