Roles of plant CBL–CIPK systems in abiotic stress responses

Abstract

IntroductionPlants have to endure various abiotic and biotic stresses as they cannot move to favorable environments. Stresses, including salt, drought, cold, low nutrition, viruses, and other pathogen attacks, have a great impact on seed germination, seedling growth, photosynthesis, and biomass accumulation (Zhou et al., 2014). Fortunately, plants have acquired the ability to sense, deliver, and respond to stresses at the molecular, cellular, and physiological levels during evolution (Li et al., 2009). External stimuli could change the concentration of calcium ion (Ca 2+ ), an acknowledged ubiquitous second messenger, which can be perceived by sensor proteins. Following sensing, a series of molecular, physiological, and biochemical reactions are triggered to cope with the stimuli. There are mainly three Ca 2+ sensor protein families: calmodulins (CaMs), calcineurin B-like proteins (CBLs), and calcium-dependent protein kinases (CDPKs) (Snedden and Fromm, 2001). CBLs interact and activate CBL-interacting protein kinases (CIPKs), forming the CBL-CIPK complex, which could help plants cope with different stresses. Moreover, the CBL-CIPK module plays an important role in plant growth and development (Pandey, 2014;.Comparative analyses have provided detailed information of the structure and function of the CBL/ CIPK family in various plants. Recent studies identified 10

Advances in Sensing, Response and Regulation Mechanism of Salt Tolerance in Rice

“…CBLs are plant-specific Ca 2+ sensors that bind with CIPKs to relay perceived Ca 2+ signal, thereby inducing downstream gene regulation for abiotic stress. The SOS3–SOS2 complex is the first evidence of CBL–CIPK interaction in plant responses to salt stress [ 121 ]. Homologues of SOS2 and SOS3 in rice, the OsCIPK24 and OsCBL4 , have been cloned, which suggests that the SOS pathway also operates in rice responses to salt stress [ 122 ].…”

Recent Advances on Cellular Signaling Paradigm and Salt Stress Responsive Genes in Halophytes

“…The activated complex of SOS3 and SOS2 gets phosphorylated along with SOS1; this triggers the SOS1 activity initiating an efflux of excess Na + from the cell (Nikalje et al 2017). Thus, the CIPK24/SOS2 and CBL4/SOS3 complex regulates the PMbound Na + /H + antiporter (SOS1) activity in roots and confreres the salt tolerance (Kudla et al 2010), whereas CBL10-CIPK24 complex regulates the shoot SOS1 activity in salt stress (Huang et al 2019). Interestingly, the CIPK24 can phosphorylate the CBL10 protein and stabilize the complex at PM, thereby conferring salt tolerance (Huang et al 2019).…”

“…Thus, the CIPK24/SOS2 and CBL4/SOS3 complex regulates the PMbound Na + /H + antiporter (SOS1) activity in roots and confreres the salt tolerance (Kudla et al 2010), whereas CBL10-CIPK24 complex regulates the shoot SOS1 activity in salt stress (Huang et al 2019). Interestingly, the CIPK24 can phosphorylate the CBL10 protein and stabilize the complex at PM, thereby conferring salt tolerance (Huang et al 2019). Moreover, CIPK24/SOS2 interacts with nucleoside triphosphate kinase 2 (NDPK2), further maintaining the ROS signaling cascade and catalyzing the enzyme activity (CAT2 and CAT3) (Verslues et al 2007).…”

“…These findings suggested that CIPK24/SOS2 kinase is an important regulatory node in the stress signaling network. Besides the SOS signaling components, CIPK orthologs were identified, which worked independently from the SOS pathway required for salt tolerance (Huang et al 2019). The CIPK controls the K + transporter, including AKT1 (Huang et al 2019).…”

“…Besides the SOS signaling components, CIPK orthologs were identified, which worked independently from the SOS pathway required for salt tolerance (Huang et al 2019). The CIPK controls the K + transporter, including AKT1 (Huang et al 2019). However, the regulation of K + homeostasis through the SOS pathway was poorly understood.…”