scholarly journals Control of glycerol biosynthesis under high salt stress in Arabidopsis

2014 ◽  
Vol 41 (1) ◽  
pp. 87 ◽  
Author(s):  
Ahmed Bahieldin ◽  
Jamal S. M. Sabir ◽  
Ahmed Ramadan ◽  
Ahmed M. Alzohairy ◽  
Rania A. Younis ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Glycerol Dehydrogenase ◽  
Growth Stages ◽  
Loss Of Function ◽  
Physiological Importance ◽  
Key Enzyme ◽  
Dna Insertion ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Gpd1 Gene

Loss-of-function and gain-of-function approaches were utilised to detect the physiological importance of glycerol biosynthesis during salt stress and the role of glycerol in conferring salt tolerance in Arabidopsis. The salt stress experiment involved wild type (WT) and transgenic Arabidopsis overexpressing the yeast GPD1 gene (analogue of Arabidopsis GLY1 gene). The experiment also involved the Arabidopsis T-DNA insertion mutants gly1 (for suppression of glycerol 3-phosphate dehydrogenase or G3PDH), gli1 (for suppression of glycerol kinase or GK), and act1 (for suppression of G3P acyltransferase or GPAT). We evaluated salt tolerance levels, in conjunction with glycerol and glycerol 3-phosphate (G3P) levels and activities of six enzymes (G3PDH, ADH (alcohol dehydrogenase), ALDH (aldehyde dehydrogenase), GK, G3PP (G3P phosphatase) and GLYDH (glycerol dehydrogenase)) involved in the glycerol pathway. The GPD1 gene was used to overexpress G3PDH, a cytosolic NAD+-dependent key enzyme of cellular glycerol biosynthesis essential for growth of cells under abiotic stresses. T2 GPD1-transgenic plants and those of the two mutants gli1 and act1 showed enhanced salt tolerance during different growth stages as compared with the WT and gly1 mutant plants. These results indicate that the participation of glycerol, rather than G3P, in salt tolerance in Arabidopsis. The results also indicate that the gradual increase in glycerol levels in T2 GPD1-transgenic, and gli1 and act1 mutant plants as NaCl level increases whereas they dropped at 200 mM NaCl. However, the activities of the G3PDH, GK, G3PP and GLYDH at 150 and 200 mM NaCl were not significantly different. We hypothesise that mechanism(s) of glycerol retention/efflux in the cell are affected at 200 mM NaCl in Arabidopsis.

scholarly journals Effects of Foliar Application of Gibberellic Acid on the Salt Tolerance of Tomato and Sweet Pepper Transplants

Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 93
Author(s):  
Alessandro Miceli ◽  
Filippo Vetrano ◽  
Alessandra Moncada
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Gibberellic Acid ◽  
Foliar Application ◽  
Saline Water ◽  
Foliar Spray ◽  
Sweet Pepper ◽  
Limiting Factor ◽  
Growth Stages ◽  
Promoting Effect

Seed germination and early seedling growth are the plant growth stages most sensitive to salt stress. Thus, the availability of poor-quality brackish water can be a big limiting factor for the nursery vegetable industry. The exogenous supplementation of gibberellic acid (GA3) may promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to test exogenous supplementation through foliar spray of 10−5 M GA3 for increasing salt tolerance of tomato and sweet pepper seedlings irrigated with increasing salinity (0, 25, and 50 mM NaCl during nursery growth. Tomato and sweet pepper seedlings suffered negative effects of salinity on plant height, biomass, shoot/root ratio, leaf number, leaf area, relative water content, and stomatal conductance. The foliar application of GA3 had a growth-promoting effect on the unstressed tomato and pepper seedlings and was successful in increasing salinity tolerance of tomato seedlings up to 25 mM NaCl and up to 50 mM NaCl in sweet pepper seedlings. This treatment could represent a sustainable strategy to use saline water in vegetable nurseries limiting its negative effect on seedling quality and production time.

scholarly journals Response of Lettuce Germplasm to Salt Stress at Different Developmental Stages

2021 ◽  
Vol 6 (5) ◽  
Author(s):  
Pavli OI ◽  
◽  
Kempapidis K ◽  
Maggioros L ◽  
Foti C ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Growth Potential ◽  
Economic Losses ◽  
Saline Soils ◽  
Growth Stages ◽  
Salt Tolerant ◽  
Whole Plant ◽  
Plant Level

Salinity is one of the most detrimental abiotic stresses leading to considerable yield and economic losses worldwide. Lettuce is a relatively salt sensitive species, thus placing the interest in the release of salt-tolerant cultivars to enhance production in saline soils. This study aimed at investigating the response of lettuce germplasm to salt stress at the germination and at the whole plant level and to examine possibilities of early selection for salt tolerant genotypes. Fifteen lettuce commercial varieties were initially screened for salt tolerance on the basis of seed germination and seedling growth potential under salt stress conditions (0, 50, 100, 150 mM NaCl). The in vitro evaluation revealed the existence of considerable genetic variation related to salt tolerance at germination and allowed for the classification of genotypes into tolerant, moderately tolerant and sensitive to salt stress. Based on this classification, six cultivars were assessed at the whole plant level using plant height, chlorophyll content and fresh and dry biomass weight as evaluation criteria. Overall findings point to the existence of a satisfactory association of genotype performance between germination and later growth stages, thus suggesting the feasibility of screening for salt tolerance at early growth stages. This approach may considerably upgrade the efficiency of selecting suitable germplasm material for cultivation in saline soils or introgression into relevant breeding programs.

scholarly journals Salt-Tolerant Synechococcus elongatus UTEX 2973 Obtained via Engineering of Heterologous Synthesis of Compatible Solute Glucosylglycerol

2021 ◽  
Vol 12 ◽  
Author(s):  
Jinyu Cui ◽  
Tao Sun ◽  
Lei Chen ◽  
Weiwen Zhang
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Carbon Flux ◽  
Synechococcus Elongatus ◽  
Compatible Solute ◽  
Microbial Cell Factories ◽  
Cell Factories ◽  
Rate Limiting Step ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Rate Limiting

The recently isolated cyanobacterium Synechococcus elongatus UTEX 2973 (Syn2973) is characterized by a faster growth rate and greater tolerance to high temperature and high light, making it a good candidate chassis for autotrophic photosynthetic microbial cell factories. However, Syn2973 is sensitive to salt stress, making it urgently important to improve the salt tolerance of Syn2973 for future biotechnological applications. Glucosylglycerol, a compatible solute, plays an important role in resisting salt stress in moderate and marine halotolerant cyanobacteria. In this study, the salt tolerance of Syn2973 was successfully improved by introducing the glucosylglycerol (GG) biosynthetic pathway (OD750 improved by 24% at 60 h). In addition, the salt tolerance of Syn2973 was further enhanced by overexpressing the rate-limiting step of glycerol-3-phosphate dehydrogenase and downregulating the gene rfbA, which encodes UDP glucose pyrophosphorylase. Taken together, these results indicate that the growth of the end-point strain M-2522-GgpPS-drfbA was improved by 62% compared with the control strain M-pSI-pSII at 60 h under treatment with 0.5 M NaCl. Finally, a comparative metabolomic analysis between strains M-pSI-pSII and M-2522-GgpPS-drfbA was performed to characterize the carbon flux in the engineered M-2522-GgpPS-drfbA strain, and the results showed that more carbon flux was redirected from ADP-GLC to GG synthesis. This study provides important engineering strategies to improve salt tolerance and GG production in Syn2973 in the future.

scholarly journals Ascorbic Acid Modulation by ABI4 Transcriptional Repression of VTC2 in The Salt Tolerance of Arabidopsis

2020 ◽  
Author(s):  
Xiamusiya Kakan ◽  
Yanwen Yu ◽  
Shenghui Li ◽  
Xiaoying Li ◽  
Rongfeng Huang ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Salt Stress ◽  
Salt Tolerance ◽  
Stress Responses ◽  
Transcriptional Repression ◽  
Early Stage ◽  
Stress Sensitivity ◽  
Loss Of Function ◽  
Ros Scavenging ◽  
Plant Salt Tolerance

Abstract Background:Abscisic acid (ABA) plays an important role in plant abiotic stress responses, and ABA INSENSITIVE 4 (ABI4) is a pivotal transcription factor in the ABA signaling pathway. In Arabidopsis, ABI4 negatively regulates salt tolerance; however, the mechanism through which ABI4 regulates plant salt tolerance is poorly understood. Our previous study showed that ABI4 directly binds to the promoter of the VITAMIN C DEFECTIVE 2 (VTC2) gene, inhibiting the transcription of VTC2 and ascorbic acid (AsA) biosynthesis.Results: In the present study, we found that treatment with exogenous AsA could alleviate salt stress sensitivity of ABI4-overexpressing transgenic plants. The decreased AsA content and increased reactive oxygen species (ROS) levels in ABI4-overexpressing seedlings under salt treatment indicated that AsA-promoted ROS scavenging was related to ABI4-mediated salt tolerance. Gene expression analysis showed that ABI4 was induced at the early stage of salt stress, giving rise to reduced VTC2 expression. Accordingly, the abundance of the VTC2 protein decreased under the same salt stress conditions, and was absent in the ABI4 loss-of-function mutants, suggesting that the transcriptional inhibition of ABI4 on VTC2 resulted in the attenuation of VTC2 function. In addition, other encoding genes in the AsA biosynthesis and recycling pathways showed different responses to salt stress, demonstrating that AsA homeostasis is complicated under salinity stress. Conclusions: This study elucidates the negative modulation of ABI4 in salt stress tolerance through the regulation of AsA biosynthesis and ROS accumulation in plants.

scholarly journals (139) A Capacity for Mannitol Biosynthesis is a Critical Component of Salt Tolerance in Celery

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1057B-1057
Author(s):  
Wayne H. Loescher ◽  
Paolo Sabbatini ◽  
Guo-Qing Song ◽  
Kenneth Sink ◽  
James Flore
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Apium Graveolens ◽  
35S Promoter ◽  
Loss Of Function ◽  
Wild Type ◽  
Salt Tolerant ◽  
Stress Effects ◽  
Antisense Transgenic Plants ◽  
Antisense Construct

Mannitol, a sugar alcohol that appears to serve as an osmoprotectant/compatible solute to cope with salt stress, is synthesized in celery (Apium graveolens L.) via the action of a NADPH dependent mannose-6-phosphate reductase (M6PR). To evaluate the abiotic stress effects of mannitol biosynthesis, we transformed celery with an antisense construct of the celery leaf M6PR gene under control of the CaMV 35S promoter. Unlike wild type (WT) celery, independent antisense M6PR transformants did not accumulate significant amounts of mannitol in any tissue, with or without salt stress. In the absence of NaCl, and despite the lack of any significant accumulation of mannitol that is normally the major photosynthetic product, antisense transformants were mostly phenotypically similar to the WT celery. However, in the presence of NaCl, mature antisense transgenic plants were significantly less salt-tolerant, with reduced growth and photosynthetic rates, and some transformant lines were killed at 200 mM NaCl, a concentration that WT celery can normally withstand. Although mannitol biosynthesis is normally enhanced in salt-treated WT celery, no such increase was observed in the antisense transformants. Like our previous gain of function results showing enhanced salt tolerance in Arabidopsis plants transgenic for a sense M6PR construct, these loss of function results, using an antisense construct in celery, demonstrate a major role for mannitol biosynthesis in developing salt-tolerant plants.

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

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.

Genetic insights into natural variation underlying salt tolerance in wheat

2020 ◽  
Author(s):  
Long Li ◽  
Zhi Peng ◽  
Xinguo Mao ◽  
Jingyi Wang ◽  
Chaonan Li ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Expression Patterns ◽  
Growth Stages ◽  
Linkage Drag ◽  
Genome Wide Association Studies ◽  
Root Number ◽  
Salt Tolerant ◽  
Root Responses ◽  
Chinese Wheat

Abstract Developing salt-tolerant crop varieties is one of the important approaches to cope with increasing soil salinization worldwide. In this study, a diversity panel of 323 wheat accessions and 150 doubled haploid lines were phenotyped for salt-responsive morphological and physiological traits across two growth stages. The comprehensive salt tolerance of each wheat accession was evaluated based on principal component analysis. A total of 269 associated loci for salt-responsive traits and/or salt tolerance indices were identified by genome-wide association studies using 395 675 single nucleotide polymorphisms, among which 22 overlapping loci were simultaneously identified by biparental quantitative trait loci mapping. Two novel candidate genes ROOT NUMBER 1 (TaRN1) and ROOT NUMBER 2 (TaRN2) involved in root responses to salt stress fell within overlapping loci, showing different expression patterns and a frameshift mutation (in TaRN2) in contrasting salt-tolerant wheat genotypes. Moreover, the decline in salt tolerance of Chinese wheat varieties was observed from genetic and phenotypic data. We demonstrate that a haplotype controlling root responses to salt stress has been diminished by strong selection for grain yield, which highlights that linkage drag constrains the salt tolerance of Chinese wheat. This study will facilitate salt-tolerant wheat breeding in terms of elite germplasm, favorable alleles and selection strategies.

scholarly journals Evaluation of Salt Tolerance in Italian Ryegrass at Different Developmental Stages

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1487
Author(s):  
Yan Xie ◽  
Xiaoying Liu ◽  
Maurice Amee ◽  
Hua Yu ◽  
Ye Huang ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Vegetative Growth ◽  
Developmental Stages ◽  
Genotypic Variation ◽  
Forage Quality ◽  
Italian Ryegrass ◽  
Neutral Detergent Fiber ◽  
Growth Stages ◽  
Tolerance Index

Soil salinity is one of the major abiotic stresses that continues to threaten plant growth and agricultural productivity. Screening germplasm with salinity tolerance is therefore necessary. This study was designed to evaluate salt tolerance based on the integrated tolerance index. Fifteen Italian ryegrass cultivars were used to evaluate the degree of genotypic variation in salt tolerance at the germination and vegetative growth stages of plant development. Evident variations in salt tolerance were observed at the germination stage under 255 mM NaCl treatment. Root growth rate, chlorophyll content, and germination rates played a vital role in determining salt tolerance. Based on combined attributes at the germination and vegetative growth stages, Gongniu, Chuangnong, Splendor, and Abundant were identified as the most tolerant cultivars. Furthermore, the constant crude protein, lower neutral detergent fiber, and acid detergent fiber contents were measured under salinity. Compared to the control, the cultivars Tetragold, Abundant, Splendor, Muyao, Harukaze, Tegao, Dongmu 70, and Doraian were identified to have high forage quality under salt stress. Finally, we selected Splendor and Abundant as the cultivars that expressed the highest degree of salt tolerance based on combined attributes related to germination, salt tolerance, and overall forage quality. In addition, gene expression analysis between salinity tolerant and sensitive cultivars revealed that the gene response to photosystem and carbohydrate synthesis may have played a mediating role in providing tolerance to salt stress.

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

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Isaiah Catalino M. Pabuayon ◽  
Jiafu Jiang ◽  
Hongjia Qian ◽  
Jung-Sung Chung ◽  
Huazhong Shi
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Cellular Level ◽  
Salt Sensitivity ◽  
Yeast Cells ◽  
Cellular Damage ◽  
Loss Of Function ◽  
Cloning And Sequencing ◽  
Gain Of Function

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.

scholarly journals Xyloglucan endotransglucosylase-hydrolase30 negatively affects salt tolerance in Arabidopsis

2019 ◽  
Vol 70 (19) ◽  
pp. 5495-5506 ◽  
Author(s):  
Jingwei Yan ◽  
Yun Huang ◽  
Huan He ◽  
Tong Han ◽  
Pengcheng Di ◽  
...  
Keyword(s):  
Cell Wall ◽  
Salt Stress ◽  
Salt Tolerance ◽  
Cortical Microtubule ◽  
Physiological Mechanism ◽  
Crystalline Cellulose ◽  
Cellulose Synthesis ◽  
Cellulose Content ◽  
Loss Of Function ◽  
Sense And Respond

AbstractPlants have evolved various strategies to sense and respond to saline environments, which severely reduce plant growth and limit agricultural productivity. Alteration to the cell wall is one strategy that helps plants adapt to salt stress. However, the physiological mechanism of how the cell wall components respond to salt stress is not fully understood. Here, we show that expression of XTH30, encoding xyloglucan endotransglucosylase-hydrolase30, is strongly up-regulated in response to salt stress in Arabidopsis. Loss-of-function of XTH30 leads to increased salt tolerance and overexpression of XTH30 results in salt hypersensitivity. XTH30 is located in the plasma membrane and is highly expressed in the root, flower, stem, and etiolated hypocotyl. The NaCl-induced increase in xyloglucan (XyG)-derived oligosaccharide (XLFG) of the wild type is partly blocked in xth30 mutants. Loss-of-function of XTH30 slows down the decrease of crystalline cellulose content and the depolymerization of microtubules caused by salt stress. Moreover, lower Na+ accumulation in shoot and lower H2O2 content are found in xth30 mutants in response to salt stress. Taken together, these results indicate that XTH30 modulates XyG side chains, altered abundance of XLFG, cellulose synthesis, and cortical microtubule stability, and negatively affecting salt tolerance.

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