The copper microRNAs

Summary Copper (Cu) micro RNA s are upregulated by Cu deficiency and mediate the post‐transcriptional downregulation of transcripts that encode Cu proteins, suggesting a role directly related to Cu. However, expression and phenotypic analyses of copper micro RNA mutants and over‐expressors have suggested roles mainly in tolerance to abiotic stresses. To reconcile available data, a model is proposed which emphasizes the mobile nature of copper micro RNA molecules in the regulation of Cu homeostasis. It is proposed that the Cu‐micro RNA regulatory circuits are further co‐opted by plants to regulate both beneficial and pathogenic interactions with microbes. Further exploration of Cu‐micro RNA functions that account for the cell‐to‐cell mobility should give novel insight into plant microbe interactions and the integration of micronutrition and development.ContentsSummary 1030 I. Introduction 1030 II. The discovery of the copper microRNAs 1030 III. Conservation and diversity of Cu‐microRNAs and their targets 1031 IV. The expression and regulation of the Cu‐microRNAs 1031 V. Towards biological functions of Cu‐microRNAs 1032 VI. Integrating local Cu homeostasis and development in plants 1033 VII. Functions of Cu‐microRNAs in biotic interactions 1034 VIII. Conclusions 1034Acknowledgements 1034References 1034