A calcium signalling network activates vacuolar K+ remobilization to enable plant adaptation to low-K environments

  title={A calcium signalling network activates vacuolar K+ remobilization to enable plant adaptation to low-K environments},
  author={Ren-Jie Tang and Fugeng Zhao and Yang Yang and Chao Wang and Kunlun Li and Thomas J. Kleist and Peggy G. Lemaux and Sheng Luan},
  journal={Nature Plants},
  pages={384 - 393}
Potassium (K) is an essential nutrient, but levels of the free K ions (K+) in soil are often limiting, imposing a constant stress on plants. We have discovered a calcium (Ca2+)-dependent signalling network, consisting of two calcineurin B-like (CBL) Ca2+ sensors and a quartet of CBL-interacting protein kinases (CIPKs), which plays a key role in plant response to K+ starvation. The mutant plants lacking two CBLs (CBL2 and CBL3) were severely stunted under low-K conditions. Interestingly, the… 

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The role of the Ca2+-CBL-CIPK pathway in cellular osmoregulation and homeostasis on exposure to nutrient excess or deprived soils is discussed and a link between taking up the nutrient in the roots and its distribution and homeOSTasis during the generation of signal for the development and survival of plants is established.

The protein kinase SlCIPK23 boosts K+ and Na+ uptake in tomato plants.

The contribution of the voltage-gated K+ channel LKT1 and the protein kinase SlCIPK23 to K+ uptake in tomato plants is studied by analyzing gene-edited knock-out tomato mutant lines, together with two-electrode voltage-clamp experiments in Xenopus oocytes and protein-protein interaction analyses.

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W Whole-plant physiological studies revealed that Oscipk9 rice mutant lacks a functional CIPK9 gene and displayed a mildly stronger phenotype, both under saline and osmotic stress conditions, suggesting an important role of H2O2 signalling as a component of plant adaptive responses to a low-K environment.

A voltage-dependent Ca2+ -homeostat operates in the plant vacuolar membrane.

Cytosolic calcium signals are evoked by a large variety of biotic and abiotic stimuli and play an important role in cellular and long distance signaling in plants. While the function of the plasma

Potassium in plant physiological adaptation to abiotic stresses

Rice Potassium Transporter OsHAK8 Mediates K+ Uptake and Translocation in Response to Low K+ Stress

This study has identified the function of the rice K+ transporter OsHAK8, whose expression level is downregulated in response to low-K+ stress, and proposes that OsHAk8 serves as a major transporter for both uptake and root-to-shoot translocation in rice plants.

Regulation Of Root Nutrient Transporters By CIPK23: "One Kinase To Rule Them All".

This review will chiefly report on the prominent roles of CIPK23 in the regulation of plant nutrient transporters and on the underlying molecular mechanisms.



A Ca2+ signaling pathway regulates a K+ channel for low-K response in Arabidopsis

It is shown that the protein kinase CIPK23 interacted with, and phosphorylated, a voltage-gated inward K+ channel (AKT1) required for K+ acquisition in Arabidopsis, confirming that the Ca2+-CBL-CIPK pathway functions to orchestrate transporting activities in planta according to external K+ availability.

The CBL-Interacting Protein Kinase CIPK23 Regulates HAK5-Mediated High-Affinity K+ Uptake in Arabidopsis Roots1[OPEN]

In vitro experiments show that the N terminus of HAK5 is phosphorylated by CIPK23, which supports the idea that phosphorylation of H AK5 induces a conformational change that increases its affinity for K+.

Tonoplast calcium sensors CBL2 and CBL3 control plant growth and ion homeostasis through regulating V-ATPase activity in Arabidopsis

It is suggested that calcium sensors CBL2 and CBL3 serve as molecular links between calcium signaling and V-ATPase, a central regulator of intracellular ion homeostasis.

Tonoplast CBL–CIPK calcium signaling network regulates magnesium homeostasis in Arabidopsis

This study uncovered a regulatory mechanism, consisting of two calcineurin B-like (CBL) Ca sensors partnering with four CBL-interacting protein kinases (CIPKs) forming a CBL–CipK network that allows plant cells to sequester the extra Mg2+ into vacuoles, thereby protecting plants from high-Mg toxicity.

Two calcineurin B-like calcium sensors, interacting with protein kinase CIPK23, regulate leaf transpiration and root potassium uptake in Arabidopsis.

Results imply that plasma membrane-localized CBL1- and CBL9-CIPK23 complexes simultaneously regulate K+ transport processes in roots and in stomatal guard cells.

The two-pore channel TPK1 gene encodes the vacuolar K+ conductance and plays a role in K+ homeostasis

The Arabidopsis thaliana genome contains five genes that encode two pore K+ (TPK) channels. The most abundantly expressed isoform of this family, TPK1, is expressed at the tonoplast where it mediates

Two spatially and temporally distinct Ca2+ signals convey Arabidopsis thaliana responses to K+ deficiency.

Together, these findings identify a critical role of cell group-specific Ca2+ signaling in low K+ responses and indicate an essential and direct role of Ca2- signals for AKT1 K+ channel activation in roots.

Molecular mechanisms involved in plant adaptation to low K(+) availability.

This review is focused on the different physiological responses induced by K(+) deprivation, their underlying molecular events, and the present knowledge and hypotheses regarding the mechanisms responsible for K(+ sensing and signalling.

CIPK9: a calcium sensor-interacting protein kinase required for low-potassium tolerance in Arabidopsis

It is reported here the identification of a calcineurin B-like protein-interacting protein kinase (CIPK9) as a critical regulator of low potassium response in Arabidopsis, which was responsive to abiotic stress conditions, and its transcript was inducible in both roots and shoots by potassium deprivation.