scholarly journals PGPB Improve Photosynthetic Activity and Tolerance to Oxidative Stress in Brassica napus Grown on Salinized Soils

2021 ◽  
Vol 11 (23) ◽  
pp. 11442
Author(s):  
Massimiliano Rossi ◽  
Ilaria Borromeo ◽  
Concetta Capo ◽  
Bernard R. Glick ◽  
Maddalena Del Gallo ◽  
...  
Keyword(s):  
Salt Stress ◽  
Brassica Napus ◽  
Plant Growth ◽  
Bacterial Species ◽  
Membrane Damage ◽  
Photosynthetic Apparatus ◽  
Soil Salinization ◽  
Saline Stress ◽  
Plant Growth Promoting Bacteria ◽  
Oxidative Stresses

Soil salinization, one of the most common causes of soil degradation, negatively affects plant growth, reproduction, and yield in plants. Saline conditions elicit some physiological changes to cope with the imposed osmotic and oxidative stresses. Inoculation of plants with some bacterial species that stimulate their growth, i.e., plant growth-promoting bacteria (PGPB), may help plants to counteract saline stress, thus improving the plant’s fitness. This manuscript reports the effects of the inoculation of a salt-sensitive cultivar of Brassica napus (canola) with five different PGPB species (separately), i.e., Azospirillum brasilense, Arthrobacter globiformis, Burkholderia ambifaria, Herbaspirillum seropedicae, and Pseudomonas sp. on plant salt stress physiological responses. The seeds were sown in saline soil (8 dS/m) and inoculated with bacterial suspensions. Seedlings were grown to the phenological stage of rosetta, when morphological and physiological features were determined. In the presence of the above-mentioned PGPB, salt exposed canola plants grew better than non-inoculated controls. The water loss was reduced in inoculated plants under saline conditions, due to a low level of membrane damage and the enhanced synthesis of the osmolyte proline, the latter depending on the bacterial strain inoculated. The reduction in membrane damage was also due to the increased antioxidant activity (i.e., higher amount of phenolic compounds, enhanced superoxide dismutase, and ascorbate peroxidase activities) in salt-stressed and inoculated Brassica napus. Furthermore, the salt-stressed and inoculated plants did not show detrimental effects to their photosynthetic apparatus, i.e., higher efficiency of PSII and low energy dissipation by heat for photosynthesis were detected. The improvement of the response to salt stress provided by PGPB paves the way to further use of PGPB as inoculants of plants grown in saline soils.

scholarly journals Overview of the Role of Rhizobacteria in Plant Salt Stress Tolerance

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1759
Author(s):  
Miguel Ayuso-Calles ◽  
José David Flores-Félix ◽  
Raúl Rivas
Keyword(s):  
Salt Stress ◽  
Plant Growth ◽  
Osmotic Stress ◽  
Nutrient Deficiency ◽  
Cost Effective ◽  
Growth And Yield ◽  
Soil Conditions ◽  
Saline Stress ◽  
Plant Growth Promoting Bacteria ◽  
Plant Tolerance

Salinity is one of the main causes of abiotic stress in plants, resulting in negative effects on crop growth and yield, especially in arid and semi-arid regions. The effects of salinity on plant growth mainly generate osmotic stress, ion toxicity, nutrient deficiency, and oxidative stress. Traditional approaches for the development of salt-tolerant crops are expensive and time-consuming, as well as not always being easy to implement. Thus, the use of plant growth-promoting bacteria (PGPB) has been reported as a sustainable and cost-effective alternative to enhance plant tolerance to salt stress. In this sense, this review aims to understand the mechanisms by which PGPB help plants to alleviate saline stress, including: (i) changes in the plant hormonal balance; (ii) release of extracellular compounds acting as chemical signals for the plant or enhancing soil conditions for plant development; (iii) regulation of the internal ionic content of the plant; or iv) aiding in the synthesis of osmoprotectant compounds (which reduce osmotic stress). The potential provided by PGPB is therefore an invaluable resource for improving plant tolerance to salinity, thereby facilitating an increase in global food production and unravelling prospects for sustainable agricultural productivity.

Salt-tolerant and plant-growth-promoting bacteria isolated from high-yield paddy soil

2018 ◽  
Vol 64 (12) ◽  
pp. 968-978 ◽  
Author(s):  
Shiying Zhang ◽  
Cong Fan ◽  
Yongxia Wang ◽  
Yunsheng Xia ◽  
Wei Xiao ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Plant Growth ◽  
Paddy Soil ◽  
Effective Strain ◽  
High Yield ◽  
Saline Stress ◽  
Plant Growth Promoting Bacteria ◽  
Salt Tolerant ◽  
Plant Growth Promoting ◽  
Growth Promoting

Growth and productivity of rice is negatively affected by soil salinity. However, some salt-tolerant bacteria improve the health of plants under saline stress. In this study, 305 bacteria were isolated from paddy soil in Taoyuan, China. Among these, 162 strains were tested for salt-tolerance; 67.3%, 28.4%, and 9.3% of the strains could grow in media with NaCl concentrations of 50, 100, and 150 g/L, respectively. The phylogenic analysis of 74 of these 162 strains indicates that these bacteria belong to Bacillales (72%), Actinomycetales (22%), Rhizobiales (1%), and Oceanospirillales (4%). Among 162 strains, 30 salt-tolerant strains were screened for their plant-growth-promoting activities under axenic conditions at 3, 6, 9, and 12 g/L NaCl; 43%–97% of the strains could improve rice germination energy or germination capacity, while 63%–87% of the strains could increase shoot and root lengths. Among various plant-growth-promoting bacteria, TY0307 was the most effective strain for promoting the growth of rice, even at high salt stress. Its promotor effects were associated with its production of 1-aminocyclopropane-1-carboxycarboxylate deaminase, indole acetic acid, and siderophores; induction of proline accumulation; and reduction of the salt-induced malondialdehyde content. These results suggest that several strains isolated from paddy soil could improve rice salt tolerance and may be used in the development of biofertilizer.

scholarly journals Bacillus pumilus increases boron uptake and inhibits rapeseed growth under boron supply irrespective of phosphorus fertilization

AoB Plants ◽  
2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Sajid Masood ◽  
Xue Qiang Zhao ◽  
Ren Fang Shen
Keyword(s):  
Brassica Napus ◽  
Plant Growth ◽  
Bacillus Pumilus ◽  
Phosphorus Fertilization ◽  
Plant Growth Promoting Bacteria ◽  
Boron Uptake ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
B Uptake ◽  
Pot Culture

AbstractThe present study was carried out to investigate how plant growth-promoting bacteria (PGPB) influence plant growth and uptake of boron (B) and phosphorus (P) in rapeseed (Brassica napus). Rapeseed was subjected to control, B, P and B + P treatments, either with or without B. pumilus (PGPB) inoculation, and grown in pot culture for 6 weeks. In the absence of B. pumilus, the addition of B, P or both elements improved the growth of rapeseed compared with the control. Interestingly, B. pumilus inoculation inhibited plant growth and enhanced B uptake under B and B + P but not under control and P conditions. In addition, B. pumilus inoculation decreased the pH of soil under B and B + P supplies. Bacillus pumilus inoculation thus increased rapeseed B uptake and inhibited growth under B supply, which suggests that the effects of PGPB on rapeseed growth depend on the addition of B to soil. Bacillus pumilus inoculation may therefore be recommended for the enhancement of rapeseed B levels in B-deficient soils but not in B-sufficient ones.

scholarly journals Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1523 ◽  
Author(s):  
Alessandra Moncada ◽  
Filippo Vetrano ◽  
Alessandro Miceli
Keyword(s):  
Salt Stress ◽  
Plant Growth ◽  
Leafy Vegetables ◽  
Mineral Nutrient ◽  
Plant Growth Promoting Bacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Leaf Lettuce ◽  
Positive Effect ◽  
Nutrient Solutions

Mediterranean areas with intensive agriculture are characterized by high salinity of groundwater. The use of this water in hydroponic cultivations can lead to nutrient solutions with an electrical conductivity that overcomes the tolerance threshold of many vegetable species. Plant growth-promoting rhizobacteria (PGPR) were shown to minimize salt stress on several vegetable crops but the studies on the application of PGPR on leafy vegetables grown in hydroponics are rather limited and have not been used under salt stress conditions. This study aimed to evaluate the use of plant growth-promoting bacteria to increase the salt tolerance of leaf lettuce grown in autumn and spring in a floating system, by adding a bacterial biostimulant (1.5 g L−1 of TNC BactorrS13 a commercial biostimulant containing 1.3 × 108 CFU g−1 of Bacillus spp.) to mineral nutrient solutions (MNS) with two salinity levels (0 and 20 mM NaCl). Leaf lettuce plants showed a significant reduction of growth and yield under salt stress, determined by the reduction of biomass, leaf number, and leaf area. Plants showed to be more tolerant to salinity in autumn than in spring. The inhibition of lettuce plant growth due to salt stress was significantly alleviated by the addition of the bacterial biostimulant to the MNS, which had a positive effect on plant growth and fresh and dry biomass accumulation of the unstressed lettuce in both cultivation seasons, and maintained this positive effect in brackish MNS, with similar or even significantly higher values of morphologic, physiologic, and yield parameters than those recorded in control unstressed plants.

scholarly journals Effect of Bacillus mesonae H20-5 Treatment on Rhizospheric Bacterial Community of Tomato Plants under Salinity Stress

2021 ◽  
Vol 37 (6) ◽  
pp. 662-672
Author(s):  
Shin Ae Lee ◽  
Hyeon Su Kim ◽  
Mee Kyung Sang ◽  
Jaekyeong Song ◽  
Hang-Yeon Weon
Keyword(s):  
Bacterial Community ◽  
Plant Growth ◽  
Soil Salinity ◽  
Bacterial Communities ◽  
Bacterial Species ◽  
Rrna Gene ◽  
Plant Growth Promoting Bacteria ◽  
Tomato Plants ◽  
Rhizosphere Soils ◽  
Salinity Levels

Plant growth-promoting bacteria improve plant growth under abiotic stress conditions. However, their effects on microbial succession in the rhizosphere are poorly understood. In this study, the inoculants of Bacillus mesonae strain H20-5 were administered to tomato plants grown in soils with different salinity levels (EC of 2, 4, and 6 dS/m). The bacterial communities in the bulk and rhizosphere soils were examined 14 days after H20-5 treatment using Illumina MiSeq sequencing of the bacterial 16S rRNA gene. Although the abundance of H20-5 rapidly decreased in the bulk and rhizosphere soils, a shift in the bacterial community was observed following H20-5 treatment. The variation in bacterial communities due to H20-5 treatment was higher in the rhizosphere than in the bulk soils. Additionally, the bacterial species richness and diversity were greater in the H20-5 treated rhizosphere than in the control. The composition and structure of the bacterial communities varied with soil salinity levels, and those in the H20-5 treated rhizosphere soil were clustered. The members of Actinobacteria genera, including Kineosporia, Virgisporangium, Actinoplanes, Gaiella, Blastococcus, and Solirubrobacter, were enriched in the H20-5 treated rhizosphere soils. The microbial co-occurrence network of the bacterial community in the H20-5 treated rhizosphere soils had more modules and keystone taxa compared to the control. These findings revealed that the strain H20-5 induced systemic tolerance in tomato plants and influenced the diversity, composition, structure, and network of bacterial communities. The bacterial community in the H20-5 treated rhizosphere soils also appeared to be relatively stable to soil salinity changes.

scholarly journals Alterations in the root proteomes of Brassica napus cultivars under salt stress

2021 ◽  
Vol 45 (1) ◽  
pp. 87-96
Author(s):  
Hakan Terzi ◽  
Mustafa Yıldız
Keyword(s):  
Salt Stress ◽  
Brassica Napus ◽  
Heat Shock ◽  
Seed Germination ◽  
Nacl Stress ◽  
Soil Salinization ◽  
Comparative Proteomics ◽  
Nacl Concentration ◽  
Protein Alterations ◽  
Root Proteins

Soil salinization is an important environmental problem affecting agricultural production worldwide. Seed germination is a critical process, and seedling establishment under saline conditions can be achieved by successful germination. In the present study, comparative proteomics combined with physiological analyses were used to investigate the protein alterations in germinating Brassica napus cultivars (Caravel and Sary) under NaCl stress. Seed germination declined with the increasing NaCl concentration. However, Caravel exhibited better performance in terms of seed germination and seedling growth under salinity stress. Therefore, Caravel was found to be more tolerant to salinity than Sary. The root proteins were extracted from B. napus cultivars germinating on a plant growth medium with or without 100 mM NaCl for seven days. After the root proteins had been separated by two-dimensional (2-D) gel electrophoresis, the differentially accumulated proteins were identified using MALDI-TOF/TOF MS. The comparative proteomics analysis revealed 12 and 27 statistically significant proteins accumulated in the NaCl-treated roots of Caravel and Sary, respectively. The identified proteins were mostly involved in protein metabolism, stress defense, cytoskeleton and cell wall metabolism, and energy metabolism. The salt-sensitive cultivar Sary displayed an elevated accumulation of proteins involved in antioxidant defense and the protein catabolic process such as superoxide dismutase [Fe], L-ascorbate peroxidase 1, and different components of the proteasome system. On the other hand, the levels of molecular chaperones including 20 kDa chaperonin, chaperonin CPN60, heat shock cognate protein HSC70, and heat shock 70 kDa protein 1 were higher in Caravel than Sary under salt stress. These findings will provide the possible mechanisms which contribute to salt tolerance and may serve as the basis for improving salinity tolerance in rapeseed.

scholarly journals Amelioration of Saline Stress on Chia (Salvia hispanica L.) Seedlings Inoculated With Halotolerant Plant Growth-Promoting Bacteria Isolated From Hypersaline Environments

2021 ◽  
Vol 3 ◽  
Author(s):  
María Florencia Yañez-Yazlle ◽  
Neli Romano-Armada ◽  
Verónica Beatriz Rajal ◽  
Verónica Patricia Irazusta
Keyword(s):  
Plant Growth ◽  
Culture Media ◽  
Saline Stress ◽  
Plant Growth Promoting Bacteria ◽  
Initial Growth ◽  
Hypersaline Environments ◽  
Salvia Hispanica ◽  
Plant Growth Promoting ◽  
Pgp Activities ◽  
Growth Promoting

The rhizosphere and microbiome of halotolerant plants could be crucial for alleviating salinity stress during plant growth. The aims of this work were (1) to isolate bacteria from rhizosphere and bulk soil samples from the Salar del Hombre Muerto (Catamarca, Argentina), (2) to characterize different plant growth-promoting (PGP) activities produced by these bacterial isolates, and (3) to evaluate their effect on the initial growth of chia (Salvia hispanica L.) under saline stress. A total of 667 microorganisms were isolated, using different culture media with NaCl, and their abilities for nitrogen fixation, phosphate solubilization, siderophores production, and indole-3-acetic acid production were evaluated. Thirteen strains were selected for showing all the tested PGP activities; they belonged to the genera Kushneria, Halomonass, Pseudomonas, Planomicrobium, and Pseudarthrobacter. The strains Kushneria sp. and Halomonas sp. showed the highest salinity tolerance (from 50 to 2,000 mM NaCl) and biomass and biofilm production. Chia seeds were treated with six of the first 13 selected strains to evaluate their plant growth-promoting effect under saline stress (without and with 50 and 100 mM NaCl). Halomonas sp. 3R.12 and Kushneria sp. T3.7 produced heavier seedlings with a balanced shoot/root length ratio, while Pseudomonas sp. AN23 showed the best effect upon chia seedlings, with a morphological response similar to non-stressed seedlings. On the other hand, seedlings displayed no responses when inoculated with Planomicrobium sp. 3S.31 and Pseudarthrobacter sp. ER25. This study contributes to the knowledge on microorganisms from hypersaline environments as plant growth promoters for their use in the production of salt-sensitive crops, among other potential uses.

scholarly journals Physiological behavior of melon cultivars submitted to soil salinity1

2018 ◽  
Vol 48 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Valéria Fernandes de Oliveira Sousa ◽  
Caciana Cavalcanti Costa ◽  
Genilson Lima Diniz ◽  
João Batista dos Santos ◽  
Marinês Pereira Bomfim
Keyword(s):  
Soil Salinity ◽  
Photosynthetic Apparatus ◽  
Poor Quality ◽  
Soil Salinization ◽  
Limiting Factor ◽  
Saline Stress ◽  
Saturation Extract ◽  
Salinity Levels ◽  
Quality Water ◽  
Poor Quality Water

ABSTRACT Melon is one of the most important vegetables for the Brazilian foreign trade. However, in semi-arid areas, the irregular rainfall, excessive use of fertilizers and, especially, poor quality water contribute to the soil salinization, becoming a limiting factor and damaging the photosynthetic apparatus, as well as affecting yield. This study aimed to evaluate the physiological behavior of melon cultivars submitted to soil salinity. For that, an experiment was conducted in a greenhouse, using a randomized block experimental design, in a 3 x 5 factorial scheme, with the first factor related to melon cultivars (Iracema, Goldex and Natal) and the second one related to soil salinity levels (0.3 dS m-1, 1.3 dS m-1, 2.3 dS m-1, 3.3 dS m-1 and 4.3 dS m-1 of electrical conductivity), with four replications. For soil salinization, a saturation extract with initial soil salinity of 0.3 dS m-1 was obtained, while the other levels were prepared by adding NaCl to the soil. The physiology of melon plants is negatively affected by the increased salinity in the soil. The evaluated cultivars do not show differences in tolerance for the physiological response to soil saline stress.

scholarly journals Plant-Growth-Promoting Bacteria Mitigating Soil Salinity Stress in Plants

2020 ◽  
Vol 10 (20) ◽  
pp. 7326
Author(s):  
Stefan Shilev
Keyword(s):  
Plant Growth ◽  
Salinity Stress ◽  
Soil Salinity ◽  
Soil Salinization ◽  
Plant Growth Promoting Bacteria ◽  
Plant Tolerance ◽  
Beneficial Effects ◽  
Negative Effect ◽  
Plant Growth Promoting ◽  
Growth Promoting

Soil deterioration has led to problems with the nutrition of the world’s population. As one of the most serious stressors, soil salinization has a negative effect on the quantity and quality of agricultural production, drawing attention to the need for environmentally friendly technologies to overcome the adverse effects. The use of plant-growth-promoting bacteria (PGPB) can be a key factor in reducing salinity stress in plants as they are already introduced in practice. Plants having halotolerant PGPB in their root surroundings improve in diverse morphological, physiological, and biochemical aspects due to their multiple plant-growth-promoting traits. These beneficial effects are related to the excretion of bacterial phytohormones and modulation of their expression, improvement of the availability of soil nutrients, and the release of organic compounds that modify plant rhizosphere and function as signaling molecules, thus contributing to the plant’s salinity tolerance. This review aims to elucidate mechanisms by which PGPB are able to increase plant tolerance under soil salinity.

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