The Mechanism of Adaptation to Copper Deficient Conditions via microRNA in Arabidopsis

Abstract

Copper is an essential trance metal for all living organisms. Cu/Zn superoxide dismutases (CSD1 and CSD2) are involved in the scavenging of reactive oxygen species in cytosol and chloroplast respectively and their expression is down-regulated under copper deficient conditions. In this work, we demonstrated that one of microRNA, miR398, was expressed under low-copper conditions, and degraded CSD1 and CSD2 mRNA directly. In addition, iron superoxide dismutase (FeSOD) is expressed instead of Cu/ZnSODs and completes the function under copper deficient conditions. On the other hand, plastocyanin (PC) involved in photosynthetic electron flow is transcribed constitutively in any copper conditions. From our results, we propose that copper is preferentially transferred to PC under copper deficient conditions, and miR398 is involved in this regulation.