Gain-of-function mutations of AtNHX1 suppress sos1 salt sensitivity and improve salt tolerance in Arabidopsis

AbstractSoil salinity severely hampers agricultural productivity. Under salt stress, excess Na+ accumulation causes cellular damage and plant growth retardation, and membrane Na+ transporters play central roles in Na+ uptake and exclusion to mitigate these adverse effects. In this study, we performed sos1 suppressor mutant (named sup) screening to uncover potential genetic interactors of SOS1 and additional salt tolerance mechanisms. Map-based cloning and sequencing identified a group of mutants harboring dominant gain-of-function mutations in the vacuolar Na+/H+ antiporter gene AtNHX1. The gain-of-function variants of AtNHX1 showed enhanced transporter activities in yeast cells and increased salt tolerance in Arabidopsis wild type plants. Ion content measurements indicated that at the cellular level, these gain-of-function mutations resulted in increased cellular Na+ accumulation likely due to enhanced vacuolar Na+ sequestration. However, the gain-of-function suppressor mutants showed reduced shoot Na+ but increased root Na+ accumulation under salt stress, indicating a role of AtNHX1 in limiting Na+ translocation from root to shoot. We also identified another group of sos1 suppressors with loss-of-function mutations in the Na+ transporter gene AtHKT1. Loss-of-function mutations in AtHKT1 and gain-of-function mutations in AtNHX1 additively suppressed sos1 salt sensitivity, which indicates that the three transporters, SOS1, AtNHX1 and AtHKT1 function independently but coordinately in controlling Na+ homeostasis and salt tolerance in Arabidopsis. Our findings provide valuable information about the target amino acids in NHX1 for gene editing to improve salt tolerance in crops.

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Exogenous Melatonin Improves Salt Tolerance by Mitigating Osmotic, Ion, and Oxidative Stresses in Maize Seedlings

Agronomy ◽

10.3390/agronomy10050663 ◽

2020 ◽

Vol 10 (5) ◽

pp. 663 ◽

Cited By ~ 3

Author(s):

Jianhong Ren ◽

Jun Ye ◽

Lina Yin ◽

Gouxia Li ◽

Xiping Deng ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Antioxidant Activities ◽

Term Treatment ◽

Plant Tolerance ◽

Short Term Treatment ◽

Exogenous Melatonin ◽

Positive Effects ◽

Oxidative Stresses

Melatonin has been confirmed extensively for the positive effects on increasing plant tolerance to various abiotic stresses. However, the roles of melatonin in mediating different stresses still need to be explored in different plants species and growth periods. To investigate the role of melatonin in mitigating salt stress, maize (Zea mays L.) seedlings growing in hydroponic solution were treated with 100 mM NaCl combined with or without 1 μM melatonin. Melatonin application had no effects on maize growth under normal condition, while it moderately alleviated the NaCl-induced inhibition of plant growth. The leaf area, biomass, and photosynthesis of melatonin-treated plants were higher than that of without melatonin under NaCl treatment. The osmotic potential was lower, and the osmolyte contents (including sucrose and fructose) were higher in melatonin-treated plants. Meanwhile, the decreases in Na+ content and increases in K+/Na+ ratio were found in shoots of melatonin-applied plant under salt stress. Moreover, both enzymatic and nonenzymatic antioxidant activities were significantly increased in leaves with melatonin application under salt treatment. These results clearly indicate that the exogenous melatonin-enhanced salt tolerance under short-term treatment could be ascribed to three aspects, including osmotic adjustment, ion balance, and alleviation of salt-induced oxidative stress.

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Melatonin Improves Cotton Salt Tolerance by Regulating ROS Scavenging System and Ca2 + Signal Transduction

Frontiers in Plant Science ◽

10.3389/fpls.2021.693690 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yuexin Zhang ◽

Yapeng Fan ◽

Cun Rui ◽

Hong Zhang ◽

Nan Xu ◽

...

Keyword(s):

Signal Transduction ◽

Salt Stress ◽

Salt Tolerance ◽

Signal Molecules ◽

Protective Mechanism ◽

Rna Seq ◽

Ros Scavenging ◽

Exogenous Melatonin ◽

Endogenous Melatonin

As one of the cash crops, cotton is facing the threat of abiotic stress during its growth and development. It has been reported that melatonin is involved in plant defense against salt stress, but whether melatonin can improve cotton salt tolerance and its molecular mechanism remain unclear. We investigated the role of melatonin in cotton salt tolerance by silencing melatonin synthesis gene and exogenous melatonin application in upland cotton. In this study, applicating of melatonin can improve salt tolerance of cotton seedlings. The content of endogenous melatonin was different in cotton varieties with different salt tolerance. The inhibition of melatonin biosynthesis related genes and endogenous melatonin content in cotton resulted in the decrease of antioxidant enzyme activity, Ca2+ content and salt tolerance of cotton. To explore the protective mechanism of exogenous melatonin against salt stress by RNA-seq analysis. Melatonin played an important role in the resistance of cotton to salt stress, improved the salt tolerance of cotton by regulating antioxidant enzymes, transcription factors, plant hormones, signal molecules and Ca2+ signal transduction. This study proposed a regulatory network for melatonin to regulate cotton’s response to salt stress, which provided a theoretical basis for improving cotton’s salt tolerance.

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Overexpression of Peroxidase Gene GsPRX9 Confers Salt Tolerance in Soybean

International Journal of Molecular Sciences ◽

10.3390/ijms20153745 ◽

2019 ◽

Vol 20 (15) ◽

pp. 3745 ◽

Cited By ~ 4

Author(s):

Ting Jin ◽

Yangyang Sun ◽

Ranran Zhao ◽

Zhong Shan ◽

Junyi Gai ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Glycine Soja ◽

Primary Root ◽

Wild Soybean ◽

Plant Tolerance ◽

Salt Tolerant ◽

Fresh Weight ◽

Peroxidase Gene

Peroxidases play prominent roles in antioxidant responses and stress tolerance in plants; however, their functions in soybean tolerance to salt stress remain unclear. Here, we investigated the role of a peroxidase gene from the wild soybean (Glycine soja), GsPRX9, in soybean tolerance to salt stress. GsPRX9 gene expression was induced by salt treatment in the roots of both salt-tolerant and -sensitive soybean varieties, and its relative expression level in the roots of salt-tolerant soybean varieties showed a significantly higher increase than in salt-sensitive varieties after NaCl treatment, suggesting its possible role in soybean response to salt stress. GsPRX9-overexpressing yeast (strains of INVSc1 and G19) grew better than the control under salt and H2O2 stress, and GsPRX9-overexpressing soybean composite plants showed higher shoot fresh weight and leaf relative water content than control plants after NaCl treatment. Moreover, the GsPRX9-overexpressing soybean hairy roots had higher root fresh weight, primary root length, activities of peroxidase and superoxide dismutase, and glutathione level, but lower H2O2 content than those in control roots under salt stress. These findings suggest that the overexpression of the GsPRX9 gene enhanced the salt tolerance and antioxidant response in soybean. This study would provide new insights into the role of peroxidase in plant tolerance to salt stress.

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An Enhancer Mutant of Arabidopsis salt overly sensitive 3 Mediates both Ion Homeostasis and the Oxidative Stress Response

Molecular and Cellular Biology ◽

10.1128/mcb.01989-06 ◽

2007 ◽

Vol 27 (14) ◽

pp. 5214-5224 ◽

Cited By ~ 88

Author(s):

Jianhua Zhu ◽

Xinmiao Fu ◽

Yoon Duck Koo ◽

Jian-Kang Zhu ◽

Francis E. Jenney ◽

...

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Salt Stress ◽

Salt Tolerance ◽

Pdz Domain ◽

Ion Homeostasis ◽

Reactive Oxygen ◽

Salt Sensitivity ◽

Oxygen Species ◽

Isolation And Characterization

ABSTRACT The myristoylated calcium sensor SOS3 and its interacting protein kinase, SOS2, play critical regulatory roles in salt tolerance. Mutations in either of these proteins render Arabidopsis thaliana plants hypersensitive to salt stress. We report here the isolation and characterization of a mutant called enh1-1 that enhances the salt sensitivity of sos3-1 and also causes increased salt sensitivity by itself. ENH1 encodes a chloroplast-localized protein with a PDZ domain at the N-terminal region and a rubredoxin domain in the C-terminal part. Rubredoxins are known to be involved in the reduction of superoxide in some anaerobic bacteria. The enh1-1 mutation causes enhanced accumulation of reactive oxygen species (ROS), particularly under salt stress. ROS also accumulate to higher levels in sos2-1 but not in sos3-1 mutants. The enh1-1 mutation does not enhance sos2-1 phenotypes. Also, enh1-1 and sos2-1 mutants, but not sos3-1 mutants, show increased sensitivity to oxidative stress. These results indicate that ENH1 functions in the detoxification of reactive oxygen species resulting from salt stress by participating in a new salt tolerance pathway that may involve SOS2 but not SOS3.

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The role of the OsCam1-1 salt stress sensor in ABA accumulation and salt tolerance in rice

Journal of Plant Biology ◽

10.1007/s12374-011-0154-8 ◽

2012 ◽

Vol 55 (3) ◽

pp. 198-208 ◽

Cited By ~ 27

Author(s):

Sukhumaporn Saeng-ngam ◽

Warintra Takpirom ◽

Teerapong Buaboocha ◽

Supachitra Chadchawan

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Stress Sensor

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Endothelial Nitric Oxide Synthase (eNOS) S1176 phosphorylation status governs atherosclerotic lesion formation

10.1101/2022.01.13.476234 ◽

2022 ◽

Author(s):

Monica Y Lee ◽

Nur-Taz Rahman ◽

Bill Sessa

Keyword(s):

Atherosclerotic Plaque ◽

Phosphorylation Site ◽

Plaque Formation ◽

Mutant Mice ◽

Single Amino Acid ◽

No Production ◽

Loss Of Function ◽

Gain Of Function ◽

Atherosclerotic Plaque Formation

Objective: We have previously demonstrated the in vivo importance of the Akt-eNOS substratekinase relationship, as defective postnatal angiogenesis characteristic of global Akt1-null mice is rescued when bred to gain-of-function eNOS S1176D mutant mice. While multiple studies support the cardioprotective role of endothelial NO generation, the causal role of Akt1-dependent eNOS S1176 phosphorylation during atherosclerotic plaque formation is not yet clear. Approach & Results: We herein bred congenic loss-of-function eNOS S1176A and gain-of function eNOS S1176D mutant mice to the proatherogenic Akt1-/-; ApoE-/- double knockout mice to definitively test the importance of Akt-mediated eNOS S1176 phosphorylation during atherogenesis. We find that a single amino acid substitution at the eNOS S1176 phosphorylation site yields divergent effects on atherosclerotic plaque formation, as an eNOS phospho-mimic aspartate (D) substitution at S1176 leads to decreased indices of atherosclerosis, even when on a proatherogenic Akt1 global deletion background. Conversely, mice harboring an unphosphorylatable mutation to alanine (S1176A) result in increased lipid deposition and cellular apoptosis, phenocopying the physiological consequence of eNOS deletion and/or impaired enzyme function. Furthermore, gene expression analyses of whole aortas indicate a combinatorial detriment from NO deficiency and Western Diet challenge, as loss-of-function eNOS SA mice on a high-fat and high-cholesterol diet present a unique expression pattern indicative of augmented T-cell activity when compared to eNOS S1176D mice. Conclusions: By using genetic epistasis approaches, we conclusively demonstrate that Akt mediated eNOS S1176 phosphorylation and subsequent activation remains to be the most physiologically relevant method of NO production to promote cardioprotective effects.

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The role of the bifunctional enzyme, fructose-6-phosphate-2-kinase/fructose-2,6-bisphosphatase, in carbon partitioning during salt stress and salt tolerance in Rice (Oryza sativa L.)

Plant Science ◽

10.1016/j.plantsci.2008.11.009 ◽

2009 ◽

Vol 176 (3) ◽

pp. 334-341 ◽

Cited By ~ 12

Author(s):

Thanikarn Udomchalothorn ◽

Somporn Maneeprasobsuk ◽

Eakaphan Bangyeekhun ◽

Preeda Boon-Long ◽

Supachitra Chadchawan

Keyword(s):

Oryza Sativa ◽

Salt Stress ◽

Salt Tolerance ◽

Oryza Sativa L ◽

Carbon Partitioning ◽

Bifunctional Enzyme

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Anatomical Modifications in two Juncus Species under Salt Stress Conditions

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha43210108 ◽

2015 ◽

Vol 43 (2) ◽

pp. 501-506

Author(s):

Mohamad Al HASSAN ◽

Gholamreza GOHARI ◽

Monica BOSCAIU ◽

Oscar VICENTE ◽

Marius N. GRIGORE

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Stress Responses ◽

Stress Conditions ◽

Anatomic Structure ◽

Anatomical Structures ◽

Efficient Mechanism ◽

Damage Indicators ◽

As Stress

The anatomic structure of roots and culms of two Juncus species with different degrees of salt tolerance was analysed in plants grown for two months under salt stress (NaCl treatments) and in control, non-treated plants. The aim of the study was not only to compare the anatomical structures of a halophyte (J. acutus) and a related glycophyte (J. articulatus), but mostly to assess whether salt stress induced anatomical modifications, by identifying differences between control and treated plants. Several slight differences have been indeed detected, in terms of endodermis type, development of aerenchyma and extent of sclerenchyma in perivascular sheaths. The role of Casparian endodermis was here discussed in relation to its complex implications in controlling salt influx at the root level that is an efficient mechanism involved in halophytes. Aerenchyma is a common feature found in marshy halophytes, allowing them to survive naturally under flooding conditions; however, when occurring in non-waterlogged plants, as is the case of this study, it should be regarded as a genetically, constitutive adaptation rather than an inducible one. Nevertheless, such anatomic modifications should be regarded as mere alterations due to stress â€“ that is, as stress responses â€“ and not as truly adaptations to salinity. In this context, the nature of these modifications â€“ either considered as adaptations or damage indicators of salt stress â€“ should be further reconsidered.

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Insights into the Physiological and Biochemical Impacts of Salt Stress on Plant Growth and Development

Agronomy ◽

10.3390/agronomy10070938 ◽

2020 ◽

Vol 10 (7) ◽

pp. 938 ◽

Cited By ~ 7

Author(s):

Muhammad Adnan Shahid ◽

Ali Sarkhosh ◽

Naeem Khan ◽

Rashad Mukhtar Balal ◽

Shahid Ali ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Salinity Tolerance ◽

Antioxidant Activities ◽

Soil Salinization ◽

Crop Plants ◽

Cellular Damage ◽

Relative Water ◽

Ionic Imbalance ◽

Highly Correlated

Climate change is causing soil salinization, resulting in crop losses throughout the world. The ability of plants to tolerate salt stress is determined by multiple biochemical and molecular pathways. Here we discuss physiological, biochemical, and cellular modulations in plants in response to salt stress. Knowledge of these modulations can assist in assessing salt tolerance potential and the mechanisms underlying salinity tolerance in plants. Salinity-induced cellular damage is highly correlated with generation of reactive oxygen species, ionic imbalance, osmotic damage, and reduced relative water content. Accelerated antioxidant activities and osmotic adjustment by the formation of organic and inorganic osmolytes are significant and effective salinity tolerance mechanisms for crop plants. In addition, polyamines improve salt tolerance by regulating various physiological mechanisms, including rhizogenesis, somatic embryogenesis, maintenance of cell pH, and ionic homeostasis. This research project focuses on three strategies to augment salinity tolerance capacity in agricultural crops: salinity-induced alterations in signaling pathways; signaling of phytohormones, ion channels, and biosensors; and expression of ion transporter genes in crop plants (especially in comparison to halophytes).

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