Calmodulin-like gene MtCML40 is involved in salt tolerance by regulating MtHKTs transporters in Medicago truncatula

Zhang, Xiuxiu; Wang, Tianzuo; Liu, Min; Sun, Wei; Zhang, Wenhao

doi:10.1016/j.envexpbot.2018.09.022

Cited by 39 publications

(26 citation statements)

References 67 publications

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“…Role of post translational modification was reported in Rice HKT1 under salt stress [32]. Recently, it has been shown in Medicago truncatula that overexpression of MtCML40 , a calmodulin-like protein, induced Na + accumulation in shoot and downregulated the expression of MtHKT transporters [33]. So, our results suggest that the significant involvement of other interactors or regulators in the expression of HKT1 other than promoter mediated induction.…”

Section: Discussionsupporting

confidence: 59%

Expression of the high-affinity K+ transporter 1 (PpHKT1) gene from almond rootstock ‘Nemaguard’ improved salt tolerance of transgenic Arabidopsis

et al. 2019

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Soil salinity affects plant growth and development, which directly impact yield. Plants deploy many mechanisms to cope with, or mitigate, salt stress. One of such mechanism is to control movement of ions from root to shoot by regulating the loading of Na+ in the transpiration stream. The high-affinity K+ transporter 1 (HKT1) is known to play a role in the removal of Na+ from the xylem and bring it back to the root. As almond is a salt-sensitive crop, the rootstock plays an important role in successful almond cultivation in salt-affected regions. We currently lack knowledge on the molecular mechanisms involved in salt tolerance of almond rootstocks. In this study, we complemented the Arabidopsis athkt1 knockout mutant with HKT1 ortholog (PpHKT1) from the almond rootstock ‘Nemaguard’. Arabidopsis transgenic lines that were generated in athkt1 background with the constitutive promoter (PpHKT1OE2.2) and the native promoter (PpHKT1NP6) were subjected to different salt treatments. Both transgenic lines survived salt concentrations up to 120 mM NaCl, however, the mutant athkt1 died after 18 days under 120 mM NaCl. At 90 mM NaCl, the dry weight of athkt1 decreased significantly compared to the transgenic lines. Both transgenic lines showed significantly longer lateral roots compared to the athkt1 mutant at 80 mM NaCl treatment. The transgenic lines, PpHKT1OE2.2 and PpHKTNP6 had lower electrolyte leakage and higher relative water content compared to athkt1, suggesting that transgenic plants coped well with increased salt concentration by maintaining the integrity of the membranes. The expression analyses showed that PpHKT1 was induced in PpHKT1OE2.2 and PpHKTNP6 lines under salt treatment, which confirmed that both over-expression and native expression of PpHKT1 in the Arabidopsis mutant can complement salt tolerance function.

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Section: Discussionsupporting

confidence: 59%

Expression of the high-affinity K+ transporter 1 (PpHKT1) gene from almond rootstock ‘Nemaguard’ improved salt tolerance of transgenic Arabidopsis

et al. 2019

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“…79 Consistently, a recent report has revealed that MtCML40 in MediCago truncatula triggers a salt stress response by targeting MtHKT-dependent Na + accumulation. 80 As Ca 2+ has potentially displayed an array of physiological roles in both signaling and nutrient uptake, HKT could be considered as a Ca 2+ mediating candidate in modulation of plant growth and development under salt stress. 75 Na + /H + (NHX) transporter has been suggested as a salt tolerance responsive transporter, since its overexpression is associated with increased tolerance to salt stress and conversely, plants with truncated NHX exhibit decreased tolerance.…”

Section: Ca +2 Signaling and Regulation Of Ion Channels Under Salt Stmentioning

confidence: 99%

Calcium signaling and salt tolerance are diversely entwined in plants

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Aliniaeifard

Shomali

et al. 2019

Plant Signaling & Behavior

144

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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.

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“…Regulation of Salt-Responsive Genes by CAMTA6: The HKT1;1 Gene as a Case Study HKT1;1 is an Na + /K + transporter that plays an important role in plant responses to salt stress (Rus et al, 2001;Laurie et al, 2002) and whose expression is regulated by both NaCl and ABA (Shkolnik-Inbar et al, 2013;Zhang et al, 2019). Here, we tested the importance of CAMTA6 in the regulation of HKT1;1.…”

Section: Phenotypes Of Camta6 Mutants: Salt Tolerance During Early Gementioning

confidence: 99%

“…To date, in Arabidopsis, the major focus has been on investigating the roles of CAMTA1 (Kaplan et al, 2006;Galon et al, 2010;Kim et al, 2013;Pandey et al, 2013), CAMTA3 (Galon et al, 2008;Du et al, 2009;Laluk et al, 2012;Kim et al, 2013Kim et al, , 2017Jacob et al, 2018), and to a lesser extent CAMTA2 (Kim et al, 2013(Kim et al, , 2017 and CAMTA5 (Kidokoro et al, 2017), whereas the functions of Arabidopsis CAMTA4 and CAMTA6 remain unclear. In Medicago truncatula, overexpression of the CaM-like protein MtCML40 resulted in down-regulation of the expression of MtHKT1;1 and MtHKT1;2 (Zhang et al, 2019), both of which encode proteins associated with Na + removal from the shoot, and caused enhanced sensitivity to salt at germination. Thus, Ca 2+ signaling is involved in maintaining Na + homeostasis during germination, partly by regulation of HKT1 expression.…”

mentioning

confidence: 99%

CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR 6: A Key Regulator of Na⁺ Homeostasis during Germination

et al. 2019

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Salinity impairs seed germination and seedling establishment. We investigated the role of Arabidopsis (Arabidopsis thaliana) CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR 6 (CAMTA6) in salinity stress responses during early germination. Compared with the wild type, the camta6-4 and camta6-5 mutants were more tolerant to NaCl and abscisic acid (ABA) and accumulated less Na +. In contrast, 4-to 11-d-old camta6 seedlings were more sensitive to NaCl. In camta6, expression of HIGH-AFFINITY K + TRANSPORTER1 (AtHKT1;1), encoding an Na + /K + transporter, was restricted to the radicles and was not enhanced by NaCl or ABA. During germination, the camta6 hkt1 double mutant was as sensitive as the wild type and hkt1 to NaCl, suggesting that HKT1;1 is crucial for the salt tolerance of camta6. An ABA response element in the HKT1;1 promoter was found to be indispensable for the enhanced expression of the gene in response to NaCl and to ABA. Transcriptome analysis of the wild type and camta6-5 with and without salt treatment revealed 1,020 up-regulated and 1,467 down-regulated saltresponsive genes in the wild type. Among these, 638 up-regulated and 1,242 down-regulated genes were classified as CAMTA6-dependent. Expression of several known salt stress-associated genes, including SALT OVERLY SENSITIVE1 and Na + /H + ANTIPORTER, was impaired in camta6 mutants. Bioinformatics analysis of the 59 upstream sequences of the saltresponsive CAMTA6-dependent up-regulated genes revealed the CACGTGTC motif as the most prominent element, representing an ABA response element and a potential CAMTA-binding site. We suggest that CAMTA6 regulates, directly or indirectly, the expression of most of the salt-responsive genes in germinating seeds, including genes that are crucial for Na + homeostasis and salt stress tolerance.

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Calmodulin-like gene MtCML40 is involved in salt tolerance by regulating MtHKTs transporters in Medicago truncatula

Cited by 39 publications

References 67 publications

Expression of the high-affinity K+ transporter 1 (PpHKT1) gene from almond rootstock ‘Nemaguard’ improved salt tolerance of transgenic Arabidopsis

Expression of the high-affinity K+ transporter 1 (PpHKT1) gene from almond rootstock ‘Nemaguard’ improved salt tolerance of transgenic Arabidopsis

Calcium signaling and salt tolerance are diversely entwined in plants

CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR 6: A Key Regulator of Na⁺ Homeostasis during Germination

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Calmodulin-like gene MtCML40 is involved in salt tolerance by regulating MtHKTs transporters in Medicago truncatula

Cited by 39 publications

References 67 publications

Expression of the high-affinity K+ transporter 1 (PpHKT1) gene from almond rootstock ‘Nemaguard’ improved salt tolerance of transgenic Arabidopsis

Expression of the high-affinity K+ transporter 1 (PpHKT1) gene from almond rootstock ‘Nemaguard’ improved salt tolerance of transgenic Arabidopsis

Calcium signaling and salt tolerance are diversely entwined in plants

CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR 6: A Key Regulator of Na+ Homeostasis during Germination

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CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR 6: A Key Regulator of Na⁺ Homeostasis during Germination