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Lastochkina O, Yuldashev R, Avalbaev A, Allagulova C, Veselova S. The Contribution of Hormonal Changes to the Protective Effect of Endophytic Bacterium Bacillus subtilis on Two Wheat Genotypes with Contrasting Drought Sensitivities under Osmotic Stress. Microorganisms 2023; 11:2955. [PMID: 38138099 PMCID: PMC10745732 DOI: 10.3390/microorganisms11122955] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/29/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
A comparative analysis was conducted to evaluate the effects of seed priming with endophytic bacterium Bacillus subtilis 10-4 (BS) on the hormonal system and cell wall tolerance (lipid peroxidation (LPO), electrolyte leakage (EL), and root lignin deposition) of two Triticum aestivum L. (wheat) varieties with contrasting drought sensitivities (Ekada 70-drought-tolerant (DT); Salavat Yulaev-drought-sensitive (DS)) under normal conditions and 12% polyethylene glycol-6000 (PEG)-induced osmotic stress. The results showed that under normal conditions, the growth stimulation in wheat plants by BS was attributed to changes in the hormonal balance, particularly an increase in endogenous indole-3-acetic acid (IAA) accumulation. However, under stress, a significant hormonal imbalance was observed in wheat seedlings, characterized by a pronounced accumulation of abscisic acid (ABA) and a decrease in the levels of IAA and cytokinins (CK). These effects were reflected in the inhibition of plant growth. BS exhibited a protective effect on stressed plants, as evidenced by a significantly lower amplitude of stress-induced changes in the hormonal system: maintaining the content of IAA at a level close to the control, reducing stress-induced ABA accumulation, and preventing CK depletion. These effects were further reflected in the normalization of growth parameters in dehydrated seedlings, as well as a decrease in leaf chlorophyll degradation, LPO, and EL, along with an increase in lignin deposition in the basal part of the roots in both genotypes. Overall, the findings demonstrate that BS, producing phytohormones, specifically IAA and ABA, had a more pronounced protective effect on DT plants, as evidenced by a smaller amplitude of stress-induced hormonal changes, higher leaf chlorophyll content, root lignin deposition, and lower cell membrane damage (LPO) and permeability (EL) compared to DS plants.
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Affiliation(s)
- Oksana Lastochkina
- Institute of Biochemistry and Genetics—Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 71 Pr. Oktyabrya, 450054 Ufa, Russia (A.A.); (S.V.)
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Maslennikova D, Knyazeva I, Vershinina O, Titenkov A, Lastochkina O. Seed Treatment with Sodium Nitroprusside Ensures a Long-Term Physiological and Protective Effect on Wheat under Salinity. Life (Basel) 2023; 13:1499. [PMID: 37511874 PMCID: PMC10381903 DOI: 10.3390/life13071499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 07/30/2023] Open
Abstract
Although salinity inhibits plant growth, the use of a nitric oxide (NO) gasotransmitter can reduce its negative effects. In this study, the influence of 200 μM sodium nitroprusside (SNP) (donor of NO) on wheat plants (Triticum aestivum L., cv. Salavat Yulaev) in conditions of salinization (100 mM NaCl) was analyzed in pot experiments. Seed priming regulated the level of endogenous NO in normal and salinity conditions throughout the entire experiment (30 and 60 days). Salinity led to the strong accumulation of NO and H2O2, which is negative for plants, and significantly reduced leaf area and photosynthetic pigments (chlorophyll a and b and carotenoids). In addition, stress caused a drop in the content of reduced glutathione (GSH) and ascorbic acid (ASA), an accumulation of oxidized glutathione (GSSG), and significantly activated glutathione reductase (GR), ascorbate peroxidase (APX), and lipid peroxidation (LPO) in wheat leaves. SNP treatment significantly attenuated the negative effects of salinity on leaf area and photosynthetic pigments. An important indicator of reducing the damaging effect of salinity on treated plants is the stabilization of the content of GSH and ASA throughout the experiment (60 days). This condition has been associated with long-term modulation of GR and APX activity. Such an effect of 200 μM SNP may be related to its ability to reduce stress-induced accumulation of NO. Additional accumulation of proline also mitigated the negative effect of salinity on plants, and this also evidenced decreased LPO and H2O2 in them. For the first time, in natural growing conditions (small-scale field experiments), it was found that pre-sowing seed treatment with 200 μM SNP led to an improvement in the main yield indicators and an increase in the content of essential amino acids in wheat grains. Thus, SNP treatment can be used as an effective approach for prolonged protection of wheat plants under salinity and to improve grain yield and its quality.
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Affiliation(s)
- Dilara Maslennikova
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
| | - Inna Knyazeva
- Federal Scientific Agroengineering Center VIM, 109428 Moscow, Russia
| | - Oksana Vershinina
- Federal Scientific Agroengineering Center VIM, 109428 Moscow, Russia
| | - Andrey Titenkov
- Federal Scientific Agroengineering Center VIM, 109428 Moscow, Russia
| | - Oksana Lastochkina
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
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Maslennikova D, Koryakov I, Yuldashev R, Avtushenko I, Yakupova A, Lastochkina O. Endophytic Plant Growth-Promoting Bacterium Bacillus subtilis Reduces the Toxic Effect of Cadmium on Wheat Plants. Microorganisms 2023; 11:1653. [PMID: 37512826 PMCID: PMC10386265 DOI: 10.3390/microorganisms11071653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/19/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Heavy metal ions, in particular cadmium (Cd), have a negative impact on the growth and productivity of major crops, including wheat. The use of environmentally friendly approaches, in particular, bacteria that have a growth-stimulating and protective effect, can increase the resistance of plants. The effects of the pre-sowing seed treatment with the plant growth-promoting endophyte Bacillus subtilis 10-4 (BS) on cadmium acetate (Cd)-stressed Triticum aestivum L. (wheat) growth, photosynthetic pigments, oxidative stress parameters, roots' lignin content, and Cd ions accumulation in plants were analyzed. The results showed that the tested Cd-tolerant BS improved the ability of wheat seeds to germinate in the presence of different Cd concentrations (0, 0.1, 0.5, and 1 mM). In addition, the bacterial treatment significantly decreased the damaging effects of Cd stress (1 mM) on seedlings' linear dimensions (lengths of roots and shoots), biomass, as well as on the integrity and permeability of the cell walls (i.e., lipid peroxidation and electrolyte leakage) and resulted in reduced H2O2 generation. The pretreatment with BS prevented the Cd-induced degradation of the leaf photosynthetic pigments chlorophyll (Chl) a, Chl b, and carotenoids. Moreover, the bacterial treatment intensified the lignin deposition in the roots under normal and, especially, Cd stress conditions, thereby enhancing the barrier properties of the cell wall. This manifested in a reduced Cd ions accumulation in the roots and in the restriction of its translocation to the aboveground parts (shoots) of the bacterized plants under Cd stress in comparison with non-bacterized controls. Thus, the pre-sowing seed treatment with the endophyte BS may serve as an eco-friendly approach to improve wheat production in Cd-contaminated areas.
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Affiliation(s)
| | - Igor Koryakov
- Institute of Biochemistry and Genetics UFRC RAS, Ufa 450054, Russia
| | - Ruslan Yuldashev
- Institute of Biochemistry and Genetics UFRC RAS, Ufa 450054, Russia
| | - Irina Avtushenko
- Institute of Biochemistry and Genetics UFRC RAS, Ufa 450054, Russia
- Department of Biology, Ufa University of Sciences and Technology, 32 Zaki Validi, Ufa 450076, Russia
| | - Albina Yakupova
- Institute of Biochemistry and Genetics UFRC RAS, Ufa 450054, Russia
- Department of Biology, Ufa University of Sciences and Technology, 32 Zaki Validi, Ufa 450076, Russia
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Vimal SR, Singh JS, Prasad SM. Prospective of Indole-3-Acteic Acid (IAA) and Endophytic Microbe Bacillus subtilis Strain SSA4 in Paddy Seedlings Development and Ascorbate-Glutathione (AsA-GSH) Cycle Regulation to Mitigate NaCl Toxicity. Mol Biotechnol 2023:10.1007/s12033-023-00743-w. [PMID: 37087717 DOI: 10.1007/s12033-023-00743-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/02/2023] [Indexed: 04/24/2023]
Abstract
Plant growth promoting endophytes significantly affected plant health. The present study demonstrates effect of endophytic isolate Bacillus subtilis strain SSA4 and exogenous Indole-3-acetic acid (IAA) on paddy seedlings growth parameters, photosynthetic pigments, photosynthesis, leaf gas exchange parameters, respiration, oxidative stress biomarkers and Ascorbate-Glutathione (AsA-GSH) cycle under different NaCl (0-300 mM) stresses. The Bacillus subtilis SSA4 was identified by 16S r-RNA gene sequence analyses and NCBI BLASTn tools. The B. subtilis SSA4 tolerated 1100 mM NaCl and produced IAA (42.15 µg m/L) at 300 mM NaCl stress. The paddy genotype (HUR 917) treated with exogenous IAA (21 µg m/L) and B. subtilis strain SSA4 egg cell based bioformulation was significantly affected seedlings physiology and biochemistry at lower (150 mM) and higher (300 mM) NaCl doses. In conclusion, co-inoculation found as effective green tool to mitigating salinity stress in paddy seedlings.
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Affiliation(s)
- Shobhit Raj Vimal
- Ranjan Plant Physiology & Biochemistry Laboratory, Department of Botany, University of Allahabad, Prayagraj, 221102, India
| | - Jay Shankar Singh
- Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow, 226025, India
| | - Sheo Mohan Prasad
- Ranjan Plant Physiology & Biochemistry Laboratory, Department of Botany, University of Allahabad, Prayagraj, 221102, India.
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Lastochkina OV, Allagulova CR. The Mechanisms of the Growth Promotion and Protective Effects of Endophytic PGP Bacteria in Wheat Plants Under the Impact of Drought (Review). APPL BIOCHEM MICRO+ 2023; 59:14-32. [DOI: 10.1134/s0003683823010039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/26/2022] [Accepted: 09/02/2022] [Indexed: 06/23/2023]
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Khakimova L, Chubukova O, Vershinina Z, Maslennikova D. Effects of Pseudomonas sp. OBA 2.4.1 on Growth and Tolerance to Cadmium Stress in Pisum sativum L. BioTech (Basel) 2023; 12:5. [PMID: 36648831 DOI: 10.3390/biotech12010005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023]
Abstract
Cadmium stress is a barrier to crop production, yield, quality, and sustainable agriculture. In the current study, we investigated the characteristics of bacterial strain Pseudomonas sp. OBA 2.4.1 under cadmium (CdCl2) stress and its influence on Cd stresses in pea (Pisum sativum L.) seedlings. It was revealed that strain OBA 2.4.1 is tolerant of up to 2 mM CdCl2, and seed treatment with the bacterium enhanced pea plant growth (length of seedlings) under 0.5 mM cadmium stress. This bacterial strain showed plant growth-promoting properties, including biofilm formation and siderophore activity. An important advantage of the studied strain OBA 2.4.1 is its ability to colonize the plant roots. Moreover, the inoculation with strain OBA 2.4.1 significantly reduced oxidative stress markers in pea seedlings under cadmium stress. These findings suggest that cadmium stress-tolerant strain OBA 2.4.1 could enhance pea plant growth by mitigating stress-caused damage, possibly providing a baseline and eco-friendly approach to address heavy metal stress for sustainable agriculture.
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Lastochkina O, Ivanov S, Petrova S, Garshina D, Lubyanova A, Yuldashev R, Kuluev B, Zaikina E, Maslennikova D, Allagulova C, Avtushenko I, Yakupova A, Farkhutdinov R. Role of Endogenous Salicylic Acid as a Hormonal Intermediate in the Bacterial Endophyte Bacillus subtilis-Induced Protection of Wheat Genotypes Contrasting in Drought Susceptibility under Dehydration. Plants (Basel) 2022; 11:3365. [PMID: 36501403 PMCID: PMC9736644 DOI: 10.3390/plants11233365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Endophytic Bacillus subtilis is a non-pathogenic beneficial bacterium which promotes plant growth and tolerance to abiotic stresses, including drought. However, the underlying physiological mechanisms are not well understood. In this study, the potential role that endogenous salicylic acid (SA) plays in regulating endophytic B. subtilis-mediated drought tolerance in wheat (Triticum aestivum L.) was examined. The study was conducted on genotypes with contrasting levels of intrinsic drought tolerance (drought-tolerant (DT) cv. Ekada70; drought-susceptible (DS) cv. Salavat Yulaev). It was revealed that B. subtilis 10-4 promoted endogenous SA accumulation and increased the relative level of transcripts of the PR-1 gene, a marker of the SA-dependent defense pathway, but two wheat cultivars responded differently, with the highest levels exhibited in DT wheat seedlings. These had a positive correlation with the ability of strain 10-4 to effectively protect DT wheat seedlings against drought injury by decreasing osmotic and oxidative damages (i.e., proline, water holding capacity (WHC), and malondialdehyde (MDA)). However, the use of the SA biosynthesis inhibitor 1-aminobenzotriazole prevented endogenous SA accumulation under normal conditions and the maintenance of its increased level under stress as well as abolished the effects of B. subtilis treatment. Particularly, the suppression of strain 10-4-induced effects on proline and WHC, which are both contributing factors to dehydration tolerance, was found. Moreover, the prevention of strain 10-4-induced wheat tolerance to the adverse impacts of drought, as judged by the degree of membrane lipid peroxidation (MDA) and plant growth (length, biomass), was revealed. Thus, these data provide an argument in favor of a key role of endogenous SA as a hormone intermediate in triggering the defense responses by B. subtilis 10-4, which also afford the foundation for the development of the bacterial-induced tolerance of these two different wheat genotypes under dehydration.
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Affiliation(s)
- Oksana Lastochkina
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Sergey Ivanov
- Ufa Institute of Chemistry UFRC RAS, 69 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Svetlana Petrova
- Ufa Institute of Chemistry UFRC RAS, 69 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Darya Garshina
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Alsu Lubyanova
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Ruslan Yuldashev
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Bulat Kuluev
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Evgenia Zaikina
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Dilara Maslennikova
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Chulpan Allagulova
- Institute of Biochemistry and Genetics UFRC RAS, 71 Pr. Oktyabrya, 450054 Ufa, Russia
| | - Irina Avtushenko
- Department of Biology, Bashkir State University, 32 Zaki Validi, 450076 Ufa, Russia
| | - Albina Yakupova
- Department of Biology, Bashkir State University, 32 Zaki Validi, 450076 Ufa, Russia
| | - Rashit Farkhutdinov
- Department of Biology, Bashkir State University, 32 Zaki Validi, 450076 Ufa, Russia
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Maslennikova DR, Lastochkina OV, Shakirova FM. Exogenous Sodium Nitroprusside Improves Salt Stress Tolerance of Wheat (Triticum aestivum L.) via Regulating the Components of Ascorbate-Glutathione Cycle, Chlorophyll Content and Stabilization of Cell Membranes State. Russ J Plant Physiol 2022; 69:130. [DOI: 10.1134/s102144372206019x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/21/2022] [Accepted: 05/11/2022] [Indexed: 06/23/2023]
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Maslennikova D, Nasyrova K, Chubukova O, Akimova E, Baymiev A, Blagova D, Ibragimov A, Lastochkina O. Effects of Rhizobium leguminosarum Thy2 on the Growth and Tolerance to Cadmium Stress of Wheat Plants. Life (Basel) 2022; 12:1675. [PMID: 36295110 PMCID: PMC9605373 DOI: 10.3390/life12101675] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 10/18/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023] Open
Abstract
Cadmium (Cd) stress is an obstacle for crop production, quality crops, and sustainable agriculture. An important role is played by the application of eco-friendly approaches to improve plant growth and stress tolerance. In the current study, a pre-sowing seed treatment with Rhizobium leguminosarum strains, isolated from the leguminous plants Phaseolus vulgaris (strain Pvu5), Vicia sylvatica (strain VSy12), Trifolium hybridium (strain Thy2), and T. pratense (strain TPr4), demonstrated different effects on wheat (Triticum aestivum L.) plant growth under normal conditions. Among all tested strains, Thy2 significantly increased seed germination, seedling length, fresh and dry biomass, and leaf chlorophyll (Chl) content. Further analysis showed that Thy2 was capable of producing indole-3-acetic acid and siderophores and fixing nitrogen. Under Cd stress, Thy2 reduced the negative effect of Cd on wheat growth and photosynthesis and had a protective effect on the antioxidant system. This was expressed in the additional accumulation of glutathione and proline and the activation of glutathione reductase. In addition, Thy2 led to a significant reduction in oxidative stress, which was evidenced by the data on the stabilization of the ascorbate content and the activity of ascorbate peroxidase. In addition, Thy2 markedly reduced Cd-induced membrane lipid peroxidation and electrolyte leakage in the plants. Thus, the findings demonstrated the ability of the R. leguminosarum strain Thy2, isolated from T. hybridium nodules, to exert a growth-promoting and anti-stress effect on wheat plants. These results suggest that the Thy2 strain may enhance wheat plant growth by mitigating Cd stress, particularly through improving photosynthesis and antioxidant capacity and reducing the severity of oxidative damage. This may provide a basic and biological approach to use the Thy2 strain as a promising, eco-friendly candidate to combat Cd stress in wheat production.
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Affiliation(s)
- Dilara Maslennikova
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
- Department of Molecular Technologis, Ufa State Petroleum Technical University, 450000 Ufa, Russia
| | - Karina Nasyrova
- Department of Molecular Technologis, Ufa State Petroleum Technical University, 450000 Ufa, Russia
| | - Olga Chubukova
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
- Department of Molecular Technologis, Ufa State Petroleum Technical University, 450000 Ufa, Russia
| | - Ekaterina Akimova
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
| | - Andrey Baymiev
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
| | - Darya Blagova
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
| | - Almaz Ibragimov
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
| | - Oksana Lastochkina
- Ufa Federal Research Center, Institute of Biochemistry and Genetics, Russian Academy of Sciences, 450054 Ufa, Russia
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Hasanuzzaman M, Raihan MRH, Nowroz F, Fujita M. Insight into the Mechanism of Salt-Induced Oxidative Stress Tolerance in Soybean by the Application of Bacillus subtilis: Coordinated Actions of Osmoregulation, Ion Homeostasis, Antioxidant Defense, and Methylglyoxal Detoxification. Antioxidants (Basel) 2022; 11:antiox11101856. [PMID: 36290578 PMCID: PMC9598349 DOI: 10.3390/antiox11101856] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
Considering the growth-promoting potential and other regulatory roles of bacteria, we investigated the possible mechanism of the role of Bacillus subtilis in conferring salt tolerance in soybean. Soybean (Glycine max cv. BARI Soybean-5) seeds were inoculated with B. subtilis, either through a presoaking with seeds or a direct application with pot soil. After 20 days of sowing, both the seed- and soil-inoculated plants were exposed to 50, 100, and 150 mM of NaCl for 30 days. A clear sign of oxidative stress was evident through a remarkable increase in lipid peroxidation, hydrogen peroxide, methylglyoxal, and electrolyte leakage in the salt treated plants. Moreover, the efficiency of the ascorbate (AsA)–glutathione (GSH) pathways was declined. Consequently, the plant growth, biomass accumulation, water relations, and content of the photosynthetic pigments were decreased. Salt stress also caused an increased Na+/K+ ratio and decreased Ca2+. On the contrary, the B. subtilis inoculated plants showed increased levels of AsA and GSH, their redox balance, and the activities of the AsA–GSH pathway enzymes, superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, and peroxidase. The B. subtilis inoculated plants also enhanced the activities of glyoxalase enzymes, which mitigated methylglyoxal toxicity in coordination with ROS homeostasis. Besides this, the accumulation of K+ and Ca2+ was increased to maintain the ion homeostasis in the B. subtilis inoculated plants under salinity. Furthermore, the plant water status was uplifted in the salt treated soybean plants with B. subtilis inoculation. This investigation reveals the potential of B. subtilis in mitigating salt-induced oxidative stress in soybean plants through modulating the antioxidant defense and glyoxalase systems along with maintaining ion homeostasis and osmotic adjustments. In addition, it was evident that the soil inoculation performed better than the seed inoculation in mitigating salt-induced oxidative damages in soybean.
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Affiliation(s)
- Mirza Hasanuzzaman
- Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka 1207, Bangladesh
- Correspondence:
| | - Md. Rakib Hossain Raihan
- Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka 1207, Bangladesh
| | - Farzana Nowroz
- Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka 1207, Bangladesh
| | - Masayuki Fujita
- Laboratory of Plant Stress Responses, Faculty of Agriculture, Kagawa University, Miki-cho, Kita-gun, Takamatsu 761-0795, Japan
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