Metal tolerance protein MTP6 affects mitochondrial iron and manganese homeostasis in cucumber

NOTICE: The Editor-in-Chief and Publisher of Journal of Experimental Botany have taken the decision to retract the article related to this dataset due to concern over image manipulation and duplication. Please note, Dryad cannot verify whether the underlying data published is reliable for reuse. Visit this link to view the retraction notice and concerns raised: https://doi.org/10.1093/jxb/ery342

Members of the cation diffusion facilitator family have been identified in all kingdoms of life. They have been divided into three subgroups – Zn-CDF, Fe/Zn-CDF and Mn-CDF – based on their putative specificity to transported metal ions. The plant metal tolerance 6 (MTP6) proteins fall into the Fe/Zn-CDF subgroup, however their function in iron/zinc transport has not been confirmed yet. Here we characterize the MTP6 protein from cucumber. When expressed in yeast and protoplasts isolated from A. thaliana cells, CsMTP6 localized in mitochondria and contributed to the efflux of iron and manganese from the mitochondria. The immunolocalization of CsMTP6 in cucumber membranes confirmed that CsMTP6 is associated with mitochondria. The root expression and protein level of CsMTP6 were significantly up-regulated in conditions of iron deficiency and iron excess but were not affected by Mn availability. These results indicate that plant MTP6 proteins contribute to the distribution of iron and manganese between the cytosol and mitochondria of plant cells and are regulated by Fe to maintain the mitochondrial and cytosolic iron homeostasis under various Fe availability.