Functional characterization of PeNRAMP5 implies its potential role in controlling cadmium accumulation in plants.

Abstract

Reducing cadmium (Cd) accumulation in plants by disrupting transporter genes involved in Cd uptake or transport often compromises normal plant growth due to the co‑transport of essential elements. Therefore, identifying genes that specifically reduce Cd accumulation without impairing micronutrient uptake remains challenging. Here, we identified and functionally characterized two duplicated Moso bamboo genes, PeNRAMP5-1 and PeNRAMP5-2. Both genes are predominantly expressed in roots, downregulated by Cd, and encode plasma membrane‑localized transporters. Immunostaining revealed non polar distribution of PeNRAMP5 proteins in all root cells. Yeast assays demonstrated their ability to transport both Cd and Mn. Expression them in rice mutant osnramp5 increased root Cd uptake but reduced Cd accumulation in shoots and grains. In contrast, root Mn uptake and accumulation in shoots and grains were largely restored. When expressed in the mutant atnramp1 or wild‑type Arabidopsis, these genes markedly enhanced root Mn uptake and its accumulation in shoots. Conversely, although Cd accumulation in roots increased, shoots Cd accumulation was strongly inhibited. These results suggest that PeNRAMP5 can limit Cd accumulation in shoots while restoring Mn uptake in plants. This work identifies PeNRAMP5 as a promising genetic resource for inter‑species application to minimize Cd accumulation and maintain Mn nutrition in plants.