A Golgi-Localized Sodium/Hydrogen Exchanger Positively Regulates Salt Tolerance by Maintaining Higher K+/Na+ Ratio in Soybean

Salt stress caused by soil salinization, is one of the main factors that reduce soybean yield and quality. A large number of genes have been found to be involved in the regulation of salt tolerance. In this study, we characterized a soybean sodium/hydrogen exchanger gene GmNHX5 and revealed its functional mechanism involved in the salt tolerance process in soybean. GmNHX5 responded to salt stress at the transcription level in the salt stress-tolerant soybean plants, but not significantly changed in the salt-sensitive ones. GmNHX5 was located in the Golgi apparatus, and distributed in new leaves and vascular, and was induced by salt treatment. Overexpression of GmNHX5 improved the salt tolerance of hairy roots induced by soybean cotyledons, while the opposite was observed when GmNHX5 was knockout by CRISPR/Cas9. Soybean seedlings overexpressing GmNHX5 also showed an increased expression of GmSOS1, GmSKOR, and GmHKT1, higher K+/Na+ ratio, and higher viability when exposed to salt stress. Our findings provide an effective candidate gene for the cultivation of salt-tolerant germplasm resources and new clues for further understanding of the salt-tolerance mechanism in plants.

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A Glycine max sodium/hydrogen exchanger enhances salt tolerance through maintaining higher Na+ efflux rate and K+/Na+ ratio in Arabidopsis

BMC Plant Biology ◽

10.1186/s12870-019-2084-4 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 4

Author(s):

Tian-Jie Sun ◽

Long Fan ◽

Jun Yang ◽

Ren-Zhi Cao ◽

Chun-Yan Yang ◽

...

Keyword(s):

Salt Stress ◽

Glycine Max ◽

Salt Tolerance ◽

Stress Condition ◽

Wild Type ◽

Efflux Rate ◽

Salt Treatment ◽

Salt Stress Condition ◽

Sodium Hydrogen ◽

High K

Abstract Background Soybean (Glycine max (L.)) is one the most important oil-yielding cash crops. However, the soybean production has been seriously restricted by salinization. It is therefore crucial to identify salt tolerance-related genes and reveal molecular mechanisms underlying salt tolerance in soybean crops. A better understanding of how plants resist salt stress provides insights in improving existing soybean varieties as well as cultivating novel salt tolerant varieties. In this study, the biological function of GmNHX1, a NHX-like gene, and the molecular basis underlying GmNHX1-mediated salt stress resistance have been revealed. Results We found that the transcription level of GmNHX1 was up-regulated under salt stress condition in soybean, reaching its peak at 24 h after salt treatment. By employing the virus-induced gene silencing technique (VIGS), we also found that soybean plants became more susceptible to salt stress after silencing GmNHX1 than wild-type and more silenced plants wilted than wild-type under salt treatment. Furthermore, Arabidopsis thaliana expressing GmNHX1 grew taller and generated more rosette leaves under salt stress condition compared to wild-type. Exogenous expression of GmNHX1 resulted in an increase of Na+ transportation to leaves along with a reduction of Na+ absorption in roots, and the consequent maintenance of a high K+/Na+ ratio under salt stress condition. GmNHX1-GFP-transformed onion bulb endothelium cells showed fluorescent pattern in which GFP fluorescence signals enriched in vacuolar membranes. Using the non-invasive micro-test technique (NMT), we found that the Na+ efflux rate of both wild-type and transformed plants after salt treatment were significantly higher than that of before salt treatment. Additionally, the Na+ efflux rate of transformed plants after salt treatment were significantly higher than that of wild-type. Meanwhile, the transcription levels of three osmotic stress-related genes, SKOR, SOS1 and AKT1 were all up-regulated in GmNHX1-expressing plants under salt stress condition. Conclusion Vacuolar membrane-localized GmNHX1 enhances plant salt tolerance through maintaining a high K+/Na+ ratio along with inducing the expression of SKOR, SOS1 and AKT1. Our findings provide molecular insights on the roles of GmNHX1 and similar sodium/hydrogen exchangers in regulating salt tolerance.

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Phosphoproteomic Analysis of Two Contrasting Maize Inbred Lines Provides Insights into the Mechanism of Salt-Stress Tolerance

International Journal of Molecular Sciences ◽

10.3390/ijms20081886 ◽

2019 ◽

Vol 20 (8) ◽

pp. 1886 ◽

Cited By ~ 7

Author(s):

Xiaoyun Zhao ◽

Xue Bai ◽

Caifu Jiang ◽

Zhen Li

Keyword(s):

Salt Stress ◽

Inbred Line ◽

Carbon Metabolism ◽

Phosphoenolpyruvate Carboxykinase ◽

Glutathione Metabolism ◽

Label Free ◽

Plasma Membrane Intrinsic Protein ◽

Sodium Hydrogen ◽

Salt Response ◽

Sodium Hydrogen Exchanger

Salinity is a major abiotic stress that limits maize yield and quality throughout the world. We investigated phosphoproteomics differences between a salt-tolerant inbred line (Zheng58) and a salt-sensitive inbred line (Chang7-2) in response to short-term salt stress using label-free quantitation. A total of 9448 unique phosphorylation sites from 4116 phosphoproteins in roots and shoots of Zheng58 and Chang7-2 were identified. A total of 209 and 243 differentially regulated phosphoproteins (DRPPs) in response to NaCl treatment were detected in roots and shoots, respectively. Functional analysis of these DRPPs showed that they were involved in carbon metabolism, glutathione metabolism, transport, and signal transduction. Among these phosphoproteins, the expression of 6-phosphogluconate dehydrogenase 2, pyruvate dehydrogenase, phosphoenolpyruvate carboxykinase, glutamate decarboxylase, glutamate synthase, l-gulonolactone oxidase-like, potassium channel AKT1, high-affinity potassium transporter, sodium/hydrogen exchanger, and calcium/proton exchanger CAX1-like protein were significantly regulated in roots, while phosphoenolpyruvate carboxylase 1, phosphoenolpyruvate carboxykinase, sodium/hydrogen exchanger, plasma membrane intrinsic protein 2, glutathione transferases, and abscisic acid-insensitive 5-like protein were significantly regulated in shoots. Zheng58 may activate carbon metabolism, glutathione and ascorbic acid metabolism, potassium and sodium transportation, and the accumulation of glutamate to enhance its salt tolerance. Our results help to elucidate the mechanisms of salt response in maize seedlings. They also provide a basis for further study of the mechanism underlying salt response and tolerance in maize and other crops.

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Transcriptomic Analysis of Betula halophila in Response to Salt Stress

International Journal of Molecular Sciences ◽

10.3390/ijms19113412 ◽

2018 ◽

Vol 19 (11) ◽

pp. 3412 ◽

Cited By ~ 10

Author(s):

Fenjuan Shao ◽

Lisha Zhang ◽

Iain Wilson ◽

Deyou Qiu

Keyword(s):

Cell Wall ◽

Salt Stress ◽

Salt Tolerance ◽

Expression Patterns ◽

Soil Salinization ◽

Sphingolipid Metabolism ◽

Sequencing Platform ◽

Resistant Varieties ◽

High Salt Tolerance ◽

Salt Overly Sensitive

Soil salinization is a matter of concern worldwide. It can eventually lead to the desertification of land and severely damage local agricultural production and the ecological environment. Betula halophila is a tree with high salt tolerance, so it is of importance to understand and discover the salt responsive genes of B. halophila for breeding salinity resistant varieties of trees. However, there is no report on the transcriptome in response to salt stress in B. halophila. Using Illumina sequencing platform, approximately 460 M raw reads were generated and assembled into 117,091 unigenes. Among these unigenes, 64,551 unigenes (55.12%) were annotated with gene descriptions, while the other 44.88% were unknown. 168 up-regulated genes and 351 down-regulated genes were identified, respectively. These Differentially Expressed Genes (DEGs) involved in multiple pathways including the Salt Overly Sensitive (SOS) pathway, ion transport and uptake, antioxidant enzyme, ABA signal pathway and so on. The gene ontology (GO) enrichments suggested that the DEGs were mainly involved in a plant-type cell wall organization biological process, cell wall cellular component, and structural constituent of cell wall molecular function. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment showed that the top-four enriched pathways were ‘Fatty acid elongation’, ‘Ribosome’, ‘Sphingolipid metabolism’ and ‘Flavonoid biosynthesis’. The expression patterns of sixteen DEGs were analyzed by qRT-PCR to verify the RNA-seq data. Among them, the transcription factor AT-Hook Motif Nuclear Localized gene and dehydrins might play an important role in response to salt stress in B. halophila. Our results provide an important gene resource to breed salt tolerant plants and useful information for further elucidation of the molecular mechanism of salt tolerance in B. halophila.

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RsSOS1 Responding to Salt Stress Might Be Involved in Regulating Salt Tolerance by Maintaining Na+ Homeostasis in Radish (Raphanus sativus L.)

Horticulturae ◽

10.3390/horticulturae7110458 ◽

2021 ◽

Vol 7 (11) ◽

pp. 458

Author(s):

Wanting Zhang ◽

Jingxue Li ◽

Junhui Dong ◽

Yan Wang ◽

Liang Xu ◽

...

Keyword(s):

Plasma Membrane ◽

Salt Stress ◽

Salt Tolerance ◽

Functional Characterization ◽

Vital Role ◽

Salt Stress Response ◽

Reading Frame ◽

Yield And Quality

Radish is a kind of moderately salt-sensitive vegetable. Salt stress seriously decreases the yield and quality of radish. The plasma membrane Na+/H+ antiporter protein Salt Overly Sensitive 1 (SOS1) plays a crucial role in protecting plant cells against salt stress, but the biological function of the RsSOS1 gene in radish remains to be elucidated. In this study, the RsSOS1 gene was isolated from radish genotype ‘NAU-TR17’, and contains an open reading frame of 3414 bp encoding 1137 amino acids. Phylogenetic analysis showed that RsSOS1 had a high homology with BnSOS1, and clustered together with Arabidopsis plasma membrane Na+/H+ antiporter (AtNHX7). The result of subcellular localization indicated that the RsSOS1 was localized in the plasma membrane. Furthermore, RsSOS1 was strongly induced in roots of radish under 150 mmol/L NaCl treatment, and its expression level in salt-tolerant genotypes was significantly higher than that in salt-sensitive ones. In addition, overexpression of RsSOS1 in Arabidopsis could significantly improve the salt tolerance of transgenic plants. Meanwhile, the transformation of RsSOS1△999 could rescue Na+ efflux function of AXT3 yeast. In summary, the plasma membrane Na+/H+ antiporter RsSOS1 plays a vital role in regulating salt-tolerance of radish by controlling Na+ homeostasis. These results provided useful information for further functional characterization of RsSOS1 and facilitate clarifying the molecular mechanism underlying salt stress response in radish.

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Galactolipid and Phospholipid Profile and Proteome Alterations in Soybean Leaves at the Onset of Salt Stress

Frontiers in Plant Science ◽

10.3389/fpls.2021.644408 ◽

2021 ◽

Vol 12 ◽

Author(s):

Ailin Liu ◽

Zhixia Xiao ◽

Zhili Wang ◽

Hon-Ming Lam ◽

Mee-Len Chye

Keyword(s):

Salt Stress ◽

Membrane Lipids ◽

Membrane Lipid ◽

Salt Treatment ◽

Short Term ◽

Lipid Profiling ◽

Soybean Seedlings ◽

Proteomic Data ◽

Before And After ◽

Soybean Leaves

Salinity is a major environmental factor that constrains soybean yield and grain quality. Given our past observations using the salt-sensitive soybean (Glycine max [L.] Merr.) accession C08 on its early responses to salinity and salt-induced transcriptomic modifications, the aim of this study was to assess the lipid profile changes in this cultivar before and after short-term salt stress, and to explore the adaptive mechanisms underpinning lipid homeostasis. To this end, lipid profiling and proteomic analyses were performed on the leaves of soybean seedlings subjected to salt treatment for 0, 0.5, 1, and 2 h. Our results revealed that short-term salt stress caused dynamic lipid alterations resulting in recycling for both galactolipids and phospholipids. A comprehensive understanding of membrane lipid adaption following salt treatment was achieved by combining time-dependent lipidomic and proteomic data. Proteins involved in phosphoinositide synthesis and turnover were upregulated at the onset of salt treatment. Salinity-induced lipid recycling was shown to enhance jasmonic acid and phosphatidylinositol biosyntheses. Our study demonstrated that salt stress resulted in a remodeling of membrane lipid composition and an alteration in membrane lipids associated with lipid signaling and metabolism in C08 leaves.

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Choline-Mediated Lipid Reprogramming as a Dominant Salt Tolerance Mechanism in Grass Species Lacking Glycine Betaine

Plant and Cell Physiology ◽

10.1093/pcp/pcaa116 ◽

2020 ◽

Author(s):

Kun Zhang ◽

Weiting Lyu ◽

Yanli Gao ◽

Xiaxiang Zhang ◽

Yan Sun ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Glycine Betaine ◽

Metabolic Pathways ◽

Poa Pratensis ◽

Choline Chloride ◽

Photochemical Efficiency ◽

Kentucky Bluegrass ◽

Grass Species ◽

Tolerance Mechanism

Abstract Choline, as a precursor of glycine betaine (GB) and phospholipids, is known to play roles in plant tolerance to salt stress, but the downstream metabolic pathways regulated by choline conferring salt tolerance are still unclear for non-GB-accumulating species. The objectives were to examine how choline affects salt tolerance in a non-GB-accumulating grass species and to determine major metabolic pathways of choline regulating salt tolerance involving GB or lipid metabolism. Kentucky bluegrass (Poa pratensis) plants were subjected to salt stress (100 mM NaCl) with or without foliar application of choline chloride (1 mM) in a growth chamber. Choline or GB alone and the combined application increased leaf photochemical efficiency, relative water content and osmotic adjustment and reduced leaf electrolyte leakage. Choline application had no effects on the endogenous GB content and GB synthesis genes did not show responses to choline under nonstress and salt stress conditions. GB was not detected in Kentucky bluegrass leaves. Lipidomic analysis revealed an increase in the content of monogalactosyl diacylglycerol, phosphatidylcholine and phosphatidylethanolamine and a decrease in the phosphatidic acid content by choline application in plants exposed to salt stress. Choline-mediated lipid reprogramming could function as a dominant salt tolerance mechanism in non-GB-accumulating grass species.

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Physiological analysis reveals relatively higher salt tolerance in roots of Ilex integra than in those of Ilex purpurea

Journal of Forestry Research ◽

10.1007/s11676-021-01386-w ◽

2021 ◽

Author(s):

Yongfan Yu ◽

Min Zhang ◽

Jianyuan Feng ◽

Sujing Sun ◽

Peng Zhou ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Membrane Lipid ◽

Soluble Carbohydrate ◽

Salt Treatment ◽

Ion Content ◽

Physiological Analysis ◽

Local Species ◽

High Salt Tolerance ◽

Antioxidant Enzymatic Activity

AbstractDetermining the responses of candidate plants to salt stress is a prerequisite for selecting and breeding suitable plants with high salt tolerance to grow in coastal mudflat areas with high salinity. Here, 2-year cutting seedlings of Ilex purpurea Hassk. (local species) and I. integra Thunb. (introduced species) were grown in pots in a glasshouse and irrigated with a Hoagland-NaCl solution at 0, 24, and 48 h. Root samples were collected at 0, 1, 6, 24, and 72 h, and concentration of Na+ ion; content of proline, soluble carbohydrate, malondialdehyde (MDA), H2O2 and ascorbate; and activity of three key antioxidative enzymes were measured. Roots of I. integra accumulated relatively less Na+ and had less membrane lipid peroxidation and H2O2 during salt stress, thus indicating a relatively higher salt tolerance than roots of I. purpurea. Values for ascorbate content and antioxidant enzymatic activity suggest that the antioxidant ascorbate and antioxidative catalase may play substantial roles for scavenging reactive oxygen species in I. integra roots during salt treatment. Thus, I. integra is apparently more suitable for growing in local highly saline coastal mudflats.

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Evaluation of Antagonistic Bacillus and Biochar against Soybean Root Rot Caused by Fusarium oxysporum

International Journal of Agriculture and Biology ◽

10.17957/ijab/15.1836 ◽

2021 ◽

Vol 26 (02) ◽

pp. 287-293

Author(s):

Fan Yang

Keyword(s):

Root Rot ◽

Fusarium Species ◽

Dry Weight ◽

Control Measures ◽

Soybean Root ◽

Soybean Seedlings ◽

Yield And Quality ◽

Soybean Plants ◽

The Impact ◽

Bacillus Strains

Soybean root rot is a worldwide soil-borne fungal disease threatening soybean production, causing huge losses in yield and quality of soybean. Fusarium species are well recognized as the important causal agent of Fusarium root rot. To screen the beneficial Bacillus strains with capability of suppressing soybean root rot and evaluate the impact of Bacillus combined with biochar against soybean root rot, a pot experiment was conducted with different treatments. In this study, as potential biological control measures, antagonistic Bacillus isolates and different types of biochar were added to soil separately and excellent antagonistic strains mixed with bamboo biochar were applied to the soil. The results showed that seven Bacillus strains promoted the growth of soybean seedlings and reduced root rot severity by 33 to 61%. Bacillus amylolique faciens NH2 was associated with the lowest incidence of soybean root rot, indicating its bio-control potential. The value of plant height, root length and plant dry weight of soybean in the sterilized soil mixed with biochar separately treatment were superior to those of soybean in the inoculated with pathogen treatment, especially the bamboo biochar treatment reduced soybean root rot caused by Fusarium significantly and which bio-control efficacy was 77.41%. The soybean plants shoot and root dry weights in the biochar mixed B. amylolique faciens NH2 or B. subtilis DBK treatments were increased by17.1, 10.7% and 19.51, 19.64%, respectively, which were significantly higher than those of the inoculated pathogen treatment. Compared to antagonistic strain or biochar individual treatments, the disease control efficiency on soybean root rot was up to 64.86% in NH2 strain mixed with bamboo biochar treatment, which reduced root rot severity significantly and showed a synergistic effect. These results suggest that antagonistic Bacillus strains mixed with biochar can be used as an effective alternative in managing soybean root rot. © 2021 Friends Science Publishers

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Salt Tolerance Mechanism of the Rhizosphere Bacterium JZ-GX1 and Its Effects on Tomato Seed Germination and Seedling Growth

Frontiers in Microbiology ◽

10.3389/fmicb.2021.657238 ◽

2021 ◽

Vol 12 ◽

Author(s):

Pu-Sheng Li ◽

Wei-Liang Kong ◽

Xiao-Qin Wu

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Seedling Growth ◽

Salt Concentration ◽

High Salt ◽

Stem Length ◽

Tolerance Mechanism ◽

Rhizosphere Bacterium ◽

Moderately Halophilic Bacterium ◽

Growth Promoting

Salinity is one of the strongest abiotic factors in nature and has harmful effects on plants and microorganisms. In recent years, the degree of soil salinization has become an increasingly serious problem, and the use of plant growth-promoting rhizobacteria has become an option to improve the stress resistance of plants. In the present study, the salt tolerance mechanism of the rhizosphere bacterium Rahnella aquatilis JZ-GX1 was investigated through scanning electron microscopy observations and analysis of growth characteristics, compatible solutes, ion distribution and gene expression. In addition, the effect of JZ-GX1 on plant germination and seedling growth was preliminarily assessed through germination experiments. R. aquatilis JZ-GX1 was tolerant to 0–9% NaCl and grew well at 3%. Strain JZ-GX1 promotes salt tolerance by stimulating the production of exopolysaccharides, and can secrete 60.6983 mg/L of exopolysaccharides under the high salt concentration of 9%. Furthermore, the accumulation of the compatible solute trehalose in cells as the NaCl concentration increased was shown to be the primary mechanism of resistance to high salt concentrations in JZ-GX1. Strain JZ-GX1 could still produce indole-3-acetic acid (IAA) and siderophores and dissolve inorganic phosphorus under salt stress, characteristics that promote the ability of plants to resist salt stress. When the salt concentration was 100 mmol/L, strain JZ-GX1 significantly improved the germination rate, germination potential, fresh weight, primary root length and stem length of tomato seeds by 10.52, 125.56, 50.00, 218.18, and 144.64%, respectively. Therefore, R. aquatilis JZ-GX1 is a moderately halophilic bacterium with good growth-promoting function that has potential for future development as a microbial agent and use in saline-alkali land resources.

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Transcriptome analysis and functional identification of GmMYB46 in soybean seedlings under salt stress

PeerJ ◽

10.7717/peerj.12492 ◽

2021 ◽

Vol 9 ◽

pp. e12492

Author(s):

Xun Liu ◽

Xinxia Yang ◽

Bin Zhang

Keyword(s):

Salt Stress ◽

Stress Response ◽

Salt Tolerance ◽

Transcriptome Analysis ◽

Molecular Mechanisms ◽

Differentially Expressed ◽

Rna Seq ◽

Functional Identification ◽

Salt Stress Response ◽

Soybean Seedlings

Salinity is one of the major abiotic stress that limits crop growth and productivity. We investigated the transcriptomes of salt-treated soybean seedlings versus a control using RNA-seq to better understand the molecular mechanisms of the soybean (Glycine max L.) response to salt stress. Transcriptome analysis revealed 1,235 differentially expressed genes (DEGs) under salt stress. Several important pathways and key candidate genes were identified by KEGG enrichment. A total of 116 differentially expressed transcription factors (TFs) were identified, and 17 TFs were found to belong to MYB families. Phylogenetic analysis revealed that these TFs may be involved in salt stress adaptation. Further analysis revealed that GmMYB46 was up-regulated by salt and mannitol and was localized in the nucleus. The salt tolerance of transgenic Arabidopsis overexpressing GmMYB46 was significantly enhanced compared to wild-type (WT). GmMYB46 activates the expression of salt stress response genes (P5CS1, SOD, POD, NCED3) in Arabidopsis under salt stress, indicating that the GmMYB46 protein mediates the salt stress response through complex regulatory mechanisms. This study provides information with which to better understand the molecular mechanism of salt tolerance in soybeans and to genetically improve the crop.

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