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Beshah A, Muleta D, Legese G, Assefa F. Exploring stress-tolerant plant growth-promoting rhizobacteria from groundnut rhizosphere soil in semi-arid regions of Ethiopia. PLANT SIGNALING & BEHAVIOR 2024; 19:2365574. [PMID: 38912872 PMCID: PMC11197918 DOI: 10.1080/15592324.2024.2365574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 06/04/2024] [Indexed: 06/25/2024]
Abstract
The potential of rhizobacteria with plant growth promoting (PGP) traits in alleviating abiotic stresses, especially drought, is significant. However, their exploitation in the semi-arid regions of Ethiopian soils remains largely unexplored. This research aimed to isolate and evaluate the PGP potential of bacterial isolates collected from groundnut cultivation areas in Ethiopia. Multiple traits were assessed, including phosphate solubilization, indole-3-acetic acid (IAA) production, ammonia production, salt and heavy metal tolerance, drought tolerance, enzyme activities, hydrogen cyanide production, antibiotic resistance, and antagonistic activity against fungal pathogens. The identification of potent isolates was carried out using MALDI-TOF MS. Out of the 82 isolates, 63 were gram-negative and 19 were gram-positive. Among them, 19 isolates exhibited phosphate solubilization, with AAURB 34 demonstrating the highest efficiency, followed by AURB 12. Fifty-six isolates produce IAA in varying amounts and all isolates produce ammonia with AAURB12, AAURB19, and AAURB34 displaying strong production. Most isolates demonstrated tolerance to temperatures up to 40°C and salt concentrations up to 3%. Notably, AAURB12 and AAURB34 exhibited remarkable drought tolerance at an osmotic potential of -2.70 Mpa. When subjected to levels above 40%, the tested isolates moderately produced lytic enzymes and hydrogen cyanide. The isolates displayed resistance to antibiotics, except gentamicin, and all isolates demonstrated resistance to zinc, with 81-91% showing resistance to other heavy metals. AAURB34 and AAURB12 exhibited suppression against fungal pathogens, with percent inhibition of 38% and 46%, respectively. Using MALDI-TOF MS, the promising PGP isolates were identified as Bacillus megaterium, Bacillus pumilus, and Enterobacter asburiae. This study provides valuable insights into the potential of rhizobacteria as PGP agents for mitigating abiotic stresses and contribute to the understanding of sustainable agricultural practices in Ethiopia and similar regions facing comparable challenges.
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Affiliation(s)
- Asnake Beshah
- Department of Cellular, Microbial and Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Driba Muleta
- Biotechnology Institute, Addis Ababa University, Addis Ababa, Ethiopia
| | - Gudina Legese
- Center for Environmental Science, Addis Ababa University, Addis Ababa, Ethiopia
| | - Fassil Assefa
- Department of Cellular, Microbial and Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia
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Kotlova ER, Senik SV, Pozhvanov GA, Prokopiev IA, Boldyrev IA, Manzhieva BS, Amigud EY, Puzanskiy RK, Khakulova AA, Serebryakov EB. Uptake and Metabolic Conversion of Exogenous Phosphatidylcholines Depending on Their Acyl Chain Structure in Arabidopsis thaliana. Int J Mol Sci 2023; 25:89. [PMID: 38203257 PMCID: PMC10778594 DOI: 10.3390/ijms25010089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/11/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024] Open
Abstract
Fungi and plants are not only capable of synthesizing the entire spectrum of lipids de novo but also possess a well-developed system that allows them to assimilate exogenous lipids. However, the role of structure in the ability of lipids to be absorbed and metabolized has not yet been characterized in detail. In the present work, targeted lipidomics of phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs), in parallel with morphological phenotyping, allowed for the identification of differences in the effects of PC molecular species introduced into the growth medium, in particular, typical bacterial saturated (14:0/14:0, 16:0/16:0), monounsaturated (16:0/18:1), and typical for fungi and plants polyunsaturated (16:0/18:2, 18:2/18:2) species, on Arabidopsis thaliana. For comparison, the influence of an artificially synthesized (1,2-di-(3-(3-hexylcyclopentyl)-propanoate)-sn-glycero-3-phosphatidylcholine, which is close in structure to archaeal lipids, was studied. The phenotype deviations stimulated by exogenous lipids included changes in the length and morphology of both the roots and leaves of seedlings. According to lipidomics data, the main trends in response to exogenous lipid exposure were an increase in the proportion of endogenic 18:1/18:1 PC and 18:1_18:2 PC molecular species and a decrease in the relative content of species with C18:3, such as 18:3/18:3 PC and/or 16:0_18:3 PC, 16:1_18:3 PE. The obtained data indicate that exogenous lipid molecules affect plant morphology not only due to their physical properties, which are manifested during incorporation into the membrane, but also due to the participation of exogenous lipid molecules in the metabolism of plant cells. The results obtained open the way to the use of PCs of different structures as cellular regulators.
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Affiliation(s)
- Ekaterina R. Kotlova
- Komarov Botanical Institute, Russian Academy of Sciences, 197022 Saint-Petersburg, Russia; (S.V.S.); (G.A.P.); (I.A.P.); (B.S.M.); (E.Y.A.); (R.K.P.)
| | - Svetlana V. Senik
- Komarov Botanical Institute, Russian Academy of Sciences, 197022 Saint-Petersburg, Russia; (S.V.S.); (G.A.P.); (I.A.P.); (B.S.M.); (E.Y.A.); (R.K.P.)
| | - Gregory A. Pozhvanov
- Komarov Botanical Institute, Russian Academy of Sciences, 197022 Saint-Petersburg, Russia; (S.V.S.); (G.A.P.); (I.A.P.); (B.S.M.); (E.Y.A.); (R.K.P.)
- Department of Botany and Ecology, Faculty of Biology, Herzen State Pedagogical University, 191186 Saint-Petersburg, Russia
| | - Ilya A. Prokopiev
- Komarov Botanical Institute, Russian Academy of Sciences, 197022 Saint-Petersburg, Russia; (S.V.S.); (G.A.P.); (I.A.P.); (B.S.M.); (E.Y.A.); (R.K.P.)
| | - Ivan A. Boldyrev
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119991 Moscow, Russia;
| | - Bairta S. Manzhieva
- Komarov Botanical Institute, Russian Academy of Sciences, 197022 Saint-Petersburg, Russia; (S.V.S.); (G.A.P.); (I.A.P.); (B.S.M.); (E.Y.A.); (R.K.P.)
| | - Ekaterina Ya. Amigud
- Komarov Botanical Institute, Russian Academy of Sciences, 197022 Saint-Petersburg, Russia; (S.V.S.); (G.A.P.); (I.A.P.); (B.S.M.); (E.Y.A.); (R.K.P.)
- Department of Botany and Ecology, Faculty of Biology, Herzen State Pedagogical University, 191186 Saint-Petersburg, Russia
| | - Roman K. Puzanskiy
- Komarov Botanical Institute, Russian Academy of Sciences, 197022 Saint-Petersburg, Russia; (S.V.S.); (G.A.P.); (I.A.P.); (B.S.M.); (E.Y.A.); (R.K.P.)
| | - Anna A. Khakulova
- Chemical Analysis and Materials Research Core Facility Center, Reseach Park, Saint-Petersburg State University, 199034 Saint-Petersburg, Russia; (A.A.K.); (E.B.S.)
| | - Evgeny B. Serebryakov
- Chemical Analysis and Materials Research Core Facility Center, Reseach Park, Saint-Petersburg State University, 199034 Saint-Petersburg, Russia; (A.A.K.); (E.B.S.)
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Medison RG, Jiang J, Medison MB, Tan LT, Kayange CD, Sun Z, Zhou Y. Evaluating the potential of Bacillus licheniformis YZCUO202005 isolated from lichens in maize growth promotion and biocontrol. Heliyon 2023; 9:e20204. [PMID: 37767471 PMCID: PMC10520788 DOI: 10.1016/j.heliyon.2023.e20204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Lichens exist in an organismal organization of mycobiont, photobiont, and non-photoautotrophic bacteria. These organisms contribute to the growth of lichens even in poor nutrition substrates. However, studies on the isolation and application of non-photoautotrophic bacteria in plant growth and biocontrol are scanty. Therefore, a study was conducted to isolate and evaluate the potential of non-photoautotrophic bacteria from lichen tissues in maize plant growth promotion and biocontrol of plant pathogens (fungi and bacteria). Five bacterial strains were isolated and tested for their ability to produce indole-3-Acetic Acid (IAA). One bacterium named YZCUO202005 produced IAA, siderophores and biofilms, solubilized phosphate and potassium and exhibited extracellular enzymes (cellulases, proteases, amylase, and β -1,3-Glucanase). Based on the 16S rRNA sequence analysis results, YZCUO202005 was identified as Bacillus licheniformis. The strain inhibited the growth of five pathogenic fungi with an inhibition percent of between 58.7% and 71.7% and two pathogenic bacteria. Under greenhouse conditions, YZCUO202005 was tested for its abilities to enhance maize seed germination, and vegetative growth. Compared with the control treatment, the strain significantly enhanced the growth of stem length (i.e. 18 ± 0.64 cm, 78 ± 0.92 cm), leaf length (i.e. 10 ± 0.36 cm, 57 ± 1.42 cm), leaf chlorophyll levels (i.e., 13 ± 0.40, 40 ± 0.43 SPAD), and root length (i.e, 9.8 ± 2.25 cm, 22.5 ± 6.59 cm). Our results demonstrated that B. licheniformis YZCUO202005 from lichens has the potential to promote plant growth and reduce fungal and bacterial pathogens' growth. Furthermore, the results suggest that lichens are naturally rich sources of plant growth promotion and biocontrol agents that would be used in agriculture.
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Affiliation(s)
- Rudoviko Galileya Medison
- Department of Plant Protection, College of Agriculture, Yangtze University, 266 Jingmi Road, Jingzhou City, Hubei Province, 434025, China
| | - Jianwei Jiang
- Department of Plant Protection, College of Agriculture, Yangtze University, 266 Jingmi Road, Jingzhou City, Hubei Province, 434025, China
| | - Milca Banda Medison
- Department of Plant Protection, College of Agriculture, Yangtze University, 266 Jingmi Road, Jingzhou City, Hubei Province, 434025, China
| | - Li-Tao Tan
- Department of Plant Protection, College of Agriculture, Yangtze University, 266 Jingmi Road, Jingzhou City, Hubei Province, 434025, China
| | - Chicco D.M. Kayange
- Department of Land Resources Conservation, Mulanje District Agriculture Office, P.O. Box 49, Mulanje, Malawi
| | - Zhengxiang Sun
- Department of Plant Protection, College of Agriculture, Yangtze University, 266 Jingmi Road, Jingzhou City, Hubei Province, 434025, China
| | - Yi Zhou
- Department of Plant Protection, College of Agriculture, Yangtze University, 266 Jingmi Road, Jingzhou City, Hubei Province, 434025, China
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Rojas-Solis D, Vences-Guzmán MÁ, Sohlenkamp C, Santoyo G. Cardiolipin synthesis in Pseudomonas fluorescens UM270 plays a relevant role in stimulating plant growth under salt stress. Microbiol Res 2023; 268:127295. [PMID: 36587534 DOI: 10.1016/j.micres.2022.127295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022]
Abstract
Membrane cardiolipin (CL) phospholipids play a fundamental role in the adaptation of bacteria to various environmental conditions, including saline stress. Here, we constructed deletion mutants of two CL synthetase genes, clsA (UM270 ∆clsA) and clsB (UM270 ∆clsB), in the rhizobacterium Pseudomonas fluorescens UM270, and evaluated their role in plant growth promotion under salt stress. UM270 ∆clsA and UM270 ∆clsB mutants showed a significant reduction in CL synthesis compared to the P. fluorescens UM270 wild-type (UM270 wt) strain (58% ∆clsA and 53% ∆clsB), and their growth rate was not affected, except when grown at 100 and 200 mM NaCl. Additionally, the root colonization capacity of both mutant strains was impaired compared with that of the wild type. Concomitant with the deletion of clsA and clsB genes, some physiological changes were observed in the UM270 ∆clsA and UM270 ∆clsB mutants, such as a reduction in indole acetic acid and biofilm production. By contrast, an increase in siderophore biosynthesis was observed. Further, inoculation of the UM270 wt strain in tomato plants (Solanum lycopersicum) grown under salt stress conditions (100 and 200 mM NaCl) resulted in an increase in root and shoot length, chlorophyll content, and dry weight. On the contrary, when each of the mutants were inoculated in tomato plants, a reduction in root length was observed when grown at 200 mM NaCl, but the shoot length, chlorophyll content, and total plant dry weight parameters were significantly reduced under normal or saline conditions (100 and 200 mM NaCl), compared to UM270 wt-inoculated plants. In conclusion, these results suggest that CL synthesis in P. fluorescens UM270 plays an important role in the promotion of tomato plant growth under normal conditions, but to a greater extent, under salt-stress conditions.
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Affiliation(s)
- Daniel Rojas-Solis
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
| | | | - Christian Sohlenkamp
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico.
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Phour M, Sindhu SS. Mitigating abiotic stress: microbiome engineering for improving agricultural production and environmental sustainability. PLANTA 2022; 256:85. [PMID: 36125564 DOI: 10.1007/s00425-022-03997-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
The responses of plants to different abiotic stresses and mechanisms involved in their mitigation are discussed. Production of osmoprotectants, antioxidants, enzymes and other metabolites by beneficial microorganisms and their bioengineering ameliorates environmental stresses to improve food production. Progressive intensification of global agriculture, injudicious use of agrochemicals and change in climate conditions have deteriorated soil health, diminished the microbial biodiversity and resulted in environment pollution along with increase in biotic and abiotic stresses. Extreme weather conditions and erratic rains have further imposed additional stress for the growth and development of plants. Dominant abiotic stresses comprise drought, temperature, increased salinity, acidity, metal toxicity and nutrient starvation in soil, which severely limit crop production. For promoting sustainable crop production in environmentally challenging environments, use of beneficial microbes has emerged as a safer and sustainable means for mitigation of abiotic stresses resulting in improved crop productivity. These stress-tolerant microorganisms play an effective role against abiotic stresses by enhancing the antioxidant potential, improving nutrient acquisition, regulating the production of plant hormones, ACC deaminase, siderophore and exopolysaccharides and accumulating osmoprotectants and, thus, stimulating plant biomass and crop yield. In addition, bioengineering of beneficial microorganisms provides an innovative approach to enhance stress tolerance in plants. The use of genetically engineered stress-tolerant microbes as inoculants of crop plants may facilitate their use for enhanced nutrient cycling along with amelioration of abiotic stresses to improve food production for the ever-increasing population. In this chapter, an overview is provided about the current understanding of plant-bacterial interactions that help in alleviating abiotic stress in different crop systems in the face of climate change. This review largely focuses on the importance and need of sustainable and environmentally friendly approaches using beneficial microbes for ameliorating the environmental stresses in our agricultural systems.
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Affiliation(s)
- Manisha Phour
- Department of Microbiology, CCS Haryana Agricultural University, Hisar, 125004, India
- University Institute of Biotechnology, Chandigarh University, Mohali, India
| | - Satyavir S Sindhu
- Department of Microbiology, CCS Haryana Agricultural University, Hisar, 125004, India.
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Progress and Applications of Plant Growth-Promoting Bacteria in Salt Tolerance of Crops. Int J Mol Sci 2022; 23:ijms23137036. [PMID: 35806037 PMCID: PMC9266936 DOI: 10.3390/ijms23137036] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Saline soils are a major challenge in agriculture, and salinization is increasing worldwide due to climate change and destructive agricultural practices. Excessive amounts of salt in soils cause imbalances in ion distribution, physiological dehydration, and oxidative stress in plants. Breeding and genetic engineering methods to improve plant salt tolerance and the better use of saline soils are being explored; however, these approaches can take decades to accomplish. A shorter-term approach to improve plant salt tolerance is to be inoculated with bacteria with high salt tolerance or adjusting the balance of bacteria in the rhizosphere, including endosymbiotic bacteria (living in roots or forming a symbiont) and exosymbiotic bacteria (living on roots). Rhizosphere bacteria promote plant growth and alleviate salt stress by providing minerals (such as nitrogen, phosphate, and potassium) and hormones (including auxin, cytokinin, and abscisic acid) or by reducing ethylene production. Plant growth-promoting rhizosphere bacteria are a promising tool to restore agricultural lands and improve plant growth in saline soils. In this review, we summarize the mechanisms of plant growth-promoting bacteria under salt stress and their applications for improving plant salt tolerance to provide a theoretical basis for further use in agricultural systems.
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Yu H, Wu X, Zhang G, Zhou F, Harvey PR, Wang L, Fan S, Xie X, Li F, Zhou H, Zhao X, Zhang X. Identification of the Phosphorus-Solubilizing Bacteria Strain JP233 and Its Effects on Soil Phosphorus Leaching Loss and Crop Growth. Front Microbiol 2022; 13:892533. [PMID: 35572684 PMCID: PMC9100411 DOI: 10.3389/fmicb.2022.892533] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphorus (P) is one of the most limiting nutrients in global agricultural ecosystems, and phosphorus-solubilizing bacteria (PSB) can convert insoluble P into soluble P, thereby improving the absorption and use of soil P by plants. Increasing leaching loss of soil P due to PSB that could lead to water eutrophication is a major concern, although no direct experimental evidence is available to evaluate these effects. In this study, a highly efficient PSB strain, Pseudomonas sp. JP233, was isolated from soil and its P-solubilizing agent was identified by metabolomics and HPLC analyses. The effects of JP233 on P contents in soil leachates were also analyzed by microcosm leaching experiments in the absence and presence of maize. JP233 could solubilize insoluble P into soluble forms, and the molybdate reactive phosphorus (MRP) content reached 258.07 mg/L in NBRIP medium containing 5 g/L Ca3(PO4)2 within 48 h. Metabolomics analysis demonstrated that the organic acid involved in JP233 P solubilization was primarily 2-keto gluconic acid (2KGA). Further, HPLC analysis revealed that 2KGA contents rapidly accumulated to 19.33 mg/mL within 48 h. Microcosm leaching experiments showed that MRP and total phosphorus (TP) contents in soil leaching solutions were not significantly higher after JP233 inoculation. However, inoculation with JP233 into maize plant soils significantly decreased MRP and TP contents in the soil leaching solutions on days 14 (P < 0.01), 21 (P < 0.01), and 28 (P < 0.05). Inoculation with strain JP233 also significantly increased the biomass of maize aerial components and that of whole plants (P < 0.05). Thus, strain JP233 exhibited a significant plant-growth-promoting effect on maize development. In conclusion, the application of PSB into soils does not significantly increase P leachate loss. Rather, the application of PSB can help reduce P leachate loss, while significantly promoting plant absorption and use of soil P.
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Affiliation(s)
- Haiyang Yu
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Xiaoqing Wu
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Guangzhi Zhang
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Fangyuan Zhou
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Paul R. Harvey
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
- CSIRO Agriculture and Food, Glen Osmond, SA, Australia
| | - Leilei Wang
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Susu Fan
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Xueying Xie
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Feng Li
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Hongzi Zhou
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Xiaoyan Zhao
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
| | - Xinjian Zhang
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji’nan, China
- *Correspondence: Xinjian Zhang,
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Paulucci NS, Cesari AB, Biasutti MA, Dardanelli MS, Perillo MA. Membrane Homeoviscous Adaptation in Sinorhizobium Submitted to a Stressful Thermal Cycle Contributes to the Maintenance of the Symbiotic Plant–Bacteria Interaction. Front Microbiol 2021; 12:652477. [PMID: 34975776 PMCID: PMC8718912 DOI: 10.3389/fmicb.2021.652477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 11/15/2021] [Indexed: 12/02/2022] Open
Abstract
Here, we estimate fast changes in the fluidity of Sinorhizobium meliloti membranes submitted to cyclic temperature changes (10°C–40°C–10°C) by monitoring the fluorescence polarization (P) of DPH and TMA-DPH of the whole cell (WC) as well as in its outer (OM) and inner (IM) membranes. Additionally, the long-term response to thermal changes is demonstrated through the dynamics of the phospholipid and fatty acid composition in each membrane. This allowed membrane homeoviscous adaptation by the return to optimal fluidity levels as measured by the PDPH/TMA-DPH in WC, OM, IM, and multilamellar vesicles of lipids extracted from OM and IM. Due to probe-partitioning preferences and membranes’ compositional characteristics, DPH and TMA-DPH exhibit different behaviors in IM and OM. The rapid effect of cyclic temperature changes on the P was the opposite in both membranes with the IM being the one that exhibited the thermal behavior expected for lipid bilayers. Interestingly, only after the incubation at 40°C, cells were unable to recover the membrane preheating P levels when cooled up to 10°C. Solely in this condition, the formation of threads and nodular structures in Medicago sativa infected with S. meliloti were delayed, indicating that the symbiotic interaction was partially altered but not halted.
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Affiliation(s)
- Natalia Soledad Paulucci
- Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
- Instituto de Biotecnología Ambiental y Salud (INBIAS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Río Cuarto, Argentina
- *Correspondence: Natalia Soledad Paulucci,
| | - Adriana Belén Cesari
- Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
- Instituto de Biotecnología Ambiental y Salud (INBIAS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Río Cuarto, Argentina
| | - María Alicia Biasutti
- Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
- Instituto para el Desarrollo Agroindustrial y de la Salud (IDAS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Río Cuarto, Argentina
| | - Marta Susana Dardanelli
- Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
- Instituto de Biotecnología Ambiental y Salud (INBIAS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Río Cuarto, Argentina
- Marta Susana Dardanelli,
| | - María Angélica Perillo
- Facultad de Ciencias Exactas, Físicas y Naturales, Instituto de Ciencia y Tecnología de Alimentos (ICTA), Departamento de Química, Cátedra de Química Biológica, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- María Angélica Perillo,
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Insights into the Interactions among Roots, Rhizosphere, and Rhizobacteria for Improving Plant Growth and Tolerance to Abiotic Stresses: A Review. Cells 2021; 10:cells10061551. [PMID: 34205352 PMCID: PMC8234610 DOI: 10.3390/cells10061551] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 06/16/2021] [Accepted: 06/17/2021] [Indexed: 01/21/2023] Open
Abstract
Abiotic stresses, such as drought, salinity, heavy metals, variations in temperature, and ultraviolet (UV) radiation, are antagonistic to plant growth and development, resulting in an overall decrease in plant yield. These stresses have direct effects on the rhizosphere, thus severely affect the root growth, and thereby affecting the overall plant growth, health, and productivity. However, the growth-promoting rhizobacteria that colonize the rhizosphere/endorhizosphere protect the roots from the adverse effects of abiotic stress and facilitate plant growth by various direct and indirect mechanisms. In the rhizosphere, plants are constantly interacting with thousands of these microorganisms, yet it is not very clear when and how these complex root, rhizosphere, and rhizobacteria interactions occur under abiotic stresses. Therefore, the present review attempts to focus on root–rhizosphere and rhizobacterial interactions under stresses, how roots respond to these interactions, and the role of rhizobacteria under these stresses. Further, the review focuses on the underlying mechanisms employed by rhizobacteria for improving root architecture and plant tolerance to abiotic stresses.
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Khan MA, Hamayun M, Asaf S, Khan M, Yun BW, Kang SM, Lee IJ. Rhizospheric Bacillus spp. Rescues Plant Growth Under Salinity Stress via Regulating Gene Expression, Endogenous Hormones, and Antioxidant System of Oryza sativa L. FRONTIERS IN PLANT SCIENCE 2021; 12:665590. [PMID: 34177981 PMCID: PMC8226221 DOI: 10.3389/fpls.2021.665590] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/19/2021] [Indexed: 05/27/2023]
Abstract
Salinity has drastically reduced crop yields and harmed the global agricultural industry. We isolated 55 bacterial strains from plants inhabiting the coastal sand dunes of Pohang, Korea. A screening bioassay showed that 14 of the bacterial isolates secreted indole-3-acetic acid (IAA), 12 isolates were capable of exopolysaccharide (EPS) production and phosphate solubilization, and 10 isolates secreted siderophores. Based on our preliminary screening, 11 bacterial isolates were tested for salinity tolerance on Luria-Bertani (LB) media supplemented with 0, 50, 100, and 150 mM of NaCl. Three bacterial isolates, ALT11, ALT12, and ALT30, had the best tolerance against elevated NaCl levels and were selected for further study. Inoculation of the selected bacterial isolates significantly enhanced rice growth attributes, viz., shoot length (22.8-42.2%), root length (28.18-59%), fresh biomass (44.7-66.41%), dry biomass (85-90%), chlorophyll content (18.30-36.15%), Chl a (29.02-60.87%), Chl b (30.86-64.51%), and carotenoid content (26.86-70%), under elevated salt stress of 70 and 140 mM. Furthermore, a decrease in the endogenous abscisic acid (ABA) content (27.9-23%) and endogenous salicylic acid (SA) levels (11.70-69.19%) was observed in inoculated plants. Antioxidant analysis revealed an increase in total protein (TP) levels (42.57-68.26%), whereas it revealed a decrease in polyphenol peroxidase (PPO) (24.63-34.57%), glutathione (GSH) (25.53-24.91%), SOA (13.88-18.67%), and LPO levels (15.96-26.06%) of bacterial-inoculated plants. Moreover, an increase in catalase (CAT) (26-33.04%), peroxidase (POD) (59.55-78%), superoxide dismutase (SOD) (13.58-27.77%), and ascorbic peroxidase (APX) (5.76-22.74%) activity was observed. Additionally, inductively coupled plasma mass spectrometry (ICP-MS) analysis showed a decline in Na+ content (24.11 and 30.60%) and an increase in K+ (23.14 and 15.45%) and Mg+ (2.82 and 18.74%) under elevated salt stress. OsNHX1 gene expression was downregulated (0.3 and 4.1-folds), whereas the gene expression of OsPIN1A, OsCATA, and OsAPX1 was upregulated by a 7-17-fold in bacterial-inoculated rice plants. It was concluded that the selected bacterial isolates, ALT11, ALT12, and ALT30, mitigated the adverse effects of salt stress on rice growth and can be used as climate smart agricultural tools in ecofriendly agricultural practices.
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Affiliation(s)
- Muhammad Aaqil Khan
- Department of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - Muhammad Hamayun
- Department of Botany, Abdul Wali Khan University, Mardan, Pakistan
| | - Sajjad Asaf
- Natural and Medical Science Research Center, University of Nizwa, Nizwa, Oman
| | - Murtaza Khan
- Department of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - Byung-Wook Yun
- Department of Botany, Abdul Wali Khan University, Mardan, Pakistan
| | - Sang-Mo Kang
- Department of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - In-Jung Lee
- Department of Applied Biosciences, Kyungpook National University, Daegu, South Korea
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11
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Santoyo G, Urtis-Flores CA, Loeza-Lara PD, Orozco-Mosqueda MDC, Glick BR. Rhizosphere Colonization Determinants by Plant Growth-Promoting Rhizobacteria (PGPR). BIOLOGY 2021; 10:biology10060475. [PMID: 34072072 PMCID: PMC8229920 DOI: 10.3390/biology10060475] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Plant growth-promoting rhizobacteria (PGPR) are an eco-friendly alternative to the use of chemicals in agricultural production and crop protection. However, the efficacy of PGPR as bioinoculants can be diminished by a low capacity to colonize spaces in the rhizosphere. In this work, we review pioneering and recent developments on several important functions that rhizobacteria exhibit in order to compete, colonize, and establish themselves in the plant rhizosphere. Therefore, the use of highly competitive strains in open field trials should be a priority, in order to have consistent and better results in agricultural production activities. Abstract The application of plant growth-promoting rhizobacteria (PGPR) in the field has been hampered by a number of gaps in the knowledge of the mechanisms that improve plant growth, health, and production. These gaps include (i) the ability of PGPR to colonize the rhizosphere of plants and (ii) the ability of bacterial strains to thrive under different environmental conditions. In this review, different strategies of PGPR to colonize the rhizosphere of host plants are summarized and the advantages of having highly competitive strains are discussed. Some mechanisms exhibited by PGPR to colonize the rhizosphere include recognition of chemical signals and nutrients from root exudates, antioxidant activities, biofilm production, bacterial motility, as well as efficient evasion and suppression of the plant immune system. Moreover, many PGPR contain secretion systems and produce antimicrobial compounds, such as antibiotics, volatile organic compounds, and lytic enzymes that enable them to restrict the growth of potentially phytopathogenic microorganisms. Finally, the ability of PGPR to compete and successfully colonize the rhizosphere should be considered in the development and application of bioinoculants.
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Affiliation(s)
- Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico;
- Correspondence:
| | - Carlos Alberto Urtis-Flores
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico;
| | - Pedro Damián Loeza-Lara
- Licenciatura en Genómica Alimentaria, Universidad de La Ciénega del Estado de Michoacán de Ocampo, Sahuayo 59103, Mexico;
| | - Ma. del Carmen Orozco-Mosqueda
- Facultad de Agrobiología “Presidente Juárez”, Universidad Michoacana de San Nicolás de Hidalgo, Melchor Ocampo, Uruapan 60170, Mexico;
| | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
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12
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Bhatia R, Gulati D, Sethi G. Biofilms and nanoparticles: applications in agriculture. Folia Microbiol (Praha) 2021; 66:159-170. [PMID: 33528768 DOI: 10.1007/s12223-021-00851-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 01/04/2021] [Indexed: 02/04/2023]
Abstract
A profound need to explore eco-friendly methods to practice sustainable agriculture leads to the research and exploration of plant growth-promoting rhizobacteria (PGPRs). Biofilms are assemblages of microbial communities within a self-secreted exopolymeric matrix, adhering to different biotic and abiotic surfaces and performing a variety of desired and undesired functions. Biofilm formation by PGPRs is governed by effective root colonization of the host plant in providing plant growth promotion and stress management. Biofilms can also provide a suitable environment for the synthesis and entrapment of nanoparticles. Together, nanoparticles and PGPRs may contribute towards biocontrol and crop management. This review discusses the significance of biofilms in agriculture and their confluence with different types of nanoparticles for plant protection and improved crop production.
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Affiliation(s)
- Ranjana Bhatia
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India.
| | - Divij Gulati
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India
| | - Gavin Sethi
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India
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13
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Getahun A, Kiros S, Muleta D, Assefa F. Genetic and metabolic diversities of rhizobacteria isolated from degraded soil of Ethiopia. Heliyon 2020; 6:e05697. [PMID: 33367126 PMCID: PMC7749386 DOI: 10.1016/j.heliyon.2020.e05697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/03/2020] [Accepted: 12/07/2020] [Indexed: 11/25/2022] Open
Abstract
Genetic and metabolic diversities of rhizobacteria are the fundamental sources for their adaptation to cope with abiotic and biotic stresses in order to enhance growth and health of plants in the soil. Thus, this study was initiated to assess the genetic and metabolic diversities of rhizobacteria isolated from plants grown in degraded soil through BOX-PCR and partial sequencing of 16S rRNA genes. A total of eighty isolates were recovered and subjected to phenotypic profiling of carbohydrate and amino acid utilization, BOX PCR and 16S rRNA profiling. The phenotypic profiling showed remarkable metabolic versatility with Ochrobactrum spp, Pseudomonas spp and Klebsiella spp, and BOX-PCR showed greater discriminatory power for fingerprinting of rhizobacterial isolates with high degree of polymorphism. Bacillus spp showed the highest Simpson's diversity Index. The 16S rRNA genes sequence assigned the rhizobacteria to phyla Proteobacteria with Gammaproteobacteria and Alphaproteobacteria classes and Firmicutes with Bacilli class. The data also showed that the most dominant species were Pseudomonas and Ochrobactrum. Genetic and metabolic diversities of the rhizobacterial isolates reveal the potential of these microbes for plant growth improvement under water deficient soil after testing other inoculant traits.
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Affiliation(s)
| | - Solomon Kiros
- AddisAbaba Institute of Technology, Addis Ababa University, Ethiopia
| | - Diriba Muleta
- College of Natural Sciences, Addis Ababa University, Ethiopia
- Corresponding author.
| | - Fassil Assefa
- College of Natural Sciences, Addis Ababa University, Ethiopia
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14
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Plant-Growth-Promoting Bacteria Mitigating Soil Salinity Stress in Plants. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10207326] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
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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15
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Ashfaq M, Hassan HM, Ghazali AHA, Ahmad M. Halotolerant potassium solubilizing plant growth promoting rhizobacteria may improve potassium availability under saline conditions. ENVIRONMENTAL MONITORING AND ASSESSMENT 2020; 192:697. [PMID: 33043403 DOI: 10.1007/s10661-020-08655-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/30/2020] [Indexed: 06/11/2023]
Abstract
Environmental change is one of the primary issues faced by the farming community. Low rainfall and high temperature in arid and semiarid regions lead to the development of secondary salinisation, thus making the problem more severe. Under saline conditions, sodium is the most crucial cation that competes with potassium (K) and adversely affects plant metabolism by inhibiting plant enzymatic activities. Potassium-solubilising bacteria (KSB) play a vital role in solubilising fixed potassium and making it accessible to plants. In the current study, 42 KSB strains were isolated from paddy rhizosphere soil grown under salt-affected conditions. The plant-growth-promoting (PGP) properties of these rhizobacteria were also evaluated. Thirteen KSB strains, positive for all tested PGP traits, were evaluated for potassium solubilisation under sodium stress, namely, 0%, 3%, 5% and 7% NaCl stress. The five best strains (Acinetobacter pittii strain L1/4, A. pittii strain L3/3, Rhizobium pusense strain L3/4, Cupriavidus oxalaticus strain L4/12 and Ochrobactrum ciceri strain L5/1) based on the K-solubilising potential were identified by amplification, sequencing and bioinformatic analysis of the 16S rDNA sequences. The maximum potassium solubilisation was measured at 30 °C and pH 7 with glucose as carbon source. The application of these KSB strains significantly improved the shoot length, fresh weight, dry weight and chlorophyll contents of paddy plants grown under saline conditions. Hence, these strains could be halotolerant KSB bioinoculants that can be used to protect plants against salt stress.
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Affiliation(s)
- Muhammad Ashfaq
- School of Biological Sciences, Universiti Sains Malaysia, 11800 USM, Pulau Pinang, Malaysia.
| | - Hasnuri Mat Hassan
- School of Biological Sciences, Universiti Sains Malaysia, 11800 USM, Pulau Pinang, Malaysia.
| | | | - Maqshoof Ahmad
- Department of Soil Science, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan
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16
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Cesari AB, Paulucci NS, Yslas EI, Dardanelli MS. Immobilization of Bradyrhizobium and Azospirillum in alginate matrix for long time of storage maintains cell viability and interaction with peanut. Appl Microbiol Biotechnol 2020; 104:10145-10164. [PMID: 33025128 DOI: 10.1007/s00253-020-10910-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 11/25/2022]
Abstract
Immobilizarion of PGPR for agricultural applications aims to provide temporary physical protection from stressful environmental conditions and the gradual release of cells for successful root colonization, release the cells gradually. In this work, we immobilized Bradyrhizobium sp. SEMIA6144 or Azospirillum brasilense Az39 cells in 2% alginate beads prepared by ionic gelation process, and then stored up to 12 months at 4 °C. Alginate matrix showed interaction with the immobilized bacteria (FTIR), allowed a constant release of cells, and improved their viability and capability to interact with Arachis hypogaea. Cell number into beads reached 107 CFU.bead-1; however, viability decreased from 4 months of storage for Az39, while it was maintained up to 12 months for SEMIA6144, showing a low metabolic activity measured by the MTT assay. Adhesion of SEMIA6144 and Az39 from new beads to peanut root was 11.5% and 16%, respectively, higher than non-immobilized bacteria. Peanut inoculation with 12 months storage SEMIA6144 beads significantly increased root length and biomass at 30 days of growth, and under restrictive water condition (RWC), nodulation and total plant N content increased compared with liquid inoculation. Our results demonstrate that immobilization of SEMIA6144 and Az39 in alginate matrix is a potential alternative to enhance peanut growth even under RWC. KEY POINTS: • Alginate encapsulation enhances viability of SEMIA6144 or Az39 under storage at 4 °C for 1 year. • Alginate beads 2% ensure the gradual release of the microorganisms. • Cells from beads stored for long periods present chemotaxis and adhesion to peanut root. • Peanut inoculation with 1-year-old SEMIA6144 beads improves nodulation and growth in RWC.
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Affiliation(s)
- Adriana B Cesari
- INBIAS, Instituto de Biotecnología Ambiental y Salud, CONICET, Rio Cuarto, Argentina
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Ruta Nacional 36, Km, 601, Rio Cuarto, Argentina
| | - Natalia S Paulucci
- INBIAS, Instituto de Biotecnología Ambiental y Salud, CONICET, Rio Cuarto, Argentina
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Ruta Nacional 36, Km, 601, Rio Cuarto, Argentina
| | - Edith I Yslas
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Ruta Nacional 36, Km, 601, Rio Cuarto, Argentina.
- IITEMA, Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados, CONICET, Rio Cuarto, Argentina.
| | - Marta Susana Dardanelli
- INBIAS, Instituto de Biotecnología Ambiental y Salud, CONICET, Rio Cuarto, Argentina.
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Ruta Nacional 36, Km, 601, Rio Cuarto, Argentina.
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17
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Rojas-Solis D, Vences-Guzmán MA, Sohlenkamp C, Santoyo G. Bacillus toyonensis COPE52 Modifies Lipid and Fatty Acid Composition, Exhibits Antifungal Activity, and Stimulates Growth of Tomato Plants Under Saline Conditions. Curr Microbiol 2020; 77:2735-2744. [PMID: 32504325 DOI: 10.1007/s00284-020-02069-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 05/30/2020] [Indexed: 02/07/2023]
Abstract
Salinity is one of the most important factors that limit the productivity of agricultural soils. Certain plant growth-promoting bacteria (PGPB) have the ability to stimulate the growth of crop plants even under salt stress. In the present study, we analysed the potential of PGPB Bacillus toyonensis COPE52 to improve the growth of tomato plants and its capacity to modify its membrane lipid and fatty acid composition under salt stress. Thus, strain COPE52 increased the relative amount of branched chain fatty acids (15:0i and 16:1∆9) and accumulation of an unknown membrane lipid, while phosphatidylethanolamine (PE) levels decreased during growth with 100 and 200 mM NaCl. Importantly, direct and indirect plant growth-promoting (PGP) mechanisms of B. toyonensis COPE52, such as indole-3-acetic acid (IAA), protease activity, biofilm formation, and antifungal activity against Botrytis cinerea, remained unchanged in the presence of NaCl in vitro, compared to controls without salt. In a greenhouse experiment, tomato plants (Lycopersicon esculentum 'Saladette') showed increased shoot and root length, higher dry biomass, and chlorophyll content when inoculated with B. toyonensis COPE52 at 0 and 100 mM NaCl. In summary, these results indicate that Bacillus toyonensis COPE52 can modify cell membrane lipid components as a potential protecting mechanism to maintain PGP traits under saline-soil conditions.
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Affiliation(s)
- Daniel Rojas-Solis
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
| | - Miguel A Vences-Guzmán
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Christian Sohlenkamp
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México. .,Laboratorio de Diversidad Genómica, Instituto de Investigaciones Químico-Biológicas de la Universidad Michoacana de San Nicolás de Hidalgo, Edificio A1´, Ciudad Universitaria, C.P. 58063, Morelia, Michoacán, México.
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Mishra SK, Khan MH, Misra S, Dixit VK, Gupta S, Tiwari S, Chandra Gupta S, Chauhan PS. Drought tolerant Ochrobactrum sp. inoculation performs multiple roles in maintaining the homeostasis in Zea mays L. subjected to deficit water stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 150:1-14. [PMID: 32097873 DOI: 10.1016/j.plaphy.2020.02.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/18/2020] [Accepted: 02/18/2020] [Indexed: 05/01/2023]
Abstract
Plant growth-promoting rhizobacteria (PGPR) improve plant health under various biotic and abiotic stresses. However, the underlying mechanisms of the protective effects of PGPR in deficit water stress (WS) remain less explored. This study aimed to characterize the role of Ochrobactrum sp. NBRISH6 inoculation on maize (Zea mays "Maharaja") under WS conditions using multiple approaches such as physiological, anatomical, metabolic, and molecular. The effect of NBRISH6 inoculation using maize as a host plant was characterized under greenhouse conditions in deficit water stress. Results from this study demonstrated that NBRISH6 significantly lowered the expression of genes involved in the abscisic acid cycle, deficit water stress-response, osmotic stress, and antioxidant enzyme activity (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and polyphenol oxidase). Phytohormones, i.e. indole acetic acid (IAA) and salicylic acid (SA) levels, intercellular CO2 concentration, metabolites such as simple sugars, amino acids, aliphatic hydrocarbons, and the number of shrunken pith cells modulated in maize roots inoculated with NBRISH6. The NBRISH6 inoculation also improved the plant vegetative properties (root length, 33.80%; shoot length, 20.68%; root dry weight, 39.21%; shoot dry weight, 61.95%), shoot nutrients, xylem cells, root hairs, vapor pressure deficit (75%), intrinsic water-use efficiency (41.67%), photosynthesis rate (83.33%), and total chlorophyll (16.15%) as compared to the respective stress controls. This study provides valuable insights into mechanistic functions of PGPR in WS amelioration and promoting plant physiological response.
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Affiliation(s)
- Shashank Kumar Mishra
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Mohammad Haneef Khan
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India
| | - Sankalp Misra
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Vijay Kant Dixit
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India
| | - Swati Gupta
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Shalini Tiwari
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India
| | - Sateesh Chandra Gupta
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Puneet Singh Chauhan
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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Selection of reference genes for measuring the expression of aiiO in Ochrobactrum quorumnocens A44 using RT-qPCR. Sci Rep 2019; 9:13129. [PMID: 31511547 PMCID: PMC6739375 DOI: 10.1038/s41598-019-49474-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 08/22/2019] [Indexed: 11/09/2022] Open
Abstract
Reverse transcription quantitative PCR (RT-qPCR), a method of choice for quantification of gene expression changes, requires stably expressed reference genes for normalization of data. So far, no reference genes were established for the Alphaproteobacteria of the genus Ochrobactrum. Here, we determined reference genes for gene expression studies in O. quorumnocens A44. Strain A44 was cultured under 10 different conditions and the stability of expression of 11 candidate genes was evaluated using geNorm, NormFinder and BestKeeper. Most stably expressed genes were found to be rho, gyrB and rpoD. Our results can facilitate the choice of reference genes in the related Ochrobactrum strains. O. quorumnocens A44 is able to inactivate a broad spectrum of N-acyl homoserine lactones (AHLs) - the quorum sensing molecules of many Gram-negative bacteria. This activity is attributed to AiiO hydrolase, yet it remains unclear whether AHLs are the primary substrate of this enzyme. Using the established RT-qPCR setup, we found that the expression of the aiiO gene upon exposure to two AHLs, C6-HLS and 3OC12-HSL, does not change above the 1-fold significance threshold. The implications of this finding are discussed in the light of the role of quorum sensing-interfering enzymes in the host strains.
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Kang SM, Shahzad R, Bilal S, Khan AL, Park YG, Lee KE, Asaf S, Khan MA, Lee IJ. Indole-3-acetic-acid and ACC deaminase producing Leclercia adecarboxylata MO1 improves Solanum lycopersicum L. growth and salinity stress tolerance by endogenous secondary metabolites regulation. BMC Microbiol 2019; 19:80. [PMID: 31023221 PMCID: PMC6485084 DOI: 10.1186/s12866-019-1450-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 04/02/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The utilization of plant growth-promoting microbes is an environment friendly strategy to counteract stressful condition and encourage plants tolerance. In this regards, the current study was designed to isolate ACC deaminase and indole-3-acetic acid (IAA) producing halotolerant bacteria to promote tomato (Solanum lycopersicum L.) growth and tolerance against salinity stress. RESULTS The selected bacterial isolate MO1 was identified as Leclercia adecarboxylata and IAA quantification results revealed that MO1 produced significant amount of IAA (9.815 ± 0.6293 μg mL- 1). The MO1 showed the presence of ACC (1-Aminocyclopropane-1-Carboxylate) deaminase responsible acdS gene and tolerance against salinity stress. A plant microbe interaction experiment using tomato (Solanum lycopersicum L.) with glycine betaine (GB) as a positive control was carried out to investigate the positive role MO1 in improving plant growth and stress tolerance. The results indicated that MO1 inoculation and GB application significantly increased growth attributes under normal as well as saline condition (120 mM NaCl). The MO1 inoculation and GB treatment approach conferred good protection against salinity stress by significantly improving glucose by 17.57 and 18.76%, sucrose by 34.2 and 12.49%, fructose by 19.9 and 10.9%, citric acid by 47.48 and 34.57%, malic acid by 52.19 and 28.38%, serine by 43.78 and 69.42%, glycine by 14.48 and 22.76%, methionine by 100 and 124.99%, threonine by 70 and 63.08%, and proline by 36.92 and 48.38%, respectively, while under normal conditions MO1 inoculation and GB treatment also enhanced glucose by 19.83 and 13.19%, sucrose by 23.43 and 15.75%, fructose by 15.79 and 8.18%, citric acid by 43.26 and 33.14%, malic acid by 36.18 and 14.48%, serine by 46.5 and 48.55%, glycine by 19.85 and 29.77%, methionine by 22.22 and 38.89%, threonine by 21.95 and 17.07%, and proline by 29.61 and 34.68% compared to levels in non-treated plants, respectively. In addition, the endogenous abscisic acid (ABA) level was noticeably lower in MO1-inoculated (30.28 and 30.04%) and GB-treated plants (45 and 35.35%) compared to their corresponding control plants under normal condition as well as salinity stress, respectively. CONCLUSION The current findings suggest that the IAA- and ACC-deaminase-producing abilities MO1 can improve plants tolerance to salinity stress.
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Affiliation(s)
- Sang-Mo Kang
- Institute of Agricultural Science and Technology, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Raheem Shahzad
- Basic and Applied Scientific Research Center, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Saqib Bilal
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Abdul Latif Khan
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, Oman
| | - Yeon-Gyeong Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Ko-Eun Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Sajjad Asaf
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, Oman
| | - Muhammad Aaqil Khan
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - In-Jung Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
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Burygin GL, Kargapolova KY, Kryuchkova YV, Avdeeva ES, Gogoleva NE, Ponomaryova TS, Tkachenko OV. Ochrobactrum cytisi IPA7.2 promotes growth of potato microplants and is resistant to abiotic stress. World J Microbiol Biotechnol 2019; 35:55. [PMID: 30900049 DOI: 10.1007/s11274-019-2633-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/08/2019] [Indexed: 11/26/2022]
Abstract
Bacteria in natural associations with agricultural crops are promising for use in the improvement of clonal micropropagation of plants. We clarified the taxonomic position of Ochrobactrum cytisi strain IPA7.2 and investigated its tolerance for salinity, high temperature, and glyphosate pollution. We also tested the strain's potential to promote the growth of potato (Solanum tuberosum L.) microplants. Using the IPA7.2 draft genome (no. NZ_MOEC00000000), we searched for housekeeping genes and also for the target genes encoding glyphosate tolerance and plant-growth-promoting ability. A multilocus sequence analysis of the gap, rpoB, dnaK, trpE, aroC, and recA housekeeping genes led us to identify isolate IPA7.2 as O. cytisi. The strain tolerated temperatures up to 50 °C and NaCl concentrations up to 3-4%, and it produced 8 µg ml-1 of indole-3-acetic acid. It also tolerated 6 mM glyphosate owing to the presence of type II 5-enolpyruvylshikimate-3-phosphate synthase. Finally, it was able to colonize the roots and tissues of potato microplants, an ability preserved by several generations after subculturing. We identified the development phase of potato microplants that was optimal for inoculation with O. cytisi IPA7.2. Inoculation of in vitro-grown 15-day-old microplants increased the mitotic index of root meristem cells (by 50%), the length of shoots (by 34%), the number of leaves (by 7%), and the number of roots (by 16%). Under ex vitro conditions, the inoculated plants had a greater leaf area (by 77%) and greater shoot and root dry weight (by 84 and 61%, respectively) than did the control plants. We recommend O. cytisi IPA 7.2 for use in the growing of potato microplants to improve the production of elite seed material.
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Affiliation(s)
- Gennady L Burygin
- Vavilov Saratov State Agrarian University, 1 Teatralnaya Ploshchad, Saratov, Russia, 410012.
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, Saratov, Russia, 410049.
| | | | - Yelena V Kryuchkova
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, Saratov, Russia, 410049
| | - Elena S Avdeeva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, Saratov, Russia, 410049
| | - Natalia E Gogoleva
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky Street, Kazan, Russia, 420111
- Kazan Federal University, 18 Ulitsa Kremlyovskaya, Kazan, Russia, 420111
| | | | - Oksana V Tkachenko
- Vavilov Saratov State Agrarian University, 1 Teatralnaya Ploshchad, Saratov, Russia, 410012
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22
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Martínez-Hidalgo P, Maymon M, Pule-Meulenberg F, Hirsch AM. Engineering root microbiomes for healthier crops and soils using beneficial, environmentally safe bacteria. Can J Microbiol 2019; 65:91-104. [DOI: 10.1139/cjm-2018-0315] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Green Revolution developed new crop varieties, which greatly improved food security worldwide. However, the growth of these plants relied heavily on chemical fertilizers and pesticides, which have led to an overuse of synthetic fertilizers, insecticides, and herbicides with serious environmental consequences and negative effects on human health. Environmentally friendly plant-growth-promoting methods to replace our current reliance on synthetic chemicals and to develop more sustainable agricultural practices to offset the damage caused by many agrochemicals are proposed herein. The increased use of bioinoculants, which consist of microorganisms that establish synergies with target crops and influence production and yield by enhancing plant growth, controlling disease, and providing critical mineral nutrients, is a potential solution. The microorganisms found in bioinoculants are often bacteria or fungi that reside within either external or internal plant microbiomes. However, before they can be used routinely in agriculture, these microbes must be confirmed as nonpathogenic strains that promote plant growth and survival. In this article, besides describing approaches for discovering plant-growth-promoting bacteria in various environments, including phytomicrobiomes and soils, we also discuss methods to evaluate their safety for the environment and for human health.
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Affiliation(s)
- Pilar Martínez-Hidalgo
- Departamento de Microbiología y Genética, Universidad de Salamanca, Spain
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095-1606, USA
| | - Maskit Maymon
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095-1606, USA
| | - Flora Pule-Meulenberg
- Department of Crop Science and Production, Botswana University of Agriculture and Natural Resources, Private Bag 0027, A1 Sebele Content Farm, Gaborone, Botswana
| | - Ann M. Hirsch
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095-1606, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095-1606, USA
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23
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Krzyżanowska DM, Maciąg T, Ossowicki A, Rajewska M, Kaczyński Z, Czerwicka M, Rąbalski Ł, Czaplewska P, Jafra S. Ochrobactrum quorumnocens sp. nov., a quorum quenching bacterium from the potato rhizosphere, and comparative genome analysis with related type strains. PLoS One 2019; 14:e0210874. [PMID: 30668584 PMCID: PMC6342446 DOI: 10.1371/journal.pone.0210874] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 01/03/2019] [Indexed: 01/09/2023] Open
Abstract
Ochrobactrum spp. are ubiquitous bacteria attracting growing attention as important members of microbiomes of plants and nematodes and as a source of enzymes for biotechnology. Strain Ochrobactrum sp. A44T was isolated from the rhizosphere of a field-grown potato in Gelderland, the Netherlands. The strain can interfere with quorum sensing (QS) of Gram-negative bacteria through inactivation of N-acyl homoserine lactones (AHLs) and protect plant tissue against soft rot pathogens, the virulence of which is governed by QS. Phylogenetic analysis based on 16S rRNA gene alone and concatenation of 16S rRNA gene and MLSA genes (groEL and gyrB) revealed that the closest relatives of A44T are O. grignonense OgA9aT, O. thiophenivorans DSM 7216T, O. pseudogrignonense CCUG 30717T, O. pituitosum CCUG 50899T, and O. rhizosphaerae PR17T. Genomes of all six type strains were sequenced, significantly expanding the possibility of genome-based analyses in Ochrobactrum spp. Average nucleotide identity (ANIb) and genome-to-genome distance (GGDC) values for A44T and the related strains were below the single species thresholds (95% and 70%, respectively), with the highest scores obtained for O. pituitosum CCUG 50899T (87.31%; 35.6%), O. rhizosphaerae PR17T (86.80%; 34.3%), and O. grignonense OgA9aT (86.30%; 33.6%). Distinction of A44T from the related type strains was supported by chemotaxonomic and biochemical analyses. Comparative genomics revealed that the core genome for the newly sequenced strains comprises 2731 genes, constituting 50–66% of each individual genome. Through phenotype-to-genotype study, we found that the non-motile strain O. thiophenivorans DSM 7216T lacks a cluster of genes related to flagella formation. Moreover, we explored the genetic background of distinct urease activity among the strains. Here, we propose to establish a novel species Ochrobactrum quorumnocens, with A44T as the type strain (= LMG 30544T = PCM 2957T).
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Affiliation(s)
- Dorota M Krzyżanowska
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Tomasz Maciąg
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Adam Ossowicki
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Magdalena Rajewska
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Zbigniew Kaczyński
- Laboratory of Structural Biochemistry, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | - Małgorzata Czerwicka
- Laboratory of Structural Biochemistry, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | - Łukasz Rąbalski
- Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Paulina Czaplewska
- Laboratory of Mass Spectrometry, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
| | - Sylwia Jafra
- Laboratory of Biological Plant Protection, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Gdansk, Poland
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24
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The influence of plant growth-promoting rhizobacteria in plant tolerance to abiotic stress: a survival strategy. Appl Microbiol Biotechnol 2018; 102:7821-7835. [PMID: 30030564 PMCID: PMC6132541 DOI: 10.1007/s00253-018-9214-z] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/29/2018] [Accepted: 07/06/2018] [Indexed: 11/26/2022]
Abstract
Action is needed to face the global threat arising from inconsistent rainfall, rise in temperature, and salinization of farm lands which may be the product of climate change. As crops are adversely affected, man and animals may face famine. Plants are severely affected by abiotic stress (drought, salinity, alkalinity, and temperature), which impairs yield and results in loss to farmers and to the nation at large. However, microbes have been shown to be of great help in the fight against abiotic stress, via their biological activities at the rhizosphere of plants. The external application of chemical substances such as glycine betaine, proline, and nutrients has helped in sustaining plant growth and productive ability. In this review, we tried to understand the part played by bioinoculants in aiding plants to resist the negative consequences arising from abiotic stress and to suggest better practices that will be of help in today’s farming systems. The fact that absolute protection and sustainability of plant yield under stress challenges has not been achieved by microbes, nutrients, nor the addition of chemicals (osmo-protectants) alone suggests that studies should focus on the integration of these units (microbes, nutrients, chemical stimulants, and osmo-protectants) into a strategy for achieving a complete tolerance to abiotic stress. Also, other species of microbes capable of shielding plant from stress, boosting yield and growth, providing nutrients, and protecting the plants from harmful invading pathogens should be sought.
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25
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Changes in the lipid composition of Bradyrhizobium cell envelope reveal a rapid response to water deficit involving lysophosphatidylethanolamine synthesis from phosphatidylethanolamine in outer membrane. Res Microbiol 2018; 169:303-312. [DOI: 10.1016/j.resmic.2018.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 04/30/2018] [Accepted: 05/25/2018] [Indexed: 11/21/2022]
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26
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Radhakrishnan R, Baek KH. Physiological and biochemical perspectives of non-salt tolerant plants during bacterial interaction against soil salinity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 116:116-126. [PMID: 28554145 DOI: 10.1016/j.plaphy.2017.05.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 05/01/2023]
Abstract
Climatic changes on earth affect the soil quality of agricultural lands, especially by increasing salt deposition in soil, which results in soil salinity. Soil salinity is a major challenge to growth and reproduction among glycophytes (including all crop plants). Soil bacteria present in the rhizosphere and/or roots naturally protect plants from the adverse effects of soil salinity by reprogramming the stress-induced physiological changes in plants. Bacteria can enrich the soil with major nutrients (nitrogen, phosphorus, and potassium) in a form easily available to plants and prevent the transport of excess sodium to roots (exopolysaccharides secreted by bacteria bind with sodium ions) for maintaining ionic balance and water potential in cells. Salinity also affects plant growth regulators and suppresses seed germination and root and shoot growth. Bacterial secretion of indole-3-acetic acid and gibberellins compensates for the salt-induced hormonal decrease in plants, and bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase synthesis decreases ethylene production to stimulate plant growth. Furthermore, bacteria modulate the redox state of salinity-affected plants by enhancing antioxidants and polyamines, which leads to increased photosynthetic efficiency. Bacteria-induced accumulation of compatible solutes in stressed plants regulates plant cellular activities and prevents salt stress damage. Plant-bacterial interaction reprograms the expression of salt stress-responsive genes and proteins in salinity-affected plants, resulting in a precise stress mitigation metabolism as a defense mechanism. Soil bacteria increase the fertility of soil and regulate the plant functions to prevent the salinity effects in glycophytes. This review explains the current understanding about the physiological changes induced in glycophytes during bacterial interaction to alleviate the adverse effects of soil salinity stress.
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Affiliation(s)
| | - Kwang Hyun Baek
- Department of Biotechnology, Yeungnam University, Gyeongsan 38541, Republic of Korea.
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27
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Carro L, Nouioui I. Taxonomy and systematics of plant probiotic bacteria in the genomic era. AIMS Microbiol 2017; 3:383-412. [PMID: 31294168 PMCID: PMC6604993 DOI: 10.3934/microbiol.2017.3.383] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/22/2017] [Indexed: 12/20/2022] Open
Abstract
Recent decades have predicted significant changes within our concept of plant endophytes, from only a small number specific microorganisms being able to colonize plant tissues, to whole communities that live and interact with their hosts and each other. Many of these microorganisms are responsible for health status of the plant, and have become known in recent years as plant probiotics. Contrary to human probiotics, they belong to many different phyla and have usually had each genus analysed independently, which has resulted in lack of a complete taxonomic analysis as a group. This review scrutinizes the plant probiotic concept, and the taxonomic status of plant probiotic bacteria, based on both traditional and more recent approaches. Phylogenomic studies and genes with implications in plant-beneficial effects are discussed. This report covers some representative probiotic bacteria of the phylum Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes, but also includes minor representatives and less studied groups within these phyla which have been identified as plant probiotics.
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Affiliation(s)
- Lorena Carro
- School of Biology, Newcastle University, Newcastle upon Tyne, UK
| | - Imen Nouioui
- School of Biology, Newcastle University, Newcastle upon Tyne, UK
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28
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Cesari AB, Paulucci NS, Biasutti MA, Reguera YB, Gallarato LA, Kilmurray C, Dardanelli MS. Reorganization of Azospirillum brasilense cell membrane is mediated by lipid composition adjustment to maintain optimal fluidity during water deficit. J Appl Microbiol 2016; 120:185-94. [PMID: 26535566 DOI: 10.1111/jam.12994] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/23/2015] [Accepted: 10/26/2015] [Indexed: 11/30/2022]
Abstract
AIMS We study the Azospirillum brasilense tolerance to water deficit and the dynamics of adaptive process at the level of the membrane. METHODS AND RESULTS Azospirillum brasilense was exposed to polyethylene glycol (PEG) growth and PEG shock. Tolerance, phospholipids and fatty acid (FA) composition and membrane fluidity were determined. Azospirillum brasilense was able to grow in the presence of PEG; however, its viability was reduced. Cells grown with PEG showed membrane fluidity similar to those grown without, the lipid composition was modified, increasing phosphatidylcholine and decreasing phosphatidylethanolamine amounts. The unsaturation FAs degree was reduced. The dynamics of the adaptive response revealed a decrease in fluidity 20 min after the addition of PEG, indicating that the PEG has a fluidizing effect on the hydrophobic region of the cell membrane. Fluidity returned to initial values after 60 min of PEG exposure. CONCLUSION Azospirillum brasilense is able to perceive osmotic changes by changing the membrane fluidity. This effect is offset by changes in the composition of membrane phospholipid and FA, contributing to the homeostasis of membrane fluidity under water deficit. SIGNIFICANCE AND IMPACT OF THE STUDY This knowledge can be used to develop new Azospirillum brasilense formulations showing an adapted membrane to water deficit.
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Affiliation(s)
- A B Cesari
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - N S Paulucci
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - M A Biasutti
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Y B Reguera
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - L A Gallarato
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - C Kilmurray
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - M S Dardanelli
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
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29
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Mahmood A, Turgay OC, Farooq M, Hayat R. Seed biopriming with plant growth promoting rhizobacteria: a review. FEMS Microbiol Ecol 2016; 92:fiw112. [PMID: 27222220 DOI: 10.1093/femsec/fiw112] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2016] [Indexed: 12/20/2022] Open
Abstract
Beneficial microbes are applied to the soil and plant tissues directly or through seed inoculation, whereas soil application is preferred when there is risk of inhibitors or antagonistic microbes on the plant tissues. Insufficient survival of the microorganisms, hindrance in application of fungicides to the seeds and exposure to heat and sunlight in subsequent seed storage in conventional inoculation methods force to explore appropriate and efficient bacterial application method. Seed priming, where seeds are hydrated to activate metabolism without actual germination followed by drying, increases the germination, stand establishment and stress tolerance in different crops. Seed priming with living bacterial inoculum is termed as biopriming that involves the application of plant growth promoting rhizobacteria. It increases speed and uniformity of germination; also ensures rapid, uniform and high establishment of crops; and hence improves harvest quality and yield. Seed biopriming allows the bacteria to enter/adhere the seeds and also acclimatization of bacteria in the prevalent conditions. This review focuses on methods used for biopriming, and also the role in improving crop productivity and stress tolerance along with prospects of this technology. The comparison of methods being followed is also reviewed proposing biopriming as a promising technique for application of beneficial microbes to the seeds.
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Affiliation(s)
- Ahmad Mahmood
- Department of Soil Science and Plant Nutrition, Faculty of Agriculture, Ankara University, 06110 Ankara, Turkey Department of Soil Science and Plant Nutrition, Faculty of Agriculture, Ankara University, 06110 Ankara, Turkey
| | - Oğuz Can Turgay
- Department of Soil Science and Plant Nutrition, Faculty of Agriculture, Ankara University, 06110 Ankara, Turkey
| | - Muhammad Farooq
- Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan
| | - Rifat Hayat
- Department of Soil Science and Soil Water Conservation, PMAS-Arid Agriculture University, Rawalpindi 46300, Pakistan
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Effects of elevated growth temperature and heat shock on the lipid composition of the inner and outer membranes of Yersinia pseudotuberculosis. Biochimie 2016; 123:103-9. [PMID: 26853818 DOI: 10.1016/j.biochi.2016.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/02/2016] [Indexed: 11/23/2022]
Abstract
Differences in the distribution of individual phospholipids between the inner (IM) and outer membranes (OM) of gram-negative bacteria have been detected in mesophilic Escherichia, Erwinia and Salmonella species but have never been investigated in the psychrotrophic Yersinia genus. Therefore, the influence of an elevated growth temperature and heat shock on the phospholipid and fatty acid (FA) compositions of the fractionated Yersinia pseudotuberculosis envelope was investigated. The shift of the growth temperature from 8 °C to 37 °C to mimic the switch from saprophytic to parasitic growth of this bacteria and the exposure of the cells to heat shock, which was induced by a sharp increase in the temperature from 8 °C to 45 °C, increased the lysophosphatidylethanolamine content from zero and 1% to 6% and 10% in the IM and OM, respectively. These changes were accompanied by a decrease in the phosphatidylethanolamine (PE) content and a drastic increase (up to 3-fold higher) in the phosphatidylglycerol (PG) level in the OM of the bacteria, which increases the net negative charge of the cell envelope. The levels of the predominant saturated palmitic (16:0) and cyclopropane FAs were approximately 1.5- and 7.5-fold higher, respectively, but the content of the predominant unsaturated palmitoleic (16:1n-7) and cis-vaccenic (18:1n-7) FAs was approximately 10-30-fold lower in both membranes that were isolated from the cells grown at elevated temperatures. Due to these changes, reflecting the process of "homeoviscous adaptation", the ratio between the unsaturated and saturated FAs decreased but remained higher in the IM than that in the OM. Simultaneously, no significant changes were observed in the FA composition of cells subjected to heat shock, demonstrating a difference between the responses of the heat-shocked and heat-adapted Y. pseudotuberculosis. The unique ability of Y. pseudotuberculosis to reciprocally regulate the ratio of anionic PG and net neutral PE and therefore adjust the negative charge of the OM may be a common strategy used by pathogenic bacteria to promote the barrier function of the OM.
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