Copper‐Zinc Superoxide Dismutases in Plants: Evolution, Enzymatic Properties, and Beyond

Abstract Superoxide dismutase (SOD) is a primary antioxidant enzyme that can be found in organisms from all kingdoms of life. Its date of origin indicates a pivotal role in the evolution of life on our planet. The SOD family is subdivided into different classes based upon the metal‐cofactor these enzymes use. In this article, we specifically emphasise the role and appearance of the youngest enzyme, copper‐zinc SOD (CuZnSOD). We discuss the evolution of CuZnSODs and the emergence of COPPER CHAPERONE FOR SUPEROXIDE DISMUTASE (CCS) proteins. SODs were initially appreciated for their antioxidant properties and potential to improve plant stress tolerance. However, recent findings indicate a role for SODs in maintaining reactive oxygen species (ROS) gradients to guide plant developmental processes. Moreover, after nearly 50 years of research on SODs, these enzymes still hold many surprises as evidenced by the recent finding that SOD in yeast acts as a transcriptional regulator. In this article, we aim at giving an overview of the current knowledge on SODs in plants and highlight avenues for future research endeavours, as there is still so much to learn.