Potassium nutrition, sodium toxicity, and calcium signaling: connections through the CBL-CIPK network. Curr Opin Plant Biol

Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
Current opinion in plant biology (Impact Factor: 7.85). 07/2009; 12(3):339-46. DOI: 10.1016/j.pbi.2009.05.003
Source: PubMed


Plant roots take up numerous minerals from the soil. Some minerals (e.g., K(+)) are essential nutrients and others (e.g., Na(+)) are toxic for plant growth and development. In addition to the absolute level, the balance among the minerals is critical for their physiological functions. For instance, [K(+)]/[Na(+)] ratio and homeostasis often determine plant growth rate. Either low-K or high-Na in the soil represents a stress condition that severely affects plant life and agricultural production. Earlier observations indicated that higher soil Ca2(+) improve plants growth under low-K or high-Na condition, implying functional interaction among the three cations. Recent studies have begun to delineate the signaling mechanisms underlying such interactions. Either low-K(+) or high-Na(+) can trigger cellular Ca2(+) changes that lead to activation of complex signaling networks. One such network consists of Ca2(+) sensor proteins (e.g., CBLs) interacting with their target kinases (CIPKs). The CBL-CIPK signaling modules interact with and regulate the activity of a number of transporting proteins involved in the uptake and translocation of K(+) and Na(+), maintaining the "balance" of these cations in plants under stress conditions.

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    • "AtCIPK23 can also phosphorylate T101 of CHL1 to maintain a low-level primary response in response to low nitrate concentrations (Yu et al., 2014). Additionally, some CIPK family genes have been shown to be involved in other developmental processes and hormone signaling, including auxin and abscisic acid (ABA; Luan et al., 2009; Weinl and Kudla, 2009). AtCIPK26 plays an important role in ABA signaling in seed germination by interacting with ABI1, ABI2, and ABI5 (Lyzenga et al., 2013). "
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    ABSTRACT: Cassava is an important food and potential biofuel crop that is tolerant to multiple abiotic stressors. The mechanisms underlying these tolerances are currently less known. CBL-interacting protein kinases (CIPKs) have been shown to play crucial roles in plant developmental processes, hormone signaling transduction, and in the response to abiotic stress. However, no data is currently available about the CPK family in cassava. In this study, a total of 25 CIPK genes were identified from cassava genome based on our previous genome sequencing data. Phylogenetic analysis suggested that 25 MeCIPKs could be classified into four subfamilies, which was supported by exon-intron organizations and the architectures of conserved protein motifs. Transcriptomic analysis of a wild subspecies and two cultivated varieties showed that most MeCIPKs had different expression patterns between wild subspecies and cultivatars in different tissues or in response to drought stress. Some orthologous genes involved in CIPK interaction networks were identified between Arabidopsis and cassava. The interaction networks and co-expression patterns of these orthologous genes revealed that the crucial pathways controlled by CIPK networks may be involved in the differential response to drought stress in different accessions of cassava. Nine MeCIPK genes were selected to investigate their transcriptional response to various stimuli and the results showed the comprehensive response of the tested MeCIPK genes to osmotic, salt, cold, oxidative stressors, and ABA signaling. The identification and expression analysis of CIPK family suggested that CIPK genes are important components of development and multiple signal transduction pathways in cassava. The findings of this study will help lay a foundation for the functional characterization of the CIPK gene family and provide an improved understanding of abiotic stress responses and signaling transduction in cassava.
    Full-text · Article · Oct 2015 · Frontiers in Plant Science
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    • "Genetic and biochemical tactics with SOS mutants presented a molecular mechanism in which the CBL-CIPK complex mediates the salt stressinduced Ca 2+ signal and shows tolerance to salt [41]. Under salt stress situation, this pathway can enhance salt tolerance in plant by multiple ways; for example, it can allow transporter to send back Na + into soil, sequester sodium ion into vacuole, or transport it to the older leaves [24]. The SOS pathway is mainly based on SOS3 (AtCBL4), SOS2 (AtCIPK24), and the plasma membrane Na + /K + antiporter; SOS1, a combined component pathway, plays a vital role in effluxing Na + from the cell through SOS1; thus it can enhance the salt tolerance of plants [40]. "
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    ABSTRACT: Abiotic stress halts the physiological and developmental process of plant. During stress condition, CBL-CIPK complex is identified as a primary element of calcium sensor to perceive environmental signals. Recent studies established that this complex regulates downstream targets like ion channels and transporters in adverse stages conditions. Crosstalks between the CBL-CIPK complex and different abiotic stresses can extend our research area, which can improve and increase the production of genetically modified crops in response to abiotic stresses. How this complex links with environmental signals and creates adjustable circumstances under unfavorable conditions is now one of the burning issues. Diverse studies are already underway to delineate this signalling mechanism underlying different interactions. Therefore, up to date experimental results should be concisely published, thus paving the way for further research. The present review will concisely recapitulate the recent and ongoing research progress of positive ions (Mg 2+ , Na + , and K + ), negative ions ( NO 3 - , PO 4 - ), and hormonal signalling, which are evolving from accumulating results of analyses of CBL and CIPK loss- or gain-of-function experiments in different species along with some progress and perspectives of our works. In a word, this review will give one step forward direction for more functional studies in this area.
    Full-text · Article · Oct 2015 · International Journal of Genomics
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    • "The Dionaea trap Na + channel is capable of processing prey-derived sodium loads While K + is the most abundant cation in the cytoplasm of plant cells, typically reaching about 100 mM, Na + is highly toxic even at low mM cytosolic concentrations (Kingsbury and Epstein, 1986; Luan et al., 2009). The key to salt tolerance is to sequester the Na + taken up by the plant to the vacuoles or transfer it to older tissues (Blumwald, 2000; Munns and Tester, 2008). "
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    ABSTRACT: The animal diet of the carnivorous Venus flytrap, Dionaea muscipula comes with a sodium load that enters the capture organ via a HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analysed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modelling, generation of model-derived point mutants and their functional testing in Xenopus oocytes. We showed that wildtype HKT1 and its Na(+) and K(+) permeable mutants, functions as ion channels rather than K(+) transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na(+)-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action-potential-based information management of the flytrap.
    Full-text · Article · Oct 2015 · Molecular Plant
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