The Transcription Factor OsNAC5 Mediates Cadmium Stress Response and Accumulation in Rice

Cadmium (Cd) is a toxic heavy metal that endangers human health via contaminated rice consumption. Reduction Cd uptake in rice is essential for minimizing grain Cd accumulation. However, the transcriptional regulatory of Cd uptake in rices remains largely elusive. This study reveals that the transcription factor OsNAC5 in Oryza sativa positively regulates the Cd transporter gene OsNRAMP1, influencing Cd uptake. OsNAC5 is primarily expressed in roots, localized to the nucleus and is upregulated by Cd induced H2O2. OsNAC5 knockout reduces Cd levels in both shoots and roots and increases Cd sensitivity. OsNRAMP1 expression, enhanced by Cd stress, dependents on OsNAC5, which binds to CATGTG motifs in the OsNRAMP1 promoters activating its expression. Loss of OsNAC5 function decreases Cd accumulation in rice grains. Our findings elucidate the transcriptional regulation of Cd stress response in rice and suggest biotechnological approaches to reduce Cd uptake in crops.