The Ca-Regulated Protein Kinase CIPK1 Modulates Plant Response to Nitrate Deficiency in .

BACKGROUND/OBJECTIVES: Nitrogen is an essential macroelement for plant growth and productivity. Calcium (Ca) acts as a critical second messenger in numerous adaptations and developmental processes in plants. The Calcineurin B-like protein (CBL)-interacting protein kinase (CIPK) signaling pathway has been demonstrated to be involved in multiple intracellular ion homeostasis of plants in response to stresses. However, whether CIPKs are involved in nitrate deficiency stress remains largely unknown.

METHODS

In this study, we screened T-DNA insertion mutants of the CIPK family under nitrate deficiency conditions by a reverse genetic strategy.

RESULTS

We found that the mutant showed a shorter primary root and had a lower fresh weight and total N content compared with wildtype (WT) plants under nitrate deficiency. The complementation lines completely rescued the sensitive phenotype. Additionally, mutation caused nitrogen-starvation marker genes to be decreased under nitrate deficiency. We further found that CIPK1 interacted with teosintebranched 1/cycloidea/proliferating cell factor 1-20 (TCP20) in a yeast two-hybrid system.

CONCLUSIONS

Collectively, our results reveal a novel role of CIPK1 in response to nitrate deficiency in .