A barley mutant with improved salt tolerance through ion homeostasis and ROS scavenging under salt stress

Nowadays, crop insufficiency resulting from soil salinization is threatening the world. On the basis that soil salinization has become a worldwide problem, studying the mechanisms of plant salt tolerance is of great theoretical and practical significance to improve crop yield, to cultivate new salt-tolerant varieties, and to make full use of saline land. Based on previous studies, this paper reviews the damage of salt stress to plants, including suppression of photosynthesis, disturbance of ion homeostasis, and membrane peroxidation. We have also summarized the physiological mechanisms of salt tolerance, including reactive oxygen species (ROS) scavenging and osmotic adjustment. Four main stress-related signaling pathways, salt overly sensitive (SOS) pathway, calcium-dependent protein kinase (CDPK) pathway, mitogen-activated protein kinase (MAPKs) pathway, and abscisic acid (ABA) pathway, are included. We have also enumerated some salt stress-responsive genes that correspond to physiological mechanisms. In the end, we have outlined the present approaches and techniques to improve salt tolerance of plants. All in all, we reviewed those aspects above, in the hope of providing valuable background knowledge for the future cultivation of agricultural and forestry plants.

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The Biochemical Mechanisms of Salt Tolerance in Plants

10.5772/intechopen.101048 ◽

2021 ◽

Author(s):

Julio Armando Massange-Sánchez ◽

Carla Vanessa Sánchez-Hernández ◽

Rosalba Mireya Hernández-Herrera ◽

Paola Andrea Palmeros-Suárez

Keyword(s):

Salt Stress ◽

Crop Yields ◽

Membrane Damage ◽

Ion Homeostasis ◽

Antioxidant Compounds ◽

Plant Tolerance ◽

Ros Scavenging ◽

Dna Structures ◽

Biochemical Mechanisms ◽

Scavenging Enzymes

Salinity is one of the most severe environmental problems worldwide and affects plant growth, reproduction, and crop yields by inducing physiological and biochemical changes due to osmotic and ionic shifts in plant cells. One of the principal modifications caused by osmotic stress is the accumulation of reactive oxygen species (ROS), which cause membrane damage and alter proteins, DNA structures, and photosynthetic processes. In response, plants increase their arsenal of antioxidant compounds, such as ROS scavenging enzymes and nonenzymatic elements like ascorbate, glutathione, flavonoids, tocopherols, and carotenoids, and their rates of osmolyte synthesis to conserve ion homeostasis and manage salt stress. This chapter describes the principal biochemical mechanisms that are employed by plants to survive under salt-stress conditions, including the most recent research regarding plant tolerance, and suggests strategies to produce valuable crops that are able to deal with soil salinity.

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Transcriptomic Profiling Identifies Candidate Genes Involved in the Salt Tolerance of the Xerophyte Pugionium cornutum

Genes ◽

10.3390/genes10121039 ◽

2019 ◽

Vol 10 (12) ◽

pp. 1039 ◽

Cited By ~ 1

Author(s):

Yan-Nong Cui ◽

Fang-Zhen Wang ◽

Cheng-Hang Yang ◽

Jian-Zhen Yuan ◽

Huan Guo ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Candidate Genes ◽

Osmotic Adjustment ◽

Assimilation Efficiency ◽

Carbon Assimilation ◽

Ros Scavenging ◽

Transport Pathway ◽

Genes Encoding ◽

Assimilation Capacity

The xerophyte Pugionium cornutum adapts to salt stress by accumulating inorganic ions (e.g., Cl−) for osmotic adjustment and enhancing the activity of antioxidant enzymes, but the associated molecular basis remains unclear. In this study, we first found that P. cornutum could also maintain cell membrane stability due to its prominent ROS-scavenging ability and exhibits efficient carbon assimilation capacity under salt stress. Then, the candidate genes associated with the important physiological traits of the salt tolerance of P. cornutum were identified through transcriptomic analysis. The results showed that after 50 mM NaCl treatment for 6 or 24 h, multiple genes encoding proteins facilitating Cl− accumulation and NO3− homeostasis, as well as the transport of other major inorganic osmoticums, were significantly upregulated in roots and shoots, which should be favorable for enhancing osmotic adjustment capacity and maintaining the uptake and transport of nutrient elements; a large number of genes related to ROS-scavenging pathways were also significantly upregulated, which might be beneficial for mitigating salt-induced oxidative damage to the cells. Meanwhile, many genes encoding components of the photosynthetic electron transport pathway and carbon fixation enzymes were significantly upregulated in shoots, possibly resulting in high carbon assimilation efficiency in P. cornutum. Additionally, numerous salt-inducible transcription factor genes that probably regulate the abovementioned processes were found. This work lays a preliminary foundation for clarifying the molecular mechanism underlying the adaptation of xerophytes to harsh environments.

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Comprehensive analysis of transcriptional regulation and functional genes induced by alkaline salt stress in roots of two switchgrass (Panicum virgatum L.) genotypes

10.21203/rs.3.rs-57429/v1 ◽

2020 ◽

Author(s):

Pan Zhang ◽

Tianqi Duo ◽

Fengdan Wang ◽

Xunzhong Zhang ◽

Zouzhuan Yang ◽

...

Keyword(s):

Transcriptional Regulation ◽

Salt Stress ◽

Salt Tolerance ◽

Ion Homeostasis ◽

Comprehensive Analysis ◽

Functional Genes ◽

Antioxidant Systems ◽

Limiting Factor ◽

Rna Seq ◽

Alkaline Salt

Abstract Background: Soil salinization is a major limiting factor for crop cultivation. Switchgrass is a perennial rhizomatous bunchgrass that is considered an ideal plant for marginal lands, including sites with saline soil. Here, we investigated the physiological responses and transcriptome changes in the roots of two switchgrass genotypes under alkaline salt stress.Results: Alkaline salt stress significantly affected the membrane, osmotic adjustment and antioxidant systems in switchgrass roots, and the ASTTI values between Alamo and AM-314/MS-155 were divergent at different time points. A total of 108,319 unigenes were obtained after reassembly, including 73,636 unigenes in AM-314/MS-155 and 65,492 unigenes in Alamo. A total of 10,219 DEGs were identified, and the number of upregulated genes in Alamo was much greater than that in AM-314/MS-155 in both the early and late stages of alkaline salt stress. The DEGs in AM-314/MS-155 were mainly concentrated in the early stage, while Alamo showed greater advantages in the late stage. These DEGs were mainly enriched in plant-pathogen interactions, ubiquitin-mediated proteolysis and glycolysis/gluconeogenesis pathways. We characterized 1,480 TF genes into 64 TF families, and the most abundant TF family was the C2H2 family, followed by the bZIP and bHLH families. A total of 1,718 PKs were predicted, including CaMK, CDPK, MAPK and RLK. WGCNA revealed that the DEGs in the blue, brown, dark magenta and light steel blue 1 modules were associated with the physiological changes in roots of switchgrass under alkaline salt stress. The consistency between the qRT-PCR and RNA-Seq results confirmed the reliability of the RNA-seq sequencing data. A molecular regulatory network of the switchgrass response to alkaline salt stress was preliminarily constructed on the basis of transcriptional regulation and functional genes.Conclusions: The alkaline salt tolerance of switchgrass may be achieved by the regulation of ion homeostasis, transport proteins, detoxification, heat shock proteins, dehydration and sugar metabolism. These findings provide a comprehensive analysis of gene transcription and regulation induced by alkaline salt stress in two switchgrass genotypes and contribute to the understanding of the alkaline salt tolerance mechanism of switchgrass and the improvement of switchgrass germplasm.

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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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Transcriptomic profiling identifies candidate genes involved in salt tolerance of the xerophyte Pugionium cornutum

10.21203/rs.2.14265/v1 ◽

2019 ◽

Author(s):

Yan-Nong Cui ◽

Fang-Zhen Wang ◽

Cheng-Hang Yang ◽

Jian-Zhen Yuan ◽

Huan Guo ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Candidate Genes ◽

Molecular Mechanisms ◽

Carbon Fixation ◽

Assimilation Efficiency ◽

Carbon Assimilation ◽

Inorganic Ions ◽

Ros Scavenging ◽

Genes Encoding

Abstract Background: Pugionium cornutum is a xerophytic plant that primarily adapts to salt stress by accumulating inorganic ions (e.g., Cl-) for osmoregulation, improving its reactive oxygen species (ROS)-scavenging ability and maintaining high photosynthetic carbon assimilation efficiency, but the associated molecular mechanisms still remain unclear. Results: Here, we present an analysis of gene responses to salt stress based on the transcriptome of P. cornutum exposed to 50 mM NaCl treatment. The data revealed that, after NaCl treatment for 6 or 24 h, the transcript levels of multiple genes encoding proteins facilitating Cl- accumulation and NO3- homeostasis such as SLAH1, CLCg, CCC1, and NPF6.4, as well as the transport of other major inorganic osmoticums were significantly upregulated in roots and shoots, which should be favorable to enhancing osmotic adjustment capacity and maintaining the plant uptake and transport of nutrient elements; a large number of genes related to ROS-scavenging pathways were also significantly upregulated, which should be beneficial for mitigating salt-induced oxidative damage to the cell metabolism. Meanwhile, many genes encoding components of the photosynthetic electron transport and carbon fixation enzymes were significantly upregulated in shoots after salt treatment, possibly resulting in a high carbon assimilation efficiency in P. cornutum. Additionally, numerous salt-inducible transcription factor genes probably regulating the abovementioned processes were found. Conclusion: Candidate genes involved in salt tolerance of P. cornutum were identified, which lays a preliminary foundation for clarifying the molecular mechanism of the xerophytes adapting to harsh environments.

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The RNA-seq transcriptomic analysis reveals genes mediating salt tolerance through rapid triggering of ion transporters in a mutant barley

10.21203/rs.2.10262/v1 ◽

2019 ◽

Author(s):

Sareh Yousefirad ◽

Hassan Soltanloo ◽

Sayad Sanaz Ramezanpour ◽

Khalil Zaynalinezhad ◽

Vahid Shariati

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Ion Homeostasis ◽

High Ratio ◽

Rna Seq ◽

Ion Transporters ◽

Wild Type ◽

Specific Expression ◽

Mutant Genotype ◽

In The Wild

Abstract Regarding the complexity of the mechanisms of salinity tolerance, the use of isogenic lines or mutants that have the same genetic background but show different tolerance to salinity is a suitable method to reduce the analytical complexity to study these mechanisms. In the current study, whole transcriptome analysis was evaluated using RNA-seq method between a salt-tolerant mutant line “73-M4-30” and its wild-type “Zarjou” cultivar at a seedling stage after six hours of exposure to salt stress (300 mM NaCl). Transcriptome sequencing yielded 20 million reads for each genotype. A total number of 7116 transcripts with differential expression were identified, 1586 and 1479 of which were obtained with significantly increased expression in the mutant and the wild-type, respectively. In addition, the families of WRKY, ERF, AP2/EREBP, NAC, CTR/DRE, AP2/ERF, MAD, MIKC, HSF, and bZIP were identified as the important transcription factors with specific expression in the mutant genotype. The RNA-seq results were confirmed in several time points using qRT-PCR of some important salt-responsive genes. In general, the results revealed that the mutant compared to its wild-type via fast stomach closure and consequently transpiration reduction under the salt stress, saved more sodium ion in the root and decreased its transfer to the shoot, and increased the amount of potassium ion leading to the maintenance a high ratio [K+]/[Na+] in the shoot. Moreover, it caused a reduction in photosynthesis and respiration, resulting in the use of the stored energy and the carbon for maintaining the plant tissues, which is a mechanism of salt tolerance in plants. Up-regulation of catalase, peroxidase, and ascorbate peroxidase genes, which was probably due to the more accumulation of H2O2 in the wild-type compared to the mutant. Therefore, the wild-type initiated rapid ROS signals lead to less oxidative scavenging than the mutant. The mutant increased expression in the ion transporters and the channels related to the salinity to retain the ion homeostasis. Totally, the results demonstrated that the mutant responded better to the salt stress under both the osmotic and the ionic stress phases. Less damage was observed in the mutant compared to its wild-type under the salt stress.

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The ThSOS3 Gene Improves the Salt Tolerance of Transgenic Tamarix hispida and Arabidopsis thaliana

Frontiers in Plant Science ◽

10.3389/fpls.2020.597480 ◽

2021 ◽

Vol 11 ◽

Author(s):

Zhongyuan Liu ◽

Qingjun Xie ◽

Feifei Tang ◽

Jing Wu ◽

Wenfang Dong ◽

...

Keyword(s):

Enzyme Activity ◽

Salt Stress ◽

Salt Tolerance ◽

Antioxidant Enzyme ◽

Electrolyte Leakage ◽

Transgenic Arabidopsis ◽

Antioxidant Enzyme Activity ◽

Tamarix Hispida ◽

Ros Scavenging ◽

Salt Stress Response

The salt overly sensitive (SOS) signal transduction pathway is one of the most highly studied salt tolerance pathways in plants. However, the molecular mechanism of the salt stress response in Tamarix hispida has remained largely unclear. In this study, five SOS genes (ThSOS1–ThSOS5) from T. hispida were cloned and characterized. The expression levels of most ThSOS genes significantly changed after NaCl, PEG6000, and abscisic acid (ABA) treatment in at least one organ. Notably, the expression of ThSOS3 was significantly downregulated after 6 h under salt stress. To further analyze ThSOS3 function, ThSOS3 overexpression and RNAi-mediated silencing were performed using a transient transformation system. Compared with controls, ThSOS3-overexpressing transgenic T. hispida plants exhibited greater reactive oxygen species (ROS)-scavenging capability and antioxidant enzyme activity, lower malondialdehyde (MDA) and H2O2 levels, and lower electrolyte leakage rates under salt stress. Similar results were obtained for physiological parameters in transgenic Arabidopsis, including H2O2 and MDA accumulation, superoxide dismutase (SOD) and peroxidase (POD) activity, and electrolyte leakage. In addition, transgenic Arabidopsis plants overexpressing ThSOS3 displayed increased root growth and fresh weight gain under salt stress. Together, these data suggest that overexpression of ThSOS3 confers salt stress tolerance on plants by enhancing antioxidant enzyme activity, improving ROS-scavenging capability, and decreasing the MDA content and lipid peroxidation of cell membranes. These results suggest that ThSOS3 might play an important physiological role in salt tolerance in transgenic T. hispida plants. This study provides a foundation for further elucidation of salt tolerance mechanisms involving ThSOSs in T. hispida.

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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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Early effects of salt stress on the physiological and oxidative status of the halophyte Lobularia maritima

Functional Plant Biology ◽

10.1071/fp19303 ◽

2020 ◽

Vol 47 (10) ◽

pp. 912

Author(s):

Anis Ben Hsouna ◽

Thaura Ghneim-Herrera ◽

Walid Ben Romdhane ◽

Amira Dabbous ◽

Rania Ben Saad ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Expression Profiles ◽

Ion Homeostasis ◽

Accumulation Pattern ◽

Moderate Salinity ◽

Lobularia Maritima ◽

Early Effects ◽

Stress Related Genes ◽

Ionic Imbalance

Soil salinity is an abiotic stress that reduces agricultural productivity. For decades, halophytes have been studied to elucidate the physiological and biochemical processes involved in alleviating cellular ionic imbalance and conferring salt tolerance. Recently, several interesting genes with proven influence on salt tolerance were isolated from the Mediterranean halophyte Lobularia maritima (L.) Desv. A better understanding of salt response in this species is needed to exploit its potential as a source of stress-related genes. We report the characterisation of L. maritima’s response to increasing NaCl concentrations (100–400 mM) at the physiological, biochemical and molecular levels. L. maritima growth was unaffected by salinity up to 100 mM NaCl and it was able to survive at 400 mM NaCl without exhibiting visual symptoms of damage. Lobularia maritima showed a Na+ and K+ accumulation pattern typical of a salt-includer halophyte, with higher contents of Na+ in the leaves and K+ in the roots of salt-treated plants. The expression profiles of NHX1, SOS1, HKT1, KT1 and VHA-E1 in salt-treated plants matched this Na+ and K+ accumulation pattern, suggesting an important role for these transporters in the regulation of ion homeostasis in leaves and roots of L. maritima. A concomitant stimulation in phenolic biosynthesis and antioxidant enzyme activity was observed under moderate salinity, suggesting a potential link between the production of polyphenolic antioxidants and protection against salt stress in L. maritima. Our findings indicate that the halophyte L. maritima can rapidly develop physiological and antioxidant mechanisms to adapt to salt and manage oxidative stress.

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