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Ahmad M, Imtiaz M, Shoib Nawaz M, Mubeen F, Imran A. What Did We Learn From Current Progress in Heat Stress Tolerance in Plants? Can Microbes Be a Solution? FRONTIERS IN PLANT SCIENCE 2022; 13:794782. [PMID: 35677244 PMCID: PMC9168681 DOI: 10.3389/fpls.2022.794782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 04/21/2022] [Indexed: 05/16/2023]
Abstract
Temperature is a significant parameter in agriculture since it controls seed germination and plant growth. Global warming has resulted in an irregular rise in temperature posing a serious threat to the agricultural production around the world. A slight increase in temperature acts as stress and exert an overall negative impact on different developmental stages including plant phenology, development, cellular activities, gene expression, anatomical features, the functional and structural orientation of leaves, twigs, roots, and shoots. These impacts ultimately decrease the biomass, affect reproductive process, decrease flowering and fruiting and significant yield losses. Plants have inherent mechanisms to cope with different stressors including heat which may vary depending upon the type of plant species, duration and degree of the heat stress. Plants initially adapt avoidance and then tolerance strategies to combat heat stress. The tolerance pathway involves ion transporter, osmoprotectants, antioxidants, heat shock protein which help the plants to survive under heat stress. To develop heat-tolerant plants using above-mentioned strategies requires a lot of time, expertise, and resources. On contrary, plant growth-promoting rhizobacteria (PGPRs) is a cost-effective, time-saving, and user-friendly approach to support and enhance agricultural production under a range of environmental conditions including stresses. PGPR produce and regulate various phytohormones, enzymes, and metabolites that help plant to maintain growth under heat stress. They form biofilm, decrease abscisic acid, stimulate root development, enhance heat shock proteins, deamination of ACC enzyme, and nutrient availability especially nitrogen and phosphorous. Despite extensive work done on plant heat stress tolerance in general, very few comprehensive reviews are available on the subject especially the role of microbes for plant heat tolerance. This article reviews the current studies on the retaliation, adaptation, and tolerance to heat stress at the cellular, organellar, and whole plant levels, explains different approaches, and sheds light on how microbes can help to induce heat stress tolerance in plants.
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Affiliation(s)
| | - Muhammad Imtiaz
- Microbial Ecology Lab, Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | | | | | - Asma Imran
- Microbial Ecology Lab, Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
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Biochar Amendments Improve Licorice ( Glycyrrhiza uralensis Fisch.) Growth and Nutrient Uptake under Salt Stress. PLANTS 2021; 10:plants10102135. [PMID: 34685945 PMCID: PMC8539127 DOI: 10.3390/plants10102135] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 01/07/2023]
Abstract
Licorice (Glycyrrhiza uralensis Fisch.) is a salt and drought tolerant legume suitable for rehabilitating abandoned saline lands, especially in dry arid regions. We hypothesized that soil amended with maize-derived biochar might alleviate salt stress in licorice by improving its growth, nutrient acquisition, and root system adaptation. Experiments were designed to determine the effect of different biochar concentrations on licorice growth parameters, acquisition of C (carbon), nitrogen (N), and phosphorus (P) and on soil enzyme activities under saline and non-saline soil conditions. Pyrolysis char from maize (600 °C) was used at concentrations of 2% (B2), 4% (B4), and 6% (B6) for pot experiments. After 40 days, biochar improved the shoot and root biomass of licorice by 80 and 41% under saline soil conditions. However, B4 and B6 did not have a significant effect on shoot growth. Furthermore, increased nodule numbers of licorice grown at B4 amendment were observed under both non-saline and saline conditions. The root architectural traits, such as root length, surface area, project area, root volume, and nodulation traits, also significantly increased by biochar application at both B2 and B4. The concentrations of N and K in plant tissue increased under B2 and B4 amendments compared to the plants grown without biochar application. Moreover, the soil under saline conditions amended with biochar showed a positive effect on the activities of soil fluorescein diacetate hydrolase, proteases, and acid phosphomonoesterases. Overall, this study demonstrated the beneficial effects of maize-derived biochar on growth and nutrient uptake of licorice under saline soil conditions by improving nodule formation and root architecture, as well as soil enzyme activity.
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Egamberdieva D, Li L, Ma H, Wirth S, Bellingrath-Kimura SD. Soil Amendment With Different Maize Biochars Improves Chickpea Growth Under Different Moisture Levels by Improving Symbiotic Performance With Mesorhizobium ciceri and Soil Biochemical Properties to Varying Degrees. Front Microbiol 2019; 10:2423. [PMID: 31749774 PMCID: PMC6842948 DOI: 10.3389/fmicb.2019.02423] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 10/07/2019] [Indexed: 12/02/2022] Open
Abstract
Chickpea (Cicer arietinum L.) is an important legume originating in the Mediterranean and the Middle East and is now cultivated in several varieties throughout the world due to its high protein and fiber content as well as its potential health benefits. However, production is drastically affected by prevalent water stress in most soybean-growing regions. This study investigates the potential of biochar to affect chickpea-Rhizobium symbiotic performance and soil biological activity in a pot experiment. Two different biochar types were produced from maize using different pyrolysis techniques, i.e., by heating at 600°C (MBC) and by batch-wise hydrothermal carbonization at 210°C (HTC), and used as soil amendments. The plant biomass, plant nutrient concentration, nodule numbers, leghemoglobin (Lb) content, soil enzyme activities, and nutrient contents of the grown chickpeas were examined. Our results indicated that plant root and shoot biomass, the acquisition of N, P, K, and Mg, soil nutrient contents, soil alkaline and acid phosphomonoesterases, and proteases were significantly increased by HTC char application in comparison to MBC char under both well-watered and drought conditions. Furthermore, the application of both biochar types caused an increase in nodule number by 52% in well-watered and drought conditions by improving the symbiotic performance of chickpea with Mesorhizobium ciceri. Rhizobial inoculation combined with HTC char showed a positive effect on soil FDA activity, proteases and alkaline phosphomonoesterases under well-watered and drought conditions compared to the control or MBC char-amended soils. This concept, whereby the type of producing biochar plays a central role in the effect of the biochar, conforms to the fact that there is a link between biochar chemical and physical properties and enhanced plant nutrient acquisition, symbiotic performance and stress tolerance.
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Affiliation(s)
- Dilfuza Egamberdieva
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
- Department of Microbiology, Faculty of Biology, National University of Uzbekistan, Tashkent, Uzbekistan
- CAS Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Ürümqi, China
| | - Li Li
- CAS Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Ürümqi, China
| | - Hua Ma
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Stephan Wirth
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
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Effect of Biochar and Irrigation on Soybean-Rhizobium Symbiotic Performance and Soil Enzymatic Activity in Field Rhizosphere. AGRONOMY-BASEL 2019. [DOI: 10.3390/agronomy9100626] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nitrogen (N) in soybean (Glycine max L.) plants derived from biological nitrogen fixation was shown to be a sustainable N resource to substitute for N fertilizer. However, the limited water supply in sandy soil is a critical factor for soybean nodulation and crop growth. This study investigated the potential mechanism of the effect of biochar and irrigation on the soybean-Rhizobium symbiotic performance and soil biological activity in a field trial. In the absence of N fertilizer, 10 t ha−1 of black cherry wood-derived biochar were applied under irrigated and rainfed conditions on an experimental, sandy field site. The plant biomass, plant nutrient concentrations, nodule number, nodule leghemoglobin content, soil enzyme activities, and soil-available nutrients were examined. Our results show that biochar application caused a significant increase in the nodule number by 35% in the irrigated condition. Shoot biomass and soil fluorescein diacetate hydrolytic activity were significantly increased by irrigation in comparison to the rainfed condition. The activity of soil protease reduced significantly, by 8%, with the biochar application in the irrigated condition. Further, a linear correlation analysis and redundancy analysis performed on the plant, nodule, and soil variables suggested that the biochar application may affect soybean N uptake in the sandy field. Nodulation was enhanced with biochar addition, however, the plant N concentration and nodule Lb content remained unaffected.
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Deciphering the Symbiotic Plant Microbiome: Translating the Most Recent Discoveries on Rhizobia for the Improvement of Agricultural Practices in Metal-Contaminated and High Saline Lands. AGRONOMY-BASEL 2019. [DOI: 10.3390/agronomy9090529] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rhizosphere and plant-associated microorganisms have been intensely studied for their beneficial effects on plant growth and health. These mainly include nitrogen-fixing bacteria (NFB) and plant-growth promoting rhizobacteria (PGPR). This beneficial fraction is involved in major functions such as plant nutrition and plant resistance to biotic and abiotic stresses, which include water deficiency and heavy-metal contamination. Consequently, crop yield emerges as the net result of the interactions between the plant genome and its associated microbiome. Here, we provide a review covering recent studies on PGP rhizobia as effective inoculants for agricultural practices in harsh soil, and we propose models for inoculant combinations and genomic manipulation strategies to improve crop yield.
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Gopalakrishnan S, Sathya A, Vijayabharathi R, Varshney RK, Gowda CLL, Krishnamurthy L. Plant growth promoting rhizobia: challenges and opportunities. 3 Biotech 2015; 5:355-377. [PMID: 28324544 PMCID: PMC4522733 DOI: 10.1007/s13205-014-0241-x] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/19/2014] [Indexed: 11/24/2022] Open
Abstract
Modern agriculture faces challenges, such as loss of soil fertility, fluctuating climatic factors and increasing pathogen and pest attacks. Sustainability and environmental safety of agricultural production relies on eco-friendly approaches like biofertilizers, biopesticides and crop residue return. The multiplicity of beneficial effects of microbial inoculants, particularly plant growth promoters (PGP), emphasizes the need for further strengthening the research and their use in modern agriculture. PGP inhabit the rhizosphere for nutrients from plant root exudates. By reaction, they help in (1) increased plant growth through soil nutrient enrichment by nitrogen fixation, phosphate solubilization, siderophore production and phytohormones production (2) increased plant protection by influencing cellulase, protease, lipase and β-1,3 glucanase productions and enhance plant defense by triggering induced systemic resistance through lipopolysaccharides, flagella, homoserine lactones, acetoin and butanediol against pests and pathogens. In addition, the PGP microbes contain useful variation for tolerating abiotic stresses like extremes of temperature, pH, salinity and drought; heavy metal and pesticide pollution. Seeking such tolerant PGP microbes is expected to offer enhanced plant growth and yield even under a combination of stresses. This review summarizes the PGP related research and its benefits, and highlights the benefits of PGP rhizobia belonging to the family Rhizobiaceae, Phyllobacteriaceae and Bradyrhizobiaceae.
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Affiliation(s)
- Subramaniam Gopalakrishnan
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Andhra Pradesh, India
| | - Arumugam Sathya
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Andhra Pradesh, India
| | - Rajendran Vijayabharathi
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Andhra Pradesh, India
| | - Rajeev Kumar Varshney
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Andhra Pradesh, India
| | - C L Laxmipathi Gowda
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Andhra Pradesh, India
| | - Lakshmanan Krishnamurthy
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Andhra Pradesh, India.
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Guerrouj K, Pérez-Valera E, Chahboune R, Abdelmoumen H, Bedmar EJ, El Idrissi MM. Identification of the rhizobial symbiont of Astragalus glombiformis in Eastern Morocco as Mesorhizobium camelthorni. Antonie van Leeuwenhoek 2013; 104:187-98. [DOI: 10.1007/s10482-013-9936-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 05/09/2013] [Indexed: 11/28/2022]
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Fahmi AI, Nagaty HH, Eissa RA, Hassan MM. Effects of salt stress on some nitrogen fixation parameters in faba bean. Pak J Biol Sci 2011; 14:385-391. [PMID: 21902062 DOI: 10.3923/pjbs.2011.385.391] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The adverse effects of sea water salinity on number of nodules, nitrogen content, nitroginase activity, Chlorophyll a and b content, proline accumulation and protein pattern of faba bean plants (Vicia faba commercial cultivar Nubaria 1) were investigated. Faba bean plants were irrigated with sea water at 20, 25, 30, 40 and 50% concentrations and inoculated with rhizobial isolate ARC307 or with gamma rays treated isolates namely; ARC1, ARC2, ARC3, ARC4, ARC5, ARC6 and ARC7. Nodules number, nitrogen content, nitroginase activity and chlorophyll a and b content parameters were decreased by increasing sea water salinity with all used isolates, while proline accumulation parameter increased. At the same time, ARC2 isolate showed the highest values for these parameters above all isolates including the parental isolate ARC307 at all studied concentrations except for proline accumulation parameter, it was the least. Therefore, ARC2 considered as a promising isolate for salt tolerance. Salinity enhanced the occurrence of particular novel proteins in faba bean plants infected with ARC2 isolate.
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Affiliation(s)
- A I Fahmi
- Department of Biotechnology, Faculty of Sciences, Taif University, Kingdom of Saudi Arabia
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Fterich A, Mahdhi M, Caviedes MA, Pajuelo E, Rivas R, Rodriguez-Llorente ID, Mars M. Characterization of root-nodulating bacteria associated to Prosopis farcta growing in the arid regions of Tunisia. Arch Microbiol 2011; 193:385-97. [PMID: 21359955 DOI: 10.1007/s00203-011-0683-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/02/2011] [Accepted: 02/04/2011] [Indexed: 10/18/2022]
Abstract
Diversity of 50 bacterial isolates recovered from root nodules of Prosopis farcta grown in different arid soils in Tunisia, was investigated. Characterization of isolates was assessed using a polyphasic approach including phenotypic characteristics, 16S rRNA gene PCR--RFLP and sequencing, nodA gene sequencing and MLSA. It was found that most of isolates are tolerant to high temperature (40°C) and salinity (3%). Genetic characterization emphasizes that isolates were assigned to the genus Ensifer (80%), Mesorhizobium (4%) and non-nodulating endophytic bacteria (16%). Forty isolates belonging to the genus Ensifer were affiliated to Ensifer meliloti, Ensifer xinjiangense/Ensifer fredii and Ensifer numidicus species. Two isolates belonged to the genus Mesorhizobium. Eight isolates failing to renodulate their host plant were endophytic bacteria and belonged to Bacillus, Paenibacillus and Acinetobacter genera. Symbiotic properties of nodulating isolates showed a diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Isolate PG29 identified as Ensifer meliloti was the most effective one. Ability of Prosopis farcta to establish symbiosis with rhizobial species confers an important advantage for this species to be used in reforestation programs. This study offered the first systematic information about the diversity of microsymbionts nodulating Prosopis farcta in the arid regions of Tunisia.
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Affiliation(s)
- A Fterich
- Laboratoire de Biotechnologies Végétales Appliquées à l'Amélioration des Cultures, Faculté des Sciences de Gabès, Université de Gabes, Cité Erriadh Zrig, 6072, Gabès, Tunisia
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Ourarhi M, Abdelmoumen H, Guerrouj K, Benata H, Muresu R, Squartini A, Missbah El Idrissi M. Colutea arborescens is nodulated by diverse rhizobia in Eastern Morocco. Arch Microbiol 2010; 193:115-24. [PMID: 21082309 DOI: 10.1007/s00203-010-0650-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2009] [Revised: 08/24/2010] [Accepted: 10/29/2010] [Indexed: 10/18/2022]
Abstract
Eighteen isolates of rhizobia isolated from root nodules of Colutea arborescens (Bladder senna) grown in different soils of the eastern area of Morocco were characterized by phenotypic and genomic analyses. All the isolates characterized were fast growers. This is may be due to the isolation procedures used. The phenotypic, symbiotic and cultural characteristics analyzed allowed the description of a wide physiological diversity among tested isolates. The results obtained suggest that the phenotype of these rhizobia might have convergent evolved to adapt the local conditions. The genetic characterization consisted in an analysis of the rep-PCR fingerprints and the PCR-based RFLP of the 16S rDNA patterns. The 16S rDNA of six isolates representing the main ribotypes obtained by the PCR-based RFLP was sequenced. A large diversity was observed among these rhizobia, and they were classified as different species of the genera Rhizobium, Sinorhizobium and Mesorhizobium. The nodC gene was also sequenced, and the results confirmed the three lineages corresponding to the three genera. The results of the sequencing of nodC and 16S rDNA genes suggest that the nodulation genes and chromosome might have co-evolved among these bacteria.
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Affiliation(s)
- Mohammed Ourarhi
- Laboratoire de Biologie des Plantes et des Microorganismes, Faculty of Sciences, Mohamed Premier University, Oujda, Morocco
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Reguera M, Lloret J, Margaret I, Vinardell JM, Martín M, Buendía A, Rivilla R, Ruiz-Sainz JE, Bonilla I, Bolaños L. GeneSMb21071of plasmid pSymB is required for osmoadaptation ofSinorhizobium meliloti1021 and is implicated in modifications of cell surface polysaccharides structure in response to hyperosmotic stress. Can J Microbiol 2009; 55:1145-52. [DOI: 10.1139/w09-073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Megaplasmid pSymB of the nitrogen-fixing symbiont Sinorhizobium meliloti , implicated in adaptation to hyperosmotic stress, contains 11 gene clusters that apparently encode surface polysaccharides. However, only 2 of these clusters, containing the exo and exp genes, have been associated with the synthesis of the acidic exopolysaccharides succinoglycan and galactoglucan, respectively. The functions of the other 9 clusters remain unsolved. The involvement of one of those regions, pSymB cluster 3, on surface polysaccharide synthesis and its possible implication in osmoadaptation were investigated. In silico analysis of cluster 3 showed that it putatively encodes for the synthesis and transport of a methylated surface polysaccharide. Mutants affected in this cluster were symbiotically effective but showed defects in growth under saline and nonsaline osmotic stress. The gene SMb21071, encoding a putative initiating glycosyltransferase, is transcriptionally induced under hyperosmotic conditions. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis and silver staining showed that osmotic stresses changed the profiles of surface polysaccharides of wild-type and mutants strains in different ways. The overall results suggest that cluster 3 is important for growth under saline stress and essential for growth under nonsaline hyperosmotic stress, and it appears to be implicated in maintaining and (or) modifying surface polysaccharides in response to osmotic stress.
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Affiliation(s)
- María Reguera
- Departamento de Biologia, Facultad de Ciencias, Universidad Autonoma de Madrid, Darwin 2, 28049-Madrid, Spain
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An orphan LuxR homolog of Sinorhizobium meliloti affects stress adaptation and competition for nodulation. Appl Environ Microbiol 2008; 75:946-55. [PMID: 19088317 DOI: 10.1128/aem.01692-08] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Sin/ExpR quorum-sensing system of Sinorhizobium meliloti plays an important role in the symbiotic association with its host plant, Medicago sativa. The LuxR-type response regulators of the Sin system include the synthase (SinI)-associated SinR and the orphan regulator ExpR. Interestingly, the S. meliloti Rm1021 genome codes for four additional putative orphan LuxR homologs whose regulatory roles remain to be identified. These response regulators contain the characteristic domains of the LuxR family of proteins, which include an N-terminal autoinducer/response regulatory domain and a C-terminal helix-turn-helix domain. This study elucidates the regulatory role of one of the orphan LuxR-type response regulators, NesR. Through expression and phenotypic analyses, nesR was determined to affect the active methyl cycle of S. meliloti. Moreover, nesR was shown to influence nutritional and stress response activities in S. meliloti. Finally, the nesR mutant was deficient in competing with the wild-type strain for plant nodulation. Taken together, these results suggest that NesR potentially contributes to the adaptability of S. meliloti when it encounters challenges such as high osmolarity, nutrient starvation, and/or competition for nodulation, thus increasing its chances for survival in the stressful rhizosphere.
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Fall D, Diouf D, Ourarhi M, Faye A, Abdelmounen H, Neyra M, Sylla SN, Missbah El Idrissi M. Phenotypic and genotypic characteristics of Acacia senegal (L.) Willd. root-nodulating bacteria isolated from soils in the dryland part of Senegal. Lett Appl Microbiol 2008; 47:85-97. [PMID: 18565139 DOI: 10.1111/j.1472-765x.2008.02389.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS We characterized phenotypically and genotypically root-nodulating bacteria associated with Acacia senegal (L.) Willd. isolated from the soils surrounding A. senegal trees in the dry land area of Senegal. METHODS AND RESULTS The phenotypical and genotypical characterizations we carried out showed a high diversity of A. senegal root-nodulating bacteria. Phenotypic patterns showed adaptations of the rhizobial strains to many environmental stresses such as heat, drought, and salinity. Twelve molecular groups were distinguished by profiles obtained using polymerase chain reaction/restriction fragment length polymorphism techniques from intergenic spacer region rDNA. The highest genetic diversity was found around the A. senegal rhizosphere. Therefore, A. senegal seemed to have a positive influence on occurrence and genotypical diversity of rhizobial populations. Rhizobial isolates obtained in this study belonged phylogenetically to the genera Mesorhizobium and Rhizobium. CONCLUSIONS Our results provided information about the genetic diversity of the rhizobial strains associated with A. senegal and suggested the adaptability of natural rhizobial populations to major ecological environmental stress within these soil environments. SIGNIFICANCE AND IMPACT OF THE STUDY These results suggested a potential selection of compatible and well adapted strains under stress conditions as inoculants for successful A. senegal growth in arid lands.
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Affiliation(s)
- D Fall
- Département de Biologie Végétale, Université Cheikh Anta Diop, Laboratoire Commun de Microbiologie, IRD/ISRA/UCAD, Dakar, Senegal
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Biswas S, Das RH, Sharma GL, Das HR. Isolation and Characterization of a Novel Cross-Infective Rhizobia from Sesbania aculeata (Dhaincha). Curr Microbiol 2007; 56:48-54. [PMID: 17896133 DOI: 10.1007/s00284-007-9037-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 07/20/2007] [Indexed: 11/28/2022]
Abstract
The Sesbania has been widely used as green manure to improve the productivity of several crops. Sinorhizobium saheli strain (SB2) was isolated from the root nodule of Sesbania aculeata. The Tn5 mutants (300) of SB2 were generated and studied for their nodulation efficiencies in its specific and cross-infective host plants. The mutant, SB2M3, was found to have two- and four fold higher nodulation efficiency than wild type in parent host and nonspecific host plant, respectively. SB2M3 differed from SB2 in exopolysaccharide and lipopolysaccharide content. SB2M3 was halotolerant and could grow in alkaline pH at comparatively high temperatures. Hence, it may find an application in agritechnology.
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Affiliation(s)
- Sagarika Biswas
- Institute of Genomics and Integrative Biology, Delhi University Campus, Mall Road, Delhi 110007, India
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Pereira SIA, Lima AIG, Figueira EMDAP. Screening possible mechanisms mediating cadmium resistance in Rhizobium leguminosarum bv. viciae isolated from contaminated Portuguese soils. MICROBIAL ECOLOGY 2006; 52:176-86. [PMID: 16897308 DOI: 10.1007/s00248-006-9057-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Accepted: 10/17/2005] [Indexed: 05/11/2023]
Abstract
Environment heavy-metal contamination is now widespread. Soils may become contaminated from a variety of anthropogenic sources, such as smelters, mining, industry, and application of metal-containing pesticides and fertilizers. Soil microorganisms are very sensitive to moderate heavy-metal concentrations. Therefore, the present work was designed to screen possible mechanisms involved in Rhizobium's Cd resistance; with this purpose, we determined the tolerance levels of several isolates originated from sites with different heavy-metal contamination. Whole-cell-soluble proteins and plasmid profiles were analyzed. We also determined Cd cell concentrations and lipopolysaccharide (LPS) amounts. Results showed different tolerances among Rhizobium isolates; according to their maximum resistance level, isolates were divided in four groups: sensitive (0-125 microM CdCl(2)), moderately tolerant (125-210 microM CdCl(2)), tolerant (250-500 microM CdCl(2)), and extremely tolerant (> or =750 microM CdCl(2)). Intracellular Cd concentrations were lower when compared to wall-bound Cd. Unexpectedly, extremely tolerant isolates accumulated higher levels of metal, suggesting the presence of intracellular agents that prevent metal interfering with important metabolic pathways. The electrophoretic patterns of whole-cell-soluble proteins evidenced cadmium as an inducer of protein metabolism alterations, which were more evident in some polypeptides. Plasmid profiles also showed differences; most tolerant isolates presented two plasmids with molecular weights of 485 and 415 kb, indicating that extrachromosomal DNA may be involved in cadmium resistance. LPS showed to be a common mechanism of resistance. However, the degree of tolerance conferred by LPS is not enough to support tolerance to the higher levels of stress imposed. Presence of other resistance mechanisms is currently being investigated.
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Affiliation(s)
- Sofia Isabel Almeida Pereira
- Centro de Biologia Celular, Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
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Rodrigues CS, Laranjo M, Oliveira S. Effect of heat and pH stress in the growth of chickpea mesorhizobia. Curr Microbiol 2006; 53:1-7. [PMID: 16775779 DOI: 10.1007/s00284-005-4515-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2004] [Accepted: 03/28/2005] [Indexed: 11/26/2022]
Abstract
The development of rhizobial inoculants requires the selection of isolates that are symbiotically efficient as well as adapted to the local environmental conditions. Our aim was to find indigenous chickpea rhizobia tolerant to adverse environmental conditions, such as temperature and pH. Thirteen isolates of chickpea mesorhizobia from southern Portugal were examined. Tolerance to stress temperatures and pH was evaluated by quantification of bacterial growth at 20-37 degrees C and pH 5-9, respectively. Tolerance to heat shocks was studied by submitting isolates to 46 degrees C and 60 degrees C. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein analysis revealed qualitative and quantitative differences when isolates were submitted to temperature stress. A 60-kDa protein was overproduced by all isolates under heat stress. Almost all isolates revealed to be more tolerant to 20 degrees C than to 37 degrees C. A positive correlation was found between the maximum growth pH and the isolate origin soil pH. Generally, isolates more tolerant to temperature stress showed a lower symbiotic efficiency.
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Shamseldin A, Nyalwidhe J, Werner D. A proteomic approach towards the analysis of salt tolerance in Rhizobium etli and Sinorhizobium meliloti strains. Curr Microbiol 2006; 52:333-9. [PMID: 16604415 DOI: 10.1007/s00284-005-6472-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 09/25/2005] [Indexed: 11/24/2022]
Abstract
Soluble proteins from the salt-tolerant Rhizobium etli strain EBRI 26 were separated by two-dimensional (2D) gel electrophoresis and visualised by Commassie staining. Six proteins are highly expressed after induction by 4% NaCl compared to the non-salt-stressed cells. These proteins have pI between 5 and 5.5 and masses of approximately 22, 25, 40, 65, 70, and 95 kDa. These proteins were analysed by Matrix-assisted laser adsorption ionization time of flight (MALDI-TOF) after digestion with trypsin. Despite having very good peptide mass fingerprint data, these proteins could not be identified, because the genome sequence of R. etli is not yet published. In a second approach, soluble proteins from salt-induced or non-salt-induced cultures from R. etli strain EBRI 26 were separately labelled with different fluorescent cyano-dyes prior to 2D difference in gel electrophoresis. Results revealed that 49 proteins are differentially expressed after the addition of sodium chloride. Fourteen proteins are overexpressed and 35 were downregulated. The genome of Sinorhizobium meliloti, a closely related species to R. etli, has been published. Similar experiments using Sinorhizobium meliloti strain 2011 identified four overexpressed and six downregulated proteins. Among the overexpressed protein is a carboxynospermidin decarboxylase, which plays an important role in the biosynthesis of spermidin (polyamine). The enzyme catalase is among the downregulated proteins. These proteins may play a role in salt tolerance.
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Affiliation(s)
- Abdelaal Shamseldin
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, Mubarak City for Scientific Research and Technological Applications, New Borg El-Arab, Alexandria, Egypt
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Räsänen LA, Lindström K. Stability of short and long O-chain lipopolysaccharide types in Rhizobium galegae and their correlation with symbiotic properties and growth conditions, tolerance of low pH, aluminum and salt in the growth medium. FEMS Microbiol Lett 2006. [DOI: 10.1111/j.1574-6968.1997.tb12680.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Nandal K, Sehrawat AR, Yadav AS, Vashishat RK, Boora KS. High temperature-induced changes in exopolysaccharides, lipopolysaccharides and protein profile of heat-resistant mutants of Rhizobium sp. (Cajanus). Microbiol Res 2005; 160:367-73. [PMID: 16255141 DOI: 10.1016/j.micres.2005.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A thermosensitive wild-type strain (PP201) of Rhizobium sp. (Cajanus) and its 14 heat-resistant mutants were characterized biochemically with regard to their cell surface (exopolysaccharides (EPSs) and lipopolysaccharides (LPSs)) properties and protein profile. Differences were observed between the parent strain and the mutants in all these parameters under high temperature conditions. At normal temperature (30 degrees C), only half of the mutant strains produced higher amounts of EPSs than the parent strain, but at 43 degrees C, all the mutants produced higher quantities of EPS. The LPS electrophoretic pattern of the parent strain PP201 and the heat-resistant mutants was almost identical at 30 degrees C. At 43 degrees C, the parent strain did not produce LPS but the mutants produced both kinds of LPSs. The protein electrophoretic pattern showed that the parent strain PP201 formed very few proteins at high temperature, whereas the mutants formed additional new proteins. A heat shock protein (Hsp) of 63-74 kDa was overproduced in all mutant strains.
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Affiliation(s)
- Kiran Nandal
- Department of Genetics, CCS Haryana Agricultural University, Hisar-125 004, Haryana, India
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20
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Arun AB, Sridhar KR. Growth Tolerance of Rhizobia Isolated from Sand Dune Legumes of the Southwest Coast of India. Eng Life Sci 2005. [DOI: 10.1002/elsc.200420061] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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21
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Boscari A, Mandon K, Poggi MC, Le Rudulier D. Functional expression of Sinorhizobium meliloti BetS, a high-affinity betaine transporter, in Bradyrhizobium japonicum USDA110. Appl Environ Microbiol 2004; 70:5916-22. [PMID: 15466533 PMCID: PMC522109 DOI: 10.1128/aem.70.10.5916-5922.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Among the Rhizobiaceae, Bradyrhizobium japonicum strain USDA110 appears to be extremely salt sensitive, and the presence of glycine betaine cannot restore its growth in medium with an increased osmolarity (E. Boncompagni, M. Osteras, M. C. Poggi, and D. Le Rudulier, Appl. Environ. Microbiol. 65:2072-2077, 1999). In order to improve the salt tolerance of B. japonicum, cells were transformed with the betS gene of Sinorhizobium meliloti. This gene encodes a major glycine betaine/proline betaine transporter from the betaine choline carnitine transporter family and is required for early osmotic adjustment. Whereas betaine transport was absent in the USDA110 strain, such transformation induced glycine betaine and proline betaine uptake in an osmotically dependent manner. Salt-treated transformed cells accumulated large amounts of glycine betaine, which was not catabolized. However, the accumulation was reversed through rapid efflux during osmotic downshock. An increased tolerance of transformant cells to a moderate NaCl concentration (80 mM) was also observed in the presence of glycine betaine or proline betaine, whereas the growth of the wild-type strain was totally abolished at 80 mM NaCl. Surprisingly, the deleterious effect due to a higher salt concentration (100 mM) could not be overcome by glycine betaine, despite a significant accumulation of this compound. Cell viability was not significantly affected in the presence of 100 mM NaCl, whereas 75% cell death occurred at 150 mM NaCl. The absence of a potential gene encoding Na(+)/H(+) antiporters in B. japonicum could explain its very high Na(+) sensitivity.
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Affiliation(s)
- Alexandre Boscari
- Unité Interactions Plantes-Microorganismes et Santé Végétale, CNRS-INRA-Université de Nice Sophia Antipolis, UMR 6192, Faculté des Sciences, Parc Valrose, 06108 Nice Cédex, France
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Zahran HH, Abdel-Fattah M, Ahmad MS, Zaky AY. Polyphasic taxonomy of symbiotic rhizobia from wild leguminous plants growing in Egypt. Folia Microbiol (Praha) 2003; 48:510-20. [PMID: 14533483 DOI: 10.1007/bf02931333] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
About 20 strains of rhizobia from wild legumes were characterized based on numerical analysis of phenotypic characteristics, nodulating ability, fatty acid methyl esters (FAME) and SDS-PAGE profiles of whole cell proteins. FAME analysis revealed that palmitic (16:0), stearic (18:0) and arachidonic (20:0) were detected in most of wild-legume rhizobia, the latter being uncommon in fatty acid profiles of Rhizobium and Sinorhizobium. Numerical analysis of FAME classified strains of wild-legume rhizobia into 9 clusters and one heterogeneous group. There was both agreement and disagreement with the clustering data based on phenotypic analysis and FAME analysis. Four strains were grouped together in the same cluster based on both methods. However, 4 another strains, which were placed in one cluster of phenotypic analysis, were distributed in several clusters after FAME analysis. SDS-PAGE of whole-cell proteins revealed that the rhizobial strains exhibited protein profiles with peptide bands ranging from 5-19 band per profile and showed molar mass of 110-183 kDa. As in the case of FAME analysis, numerical analysis of protein bands was compared with clustering of phenotypic analysis. Agreement of the two methods was obvious when clustering some strains but conflicted in the classification of some other strains. However, integration of the three methods could be the basis of a polyphasic taxonomy. The twenty strains of wild-legume rhizobia were finally classified as follows: 12 strains related to Rhizobium leguminosarum, 5 strains related to Sinorhizobium meliloti and 3 strains to Rhizobium spp. Rhizobia nodulating wild herb legumes are among indigenous strains nodulating crop legumes in cultivated as well as noncultivated lands.
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Affiliation(s)
- H H Zahran
- Department of Botany, Faculty of Science, Cairo University, Beni-Suef 62 411, Egypt.
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Soussi M, Santamaría M, Ocaña A, Lluch C. Effects of salinity on protein and lipopolysaccharide pattern in a salt-tolerant strain of Mesorhizobium ciceri. J Appl Microbiol 2001; 90:476-81. [PMID: 11298245 DOI: 10.1046/j.1365-2672.2001.01269.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To characterize the physiological and metabolic responses of Mesorhizobium ciceri strain ch-191 to salt stress, investigating the changes induced by salinity in protein and lipopolysaccharide profiles, as well as determining the accumulation of amino acids, glutamate and proline. METHODS AND RESULTS Strain ch-191 of M. ciceri was grown with different NaCl concentrations. Protein and lipopolysaccharide patterns were determined by electrophoresis. The strain ch-191 tolerated up to 200 mmol l-1 NaCl, although higher salt dosages limited its growth and induced changes in the protein profile. The most noteworthy change in the LPS-I pattern was the decrease in the slowest band and the appearance of an intermediate mobility band. The accumulation of proline in response to salt stress surpassed that of glutamate. CONCLUSION The protein profile showed major alterations at salinity levels which inhibited growth. However, the alterations in the LPS profile and accumulation of compatible solutes were evident from the lowest levels, suggesting that these changes may constitute adaptative responses to salt, allowing normal growth. SIGNIFICANCE AND IMPACT OF THE STUDY The selection and characterization of salt-tolerant strains, which also show efficient symbiotic performance under salinity, may constitute a strategy for improving Cicer arietinum-Mesorhizobium ciceri symbiosis in adverse environments.
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Affiliation(s)
- M Soussi
- Departamento de Biología Vegetal, Facultad de Ciencias, Universidad de Granada, Spain
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Zahran HH. Rhizobium-legume symbiosis and nitrogen fixation under severe conditions and in an arid climate. Microbiol Mol Biol Rev 1999; 63:968-89, table of contents. [PMID: 10585971 PMCID: PMC98982 DOI: 10.1128/mmbr.63.4.968-989.1999] [Citation(s) in RCA: 526] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biological N(2) fixation represents the major source of N input in agricultural soils including those in arid regions. The major N(2)-fixing systems are the symbiotic systems, which can play a significant role in improving the fertility and productivity of low-N soils. The Rhizobium-legume symbioses have received most attention and have been examined extensively. The behavior of some N(2)-fixing systems under severe environmental conditions such as salt stress, drought stress, acidity, alkalinity, nutrient deficiency, fertilizers, heavy metals, and pesticides is reviewed. These major stress factors suppress the growth and symbiotic characteristics of most rhizobia; however, several strains, distributed among various species of rhizobia, are tolerant to stress effects. Some strains of rhizobia form effective (N(2)-fixing) symbioses with their host legumes under salt, heat, and acid stresses, and can sometimes do so under the effect of heavy metals. Reclamation and improvement of the fertility of arid lands by application of organic (manure and sewage sludge) and inorganic (synthetic) fertilizers are expensive and can be a source of pollution. The Rhizobium-legume (herb or tree) symbiosis is suggested to be the ideal solution to the improvement of soil fertility and the rehabilitation of arid lands and is an important direction for future research.
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Affiliation(s)
- H H Zahran
- Department of Botany, Faculty of Science, Beni-Suef, 62511 Egypt
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25
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Kulkarni S, Nautiyal CS. Characterization of high temperature-tolerant rhizobia isolated from Prosopis juliflora grown in alkaline soil. J GEN APPL MICROBIOL 1999; 45:213-220. [PMID: 12501363 DOI: 10.2323/jgam.45.213] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A method was developed for the fast screening and selection of high-temperature tolerant rhizobial strains from root nodules of Prosopis juliflora growing in alkaline soils. The high-temperature tolerant rhizobia were selected from 2,500 Rhizobium isolates with similar growth patterns on yeast mannitol agar plates after 72 h incubation at 30 and 45 degrees C, followed by a second screening at 47.5 degrees C. Seventeen high-temperature tolerant rhizobial strains having distinguishable protein band patterns were finally selected for further screening by subjecting them to temperature stress up to 60 degrees C in yeast mannitol broth for 6 h. The high-temperature tolerant strains were NBRI12, NBRI329, NBRI330, NBRI332, and NBRI133. Using this procedure, a large number of rhizobia from root nodules of P. juliflora were screened for high-temperature tolerance. The assimilation of several carbon sources, tolerance to high pH and salt stress, and ability to nodulate P. juliflora growing in a glasshouse and nursery of the strains were studied. All five isolates had higher plant dry weight in the range of 29.9 to 88.6% in comparison with uninoculated nursery-grown plants. It was demonstrated that it is possible to screen in nature for superior rhizobia exemplified by the isolation of temperature-tolerant strains, which established effective symbiosis with nursery-grown P. juliflora. These findings indicate a correlation between strain performance under in vitro stress in pure culture and strain behavior under symbiotic conditions. Pure culture evaluation may be a useful tool in search for Rhizobium strains better suited for soil environments where high temperature, pH, and salt stress constitutes a limitation for symbiotic biological nitrogen fixation.
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Affiliation(s)
- Suneeta Kulkarni
- Microbiology Group, National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
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Lloret J, Wulff BB, Rubio JM, Downie JA, Bonilla I, Rivilla R. Exopolysaccharide II production is regulated by salt in the halotolerant strain Rhizobium meliloti EFB1. Appl Environ Microbiol 1998; 64:1024-8. [PMID: 9501442 PMCID: PMC106361 DOI: 10.1128/aem.64.3.1024-1028.1998] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The halotolerant strain Rhizobium meliloti EFB1 modifies the production of extracellular polysaccharides in response to salt. EFB1 colonies grown in the presence of 0.3 M NaCl show a decrease in mucoidy, and in salt-supplemented liquid medium this organism produces 40% less exopolysaccharides. We isolated transposon-induced mutant that, when grown in the absence of salt, had a colony morphology (nonmucoid) similar to the colony morphology of the wild type grown in the presence of salt. Calcofluor fluorescence, proton nuclear magnetic resonance spectroscopy, and genetic analysis of the mutant indicated that galactoglucan, which is not produced under normal conditions by other R. meliloti strains, is produced by strain EFB1 and that production of this compound decreases when the organism is grown in the presence of salt. The mutant was found to be affected in a genetic region highly homologous to genes for galactoglucan production in R. meliloti Rm2011 (expE genes). However, sequence divergence occurs in a putative expE promoter region. A transcriptional fusion of the promoter with lacZ demonstrated that, unlike R. meliloti Rm2011, galactoglucan is produced constitutively by EFB1 and that its expression is reduced 10-fold during exponential growth in the presence of salt.
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Affiliation(s)
- J Lloret
- Departamento de Biología, Universidad Autónoma de Madrid, Spain
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Surange S, Wollum II AG, Kumar N, Nautiyal CS. Characterization of Rhizobium from root nodules of leguminous trees growing in alkaline soils. Can J Microbiol 1997. [DOI: 10.1139/m97-130] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High temperature, pH, and salt stresses in tropical alkaline soils limit nodulation and dinitrogen fixation by strains of Rhizobium from the root nodules of nitrogen fixing trees (NFTs). This study was conducted to determine the variability among Rhizobium strains isolated from different NFTs in growth response to high temperature, pH, and salt concentrations. Variable response to increases in temperature, pH, and salt concentrations was observed. Rhizobium strain isolated from Albizia lebbek survived at 50 °C, while Rhizobium strains isolated from Sesbania formosa, Acacia farnesiana, and Dalbergia sissoo were well adapted to grow on pH 12.0. All the Rhizobium strains tolerated salt concentrations up to 5.0%. Strains were further characterized with respect to utilization of 27 carbon sources and for their effectiveness in substrate utilization at pH 7.0 and 9.0. Generally higher rates of O2 consumption were observed at pH 7.0 compared with pH 9.0.Key words: Rhizobium, leguminous trees, root nodules, stress tolerance.
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28
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Zahran HH. Chemotaxonomic characterization of some fast-growing rhizobia nodulating leguminous trees. Folia Microbiol (Praha) 1997. [DOI: 10.1007/bf02816952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Diversity of Partial 16S rRNA Sequences Among and Within Strains of African Rhizobia Isolated from Acacia and Prosopis. Syst Appl Microbiol 1996. [DOI: 10.1016/s0723-2020(96)80062-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Saxena D, Khanna S, Amin M. Modulation of protein profiles inRhizobiumsp. under salt stress. Can J Microbiol 1996. [DOI: 10.1139/m96-084] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Salinity-induced changes in the protein profiles in Rhizobium sp. exhibited alterations in the expression of as many as 19 proteins, which either showed an enhanced rate of synthesis or a decline in the levels as compared with controls. All these proteins were predominantly of low molecular mass (below 40 kDa) except for one (52 kDa). Induction and repression of proteins in salt-grown cells and salt-shocked cells were qualitatively similar. However, the difference in the protein profiles was more marked in salt-grown cells as compared with salt-shocked cells.Key words: Rhizobium, SDS–PAGE, salt stress, proteins.
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Lloret J, Bolanos L, Lucas MM, Peart JM, Brewin NJ, Bonilla I, Rivilla R. Ionic Stress and Osmotic Pressure Induce Different Alterations in the Lipopolysaccharide of a Rhizobium meliloti Strain. Appl Environ Microbiol 1995; 61:3701-4. [PMID: 16535151 PMCID: PMC1388713 DOI: 10.1128/aem.61.10.3701-3704.1995] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A halotolerant strain of Rhizobium meliloti was isolated from nodules of a Melilotus plant growing in a salt marsh in Donana National Park (southwest Spain). This strain, EFB1, is able to grow at NaCl concentrations of up to 500 mM, and no effect on growth is produced by 300 mM NaCl. EFB1 showed alterations on its lipopolysaccharide (LPS) structure that can be related to salt stress: (i) silver-stained electrophoretic profiles showed a different mobility that was dependent on ionic stress but not on osmotic pressure, and (ii) a monoclonal antibody, JIM 40, recognized changes in LPS that were dependent on osmotic stress. Both modifications on LPS may form part of the adaptive mechanism of this bacterium for saline environments.
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Cortiñas TI, Micalizzi B, de Guzman AM. Influence of culture conditions on growth and protective antigenicity of Clostridium chauvoei. THE JOURNAL OF APPLIED BACTERIOLOGY 1994; 77:382-7. [PMID: 7989266 DOI: 10.1111/j.1365-2672.1994.tb03438.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effect of culture conditions on growth and immunogenicity of Clostridium chauvoei were examined. The pH control and partial feeding of the carbon source at high concentrations were beneficial for growth. The biomass yield was significatively improved, however the butanol concentration reached toxic levels hampering further growth. For each experimental condition the immunogenicity of cells was tested. No differences were found with cells obtained at different temperatures, but it decreased significatively with the partial supply of the carbon source and pH control.
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Affiliation(s)
- T I Cortiñas
- Area de Microbiología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Argentina
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