Calcineurin B-Like Protein-Interacting Protein Kinase CIPK21 Regulates Osmotic and Salt Stress Responses in Arabidopsis

Abstract

The role of calcium-mediated signaling has been extensively studied in plant responses to abiotic stress signals. Calcineurin Blike proteins (CBLs) and CBL-interacting protein kinases (CIPKs) constitute a complex signaling network acting in diverse plant stress responses. Osmotic stress imposed by soil salinity and drought is a major abiotic stress that impedes plant growth and development and involves calcium-signaling processes. In this study, we report the functional analysis of CIPK21, an Arabidopsis (Arabidopsis thaliana) CBL-interacting protein kinase, ubiquitously expressed in plant tissues and up-regulated under multiple abiotic stress conditions. The growth of a loss-of-function mutant of CIPK21, cipk21, was hypersensitive to high salt and osmotic stress conditions. The calcium sensors CBL2 and CBL3 were found to physically interact with CIPK21 and target this kinase to the tonoplast. Moreover, preferential localization of CIPK21 to the tonoplast was detected under salt stress condition when coexpressed with CBL2 or CBL3. These findings suggest that CIPK21 mediates responses to salt stress condition in Arabidopsis, at least in part, by regulating ion and water homeostasis across the vacuolar membranes.

CIPK11-Dependent Phosphorylation Modulates FIT Activity to Promote Arabidopsis Iron Acquisition in Response to Calcium Signaling

“…Different signaling read-out could explain why the activity of AHA2 is increased under Fe deficiency, despite the activation of CIPK11. In this context, it is interesting to note that CBL2/3 affect CIPK21 activity (Pandey et al, 2015). An interaction of CIPK21 with FIT, as suggested by our work, would be interesting to study.…”

Identification of Submergence-Responsive MicroRNAs and Their Targets Reveals Complex MiRNA-Mediated Regulatory Networks in Lotus (Nelumbo nucifera Gaertn)

“…The down-regulation of NNU_ghr-miR393, NNU_gma-miR393h, and NNU_ata-miR393-5p resulted in increased expression level of TIR1 genes. We also identified the accumulation of two other genes including CIPK21 (Pandey et al, 2015) and SR160 (Scheer et al, 2003) which could enhance lotus stress tolerance due to a decrease of NNU_atr-miR397b and novel_mir_53 respectively.…”

AGlycine sojamethionine sulfoxide reductase B5a interacts with the Ca2+/CAM‐binding kinase GsCBRLKand activatesROSsignaling under carbonate alkaline stress

“…The most famous pathways are SOS3/ScaBP8–SOS2–SOS1 for salt stress (Liu et al ., ; Shi et al ., ; Qiu et al ., ; Kim et al ., ; Quan et al ., ; Lin et al ., ; Yu et al ., ; Zhao et al ., ; Ye et al ., ; Zhou et al ., ) and ScaBP1–PKS5/24–AHA2 for high‐pH stress (Fuglsang et al ., ; Du et al ., ; Liu and Guo, ; Liu et al ., ; Xu et al ., ; Lin et al ., ). Notably, the SOS3‐like Ca 2+ ‐binding proteins (SCaBPs) and SOS2‐like protein kinases (PKSs) are considered to play central roles during signal transduction under both salt and high‐pH stresses (Liu et al ., ; Kim et al ., ; Zhao et al ., ; Ye et al ., ; Pandey et al ., ). In Arabidopsis, SCaBPs could sense the increase in cytosolic Ca 2+ concentration caused by salt and high‐pH stresses that directly associated with and activated PKSs (Fuglsang et al ., ; Quan et al ., ; Lin et al ., , ; Du et al ., ).…”