Exposure of Arabidopsis thaliana to excess Zn reveals a Zn-specific oxidative stress signature

► In roots, excess Zn affects Mg uptake, glutathione reductase activity and GSH levels. ► Zn excess disturbs the connected regulation of Cu/ZnSOD and FeSOD mRNA levels. ► Total MIR398 transcription was upregulated instead of the expected downregulation. ► Oppositely regulated miR398 subspecies may explain opposite CSD1 and CSD2 expression. ► Evidence of Zn-specific signal transduction pathways influencing anti-oxidative responses.