Calcium signaling and salt tolerance are diversely entwined in plants

Abstract

In plants dehydration imposed by salinity can invoke physical changes at the interface of the plasma membrane and cell wall. Changes in hydrostatic pressure activate ion channels and cause depolarization of the plasma membrane due to disturbance in ion transport. During the initial phases of salinity stress, the relatively high osmotic potential of the rhizosphere enforces the plant to use a diverse spectrum of strategies to optimize water and nutrient uptake. Signals of salt stress are recognized by specific root receptors that activate an osmosensing network. Plant response to hyperosmotic tension is closely linked to the calcium (Ca 2+) channels and interacting proteins such as calmodulin. A rapid rise in cytosolic Ca 2+ levels occurs within seconds of exposure to salt stress. Plants employ multiple sensors and signaling components to sense and respond to salinity stress, of which most are closely related to Ca 2+ sensing and signaling. Several tolerance strategies such as osmoprotectant accumulation, antioxidant boosting, polyaminses and nitric oxide (NO) machineries are also coordinated by Ca 2+ signaling. Substantial research has been done to discover the salt stress pathway and tolerance mechanism in plants, resulting in new insights into the perception of salt stress and the downstream signaling that happens in response. Nevertheless, the role of multifunctional components such as Ca 2+ has not been sufficiently addressed in the context of salt stress. In this review, we elaborate that the salt tolerance signaling pathway converges with Ca 2+ signaling in diverse pathways. We summarize knowledge related to different dimensions of salt stress signaling pathways in the cell by emphasizing the administrative role of Ca 2+ signaling on salt perception, signaling, gene expression, ion homeostasis and adaptive responses.

Identification and Validation a Major QTL from “Sea Rice 86” Seedlings Conferred Salt Tolerance

“…Numerous potential salt-responsive genes are located within qST1.1, which contains 198 ORFs, including 34 retrotransposon proteins, 26 transposon proteins, 57 expressed proteins, 9 hypothetical proteins, 7 peroxidase precursors, 5 transcription factors (TFs), namely OsMADS89 (LOC_Os01g18440), OsWRKY9 (LOC_Os01g18584), OsSPL12 (LOC_Os01g18850), OsMYB78L (LOC_Os01g19330), and OsMYBL (LOC_Os01g19970), and other genes such as PIF1 family genes, and protein kinase genes. Transcription factors play an essential role in rice development and responses to biotic and abiotic stresses [36][37][38][39]; these five TFs have been reported to respond to salt stress in rice to varying degrees [40,41]. The reactive oxygen species signaling pathway mediated by peroxidase was also critical, as it evoked a cascade of responses related to stress tolerance [42][43][44].…”

Changes in Expression Level of OsHKT1;5 Alters Activity of Membrane Transporters Involved in K+ and Ca2+ Acquisition and Homeostasis in Salinized Rice Roots

“…Salinity-induced elevation in the cytosolic free Ca 2+ is an essential component of salt-stress signaling [52]. Amongst other things, such signaling is essential for the activation of the SOS1 Na + /H + exchanger that operates in the removal of excessive Na + from the cytosol [5].…”

Ca2+/Calmodulin Complex Triggers CAMTA Transcriptional Machinery Under Stress in Plants: Signaling Cascade and Molecular Regulation

“…Much evidence indicates that Ca 2+ -mediated signaling is implicated in the relay of stress signals such as light ( Kim et al, 2003 ; Liang et al, 2009 ; Hochmal et al, 2015 ; Hou et al, 2019 ), temperature ( Teige, 2019 ), salt ( Rahman A. et al, 2016 ; Manishankar et al, 2018 ; Seifikalhor et al, 2019 ), cold ( Shi et al, 2014 ; Yuan et al, 2018b ), and gravity ( Kordyum, 2003 ; Toyota et al, 2008 ; Salmi et al, 2011 ); oxidative signals such as pathogen attack ( Kiep et al, 2015 ; Aldon et al, 2018 ; Tian et al, 2019 ) and reactive oxygen species ( Mori and Schroeder, 2004 ; Monshausen et al, 2009 ; Kurusu et al, 2015 ); and hormone signals such as ethylene ( Li et al, 2018 ; Zhu et al, 2018 ), abscisic acid (ABA) ( Edel and Kudla, 2016 ; Chen et al, 2017 ; Yuenyong et al, 2018 ), gibberellins ( Abbasi et al, 2004 ; Nakata et al, 2009 ; Li et al, 2013 ), and auxins ( Vanneste and Friml, 2013 ; Hazak et al, 2019 ). In plants, oodles of Ca 2+ -binding proteins function as Ca 2+ sensors decoding complex Ca 2+ signatures ( Kudla et al, 2018 ).…”