Skip Navigation



Molecular Plant Advance Access published online on October 21, 2009
Molecular Plant, doi:10.1093/mp/ssp084
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary Data
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Cohu, C. M.
Right arrow Articles by Pilon, M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2009. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPP and IPPE, SIBS, CAS.

Copper Delivery by the Copper Chaperone for Chloroplast and Cytosolic Copper/Zinc-Superoxide Dismutases: Regulation and Unexpected Phenotypes in an Arabidopsis Mutant

Christopher M. Cohua, Salah E. Abdel-Ghanya, Kathryn A. Gogolin Reynoldsa, Alexander M. Onofrioa, Jared R. Bodeckera, Jeffrey A. Kimbrela, Krishna K. Niyogib and Marinus Pilona,1

a Biology Department, Colorado State University, Fort Collins, CO 80523-1878, USA
b Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA

1 To whom correspondence should be addressed. E-mail pilon{at}lamar.colostate.edu, fax 970-491-0649, tel. 970-491-0803.

Copper (Cu) is an important mineral nutrient found in chloroplasts as a cofactor associated with plastocyanin and Cu/Zn superoxide dismutase (Cu/ZnSOD). Superoxide dismutases are metallo-enzymes found in most oxygenic organisms with proposed roles in reducing oxidative stress. Several recent studies in Arabidopsis have shown that microRNAs and a SQUAMOSA promoter binding protein-like7 (SPL7) transcription factor function to down-regulate the expression of many Cu-proteins, including Cu/ZnSOD in both plastids and the cytosol, during growth on low Cu. Plants contain the Cu Chaperone for SOD (CCS) that delivers Cu to Cu/ZnSODs, and, in Arabidopsis, both cytosolic and plastidic CCS versions are encoded by one gene. In this study, we demonstrate that Arabidopsis CCS transcript levels are regulated by Cu, mediated by microRNA 398 that was not previously predicted to target CCS. The microRNA target site is conserved in CCS of Oryza sativa. The data suggest that Cu-regulated microRNAs may have more mRNA targets than was previously predicted. A CCS null mutant has no measurable SOD activity in the chloroplast and cytosol, indicating an absolute requirement for CCS. When the CCS null mutant was grown on high Cu media, it lacked both Fe superoxide dismutase (FeSOD) and Cu/ZnSOD activity. However, this did not lead to a visual phenotype and no photosynthetic deficiencies were detected, even after high light stress. These results indicate that Cu/ZnSOD is not a pivotal component of the photosynthetic anti-oxidant system during growth in laboratory conditions.

Key Words: Chloroplast • photosynthesis • copper homeostasis • superoxide dismutase • microRNA


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.