|Wu, Qingyu -|
|Shigaki, Toshiro -|
|Han, Jeun-Sul -|
|Kim, Chang Kil -|
|Hirschi, Kendal -|
|Park, Sunghun -|
Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 14, 2012
Publication Date: September 25, 2012
Citation: Wu, Q., Shigaki, T., Han, J., Kim, C., Hirschi, K.D., Park, S. 2012. Ectopic expression of a maize calreticulin mitigates calcium deficiency-like disorders in "sCAX1"-expressing tobacco and tomato. Plant Molecular Biology. 80(6):609-619. Interpretive Summary: Our goal is to improve the calcium content in crops while maintaining high yields. Sometimes single modifications that improve calcium content can impair plant growth. Here we have devised a "gene stacking" approach that adds two modifications to improve calcium content and maintain plant vigor. This approach of using two means to improve the calcium content in the plant appears to provide a synergistic effect. Each manipulation appears to buffer against the deleterious effects of the other modification. The "stacked" plants grow better when plants with single modification and higher calcium content have either of these traits expressed. This fundamental research can now be applied to numerous crops to boost calcium content and assure high plant yields.
Technical Abstract: Deregulated expression of an Arabidopsis H(+)/Ca(2+) antiporter (sCAX1) in agricultural crops increases total calcium (Ca(2+)) but may result in yield losses due to Ca(2+) deficiency-like symptoms. Here we demonstrate that co-expression of a maize calreticulin (CRT, a Ca(2+) binding protein located at endoplasmic reticulum) in sCAX1-expressing tobacco and tomato plants mitigated these adverse effects while maintaining enhanced Ca(2+) content. Co-expression of CRT and sCAX1 could alleviate the hypersensitivity to ion imbalance in tobacco plants. Furthermore, blossom-end rot (BER) in tomato may be linked to changes in CAX activity and enhanced CRT expression mitigated BER in sCAX1 expressing lines. These findings suggest that co-expressing Ca(2+) transporters and binding proteins at different intracellular compartments can alter the content and distribution of Ca(2+) within the plant matrix.