Ectopic expression of a maize calreticulin mitigates calcium deficiency-like disorders in sCAX1-expressing tobacco and tomato
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Deregulated expression of an Arabidopsis H+/Ca2+ antiporter (sCAX1) in agricultural crops increases total calcium (Ca2+) but may result in yield losses due to Ca2+ deficiency-like symptoms. Here we demonstrate that co-expression of a maize calreticulin (CRT, a Ca2+ binding protein located at endoplasmic reticulum) in sCAX1-expressing tobacco and tomato plants mitigated these adverse effects while maintaining enhanced Ca2+ 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 Ca2+ transporters and binding proteins at different intracellular compartments can alter the content and distribution of Ca2+ within the plant matrix.
KeywordsCalcium CAX CRT Co-expression Tomato
This research was supported by the Kansas State University AES project NAHF381121 (to SHP), the NIHHS RDA-KSU Cooperative Research Project (JSH) and the Technology Development Program for Agriculture and Forestry, Ministry of Agriculture and Forestry, Republic of Korea (CKK). We thank Dr. Wendy Boss for her inspiration and Dr. Staffan Persson (Max-Planck-Institute, Germany) for supplying the pE1775::CRT expression vector.
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