The vacuolar Na+ - H+ antiport gene TaNHX2 confers salt tolerance on transgenic alfalfa (Medicago sativa)

TaNHX2, a vacuolar Na+–H+ antiport gene from wheat (Triticum aestivum L.), was transformed into alfalfa (Medicago sativa L.) via Agrobacterium-mediated transformation to evaluate the role of vacuolar energy providers in plant salt stress responses. PCR and Southern blotting analysis showed that the target gene was integrated into the Medicago genome. Reverse transcription–PCR indicated that gene TaNHX2 was expressed at the transcriptional level. The relative electrical conductivity in the T2 transgenic plants was lower and the osmotic potential was higher compared to the wild-type plants under salt stress conditions. The tonoplast H+-ATPase, H+-pyrophosphatase (PPase) hydrolysis activities and ATP-dependent proton pump activities in transgenic plants were all higher than those of wild-type plants, and the enzyme activities could be induced by salt stress. The PPi-dependent proton pump activities decreased when NaCl concentrations increased from 100 mM to 200 mM, especially in transgenic plants. The vacuolar Na+–H+ antiport activities of transgenic plants were 2–3 times higher than those of the wild -type plants under 0 mM and 100 mM NaCl stress. Na+–H+ antiport activity was not detectable for wild-type plants under 200 mM NaCl, but for transgenic plants, it was further increased with an increment in salt stress intensity. These results demonstrated that expression of the foreign TaNHX2 gene enhanced salt tolerance in transgenic alfalfa.

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Ectopic Expression of Gs5PTase8, a Soybean Inositol Polyphosphate 5-Phosphatase, Enhances Salt Tolerance in Plants

International Journal of Molecular Sciences ◽

10.3390/ijms21031023 ◽

2020 ◽

Vol 21 (3) ◽

pp. 1023 ◽

Cited By ~ 2

Author(s):

Qi Jia ◽

Song Sun ◽

Defeng Kong ◽

Junliang Song ◽

Lumei Wu ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Stress Responses ◽

Transgenic Arabidopsis ◽

Glycine Soja ◽

Critical Role ◽

Ectopic Expression ◽

Wild Soybean ◽

Inositol Polyphosphate ◽

Wild Type

Inositol polyphosphate 5-phosphatases (5PTases) function in inositol signaling by regulating the catabolism of phosphoinositol derivatives. Previous reports showed that 5PTases play a critical role in plant development and stress responses. In this study, we identified a novel 5PTase gene, Gs5PTase8, from the salt-tolerance locus of chromosome 3 in wild soybean (Glycine soja). Gs5PTase8 is highly up-regulated under salt treatment. It is localized in the nucleus and plasma membrane with a strong signal in the apoplast. Ectopic expression of Gs5PTase8 significantly increased salt tolerance in transgenic BY-2 cells, soybean hairy roots and Arabidopsis, suggesting Gs5PTase8 could increase salt tolerance in plants. The overexpression of Gs5PTase8 significantly enhanced the activities of catalase and ascorbate peroxidase under salt stress. The seeds of Gs5PTase8-transgenic Arabidopsis germinated earlier than the wild type under abscisic acid treatment, indicating Gs5PTase8 would alter ABA sensitivity. Besides, transcriptional analyses showed that the stress-responsive genes, AtRD22, AtRD29A and AtRD29B, were induced with a higher level in the Gs5PTase8-transgenic Arabidopsis plants than in the wild type under salt stress. These results reveal that Gs5PTase8 play a positive role in salt tolerance and might be a candidate gene for improving soybean adaptation to salt stress.

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PLATZ2 negatively regulates salt tolerance in Arabidopsis seedlings by directly suppressing the expression of the CBL4/SOS3 and CBL10/SCaBP8 genes

Journal of Experimental Botany ◽

10.1093/jxb/eraa259 ◽

2020 ◽

Vol 71 (18) ◽

pp. 5589-5602

Author(s):

Shasha Liu ◽

Rui Yang ◽

Miao Liu ◽

Shizhong Zhang ◽

Kang Yan ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Transgenic Plants ◽

Loss Of Function ◽

Wild Type ◽

Salt Stress Response ◽

In The Wild ◽

Plant Salt Tolerance

Abstract Although the salt overly sensitive (SOS) pathway plays essential roles in conferring salt tolerance in Arabidopsis thaliana, the regulatory mechanism underlying SOS gene expression remains largely unclear. In this study, AtPLATZ2 was found to function as a direct transcriptional suppressor of CBL4/SOS3 and CBL10/SCaBP8 in the Arabidopsis salt stress response. Compared with wild-type plants, transgenic plants constitutively overexpressing AtPLATZ2 exhibited increased sensitivity to salt stress. Loss of function of PLATZ2 had no observed salt stress phenotype in Arabidopsis, while the double mutant of PLATZ2 and PLATZ7 led to weaker salt stress tolerance than wild-type plants. Overexpression of AtPLATZ2 in transgenic plants decreased the expression of CBL4/SOS3 and CBL10/SCaBP8 under both normal and saline conditions. AtPLATZ2 directly bound to A/T-rich sequences in the CBL4/SOS3 and CBL10/SCaBP8 promoters in vitro and in vivo, and inhibited CBL4/SOS3 promoter activity in the plant leaves. The salt sensitivity of #11 plants constitutively overexpressing AtPLATZ2 was restored by the overexpression of CBL4/SOS3 and CBL10/SCaBP8. Salt stress-induced Na+ accumulation in both the shoots and roots was more exaggerated in AtPLATZ2-overexpressing plants than in the wild type. The salt stress-induced Na+ accumulation in #11 seedlings was also rescued by the overexpression of CBL4/SOS3 and CBL10/SCaBP8. Furthermore, the transcription of AtPLATZ2 was induced in response to salt stress. Collectively, these results suggest that AtPLATZ2 suppresses plant salt tolerance by directly inhibiting CBL4/SOS3 and CBL10/SCaBP8, and functions redundantly with PLATZ7.

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The long non-coding RNA lncRNA973 is involved in cotton response to salt stress

BMC Plant Biology ◽

10.1186/s12870-019-2088-0 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 7

Author(s):

Xiaopei Zhang ◽

Jie Dong ◽

Fenni Deng ◽

Wei Wang ◽

Yingying Cheng ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Transgenic Plants ◽

Germination Rate ◽

Stress Conditions ◽

Virus Induced Gene Silencing ◽

Wild Type ◽

Rna Molecules ◽

Regulatory Processes ◽

Reduced Salt

Abstract Background Long non-coding (lnc) RNAs are a class of functional RNA molecules greater than 200 nucleotides in length, and lncRNAs play important roles in various biological regulatory processes and response to the biotic and abiotic stresses. LncRNAs associated with salt stress in cotton have been identified through RNA sequencing, but the function of lncRNAs has not been reported. We previously identified salt stress-related lncRNAs in cotton (Gossypium spp.), and discovered the salt-related lncRNA-lncRNA973. Results In this study, we identified the expression level, localization, function, and preliminary mechanism of action of lncRNA973. LncRNA973, which was localized in the nucleus, was expressed at a low level under nonstress conditions but can be significantly increased by salt treatments. Here lncRNA973 was transformed into Arabidopsis and overexpressed. Along with the increased expression compared with wild type under salt stress conditions in transgenic plants, the seed germination rate, fresh weights and root lengths of the transgenic plants increased. We also knocked down the expression of lncRNA973 using virus-induced gene silencing technology. The lncRNA973 knockdown plants wilted, and the leaves became yellowed and dropped under salt-stress conditions, indicating that the tolerance to salt stress had decreased compared with wild type. LncRNA973 may be involved in the regulation of reactive oxygen species-scavenging genes, transcription factors and genes involved in salt stress-related processes in response to cotton salt stress. Conclusions LncRNA973 was localized in the nucleus and its expression was increased by salt treatment. The lncRNA973-overexpression lines had increased salt tolerance compared with the wild type, while the lncRNA973 knockdown plants had reduced salt tolerance. LncRNA973 regulated cotton responses to salt stress by modulating the expression of a series of salt stress-related genes. The data provides a basis for further studies on the mechanisms of lncRNA973-associated responses to salt stress in cotton.

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Stomatal and Metabolic Limitations to Photosynthesis Resulting from NaCl Stress in Perennial Ryegrass Genotypes Differing in Salt Tolerance

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.138.5.350 ◽

2013 ◽

Vol 138 (5) ◽

pp. 350-357 ◽

Cited By ~ 9

Author(s):

Tao Hu ◽

Haiying Yi ◽

Longxing Hu ◽

Jinmin Fu

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Perennial Ryegrass ◽

Stress Responses ◽

Large Subunit ◽

Nacl Stress ◽

Expression Level ◽

Transcriptional Level ◽

Salt Tolerant ◽

Rubisco Activity

Plants possess abiotic stress responses that alter photosynthetic metabolism under salinity stress. The objective of this study was to identify the stomatal and metabolic changes associated with photosynthetic responses to NaCl stress in perennial ryegrass (Lolium perenne). Five-week-old seedlings of two perennial ryegrass genotypes, PI 516605 (salt-sensitive) and BARLP 4317 (salt-tolerant), were subjected to 0 and 250 mm NaCl for 8 days. The salt tolerance in perennial ryegrass was significantly associated with leaf relative water content (RWC) and photosynthetic capacity through the maintenance of greater metabolic activities under prolonged salt stress. BARLP 4317 maintained greater turf quality, RWC, and stomatal limitations but a lower level of lipid peroxidation [malondialdehyde (MDA)] and intercellular CO2 concentration than PI 516605 at 8 days after treatment (DAT). Ribulose-1, 5-bisphosphate carboxylase:oxygenase (Rubisco) activity and activation state, transcriptional level of rbcL gene, and expression level of Rubisco large subunit (LSU) declined in stressed perennial ryegrass but were higher in salt-tolerant genotype at 8 DAT. Furthermore, photosynthetic rate increased linearly with increasing Rubisco activity, Rubisco activation state, and RWC in both genotypes. The same linear relationship was found between RWC and Rubisco activity. However, MDA content decreased linearly with increasing RWC in both genotypes. Salinity-induced inhibition of photosynthesis in perennial ryegrass was mainly the result of stomatal limitation during early salt stress and metabolic limitation associated with the inhibition of RWC, activity of Rubisco, expression level of rbcL gene, and LSU under a prolonged period of severe salinity.

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OsNAC45 is Involved in ABA Response and Salt Tolerance in Rice

Rice ◽

10.1186/s12284-020-00440-1 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Xiang Zhang ◽

Yan Long ◽

Jingjing Huang ◽

Jixing Xia

Keyword(s):

Transcription Factors ◽

Salt Stress ◽

Salt Tolerance ◽

Stress Responses ◽

Crop Yields ◽

Plant Stress ◽

Root Cells ◽

Nac Transcription Factors ◽

Rice Plants ◽

Plant Stress Responses

Abstract Background Salt stress threatens crop yields all over the world. Many NAC transcription factors have been reported to be involved in different abiotic stress responses, but it remains unclear how loss of these transcription factors alters the transcriptomes of plants. Previous reports have demonstrated that overexpression of OsNAC45 enhances salt and drought tolerance in rice, and that OsNAC45 may regulate the expression of two specific genes, OsPM1 and OsLEA3–1. Results Here, we found that ABA repressed, and NaCl promoted, the expression of OsNAC45 in roots. Immunostaining showed that OsNAC45 was localized in all root cells and was mainly expressed in the stele. Loss of OsNAC45 decreased the sensitivity of rice plants to ABA and over-expressing this gene had the opposite effect, which demonstrated that OsNAC45 played an important role during ABA signal responses. Knockout of OsNAC45 also resulted in more ROS accumulation in roots and increased sensitivity of rice to salt stress. Transcriptome sequencing assay found that thousands of genes were differently expressed in OsNAC45-knockout plants. Most of the down-regulated genes participated in plant stress responses. Quantitative real time RT-PCR suggested that seven genes may be regulated by OsNAC45 including OsCYP89G1, OsDREB1F, OsEREBP2, OsERF104, OsPM1, OsSAMDC2, and OsSIK1. Conclusions These results indicate that OsNAC45 plays vital roles in ABA signal responses and salt tolerance in rice. Further characterization of this gene may help us understand ABA signal pathway and breed rice plants that are more tolerant to salt stress.

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A Functional Alternative Oxidase Modulates Plant Salt Tolerance in Physcomitrella patens

Plant and Cell Physiology ◽

10.1093/pcp/pcz099 ◽

2019 ◽

Vol 60 (8) ◽

pp. 1829-1841 ◽

Cited By ~ 5

Author(s):

Guochun Wu ◽

Sha Li ◽

Xiaochuan Li ◽

Yunhong Liu ◽

Shuangshuang Zhao ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Stress Responses ◽

Alternative Oxidase ◽

Physcomitrella Patens ◽

Redox Homeostasis ◽

Respiratory Pathway ◽

Functional Link ◽

Salt Stress Condition ◽

Plant Salt Tolerance

Abstract Alternative oxidase (AOX) has been reported to be involved in mitochondrial function and redox homeostasis, thus playing an essential role in plant growth as well as stress responses. However, its biological functions in nonseed plants have not been well characterized. Here, we report that AOX participates in plant salt tolerance regulation in moss Physcomitrella patens (P. patens). AOX is highly conserved and localizes to mitochondria in P. patens. We observed that PpAOX rescued the impaired cyanide (CN)-resistant alternative (Alt) respiratory pathway in Arabidopsis thaliana (Arabidopsis) aox1a mutant. PpAOX transcription and Alt respiration were induced upon salt stress in P. patens. Using homologous recombination, we generated PpAOX-overexpressing lines (PpAOX OX). PpAOX OX plants exhibited higher Alt respiration and lower total reactive oxygen species accumulation under salt stress condition. Strikingly, we observed that PpAOX OX plants displayed decreased salt tolerance. Overexpression of PpAOX disturbed redox homeostasis in chloroplasts. Meanwhile, chloroplast structure was adversely affected in PpAOX OX plants in contrast to wild-type (WT) P. patens. We found that photosynthetic activity in PpAOX OX plants was also lower compared with that in WT. Together, our work revealed that AOX participates in plant salt tolerance in P. patens and there is a functional link between mitochondria and chloroplast under challenging conditions.

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Variations in leaf gas exchange, chlorophyll fluorescence and membrane potential of Medicago sativa root cortex cells exposed to increased salinity: The role of the antioxidant potential in salt tolerance

Archives of Biological Sciences ◽

10.2298/abs171019001f ◽

2018 ◽

Vol 70 (3) ◽

pp. 413-423 ◽

Cited By ~ 2

Author(s):

Mohamed Farissi ◽

Mohammed Mouradi ◽

Omar Farssi ◽

Abdelaziz Bouizgaren ◽

Cherki Ghoulam

Keyword(s):

Antioxidant Enzymes ◽

Salt Stress ◽

Chlorophyll Fluorescence ◽

Membrane Potential ◽

Salt Tolerance ◽

Gas Exchange ◽

Medicago Sativa ◽

Leaf Gas Exchange ◽

Root Cortex ◽

Root Cortex Cells

Salinity is one of the most serious agricultural problems that adversely affects growth and productivity of pasture crops such as alfalfa. In this study, the effects of salinity on some ecophysiological and biochemical criteria associated with salt tolerance were assessed in two Moroccan alfalfa (Medicago sativa L.) populations, Taf 1 and Tata. The experiment was conducted in a hydro-aeroponic system containing nutrient solutions, with the addition of NaCl at concentrations of 100 and 200 mM. The salt stress was applied for a month. Several traits in relation to salt tolerance, such as plant dry biomass, relative water content, leaf gas exchange, chlorophyll fluorescence, nutrient uptake, lipid peroxidation and antioxidant enzymes, were analyzed at the end of the experiment. The membrane potential was measured in root cortex cells of plants grown with or without NaCl treatment during a week. The results indicated that under salt stress, plant growth and all of the studied physiological and biochemical traits were significantly decreased, except for malondialdehyde and H2O2 contents, which were found to be increased under salt stress. Depolarization of membrane root cortex cells with the increase in external NaCl concentration was noted, irrespective of the growth conditions. The Tata population was more tolerant to high salinity (200 mM NaCl) and its tolerance was associated with the ability of plants to maintain adequate levels of the studied parameters and their ability to overcome oxidative stress by the induction of antioxidant enzymes, such as guaiacol peroxidase, catalase and superoxide dismutase.

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Identification of Key Genes in ‘Luang Pratahn’, Thai Salt-Tolerant Rice, Based on Time-Course Data and Weighted Co-expression Networks

Frontiers in Plant Science ◽

10.3389/fpls.2021.744654 ◽

2021 ◽

Vol 12 ◽

Author(s):

Pajaree Sonsungsan ◽

Pheerawat Chantanakool ◽

Apichat Suratanee ◽

Teerapong Buaboocha ◽

Luca Comai ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Stress Responses ◽

Time Course ◽

Rice Variety ◽

Enrichment Analysis ◽

Normal Growth ◽

Growth Conditions ◽

Pathway Enrichment Analysis ◽

Key Genes

Salinity is an important environmental factor causing a negative effect on rice production. To prevent salinity effects on rice yields, genetic diversity concerning salt tolerance must be evaluated. In this study, we investigated the salinity responses of rice (Oryza sativa) to determine the critical genes. The transcriptomes of ‘Luang Pratahn’ rice, a local Thai rice variety with high salt tolerance, were used as a model for analyzing and identifying the key genes responsible for salt-stress tolerance. Based on 3' Tag-Seq data from the time course of salt-stress treatment, weighted gene co-expression network analysis was used to identify key genes in gene modules. We obtained 1,386 significantly differentially expressed genes in eight modules. Among them, six modules indicated a significant correlation within 6, 12, or 48h after salt stress. Functional and pathway enrichment analysis was performed on the co-expressed genes of interesting modules to reveal which genes were mainly enriched within important functions for salt-stress responses. To identify the key genes in salt-stress responses, we considered the two-state co-expression networks, normal growth conditions, and salt stress to investigate which genes were less important in a normal situation but gained more impact under stress. We identified key genes for the response to biotic and abiotic stimuli and tolerance to salt stress. Thus, these novel genes may play important roles in salinity tolerance and serve as potential biomarkers to improve salt tolerance cultivars.

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Overexpression of a Novel ROP Gene from the Banana (MaROP5g) Confers Increased Salt Stress Tolerance

International Journal of Molecular Sciences ◽

10.3390/ijms19103108 ◽

2018 ◽

Vol 19 (10) ◽

pp. 3108 ◽

Cited By ~ 4

Author(s):

Hongxia Miao ◽

Peiguang Sun ◽

Juhua Liu ◽

Jingyi Wang ◽

Biyu Xu ◽

...

Keyword(s):

Salt Stress ◽

Abiotic Stress ◽

Salt Tolerance ◽

Stress Tolerance ◽

Abiotic Stress Tolerance ◽

Survival Rates ◽

Wild Type ◽

Ion Distribution ◽

Membrane Injury ◽

Primary Roots

Rho-like GTPases from plants (ROPs) are plant-specific molecular switches that are crucial for plant survival when subjected to abiotic stress. We identified and characterized 17 novel ROP proteins from Musa acuminata (MaROPs) using genomic techniques. The identified MaROPs fell into three of the four previously described ROP groups (Groups II–IV), with MaROPs in each group having similar genetic structures and conserved motifs. Our transcriptomic analysis showed that the two banana genotypes tested, Fen Jiao and BaXi Jiao, had similar responses to abiotic stress: Six genes (MaROP-3b, -5a, -5c, -5f, -5g, and -6) were highly expressed in response to cold, salt, and drought stress conditions in both genotypes. Of these, MaROP5g was most highly expressed in response to salt stress. Co-localization experiments showed that the MaROP5g protein was localized at the plasma membrane. When subjected to salt stress, transgenic Arabidopsis thaliana overexpressing MaROP5g had longer primary roots and increased survival rates compared to wild-type A. thaliana. The increased salt tolerance conferred by MaROP5g might be related to reduced membrane injury and the increased cytosolic K+/Na+ ratio and Ca2+ concentration in the transgenic plants as compared to wild-type. The increased expression of salt overly sensitive (SOS)-pathway genes and calcium-signaling pathway genes in MaROP5g-overexpressing A. thaliana reflected the enhanced tolerance to salt stress by the transgenic lines in comparison to wild-type. Collectively, our results suggested that abiotic stress tolerance in banana plants might be regulated by multiple MaROPs, and that MaROP5g might enhance salt tolerance by increasing root length, improving membrane injury and ion distribution.

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