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

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.

scholarly journals The full-length transcriptome of Spartina alterniflora reveals the complexity of high salt tolerance in monocotyledonous halophyte

2019 ◽  
Author(s):  
Wenbin Ye ◽  
Taotao Wang ◽  
Wei Wei ◽  
Shuaitong Lou ◽  
Faxiu Lan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salt Stress ◽  
Alternative Splicing ◽  
Salt Tolerance ◽  
Protein Kinases ◽  
Spartina Alterniflora ◽  
High Salt ◽  
Full Length ◽  
Salt Tolerant ◽  
High Salt Tolerance

ABSTRACTSpartina alterniflora (Spartina) is the only halophyte in the salt marsh. However, the molecular basis of its high salt tolerance remains elusive. In this study, we used PacBio full-length single molecule long-read sequencing and RNA-seq to elucidate the transcriptome dynamics of high salt tolerance in Spartina by salt-gradient experiments (0, 350, 500 and 800 mM NaCl). We systematically analyzed the gene expression diversity and deciphered possible roles of ion transporters, protein kinases and photosynthesis in salt tolerance. Moreover, the co-expression network analysis revealed several hub genes in salt stress regulatory networks, including protein kinases such as SaOST1, SaCIPK10 and three SaLRRs. Furthermore, high salt stress affected the gene expression of photosynthesis through down-regulation at the transcription level and alternative splicing at the post-transcriptional level. In addition, overexpression of two Spartina salt-tolerant genes SaHSP70-I and SaAF2 in Arabidopsis significantly promoted the salt tolerance of transgenic lines. Finally, we built the SAPacBio website for visualizing the full-length transcriptome sequences, transcription factors, ncRNAs, salt-tolerant genes, and alternative splicing events in Spartina. Overall, this study sheds light on the high salt tolerance mechanisms of monocotyledonous-halophyte and demonstrates the potential of Spartina genes for engineering salt-tolerant plants.

Physiological response of chickpea (Cicer arietinum L.) at early seedling stage under salt stress conditions

2019 ◽  
Author(s):  
Anita Mann ◽  
Gurpreet Kaur ◽  
Ashwani Kumar ◽  
Satish Kumar Sanwal ◽  
Jogendra Singh ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Seedling Growth ◽  
Root Length ◽  
Dry Weight ◽  
Shoot Length ◽  
Seedling Stage ◽  
Tolerance Index ◽  
Early Seedling Growth ◽  
Early Seedling

Screening of chickpea lines for salt tolerance through seed germination and early seedling growth is crucial for their evaluation. Seeds of 30 chickpea genotypes were germinated on a sand bed irrigated with saline (3, 6, 9, 12 dS/m) and control solutions upto 30 days. At the early seedling stage (25-30 days), germination percentage, chlorophyll content, proline, root length, shoot length and seedling dry weight were found to be affected due to salinity. Salt tolerance index (STI) for plant biomass maintained a significant correlation with chlorophyll, proline, shoot length, and root length, which indicated that these parameters could be used as selection criteria for screening chickpea genotypes against salt stress. Significant differences in shoot length, root length, and seedling dry weight in 30-day-old seedlings were observed among selected chickpea genotypes as well. From the overall observation of germination characterstics and early seedling growth, it is concluded that the chickpea genotypes, HC-1, HC-5, ICC 867, ICC 5003, H-10-41 showed better salt tolerance as compared to the available salt tolerant check variety.

scholarly journals Exogenous melatonin improves salt stress adaptation of cotton seedlings by regulating active oxygen metabolism

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10486
Author(s):  
Dan Jiang ◽  
Bin Lu ◽  
Liantao Liu ◽  
Wenjing Duan ◽  
Li Chen ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Seedling Growth ◽  
Lipid Membrane ◽  
Soluble Sugars ◽  
Oxygen Metabolism ◽  
Membrane Lipid ◽  
Biotic And Abiotic Stress ◽  
Exogenous Melatonin ◽  
Cotton Seedling

Melatonin is a small-molecule indole hormone that plays an important role in participating in biotic and abiotic stress resistance. Melatonin has been confirmed to promote the normal development of plants under adversity stress by mediating physiological regulation mechanisms. However, the mechanisms by which exogenous melatonin mediates salt tolerance via regulation of antioxidant activity and osmosis in cotton seedlings remain largely unknown. In this study, the regulatory effects of melatonin on reactive oxygen species (ROS), the antioxidant system, and osmotic modulators of cotton seedlings were determined under 0–500 µM melatonin treatments with salt stress induced by 150 mM NaCl treatment. Cotton seedlings under salt stress exhibited an inhibition of growth, excessive hydrogen peroxide (H2O2), superoxide anion (O2−), and malondialdehyde (MDA) accumulations in leaves, increased activity levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and elevated ascorbic acid (AsA) and glutathione (GSH) content in leaves. However, the content of osmotic regulators (i.e., soluble sugars and proteins) in leaves was reduced under salt stress. This indicates high levels of ROS were produced, and the cell membrane was damaged. Additionally, osmotic regulatory substance content was reduced, resulting in osmotic stress, which seriously affected cotton seedling growth under salt stress. However, exogenous melatonin at different concentrations reduced the contents of H2O2, O2−, and MDA in cotton leaves, increased the activity of antioxidant enzymes and the content of reductive substances (i.e., AsA and GSH), and promoted the accumulation of osmotic regulatory substances in leaves under salt stress. These results suggest that melatonin can inhibit ROS production in cotton seedlings, improve the activity of the antioxidant enzyme system, raise the content of osmotic regulation substances, reduce the level of membrane lipid peroxidation, and protect the integrity of the lipid membrane under salt stress, which reduces damage caused by salt stress to seedlings and effectively enhances inhibition of salt stress on cotton seedling growth. These results indicate that 200 µM melatonin treatment has the best effect on the growth and salt tolerance of cotton seedlings.

scholarly journals Volatile Organic Compounds of the Plant Growth-Promoting Rhizobacteria JZ-GX1 Enhanced the Tolerance of Robinia pseudoacacia to Salt Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Pu-Sheng Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu ◽  
Yu Zhang
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Plant Growth ◽  
Lateral Root ◽  
Robinia Pseudoacacia ◽  
Plant Growth Promoting Rhizobacteria ◽  
Stress Conditions ◽  
Volatile Organic ◽  
Plant Growth Promoting ◽  
Growth Promoting

Salt stress is one of the major abiotic stresses that affects plant growth and development. The use of plant growth-promoting rhizobacteria to mitigcate salt stress damage in plants is an important way to promote crop growth under salt stress conditions. Rahnella aquatilis JZ-GX1 is a plant growth-promoting rhizobacterial strain, but it is not clear whether it can improve the salt tolerance of plants, and in particular, the role of volatile substances in plant salt tolerance is unknown. We investigated the effects of volatile organic compounds (VOCs) from JZ-GX1 on the growth performance, osmotic substances, ionic balance and antioxidant enzyme activities of acacia seedlings treated with 0 and 100mm NaCl and explored the VOCs associated with the JZ-GX1 strain. The results showed that compared to untreated seedlings, seedlings exposed to plant growth-promoting rhizobacterium JZ-GX1 via direct contact with plant roots under salt stress conditions exhibited increases in fresh weight, lateral root number and primary root length equal to approximately 155.1, 95.4, and 71.3%, respectively. Robinia pseudoacacia seedlings exposed to VOCs of the JZ-GX1 strain showed increases in biomass, soil and plant analyser development values and lateral root numbers equal to 132.1, 101.6, and 166.7%, respectively. Additionally, decreases in malondialdehyde, superoxide anion (O2−) and hydrogen peroxide (H2O2) contents and increases in proline contents and superoxide dismutase, peroxidase and glutathione reductase activities were observed in acacia leaves. Importantly, the sodium-potassium ratios in the roots, stems, and leaves of acacia exposed to VOCs of the JZ-GX1 strain were significantly lower than those in the control samples, and this change in ion homeostasis was consistent with the upregulated expression of the (Na+, K+)/H+ reverse cotransporter RpNHX1 in plant roots. Through GC-MS and creatine chromatography, we also found that 2,3-butanediol in the volatile gases of the JZ-GX1 strain was one of the important signaling substances for improving the salt tolerance of plants. The results showed that R. aquatilis JZ-GX1 can promote the growth and yield of R. pseudoacacia under normal and salt stress conditions. JZ-GX1 VOCs have good potential as protectants for improving the salt tolerance of plants, opening a window of opportunity for their application in salinized soils.

scholarly journals Transcriptome Analysis of Ice Plant Growth-Promoting Endophytic Bacterium Halomonas sp. Strain MC1 to Identify the Genes Involved in Salt Tolerance

2020 ◽  
Vol 8 (1) ◽  
pp. 88 ◽  
Author(s):  
Jian Zhang ◽  
Pengcheng Wang ◽  
Hongmei Tian ◽  
Zhen Tao ◽  
Tingting Guo
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Endophytic Bacterium ◽  
Complex Salt ◽  
Rna Seq ◽  
Ice Plant ◽  
Soil Ecosystems ◽  
Plant Growth Promoting ◽  
Microbe Interactions ◽  
Growth Promoting

Salt stress is an important adverse condition encountered during plant and microbe growth in terrestrial soil ecosystems. Currently, how ice plant (Mesembryanthemum crystallinum) growth-promoting endophytic bacteria (EB) cope with salt stress and regulate growth and the genes responsible for salt tolerance remain unknown. We applied RNA-Seq technology to determine the growth mechanism of the EB Halomonas sp. MC1 strain and the genes involved in salt tolerance. A total of 893 genes were significantly regulated after salt treatment. These genes included 401 upregulated and 492 downregulated genes. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes analysis revealed that the most enriched genes included those related to the outer membrane-bounded periplasmic space, ATPase activity, catabolic process, and proton transmembrane transport. The quantitative real-time polymerase chain reaction data were similar to those obtained from RNA-Seq. The MC1 strain maintained survival under salt stress by regulating cellular and metabolic processes and pyruvate metabolism pathways such as organic and carboxylic acid catabolic pathways. We highlighted the response mechanism of Halomonas sp. MC1 to fully understand the dynamics of complex salt–microbe interactions.

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

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.

scholarly journals Newly Identified Wild Rice Accessions Conferring High Salt Tolerance Might Use a Tissue Tolerance Mechanism in Leaf

2018 ◽  
Vol 9 ◽  
Author(s):  
Manas R. Prusty ◽  
Sung-Ryul Kim ◽  
Ricky Vinarao ◽  
Frederickson Entila ◽  
James Egdane ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Wild Rice ◽  
High Salt ◽  
Tolerance Mechanism ◽  
High Salt Tolerance

Rhizobacteria containing ACC-deaminase confer salt tolerance in maize grown on salt-affected fields

2009 ◽  
Vol 55 (11) ◽  
pp. 1302-1309 ◽  
Author(s):  
Sajid Mahmood Nadeem ◽  
Zahir Ahmad Zahir ◽  
Muhammad Naveed ◽  
Muhammad Arshad
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Plant Growth ◽  
Ethylene Production ◽  
Acc Deaminase ◽  
Plant Growth Promoting Rhizobacteria ◽  
Growth And Yield ◽  
Negative Effect ◽  
Plant Growth Promoting ◽  
Growth Promoting

Salt stress is one of the major constraints hampering agricultural production owing to its impact on ethylene production and nutritional imbalance. A check on the accelerated ethylene production in plants could be helpful in minimizing the negative effect of salt stress on plant growth and development. Four Pseudomonas , 1 Flavobacterium , and 1 Enterobacter strain of plant growth promoting rhizobacteria containing 1-aminocyclopropane-1-carboxylate (ACC)-deaminase were selected and their effects on growth and yield of maize were investigated to improve the salt tolerance of maize grown on salt-affected fields. The selected rhizobacterial isolates reduced or eliminated the classical “triple” response, indicating their ability to reduce stress-induced ethylene levels. Results showed that rhizobacterial strains, particularly Pseudomonas and Enterobacter spp., significantly promoted the growth and yield of maize compared with the non-inoculated control. Pseudomonas fluorescens increased plant height, biomass, cob yield, grain yield, 1000 grain mass, and straw yield of maize up to 29%, 127%, 67%, 60%, 17%, and 166%, respectively, over the control. Under stress conditions, more N, P, and K uptake and high K+–Na+ ratios were recorded in inoculated plants compared with the control. The results imply that inoculation with plant growth promoting rhizobacteria containing ACC-deaminase could be a useful approach for improving growth and yield of maize under salt-stressed conditions.

Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress

2012 ◽  
Vol 92 (2) ◽  
pp. 311-319 ◽  
Author(s):  
Cheng-Wu Jin ◽  
Yan-Lin Sun ◽  
Dong-Ha Cho
Keyword(s):  
Salt Stress ◽  
Water Potential ◽  
Treatment Period ◽  
Photosynthetic Rate ◽  
Salt Concentration ◽  
Proline Content ◽  
High Salt ◽  
Hibiscus Cannabinus ◽  
Salt Adaptation ◽  
Salt Treatment

Jin, C.-W., Sun, Y.-L. and Cho, D.-H. 2012. Changes in photosynthetic rate, water potential, and proline content in kenaf seedlings under salt stress. Can. J. Plant Sci. 92: 311–319. As irrigation water salinization has become a serious constraint for crop production, as well as soil salinity, the selection and use of salt-tolerant species is urgently required. In this study, we describe the salt responses of three kenaf (Hibiscus cannabinus L.) cultivars and select the cultivar with high salt tolerance. Responses to salt stress were investigated in terms of growth, water potentials, photosynthesis, and proline contents. Photosynthesis, evaluated by net CO2 assimilation rate, stomatal conductance, and intercellular CO2 concentration, did not show any significant effects among the cultivars. Leaf water potential decreased depending on salt concentration and salt treatment period. Proline accumulation was enhanced, particularly depending on salt concentration, but not salt treatment period. As salt concentration increased, seedling growth was inhibited to a certain extent, and the inhibition of growth depended mainly on salt concentration. At the early stage of treatment, Dowling was more tolerant to salt stress than Everglade-41 and Tainung-2. Although Dowling showed a lower decrease in fresh weight, Tainung-2 always maintained a relatively high vegetative yield, even under high salt stress. Tainung-2, having greater salt adaptation, was therefore considered an ideal cultivar for popularization and farm cultivation.

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