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Liu GH, Yang S, Han S, Xie CJ, Liu X, Rensing C, Zhou SG. Nitrogen fixation and transcriptome of a new diazotrophic Geomonas from paddy soils. mBio 2023; 14:e0215023. [PMID: 37855611 PMCID: PMC10746287 DOI: 10.1128/mbio.02150-23] [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: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE The ability of Geomonas species to fix nitrogen gas (N2) is an important metabolic feature for its application as a plant growth-promoting rhizobacterium. This research is of great importance as it provides the first comprehensive direct experimental evidence of nitrogen fixation by the genus Geomonas in pure culture. We isolated a number of Geomonas strains from paddy soils and determined that nifH was present in these strains. This study demonstrated that these Geomonas species harbored genes encoding nitrogenase, as do Geobacter and Anaeromyxobacter in the same class of Deltaproteobacteria. We demonstrated N2-dependent growth of Geomonas and determined regulation of gene expression associated with nitrogen fixation. The research establishes and advances our understanding of nitrogen fixation in Geomonas.
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Affiliation(s)
- Guo-Hong Liu
- Institute of Resources, Environment and Soil Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou City, Fujian Province, China
| | - Shang Yang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shuang Han
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Cheng-Jie Xie
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shun-Gui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
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Zahra ST, Tariq M, Abdullah M, Zafar M, Yasmeen T, Shahid MS, Zaki HEM, Ali A. Probing the potential of salinity-tolerant endophytic bacteria to improve the growth of mungbean [ Vigna radiata (L.) Wilczek]. Front Microbiol 2023; 14:1149004. [PMID: 38111636 PMCID: PMC10725929 DOI: 10.3389/fmicb.2023.1149004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 11/15/2023] [Indexed: 12/20/2023] Open
Abstract
Soil salinity is one of the major limiting factors in plant growth regulation. Salinity-tolerant endophytic bacteria (STEB) can be used to alleviate the negative effects of salinity and promote plant growth. In this study, thirteen endophytic bacteria were isolated from mungbean roots and tested for NaCl salt-tolerance up to 4%. Six bacterial isolates, TMB2, TMB3, TMB5, TMB6, TMB7 and TMB9, demonstrated the ability to tolerate salt. Plant growth-promoting properties such as phosphate solubilization, indole-3-acetic acid (IAA) production, nitrogen fixation, zinc solubilization, biofilm formation and hydrolytic enzyme production were tested in vitro under saline conditions. Eight bacterial isolates indicated phosphate solubilization potential ranging from 5.8-17.7 μg mL-1, wherein TMB6 was found most efficient. Ten bacterial isolates exhibited IAA production ranging from 0.3-2.1 μg mL-1, where TMB7 indicated the highest potential. All the bacterial isolates except TMB13 exhibited nitrogenase activity. Three isolates, TMB6, TMB7 and TMB9, were able to solubilize zinc on tris-minimal media. All isolates were capable of forming biofilm except TMB12 and TMB13. Only TMB2, TMB6 and TMB7 exhibited cellulase activity, while TMB2 and TMB7 exhibited pectinase production. Based on in vitro testing, six efficient STEB were selected and subjected to the further studies. 16S rRNA gene sequencing of efficient STEB revealed the maximum similarity between TMB2 and Rhizobium pusense, TMB3 and Agrobacterium leguminum, TMB5 and Achromobacter denitrificans, TMB6 and Pseudomonas extremorientalis, TMB7 and Bradyrhizobium japonicum and TMB9 and Serratia quinivorans. This is the first international report on the existence of A. leguminum, A. denitrificans, P. extremorientalis and S. quinivorans inside the roots of mungbean. Under controlled-conditions, inoculation of P. extremorientalis TMB6, B. japonicum TMB7 and S. quinivorans TMB9 exhibited maximum potential to increase plant growth parameters; specifically plant dry weight was increased by up to 52%, 61% and 45%, respectively. Inoculation of B. japonicum TMB7 displayed the highest potential to increase plant proline, glycine betaine and total soluble proteins contents by 77%, 78% and 64%, respectively, compared to control under saline conditions. It is suggested that the efficient STEB could be used as biofertilizers for mungbean crop productivity under saline conditions after field-testing.
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Affiliation(s)
- Syeda Tahseen Zahra
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Mohsin Tariq
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Muhammad Abdullah
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Marriam Zafar
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Tahira Yasmeen
- Department of Environmental Sciences, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Muhammad Shafiq Shahid
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
| | - Haitham E. M. Zaki
- Horticulture Department, Faculty of Agriculture, Minia University, El-Minia, Egypt
- Applied Biotechnology Department, University of Technology and Applied Sciences-Sur, Sur, Oman
| | - Amanat Ali
- Nuclear Institute of Agriculture (NIA), Tandojam, Pakistan
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Abdullah M, Tariq M, Zahra ST, Ahmad A, Zafar M, Ali S. Potential of psychrotolerant rhizobacteria for the growth promotion of wheat ( Triticum aestivum L.). PeerJ 2023; 11:e16399. [PMID: 38050608 PMCID: PMC10693821 DOI: 10.7717/peerj.16399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/12/2023] [Indexed: 12/06/2023] Open
Abstract
Wheat is the second most important staple crop grown and consumed worldwide. Temperature fluctuations especially the cold stress during the winter season reduces wheat growth and grain yield. Psychrotolerant plant growth-promoting rhizobacteria (PGPR) may improve plant stress-tolerance in addition to serve as biofertilizer. The present study aimed to isolate and identify PGPR, with the potential to tolerate cold stress for subsequent use in supporting wheat growth under cold stress. Ten psychrotolerant bacteria were isolated from the wheat rhizosphere at 4 °C and tested for their ability to grow at wide range of temperature ranging from -8 °C to 36 °C and multiple plant beneficial traits. All bacteria were able to grow at 4 °C to 32 °C temperature range and solubilized phosphorus except WR23 at 4 °C, whereas all the bacteria solubilized phosphorus at 28 °C. Seven bacteria produced indole-3-acetic acid at 4 °C, whereas all produced indole-3-acetic acid at 28 °C. Seven bacteria showed the ability to fix nitrogen at 4 °C, while all the bacteria fixed nitrogen at 28 °C. Only one bacterium showed the potential to produce cellulase at 4 °C, whereas four bacteria showed the potential to produce cellulase at 28 °C. Seven bacteria produced pectinase at 4 °C, while one bacterium produced pectinase at 28 °C. Only one bacterium solubilized the zinc at 4 °C, whereas six bacteria solubilized the zinc at 28 °C using ZnO as the primary zinc source. Five bacteria solubilized the zinc at 4 °C, while seven bacteria solubilized the zinc at 28 °C using ZnCO3 as the primary zinc source. All the bacteria produced biofilm at 4 °C and 28 °C. In general, we noticed behavior of higher production of plant growth-promoting substances at 28 °C, except pectinase assay. Overall, in vitro testing confirms that microbes perform their inherent properties efficiently at optimum temperatures rather than the low temperatures due to high metabolic rate. Five potential rhizobacteria were selected based on the in vitro testing and evaluated for plant growth-promoting potential on wheat under controlled conditions. WR22 and WR24 significantly improved wheat growth, specifically increasing plant dry weight by 42% and 58%, respectively. 16S rRNA sequence analysis of WR22 showed 99.78% similarity with Cupriavidus campinensis and WR24 showed 99.9% similarity with Enterobacter ludwigii. This is the first report highlighting the association of C. campinensis and E. ludwigii with wheat rhizosphere. These bacteria can serve as potential candidates for biofertilizer to mitigate the chilling effect and improve wheat production after field-testing.
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Affiliation(s)
- Muhammad Abdullah
- Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Mohsin Tariq
- Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Syeda Tahseen Zahra
- Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Azka Ahmad
- Center of Excellence in Molecular Biology (CEMB), University of the Punjab, Lahore, Punjab, Pakistan
| | - Marriam Zafar
- Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Shad Ali
- Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
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Schmidt H, Gorka S, Seki D, Schintlmeister A, Woebken D. Gold-FISH enables targeted NanoSIMS analysis of plant-associated bacteria. THE NEW PHYTOLOGIST 2023; 240:439-451. [PMID: 37381111 PMCID: PMC10962543 DOI: 10.1111/nph.19112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 06/14/2023] [Indexed: 06/30/2023]
Abstract
Bacteria colonize plant roots and engage in reciprocal interactions with their hosts. However, the contribution of individual taxa or groups of bacteria to plant nutrition and fitness is not well characterized due to a lack of in situ evidence of bacterial activity. To address this knowledge gap, we developed an analytical approach that combines the identification and localization of individual bacteria on root surfaces via gold-based in situ hybridization with correlative NanoSIMS imaging of incorporated stable isotopes, indicative of metabolic activity. We incubated Kosakonia strain DS-1-associated, gnotobiotically grown rice plants with 15 N-N2 gas to detect in situ N2 fixation activity. Bacterial cells along the rhizoplane showed heterogeneous patterns of 15 N enrichment, ranging from the natural isotope abundance levels up to 12.07 at% 15 N (average and median of 3.36 and 2.85 at% 15 N, respectively, n = 697 cells). The presented correlative optical and chemical imaging analysis is applicable to a broad range of studies investigating plant-microbe interactions. For example, it enables verification of the in situ metabolic activity of host-associated commercialized strains or plant growth-promoting bacteria, thereby disentangling their role in plant nutrition. Such data facilitate the design of plant-microbe combinations for improvement of crop management.
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Affiliation(s)
- Hannes Schmidt
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaVienna1030Austria
| | - Stefan Gorka
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaVienna1030Austria
- Doctoral School in Microbiology and Environmental ScienceUniversity of ViennaVienna1030Austria
| | - David Seki
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaVienna1030Austria
| | - Arno Schintlmeister
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaVienna1030Austria
- Large‐Instrument Facility for Environmental and Isotope Mass Spectrometry, Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaVienna1030Austria
| | - Dagmar Woebken
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaVienna1030Austria
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Muratova A, Golubev S, Romanova V, Sungurtseva I, Nurzhanova A. Effect of Heavy-Metal-Resistant PGPR Inoculants on Growth, Rhizosphere Microbiome and Remediation Potential of Miscanthus × giganteus in Zinc-Contaminated Soil. Microorganisms 2023; 11:1516. [PMID: 37375018 DOI: 10.3390/microorganisms11061516] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Microbial-assisted phytoremediation is considered a more effective approach to soil rehabilitation than the sole use of plants. Mycolicibacterium sp. Pb113 and Chitinophaga sp. Zn19, heavy-metal-resistant PGPR strains originally isolated from the rhizosphere of Miscanthus × giganteus, were used as inoculants of the host plant grown in control and zinc-contaminated (1650 mg/kg) soil in a 4-month pot experiment. The diversity and taxonomic structure of the rhizosphere microbiomes, assessed with metagenomic analysis of rhizosphere samples for the 16S rRNA gene, were studied. Principal coordinate analysis showed differences in the formation of the microbiomes, which was affected by zinc rather than by the inoculants. Bacterial taxa affected by zinc and the inoculants, and the taxa potentially involved in the promotion of plant growth as well as in assisted phytoremediation, were identified. Both inoculants promoted miscanthus growth, but only Chitinophaga sp. Zn19 contributed to significant Zn accumulation in the aboveground part of the plant. In this study, the positive effect of miscanthus inoculation with Mycolicibacterium spp. and Chitinophaga spp. was demonstrated for the first time. On the basis of our data, the bacterial strains studied may be recommended to improve the efficiency of M. × giganteus phytoremediation of zinc-contaminated soil.
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Affiliation(s)
- Anna Muratova
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), 410049 Saratov, Russia
| | - Sergey Golubev
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), 410049 Saratov, Russia
| | - Valeria Romanova
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420021 Kazan, Russia
| | - Irina Sungurtseva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), 410049 Saratov, Russia
| | - Asil Nurzhanova
- Institute of Plant Biology and Biotechnology, Almaty 050040, Kazakhstan
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Pinheiro Y, Faria da Mota F, Peixoto RS, van Elsas JD, Lins U, Mazza Rodrigues JL, Rosado AS. A thermophilic chemolithoautotrophic bacterial consortium suggests a mutual relationship between bacteria in extreme oligotrophic environments. Commun Biol 2023; 6:230. [PMID: 36859706 PMCID: PMC9977764 DOI: 10.1038/s42003-023-04617-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 02/21/2023] [Indexed: 03/03/2023] Open
Abstract
A thermophilic, chemolithoautotrophic, and aerobic microbial consortium (termed carbonitroflex) growing in a nutrient-poor medium and an atmosphere containing N2, O2, CO2, and CO is investigated as a model to expand our understanding of extreme biological systems. Here we show that the consortium is dominated by Carbonactinospora thermoautotrophica (strain StC), followed by Sphaerobacter thermophilus, Chelatococcus spp., and Geobacillus spp. Metagenomic analysis of the consortium reveals a mutual relationship among bacteria, with C. thermoautotrophica StC exhibiting carboxydotrophy and carbon-dioxide storage capacity. C. thermoautotrophica StC, Chelatococcus spp., and S. thermophilus harbor genes encoding CO dehydrogenase and formate oxidase. No pure cultures were obtained under the original growth conditions, indicating that a tightly regulated interactive metabolism might be required for group survival and growth in this extreme oligotrophic system. The breadwinner hypothesis is proposed to explain the metabolic flux model and highlight the vital role of C. thermoautotrophica StC (the sole keystone species and primary carbon producer) in the survival of all consortium members. Our data may contribute to the investigation of complex interactions in extreme environments, exemplifying the interconnections and dependency within microbial communities.
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Affiliation(s)
- Yuri Pinheiro
- Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabio Faria da Mota
- Computational and Systems Biology Laboratory, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
| | - Raquel S Peixoto
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | | | - Ulysses Lins
- Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jorge L Mazza Rodrigues
- Department of Land, Air, and Water Resources, University of California Davis, Davis, CA, USA
| | - Alexandre Soares Rosado
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
- Bioscience Program, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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Tariq M, Hasnain N, Rasul I, Asad MA, Javed A, Rashid K, Shafique J, Iram W, Hameed A, Zafar M. Reconnoitering the capabilities of nodule endophytic Pantoea dispersa for improved nodulation and grain yield of chickpea (Cicer arietinum L.). World J Microbiol Biotechnol 2023; 39:85. [PMID: 36705812 DOI: 10.1007/s11274-023-03525-3] [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: 08/02/2022] [Accepted: 01/11/2023] [Indexed: 01/28/2023]
Abstract
Microorganisms belonging to root and soil provide a wide range of services and benefits to the plant by promoting plant growth and controlling phytopathogens. This study aimed to isolate endophytic bacteria from the root nodules of chickpea (Cicer arietinum L.) and determine their potential in improving plant growth. A total of nineteen different bacterial morphotypes were isolated from root nodules of chickpea and characterized in vitro for plant growth promotion abilities. All bacterial isolates were able to produce indole acetic acid at varying levels, out of which MCA19 was screened as the most efficient indole acetic acid producer (10.25 µg mL-1). MCA8, MCA9, MCA10, MCA11, MCA16, MCA17 and MCA19 were positive for phosphate solubilization, out of which MCA9 was best phosphate solubilizer (18.8 µg mL-1). All bacterial strains showed varying ability to grow on nitrogen-free media. Hydrogen cyanide, pectinase, and cellulase production ability were also observed in isolates, in which MCA9, MCA12, MCA17 and MCA19 were found best. Based on in vitro testing, five isolates MCA2, MCA9, MCA11, MCA17 and MCA19 were selected for further studies. Bacterial isolates MCA9, MCA11, MCA17 and MCA19 were identified by 16S rRNA gene sequence analysis as Pantoea dispersa while MCA2 as Rhizobium pusense. This is the first report on the existence of Pantoea dispersa in the root nodules of chickpea. In pot experiment, a maximum increase of 30% was recorded in plant dry weight upon the application of MCA19. Under field conditions, bacterial isolates, MCA2, MCA11 and MCA19 significantly enhanced nodulation and yield parameters of chickpea, compared to control. Pantoea dispersa MCA19 displayed the highest plant growth-promoting potential by increasing 38% grain yield. Our results indicate that Pantoea dispersa MCA19 is a promising biofertilizer for future applications.
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Affiliation(s)
- Mohsin Tariq
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan.
| | - Nayab Hasnain
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Ijaz Rasul
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | | | - Aqsa Javed
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Kamran Rashid
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Javeria Shafique
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Wajeeha Iram
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Amir Hameed
- Plant Breeding and Acclimatization Institute, National Research Institute, 05-870, Radzikow, Blonie, Poland
| | - Marriam Zafar
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
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Agbavor C, Mirza BS, Wait A. The Effects of Phyllosphere Bacteria on Plant Physiology and Growth of Soybean Infected with Pseudomonas syringae. PLANTS (BASEL, SWITZERLAND) 2022; 11:2634. [PMID: 36235499 PMCID: PMC9571934 DOI: 10.3390/plants11192634] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/28/2022] [Accepted: 10/01/2022] [Indexed: 06/16/2023]
Abstract
Phyllosphere bacteria are an important determinant of plant growth and resistance to pathogens. However, the efficacy of phyllosphere bacteria in regulating infection of Pseudomonas syringae pv. glycinea (Psg) and its influence on soybean growth and physiology is unknown. In a greenhouse study, we assessed the influence of a phyllosphere bacterial consortium (BC) of 13 species isolated from field-grown soybean leaves on uninfected and deliberately Psg infected soybean plants. We measured Psg density on infected leaves with and without the application of the BC. The BC application resulted in a significant reduction in Psg cells. We also measured plant biomass, nodule mass and number, gas exchange, and leaf chlorophyll and nitrogen in four treatment groups: control plants, plants with a BC and no infection (BC), plants with BC and infected with Psg (BC + Psg), and plants infected with Psg alone. For all variables, plants infected with Psg alone showed significant reduction in measured variables compared to both BC treatments. Therefore, the bacterial consortium was effective in controlling the negative effects of Psg on growth and physiology. The BC treatment sometimes resulted in increases in measured variables such as plant biomass, nodule numbers, and leaf chlorophyll as compared to control and BC + Psg treatments. Overall, the positive influence of BC treatment on plant growth and physiology highlights its potential applications to increase crop yield and control bacterial pathogens.
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Affiliation(s)
| | - Babur S. Mirza
- Correspondence: ; Tel.: +1-417-836-5062; Fax: +1-417-836-4204
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Khleifat K, Magharbeh M, Alqaraleh M, Al-Sarayrah M, Alfarrayeh I, Al Qaisi Y, Alsarayreh A, Alkafaween M. Biodegradation modeling of phenol using Curtobacterium flaccumfaciens as plant-growth-promoting bacteria. Heliyon 2022; 8:e10490. [PMID: 36110244 PMCID: PMC9469665 DOI: 10.1016/j.heliyon.2022.e10490] [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: 03/25/2022] [Revised: 06/17/2022] [Accepted: 08/25/2022] [Indexed: 11/20/2022] Open
Abstract
Phenol is a major worry pollutant resulting from industrialized manufacturing and chemical reactions. The growth kinetics and biodegradation of phenol were initially investigated using C. flaccumfaciens, a recently identified plant growth stimulating bacterium. Based on the Haldane inhibition model, Haldane's growth kinetics inhibition coefficient (Ki), half-saturation coefficient (Ks), and the maximum specific growth rate (max) for phenol-dependent growth kinetics were estimated to be 329 (mg/L), 9.14 (mg/L), and 1.05 (h-1), respectively. With a sum of squared error (SSR) of 1.36 × 10-3, the Haldane equation is well adapted to empirical data. The improved Gombertz model also accurately predicts phenol biodegradation trends. The rate of phenol biodegradation and the lag time both increased as the initial phenol concentrations were increased. C. flaccumfaciens growth and phenol biodegradation were best achieved at a pH of 7.0 at a temperature of 28 °C incubation. A phenol biodegradation mechanism by C. flaccumfaciens has been proposed. In conclusion, this study revealed the ability of C. flaccumfaciens to promote plant growth and biodegrade phenol simultaneously. This could aid in rhizoremediation and crop yield preservation in phenol-stressed conditions.
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Affiliation(s)
- Khaled Khleifat
- Faculty of Allied Medical Sciences, Al-Ahliyya Amman University, Amman, Jordan
- Department of Biological Sciences, Faculty of Science, Mutah University, 61710 Al-Karak, Jordan
| | - Mousa Magharbeh
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mutah University, Al-Karak 61710, Jordan
| | - Moath Alqaraleh
- Pharmacological and Diagnostic Research Center, Faculty of Pharmacy, Al-Ahliyya Amman University, Amman, Jordan
| | - Mutaz Al-Sarayrah
- Department of Biological Sciences, Faculty of Science, Mutah University, 61710 Al-Karak, Jordan
| | - Ibrahim Alfarrayeh
- Department of Biological Sciences, Faculty of Science, Mutah University, 61710 Al-Karak, Jordan
- Department of Applied Biology, Faculty of Science, Tafila Technical University, 66110 Tafila, Jordan
| | - Yaseen Al Qaisi
- Department of Biological Sciences, Faculty of Science, Mutah University, 61710 Al-Karak, Jordan
| | - Ahmad Alsarayreh
- Department of Biological Sciences, Faculty of Science, Mutah University, 61710 Al-Karak, Jordan
| | - Mohammad Alkafaween
- Faculty of Pharmacy, Department of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
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Della Mónica IF, Wong Villarreal A, Stefanoni Rubio PJ, Vaca-Paulín R, Yañez-Ocampo G. Exploring plant growth-promoting rhizobacteria as stress alleviators: a methodological insight. Arch Microbiol 2022; 204:316. [PMID: 35556177 DOI: 10.1007/s00203-022-02909-7] [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: 11/09/2021] [Revised: 03/29/2022] [Accepted: 04/11/2022] [Indexed: 11/29/2022]
Abstract
Rhizospheric and root-endophyte bacteria can stimulate plant growth through diverse biochemical mechanisms and pathways, particularly under biotic and abiotic stresses. For this reason, biotechnological trends on plant growth-promoting rhizobacteria (PGPR) application as biofertilizers, bioremediators, and stress alleviators are gaining increasing interest as ecofriendly strategies for sustainable agriculture management and soil restoration. The first steps needed to implement these technologies are isolation, screening, and characterization of PGPR that can be potentially applied as bioinoculants to alleviate biotic and/or abiotic stresses. Therefore, a complete and accurate methodological study and laboratory techniques are required to warrant the correct achievement of these steps. This review compiles and details the fundamentals, methods, and procedures of key protocols used in isolation and characterization of PGPR for plant stress alleviation.
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Affiliation(s)
- Ivana F Della Mónica
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica, Consejo Nacional de Investigaciones Científicas y Tecnológicas (INMIBO-CONICET), Universidad de Buenos Aires (UBA), Lab. 69, 4 Piso, Pabellón II, Ciudad Universitaria, Intendente Güiraldes 2160, 1428, Buenos Aires, Argentina.
| | - Arnoldo Wong Villarreal
- División Agroalimentaria, Universidad Tecnológica de la Selva, Ocosingo, 29950, Chiapas, Mexico
| | - Pablo J Stefanoni Rubio
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica, Consejo Nacional de Investigaciones Científicas y Tecnológicas (INMIBO-CONICET), Universidad de Buenos Aires (UBA), Lab. 69, 4 Piso, Pabellón II, Ciudad Universitaria, Intendente Güiraldes 2160, 1428, Buenos Aires, Argentina
| | - Rocío Vaca-Paulín
- Laboratorio de Edafología y Ambiente, Facultad de Ciencias, Universidad Autónoma del Estado de México, 50000, Toluca, Estado de México, México
| | - Gustavo Yañez-Ocampo
- Laboratorio de Edafología y Ambiente, Facultad de Ciencias, Universidad Autónoma del Estado de México, 50000, Toluca, Estado de México, México.
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11
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Mir MI, Hameeda B, Quadriya H, Kumar BK, Ilyas N, Kee Zuan AT, El Enshasy HA, Dailin DJ, Kassem HS, Gafur A, Sayyed RZ. Multifarious Indigenous Diazotrophic Rhizobacteria of Rice ( Oryza sativa L.) Rhizosphere and Their Effect on Plant Growth Promotion. Front Nutr 2022; 8:781764. [PMID: 35096930 PMCID: PMC8793879 DOI: 10.3389/fnut.2021.781764] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
A diverse group of rhizobacteria persists in the rhizospheric soil, on the surface of roots, or in association with rice plants. These bacteria colonize plant root systems, enhance plant growth and crop yield. Indigenous rhizobacteria are known to promote soil health, grain production quality and serve as sustainable bioinoculant. The present study was aimed to isolate, identify and characterize indigenous plant growth promoting (PGP) diazotrophic bacteria associated with the rhizosphere of rice fields from different areas of Jammu and Kashmir, India. A total of 15 bacteria were isolated and evaluated for various PGP traits, antagonistic activity against phytopathogens, production of hydrolytic enzymes and biofilm formation under in-vitro conditions. The majority of the isolated bacteria were Gram-negative. Out of 15 bacterial isolates, nine isolates produced IAA (12.24 ± 2.86 to 250.3 ± 1.15 μg/ml), 6 isolates exhibited phosphate solubilization activity (36.69 ± 1.63 to 312.4 ± 1.15 μg/ml), 7 isolates exhibited rock phosphate solubilization while 5 isolates solubilized zinc (10-18 mm), 7 isolates showed siderophore production, 8 isolates exhibited HCN production, 6 isolates exhibited aminocyclopropane-1-carboxylate (ACC) deaminase activity, 13 isolates exhibited cellulase activity, nine isolates exhibited amylase and lipase activity and six isolates exhibited chitinase activity. In addition, 5 isolates showed amplification with the nifH gene and showed a significant amount of nitrogenase activity in a range of 0.127-4.39 μmol C2H4/mg protein/h. Five isolates viz., IHK-1, IHK-3, IHK-13, IHK-15 and IHK-25 exhibited most PGP attributes and successfully limited the mycelial growth of Rhizoctonia solani and Fusarium oxysporum in-vitro. All the five bacterial isolates were identified based on morphological, biochemical and 16S rDNA gene sequencing study, as Stenotrophomonas maltophilia, Enterobacter sp., Bacillus sp., Ochrobactrum haematophilum and Pseudomonas aeruginosa. Rice plants developed from seeds inoculated with these PGP strains individually had considerably higher germination percentage, seed vigor index and total dry biomass when compared to control. These findings strongly imply that the PGP diazotrophic bacteria identified in this work could be employed as plant growth stimulators in rice.
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Affiliation(s)
- Mohammad Imran Mir
- Department of Botany, University College of Science, Osmania University, Hyderabad, India
| | - Bee Hameeda
- Department of Microbiology, University College of Science, Osmania University, Hyderabad, India
| | - Humera Quadriya
- Department of Microbiology, University College of Science, Osmania University, Hyderabad, India
| | - B. Kiran Kumar
- Department of Botany, University College of Science, Osmania University, Hyderabad, India
| | - Noshin Ilyas
- Department of Botany, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan
| | - Ali Tan Kee Zuan
- Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Malaysia
| | - Hesham Ali El Enshasy
- Institute of Bioproduct Development, Universiti Teknologi Malaysia, Skudai, Malaysia
- School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Skudai, Malaysia
- City of Scientific Research and Technology Applications, New Burg Al Arab, Alexandria, Egypt
| | - Daniel Joe Dailin
- Institute of Bioproduct Development, Universiti Teknologi Malaysia, Skudai, Malaysia
| | - Hazem S. Kassem
- Department of Agricultural Extension and Rural Society, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Abdul Gafur
- Sinarmas Forestry Corporate Research and Development, Perawang, Indonesia
| | - R. Z. Sayyed
- Asian Plant Growth Promoting Rhizobacteria Society (PGPR) for Sustainable Agriculture, Auburn University, Auburn, AL, United States
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12
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Chen Y, Zhang X, Liu W. Effect of metal and metal oxide engineered nano particles on nitrogen bio-conversion and its mechanism: A review. CHEMOSPHERE 2022; 287:132097. [PMID: 34523458 DOI: 10.1016/j.chemosphere.2021.132097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/26/2021] [Accepted: 08/28/2021] [Indexed: 06/13/2023]
Abstract
Metal and metal oxide engineered nano particles (MMO-ENPs) are widely applied in various industries due to their unique properties. Thus, many researches focused on the influence on nitrogen transformation processes by MMO-ENPs. This review focuses on the effect of MMO-ENPs on nitrogen fixation, nitrification, denitrification and Anammox. Firstly, based on most of the researches, it can be concluded MMO-ENPs have negative effect on nitrogen fixation, nitrification and denitrification while the MMO-ENPs have no promotion effect on Anammox. Then, the influence factors are discussed in detail, including MMO-ENPs dosage, MMO-ENPs kind and exposure time. Both the microbial morphology and population structure were altered by MMO-ENPs. Also, the mechanisms of MMO-ENPs affecting the nitrogen transformation are reviewed. The inhibition of key enzymes and functional genes, the promotion of reactive oxygen species (ROS) production, MMO-ENPs themselves and the suppression of electron transfer all contribute to the negative effect. Finally, the key points for future investigation are proposed that more attention should be attached to the effect on Anammox and the further mechanism in the future studies.
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Affiliation(s)
- Yinguang Chen
- Coll Resource & Environm Sci, Xinjiang Univ, 666 Shengli Rd, Urumqi, PR China; Coll Environm Sci & Engn, Tongji Univ, 1239 Siping Rd, Shanghai, PR China
| | - Xiaoyang Zhang
- Coll Environm Sci & Engn, Tongji Univ, 1239 Siping Rd, Shanghai, PR China.
| | - Weiguo Liu
- Coll Resource & Environm Sci, Xinjiang Univ, 666 Shengli Rd, Urumqi, PR China
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13
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Al-Tarawneh A, Khleifat KM, Tarawneh IN, Shiyyab K, El-Hasan T, Sprocati AR, Alisi C, Tasso F, Alqaraleh M. Phenol biodegradation by plant growth promoting bacterium, S. odorifera: kinetic modeling and process optimization. Arch Microbiol 2021; 204:104. [PMID: 34967929 DOI: 10.1007/s00203-021-02691-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/17/2021] [Accepted: 11/01/2021] [Indexed: 11/25/2022]
Abstract
One of the main organic pollutants that could result from industrial products and chemical transformations is phenol. In the current study, the kinetics of Serratia odorifera, which was isolated from arable soil, was studied by growing it on broth minimal medium spiked with phenol as only carbon source and energy. The newly isolated plant growth-promoting bacterium (PGPB), S. odorifera, was used for the first time for phenol biodegradation. The growth kinetics parameters (phenol-dependent) including maximum specific growth rate (μmax), half-saturation coefficient (Ks), and the Haldane's growth kinetics inhibition coefficient (Ki), were tested via Haldane inhibition model and resulted on the 0.469 (h -1), 26.6 (mgL-1), and 292 (mgL-1), respectively. The sum of squared error (SSR) of 4.89 × 10-3 was fitted to the experimental data by Haldane equation. The results of phenol biodegradation were fitted into the modified Gombertz model. The increase of phenol concentrations led to increases in both the rate of phenol biodegradation and lagging time. The optimal phenol biodegradation and bacterial growth obtained by S. odorifera, were at 28 °C incubation temperature and a pH of 7.0. The pathway of phenol biodegradation by S. odorifera was proposed in the current study to provide a new insight into synchronization of phenol biodegradation and plant growth-promoting bacteria. This may play an important role in remediation of phenol-contaminated soil besides promoting the plant growth, thus lessening the plant stress.
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Affiliation(s)
- Amjad Al-Tarawneh
- Prince Faisal Center for Dead Sea, Environmental and Energy Research, Mutah University, Al-Karak, Jordan
| | - Khaled M Khleifat
- Department of Biology, College of Science, Mutah University, Al-Karak, 61710, Jordan.
- Faculty of Allied Medical Sciences, Al-Ahliyya Amman University, Amman, 19328, Jordan.
| | - Ibrahim N Tarawneh
- Department of Chemistry, Al-Balqa Applied University, Al-Salt, 19117, Jordan
| | - Kholoud Shiyyab
- Department of Biology, College of Science, Mutah University, Al-Karak, 61710, Jordan
| | - Tayel El-Hasan
- Department of Chemistry, College of Science, Mutah University, Al-Karak, Jordan
| | - Anna Rosa Sprocati
- Territorial and Production Systems Sustainability Department, ENEA, via Anguillarese 301, 00123, Rome, Italy
| | - Chiara Alisi
- Territorial and Production Systems Sustainability Department, ENEA, via Anguillarese 301, 00123, Rome, Italy
| | - Flavia Tasso
- Territorial and Production Systems Sustainability Department, ENEA, via Anguillarese 301, 00123, Rome, Italy
| | - Moath Alqaraleh
- Pharmacological and Diagnostic Research Center (PDRC), Faculty of Pharmacy, Al-Ahliyya Amman University, Amman, 19328, Jordan
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14
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Heijo G, Taulé C, Mareque C, Stefanello A, Souza EM, Battistoni F. Interaction among endophytic bacteria, sweet sorghum (Sorghum bicolor) cultivars and chemical nitrogen fertilization. FEMS Microbiol Ecol 2021; 97:6007735. [PMID: 33245748 DOI: 10.1093/femsec/fiaa245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 11/25/2020] [Indexed: 11/14/2022] Open
Abstract
The application of new agricultural technologies to attain sustainable production systems is necessary. The use of plant growth-promoting bacteria to improve plant growth and health has been studied for decades. This work aimed to isolate diazotrophic endophytic bacteria associated with sweet sorghum plants and study the interaction of their inoculation in combination with chemical N-fertilization on different sorghum cultivars. A bacterial collection of 181 isolates was constructed and characterized in vitro and in vivo. From that, the strains Enterobacter sp. UYSB89 and Kosakonia sp. UYSB139 were nifH+, produce IAA, defined as true endophytes and able to promote growth of two sweet sorghum under greenhouse conditions. The evaluated cultivars responded differentially to bacterial inoculation, the nitrogen fertilization doses and their interaction. Thus, plant growth is a multifactorial consequence of the interrelation between crop practices and the plant genotypes. This knowledge is a valuable factor in terms of understanding plant-bacteria endophyte interactions to preserve environmental sustainability during the implementation of agronomic practices.
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Affiliation(s)
- Gabriela Heijo
- Microbial Biochemistry and Genomics Department, Clemente Estable Biological Research Institute, Avenida Italia 3318, Montevideo, 11600, Uruguay
| | - Cecilia Taulé
- Microbial Biochemistry and Genomics Department, Clemente Estable Biological Research Institute, Avenida Italia 3318, Montevideo, 11600, Uruguay
| | - Cintia Mareque
- Microbial Biochemistry and Genomics Department, Clemente Estable Biological Research Institute, Avenida Italia 3318, Montevideo, 11600, Uruguay
| | - Adriano Stefanello
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, Coronel Francisco H. dos Santos Street, Curitiba, Paraná 81531-980, Brazil
| | - Emanuel M Souza
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, Coronel Francisco H. dos Santos Street, Curitiba, Paraná 81531-980, Brazil
| | - Federico Battistoni
- Microbial Biochemistry and Genomics Department, Clemente Estable Biological Research Institute, Avenida Italia 3318, Montevideo, 11600, Uruguay
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15
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The Importance of Microbial Inoculants in a Climate-Changing Agriculture in Eastern Mediterranean Region. ATMOSPHERE 2020. [DOI: 10.3390/atmos11101136] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Climate change has gained importance due to its severe consequences for many aspects of life. Increasing temperature, drought and greenhouse gases affect directly or indirectly the productivity of agricultural and natural ecosystems as well as human health. The nutrient supply capacity of the soil is diminishing, while food requirements for the growing population are increasing. The ongoing application of agrochemicals results in adverse effects on ecosystem functioning and food chain. Now, more than ever, there is a need to mitigate the effects of agricultural activities on climate change using environmentally friendly techniques. The role of plant beneficial microorganisms on this global challenge is increasingly being explored, and there is strong evidence that could be important. The use of functional microbial guilds forms an alternative or even a supplementary approach to common agricultural practices, due to their ability to act as biofertilizers and promote plant growth. Application of microbial inocula has a significantly lower impact on the environment compared to chemical inputs, while the agricultural sector will financially benefit, and consumers will have access to quality products. Microbial inoculants could play an important role in agricultural stress management and ameliorate the negative impacts of climate change. This short review highlights the role of microbes in benefiting agricultural practices against climate-changing conditions. In particular, the main microbial plant growth-promoting functional traits that are related to climate change are presented and discussed. The importance of microbial inoculants’ multifunctionality is debated, while future needs and challenges are also highlighted.
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16
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A symbiotic nutrient exchange within the cyanosphere microbiome of the biocrust cyanobacterium, Microcoleus vaginatus. ISME JOURNAL 2020; 15:282-292. [PMID: 32968213 DOI: 10.1038/s41396-020-00781-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/26/2020] [Accepted: 09/10/2020] [Indexed: 02/01/2023]
Abstract
Microcoleus vaginatus plays a prominent role as both primary producer and pioneer in biocrust communities from dryland soils. And yet, it cannot fix dinitrogen, essential in often nitrogen-limited drylands. But a diazotroph-rich "cyanosphere" has been described in M. vaginatus, hinting that there exists a C for N exchange between the photoautotroph and heterotrophic diazotrophs. We provide evidence for this by establishing such a symbiosis in culture and by showing that it is selective and dependent on nitrogen availability. In natural populations, provision of nitrogen resulted in loss of diazotrophs from the cyanosphere of M. vaginatus compared to controls, but provision of phosphorus did not. Co-culturing of pedigreed cyanosphere diazotroph isolates with axenic M. vaginatus resulted in copious growth in C and N-free medium, but co-culture with non-cyanosphere diazotrophs or other heterotrophs did not. Unexpectedly, bundle formation in M. vaginatus, diacritical to the genus but not seen in axenic culture, was restored in vitro by imposed nitrogen limitation or, even more strongly, by co-culture with diazotrophic partners, implicating this trait in the symbiosis. Our findings provide direct evidence for a symbiotic relationship between M. vaginatus and its cyanosphere and help explain how it can be a global pioneer in spite of its genetic shortcomings.
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17
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McGee CF. The effects of silver nanoparticles on the microbial nitrogen cycle: a review of the known risks. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:31061-31073. [PMID: 32514926 DOI: 10.1007/s11356-020-09548-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/01/2020] [Indexed: 05/16/2023]
Abstract
The nitrogen cycle is an integral biogeochemical function for maintaining healthy environments. Nitrogen is a key nutrient that must be continuously replenished through recycling mechanisms to sustain ecosystems, disruption to which can result in compromised ecosystem functioning. Certain stages in the microbial conversion of nitrogen compounds are performed by a limited range of micro-organisms making these key functional species in ecosystems. The growing industrial use of silver nanoparticles (AgNPs) potentially poses significant risks for microbial nitrogen cycling species. AgNPs possess potent antimicrobial properties and are expected to reach a range of natural environments through several routes of exposure. Certain functional nitrogen cycling microbes have been shown to be highly susceptible to AgNP toxicity. The current literature indicates that AgNPs can negatively affect certain nitrogen fixing, nitrifying and denitrifying microbes in vitro. In vivo studies investigating the effect of AgNPs on nitrogen cycling microbial communities and nitrogen transformation rates in soil, sediment and sludge environments have also indicated disruption of these functional processes. This review provides a comprehensive description of the current state of knowledge regarding the toxicity of AgNPs to nitrogen cycling communities. The aim of the review is to highlight the most susceptible stages in the nitrogen cycle and the implications for the affected ecosystems.
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Affiliation(s)
- Conor Francis McGee
- Department of Agriculture, Food and the Marine, Cellbridge, Co. Kildare, Ireland.
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18
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Khan MAW, Bohannan BJM, Nüsslein K, Tiedje JM, Tringe SG, Parlade E, Barberán A, Rodrigues JLM. Deforestation impacts network co-occurrence patterns of microbial communities in Amazon soils. FEMS Microbiol Ecol 2019; 95:5211045. [PMID: 30481288 PMCID: PMC6294608 DOI: 10.1093/femsec/fiy230] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 11/26/2018] [Indexed: 01/28/2023] Open
Abstract
Co-occurrence networks allow for the identification of potential associations among species, which may be important for understanding community assembly and ecosystem functions. We employed this strategy to examine prokaryotic co-occurrence patterns in the Amazon soils and the response of these patterns to land use change to pasture, with the hypothesis that altered microbial composition due to deforestation will mirror the co-occurrence patterns across prokaryotic taxa. In this study, we calculated Spearman correlations between operational taxonomic units (OTUs) as determined by 16S rRNA gene sequencing, and only robust correlations were considered for network construction (-0.80 ≥ P ≥ 0.80, adjusted P < 0.01). The constructed network represents distinct forest and pasture components, with altered compositional and topological features. A comparative analysis between two representative modules of these contrasting ecosystems revealed novel information regarding changes to metabolic pathways related to nitrogen cycling. Our results showed that soil physicochemical properties such as temperature, C/N and H++Al3+ had a significant impact on prokaryotic communities, with alterations to network topologies. Taken together, changes in co-occurrence patterns and physicochemical properties may contribute to ecosystem processes including nitrification and denitrification, two important biogeochemical processes occurring in tropical forest systems.
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Affiliation(s)
- M A Wadud Khan
- Department of Biology, University of Texas, Arlington, TX 76019, USA
| | | | - Klaus Nüsslein
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - James M Tiedje
- Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA
| | - Susannah G Tringe
- Joint Genome Institute, United States Department of Energy, Walnut Creek, CA 94598, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Eloi Parlade
- Department of Land, Air and Water Resources, University of California - Davis, Davis, CA 95616, USA
| | - Albert Barberán
- Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ 85721, USA
| | - Jorge L M Rodrigues
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Land, Air and Water Resources, University of California - Davis, Davis, CA 95616, USA
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19
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Taulé C, Luizzi H, Beracochea M, Mareque C, Platero R, Battistoni F. The Mo- and Fe-nitrogenases of the endophyte Kosakonia sp. UYSO10 are necessary for growth promotion of sugarcane. ANN MICROBIOL 2019. [DOI: 10.1007/s13213-019-01466-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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20
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Rilling JI, Acuña JJ, Sadowsky MJ, Jorquera MA. Putative Nitrogen-Fixing Bacteria Associated With the Rhizosphere and Root Endosphere of Wheat Plants Grown in an Andisol From Southern Chile. Front Microbiol 2018; 9:2710. [PMID: 30524385 PMCID: PMC6256256 DOI: 10.3389/fmicb.2018.02710] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/23/2018] [Indexed: 11/17/2022] Open
Abstract
Acidic ash derived volcanic soils (Andisols) support 50% of cereal production in Chile. Nitrogen (N) is essential for cereal crops and commonly added as urea with consequent environmental concerns due to leaching. Despite the relevance of N to plant growth, few studies have focused on understanding the application, management and ecological role of N2-fixing bacterial populations as tool for improve the N nutrition of cereal crops in Chile. It is known that N2-fixing bacteria commonly inhabits diverse plant compartments (e.g., rhizosphere and root endosphere) where they can supply N for plant growth. Here, we used culture-independent and dependent approaches to characterize and compare the putative N2-fixing bacteria associated with the rhizosphere and root endosphere of wheat plants grown in an Andisol from southern Chile. Our results showed significantly greater bacterial loads in the rhizosphere than the root endosphere. Quantitative PCR results indicated that the copy number of the 16S rRNA gene ranged from 1012~1013 and 107~108 g-1 sample in rhizosphere and root endosphere, respectively. The nifH gene copy number ranged from 105~106 and 105 g-1 sample in rhizosphere and root endosphere, respectively. The total culturable bacteria number ranged from 109~1010 and 107~108 CFU g-1 sample in rhizosphere and 104~105 and 104 CFU g-1 sample in root endosphere using LB and NM-1 media, respectively. Indirect counts of putative N2-fixing bacteria were 103 and 102~103 CFU g-1 sample in rhizosphere and root endosphere using NFb medium, respectively. Sequencing of 16S rRNA genes from randomly selected putative N2-fixing bacteria revealed the presence of members of Proteobacteria (Bosea and Roseomonas), Actinobacteria (Georgenia, Mycobacterium, Microbacterium, Leifsonia, and Arthrobacter), Bacteroidetes (Chitinophaga) and Firmicutes (Bacillus and Psychrobacillus) taxa. Differences in 16S rRNA and putative nifH-containing bacterial communities between rhizosphere and root endosphere were shown by denaturing gradient gel electrophoresis (DGGE). This study shows a compartmentalization between rhizosphere and root endosphere for both the abundance and diversity of total (16S rRNA) and putative N2-fixing bacterial communities on wheat plants grown in Chilean Andisols. This information can be relevant for the design and application of agronomic strategies to enhance sustainable N-utilization in cereal crops in Chile.
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Affiliation(s)
- Joaquin I. Rilling
- Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Temuco, Chile
| | - Jacquelinne J. Acuña
- Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile
| | - Michael J. Sadowsky
- Department of Soil, Water, and Climate, Department of Plant and Microbial Biology, BioTechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Milko A. Jorquera
- Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile
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21
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Nishihara A, Thiel V, Matsuura K, McGlynn SE, Haruta S. Phylogenetic Diversity of Nitrogenase Reductase Genes and Possible Nitrogen-Fixing Bacteria in Thermophilic Chemosynthetic Microbial Communities in Nakabusa Hot Springs. Microbes Environ 2018; 33:357-365. [PMID: 30404970 PMCID: PMC6307998 DOI: 10.1264/jsme2.me18030] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chemosynthetic microbial communities develop and form dense cell aggregates in slightly alkaline sulfidic hot springs in the temperature range of 70–86°C at Nakabusa, Japan. Nitrogenase activity has recently been detected in the microbial communities collected. To identify possible members capable of nitrogen fixation, we examined the diversities of 16S rRNA and nitrogenase reductase (NifH) gene sequences in four types of chemosynthetic communities with visually different colors and thicknesses. The results of a 16S rRNA gene analysis indicated that all four microbial communities had similar bacterial constituents; the phylum Aquificae was the dominant member, followed in abundance by Thermodesulfobacteria, Firmicutes, and Thermotogae. Most of the NifH sequences were related to sequences reported in hydrothermal vents and terrestrial hot springs. The results of a phylogenetic analysis of NifH sequences revealed diversity in this gene among the communities collected, distributed within 7 phylogenetic groups. NifH sequences affiliated with Aquificae (Hydrogenobacter/Thermocrinis) and Firmicutes (Caldicellulosiruptor) were abundant. At least two different energy metabolic pathways appeared to be related to nitrogen fixation in the communities analyzed; aerobic sulfur/hydrogen-oxidizing bacteria in Aquificae and fermentative bacteria in Firmicutes. The metabolic characteristics of these two dominant phyla differed from those previously inferred from nitrogenase activity assays on chemosynthetic communities, which were associated with hydrogen-dependent autotrophic sulfate reduction. These assays may correspond to the observed NifH sequences that are distantly related to the known species of Thermodesulfovibrio sp. (Nitrospirae) detected in the present study. The activities of nitrogen-fixing organisms in communities may depend on redox states as well as the availability of electron donors, acceptors, and carbon sources.
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Affiliation(s)
- Arisa Nishihara
- Department of Biological Sciences, Tokyo Metropolitan University
| | - Vera Thiel
- Department of Biological Sciences, Tokyo Metropolitan University
| | - Katsumi Matsuura
- Department of Biological Sciences, Tokyo Metropolitan University
| | - Shawn E McGlynn
- Department of Biological Sciences, Tokyo Metropolitan University.,Earth-Life Science Institute, Tokyo Institute of Technology.,Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science.,Blue Marble Space Institute of Science
| | - Shin Haruta
- Department of Biological Sciences, Tokyo Metropolitan University
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22
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Rilling JI, Acuña JJ, Sadowsky MJ, Jorquera MA. Putative Nitrogen-Fixing Bacteria Associated With the Rhizosphere and Root Endosphere of Wheat Plants Grown in an Andisol From Southern Chile. Front Microbiol 2018. [PMID: 30524385 DOI: 10.3389/fmicb.2018.02710/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023] Open
Abstract
Acidic ash derived volcanic soils (Andisols) support 50% of cereal production in Chile. Nitrogen (N) is essential for cereal crops and commonly added as urea with consequent environmental concerns due to leaching. Despite the relevance of N to plant growth, few studies have focused on understanding the application, management and ecological role of N2-fixing bacterial populations as tool for improve the N nutrition of cereal crops in Chile. It is known that N2-fixing bacteria commonly inhabits diverse plant compartments (e.g., rhizosphere and root endosphere) where they can supply N for plant growth. Here, we used culture-independent and dependent approaches to characterize and compare the putative N2-fixing bacteria associated with the rhizosphere and root endosphere of wheat plants grown in an Andisol from southern Chile. Our results showed significantly greater bacterial loads in the rhizosphere than the root endosphere. Quantitative PCR results indicated that the copy number of the 16S rRNA gene ranged from 1012~1013 and 107~108 g-1 sample in rhizosphere and root endosphere, respectively. The nifH gene copy number ranged from 105~106 and 105 g-1 sample in rhizosphere and root endosphere, respectively. The total culturable bacteria number ranged from 109~1010 and 107~108 CFU g-1 sample in rhizosphere and 104~105 and 104 CFU g-1 sample in root endosphere using LB and NM-1 media, respectively. Indirect counts of putative N2-fixing bacteria were 103 and 102~103 CFU g-1 sample in rhizosphere and root endosphere using NFb medium, respectively. Sequencing of 16S rRNA genes from randomly selected putative N2-fixing bacteria revealed the presence of members of Proteobacteria (Bosea and Roseomonas), Actinobacteria (Georgenia, Mycobacterium, Microbacterium, Leifsonia, and Arthrobacter), Bacteroidetes (Chitinophaga) and Firmicutes (Bacillus and Psychrobacillus) taxa. Differences in 16S rRNA and putative nifH-containing bacterial communities between rhizosphere and root endosphere were shown by denaturing gradient gel electrophoresis (DGGE). This study shows a compartmentalization between rhizosphere and root endosphere for both the abundance and diversity of total (16S rRNA) and putative N2-fixing bacterial communities on wheat plants grown in Chilean Andisols. This information can be relevant for the design and application of agronomic strategies to enhance sustainable N-utilization in cereal crops in Chile.
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Affiliation(s)
- Joaquin I Rilling
- Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Temuco, Chile
| | - Jacquelinne J Acuña
- Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile
| | - Michael J Sadowsky
- Department of Soil, Water, and Climate, Department of Plant and Microbial Biology, BioTechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Milko A Jorquera
- Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile
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Devi KA, Pandey G, Rawat AKS, Sharma GD, Pandey P. The Endophytic Symbiont- Pseudomonas aeruginosa Stimulates the Antioxidant Activity and Growth of Achyranthes aspera L. Front Microbiol 2017; 8:1897. [PMID: 29021789 PMCID: PMC5623812 DOI: 10.3389/fmicb.2017.01897] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/15/2017] [Indexed: 11/13/2022] Open
Abstract
A plant growth promoting bacterial endophyte designated as AL2-14B isolated from the leaves of Achyranthes aspera L. was identified as Pseudomonas aeruginosa based on its phenotypic and physiological features, and 16S rRNA gene sequence analysis. AL2-14B had plant growth stimulating attributes including siderophore and indole acetic acid release, inorganic phosphate solubilization, along with nitrogenase, ammonification, and protease activities. It also exhibited antifungal property against Rhizoctonia solani. The plantlets grown in germ-free condition were inoculated with AL2-14B and studied for the colonization of endophyte. Significant increase in population of AL2-14B between 3rd and 5th days after inoculation was recorded. The treatment of plants with endophytic P. aeruginosa AL2-14B increased nitrogen, phosphorus, potassium (NPK) contents in plant by 3.8, 12.59, and 19.15%, respectively. Significant enhancement of shoot and root length, dry leaf, dry shoot and dry root weight, and leaf surface area as compared to control (P < 0.05) was recorded in AL2-14B inoculated plants. The antioxidant activities increased in plants grown in germ-free conditions and inoculated with AL2-14B. The present study emphasizes on the role of diazotrophic endophyte P. aeruginosa AL2-14B in stimulating growth of A. aspera L. and improvement of its medicinal properties. Significant increase in growth and antioxidant content of P. aeruginosa AL2-14B treated plants suggests the possibility of an economical and eco-friendly mean of achieving antioxidants rich, healthier A. aspera plants.
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Affiliation(s)
- Khaidem A. Devi
- Department of Microbiology, Assam University, Silchar, India
| | - Garima Pandey
- Pharmacognosy and Ethnopharmacology Division, Council of Scientific & Industrial Research-National Botanical Research Institute, Lucknow, India
| | - A. K. S. Rawat
- Pharmacognosy and Ethnopharmacology Division, Council of Scientific & Industrial Research-National Botanical Research Institute, Lucknow, India
| | | | - Piyush Pandey
- Department of Microbiology, Assam University, Silchar, India
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Yousuf J, Thajudeen J, Rahiman M, Krishnankutty S, P. Alikunj A, A. Abdulla MH. Nitrogen fixing potential of various heterotrophicBacillusstrains from a tropical estuary and adjacent coastal regions. J Basic Microbiol 2017; 57:922-932. [DOI: 10.1002/jobm.201700072] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 06/18/2017] [Accepted: 07/07/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Jesmi Yousuf
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences; Cochin University of Science and Technology; Cochin Kerala India
- School of Environmental Sciences; Mahatma Gandhi University; Kottayam Kerala India
| | - Jabir Thajudeen
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences; Cochin University of Science and Technology; Cochin Kerala India
| | - Mujeeb Rahiman
- Post Graduate and Research Department of Aquaculture and Fishery Microbiology; M.E.S Ponnani College; Ponnani Kerala India
| | - Soumya Krishnankutty
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences; Cochin University of Science and Technology; Cochin Kerala India
| | - Aneesa P. Alikunj
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences; Cochin University of Science and Technology; Cochin Kerala India
| | - Mohamed H. A. Abdulla
- Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences; Cochin University of Science and Technology; Cochin Kerala India
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Mirza BS, Sorensen DL, Dupont RR, McLean JE. New Arsenate Reductase Gene (arrA) PCR Primers for Diversity Assessment and Quantification in Environmental Samples. Appl Environ Microbiol 2017; 83:e02725-16. [PMID: 27913413 PMCID: PMC5288830 DOI: 10.1128/aem.02725-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/28/2016] [Indexed: 11/20/2022] Open
Abstract
The extent of arsenic contamination in drinking water and its potential threat to human health have resulted in considerable research interest in the microbial species responsible for arsenic reduction. The arsenate reductase gene (arrA), an important component of the microbial arsenate reduction system, has been widely used as a biomarker to study arsenate-reducing microorganisms. A new primer pair was designed and evaluated for quantitative PCR (qPCR) and high-throughput sequencing of the arrA gene, because currently available PCR primers are not suitable for these applications. The primers were evaluated in silico and empirically tested for amplification of arrA genes in clones and for amplification and high-throughput sequencing of arrA genes from soil and groundwater samples. In silico, this primer pair matched (≥90% DNA identity) 86% of arrA gene sequences from GenBank. Empirical evaluation showed successful amplification of arrA gene clones of diverse phylogenetic groups, as well as amplification and high-throughput sequencing of independent soil and groundwater samples without preenrichment, suggesting that these primers are highly specific and can amplify a broad diversity of arrA genes. The arrA gene diversity from soil and groundwater samples from the Cache Valley Basin (CVB) in Utah was greater than anticipated. We observed a significant correlation between arrA gene abundance, quantified through qPCR, and reduced arsenic (AsIII) concentrations in the groundwater samples. Furthermore, we demonstrated that these primers can be useful for studying the diversity of arsenate-reducing microbial communities and the ways in which their relative abundance in groundwater may be associated with different groundwater quality parameters. IMPORTANCE Arsenic is a major drinking water contaminant that threatens the health of millions of people worldwide. The extent of arsenic contamination and its potential threat to human health have resulted in considerable interest in the study of microbial species responsible for the reduction of arsenic, i.e., the conversion of AsV to AsIII In this study, we developed a new primer pair to evaluate the diversity and abundance of arsenate-reducing microorganisms in soil and groundwater samples from the CVB in Utah. We observed significant arrA gene diversity in the CVB soil and groundwater samples, and arrA gene abundance was significantly correlated with the reduced arsenic (AsIII) concentrations in the groundwater samples. We think that these primers are useful for studying the ecology of arsenate-reducing microorganisms in different environments.
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Affiliation(s)
- Babur S Mirza
- Utah Water Research Laboratory, Utah State University, Logan, Utah, USA
| | - Darwin L Sorensen
- Utah Water Research Laboratory, Utah State University, Logan, Utah, USA
| | - R Ryan Dupont
- Utah Water Research Laboratory, Utah State University, Logan, Utah, USA
- Department of Civil and Environmental Engineering, Utah State University, Logan, Utah, USA
| | - Joan E McLean
- Utah Water Research Laboratory, Utah State University, Logan, Utah, USA
- Department of Civil and Environmental Engineering, Utah State University, Logan, Utah, USA
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Dahal B, NandaKafle G, Perkins L, Brözel VS. Diversity of free-Living nitrogen fixing Streptomyces in soils of the badlands of South Dakota. Microbiol Res 2017; 195:31-39. [DOI: 10.1016/j.micres.2016.11.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 11/04/2016] [Accepted: 11/12/2016] [Indexed: 11/25/2022]
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Bombar D, Paerl RW, Riemann L. Marine Non-Cyanobacterial Diazotrophs: Moving beyond Molecular Detection. Trends Microbiol 2016; 24:916-927. [PMID: 27476748 DOI: 10.1016/j.tim.2016.07.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/20/2016] [Accepted: 07/07/2016] [Indexed: 11/17/2022]
Abstract
The nitrogen input through biological N2 fixation is essential for life in vast areas of the global ocean. The belief is that cyanobacteria are the only relevant N2-fixing (diazotrophic) organisms. It has, however, now become evident that non-cyanobacterial diazotrophs, bacteria and archaea with ecologies fundamentally distinct from those of cyanobacteria, are widespread and occasionally fix N2 at significant rates. The documentation of a globally relevant nitrogen input from these diazotrophs would constitute a new paradigm for research on oceanic nitrogen cycling. Here we highlight the need for combining rate measurements and molecular analyses of field samples with cultivation studies in order to clarify the ecology of non-cyanobacteria and their contribution to marine N2 fixation on local and global scales.
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Affiliation(s)
- Deniz Bombar
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Ryan W Paerl
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
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Madhaiyan M, Alex THH, Ngoh ST, Prithiviraj B, Ji L. Leaf-residing Methylobacterium species fix nitrogen and promote biomass and seed production in Jatropha curcas. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:222. [PMID: 26697111 PMCID: PMC4687150 DOI: 10.1186/s13068-015-0404-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 11/30/2015] [Indexed: 05/06/2023]
Abstract
BACKGROUND Jatropha curcas L. (Jatropha) is a potential biodiesel crop that can be cultivated on marginal land because of its strong tolerance to drought and low soil nutrient content. However, seed yield remains low. To enhance the commercial viability and green index of Jatropha biofuel, a systemic and coordinated approach must be adopted to improve seed oil and biomass productivity. Here, we present our investigations on the Jatropha-associated nitrogen-fixing bacteria with an aim to understand and exploit the unique biology of this plant from the perspective of plant-microbe interactions. RESULTS An analysis of 1017 endophytic bacterial isolates derived from different parts of Jatropha revealed that diazotrophs were abundant and diversely distributed into five classes belonging to α, β, γ-Proteobacteria, Actinobacteria and Firmicutes. Methylobacterium species accounted for 69.1 % of endophytic bacterial isolates in leaves and surprisingly, 30.2 % which were able to fix nitrogen that inhabit in leaves. Among the Methylobacterium isolates, strain L2-4 was characterized in detail. Phylogenetically, strain L2-4 is closely related to M. radiotolerans and showed strong molybdenum-iron dependent acetylene reduction (AR) activity in vitro and in planta. Foliar spray of L2-4 led to successful colonization on both leaf surface and in internal tissues of systemic leaves and significantly improved plant height, leaf number, chlorophyll content and stem volume. Importantly, seed production was improved by 222.2 and 96.3 % in plants potted in sterilized and non-sterilized soil, respectively. Seed yield increase was associated with an increase in female-male flower ratio. CONCLUSION The ability of Methylobacterium to fix nitrogen and colonize leaf tissues serves as an important trait for Jatropha. This bacteria-plant interaction may significantly contribute to Jatropha's tolerance to low soil nutrient content. Strain L2-4 opens a new possibility to improve plant's nitrogen supply from the leaves and may be exploited to significantly improve the productivity and Green Index of Jatropha biofuel.
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Affiliation(s)
- Munusamy Madhaiyan
- />Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Tan Hian Hwee Alex
- />Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Si Te Ngoh
- />Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Bharath Prithiviraj
- />Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401 USA
| | - Lianghui Ji
- />Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
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Identification and characterization of the part of the bacterial community associated with field-grown tall fescue (Festuca arundinacea) cv. SFRO Don Tomás in Uruguay. ANN MICROBIOL 2015. [DOI: 10.1007/s13213-015-1113-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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30
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Mirza BS, Muruganandam S, Meng X, Sorensen DL, Dupont RR, McLean JE. Arsenic(V) reduction in relation to Iron(III) transformation and molecular characterization of the structural and functional microbial community in sediments of a basin-fill aquifer in Northern Utah. Appl Environ Microbiol 2014; 80:3198-208. [PMID: 24632255 PMCID: PMC4018920 DOI: 10.1128/aem.00240-14] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 03/07/2014] [Indexed: 11/20/2022] Open
Abstract
Basin-fill aquifers of the Southwestern United States are associated with elevated concentrations of arsenic (As) in groundwater. Many private domestic wells in the Cache Valley Basin, UT, have As concentrations in excess of the U.S. EPA drinking water limit. Thirteen sediment cores were collected from the center of the valley at the depth of the shallow groundwater and were sectioned into layers based on redoxmorphic features. Three of the layers, two from redox transition zones and one from a depletion zone, were used to establish microcosms. Microcosms were treated with groundwater (GW) or groundwater plus glucose (GW+G) to investigate the extent of As reduction in relation to iron (Fe) transformation and characterize the microbial community structure and function by sequencing 16S rRNA and arsenate dissimilatory reductase (arrA) genes. Under the carbon-limited conditions of the GW treatment, As reduction was independent of Fe reduction, despite the abundance of sequences related to Geobacter and Shewanella, genera that include a variety of dissimilatory iron-reducing bacteria. The addition of glucose, an electron donor and carbon source, caused substantial shifts toward domination of the bacterial community by Clostridium-related organisms, and As reduction was correlated with Fe reduction for the sediments from the redox transition zone. The arrA gene sequencing from microcosms at day 54 of incubation showed the presence of 14 unique phylotypes, none of which were related to any previously described arrA gene sequence, suggesting a unique community of dissimilatory arsenate-respiring bacteria in the Cache Valley Basin.
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Affiliation(s)
- Babur S Mirza
- Utah Water Research Laboratory, Utah State University, Logan, Utah, USA
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Bentzon-Tilia M, Farnelid H, Jürgens K, Riemann L. Cultivation and isolation of N2-fixing bacteria from suboxic waters in the Baltic Sea. FEMS Microbiol Ecol 2014; 88:358-71. [PMID: 24579891 DOI: 10.1111/1574-6941.12304] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/20/2014] [Accepted: 02/10/2014] [Indexed: 11/30/2022] Open
Abstract
Nitrogenase genes (nifH) from heterotrophic dinitrogen (N2)-fixing bacteria appear ubiquitous in marine bacterioplankton, but the significance of these bacteria for N cycling is unknown. Quantitative data on the N2-fixation potential of marine and estuarine heterotrophs are scarce, and the shortage of cultivated specimens currently precludes ecophysiological characterization of these bacteria. Through the cultivation of diazotrophs from suboxic (1.79 μmol O2 L(-1)) Baltic Sea water in an artificial seawater medium devoid of combined N, we report the cultivability of a considerable fraction of the diazotrophic community in the Gotland Deep. Two nifH clades were present both in situ and in enrichment cultures showing gene abundances of up to 4.6 × 10(5) and 5.8 × 10(5) nifH gene copies L(-1) within two vertical profiles in the Baltic Sea. The distributions of the two clades suggested a relationship with the O2 concentrations in the water column as abundances increased in the suboxic and anoxic waters. It was possible to cultivate and isolate representatives from one of these prevalent clades, and preliminary analysis of their ecophysiology demonstrated growth optima at 0.5-15 μmol O2 L(-1) and 186-194 μmol O2 L(-1) in the absence of combined N.
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Affiliation(s)
- Mikkel Bentzon-Tilia
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
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Farnelid H, Harder J, Bentzon-Tilia M, Riemann L. Isolation of heterotrophic diazotrophic bacteria from estuarine surface waters. Environ Microbiol 2013; 16:3072-82. [PMID: 24330580 DOI: 10.1111/1462-2920.12335] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 11/07/2013] [Indexed: 11/30/2022]
Abstract
The wide distribution of diverse nitrogenase (nifH) genes affiliated with those of heterotrophic bacteria in marine and estuarine waters indicates ubiquity and an ecologically relevant role for heterotrophic N2 -fixers (diazotrophs) in aquatic nitrogen (N) cycling. However, the lack of cultivated representatives currently precludes an evaluation of their N2 -fixing capacity. In this study, microoxic or anoxic N-free media were inoculated with estuarine Baltic Sea surface water to select for N2 -fixers. After visible growth and isolation of single colonies on oxic plates or in anoxic agar tubes, nifH gene amplicons were obtained from 64 strains and nitrogenase activity, applying the acetylene reduction assay, was confirmed for 40 strains. Two strains, one Gammaproteobacterium affiliated with Pseudomonas and one Alphaproteobacterium affiliated with Rhodopseudomonas were shown to represent established members of the indigenous diazotrophic community in the Baltic Sea, with abundances of up to 7.9 × 10(4) and 4.7 × 10(4) nifH copies l(-1) respectively. This study reports media for successful isolation of heterotrophic diazotrophs. The applied methodology and the obtained strains will facilitate future identification of factors controlling heterotrophic diazotrophic activity in aquatic environments, which is a prerequisite for understanding and evaluating their ecology and contribution to N cycling at local and regional scales.
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Affiliation(s)
- Hanna Farnelid
- Department of Natural Sciences, Linnaeus University, Kalmar, Sweden
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Response of free-living nitrogen-fixing microorganisms to land use change in the Amazon rainforest. Appl Environ Microbiol 2013; 80:281-8. [PMID: 24162570 DOI: 10.1128/aem.02362-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Amazon rainforest, the largest equatorial forest in the world, is being cleared for pasture and agricultural use at alarming rates. Tropical deforestation is known to cause alterations in microbial communities at taxonomic and phylogenetic levels, but it is unclear whether microbial functional groups are altered. We asked whether free-living nitrogen-fixing microorganisms (diazotrophs) respond to deforestation in the Amazon rainforest, using analysis of the marker gene nifH. Clone libraries were generated from soil samples collected from a primary forest, a 5-year-old pasture originally converted from primary forest, and a secondary forest established after pasture abandonment. Although diazotroph richness did not significantly change among the three plots, diazotroph community composition was altered with forest-to-pasture conversion, and phylogenetic similarity was higher among pasture communities than among those in forests. There was also 10-fold increase in nifH gene abundance following conversion from primary forest to pasture. Three environmental factors were associated with the observed changes: soil acidity, total N concentration, and C/N ratio. Our results suggest a partial restoration to initial levels of abundance and community structure of diazotrophs following pasture abandonment, with primary and secondary forests sharing similar communities. We postulate that the response of diazotrophs to land use change is a direct consequence of changes in plant communities, particularly the higher N demand of pasture plant communities for supporting aboveground plant growth.
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Abstract
Competition for molecular oxygen (O(2)) among respiratory microorganisms is intense because O(2) is a potent electron acceptor. This competition leads to the formation of microoxic environments wherever microorganisms congregate in aquatic, terrestrial and host-associated communities. Bacteria can harvest O(2) present at low, even nanomolar, concentrations using high-affinity terminal oxidases. Here, we report the results of surveys searching for high-affinity terminal oxidase genes in sequenced bacterial genomes and shotgun metagenomes. The results indicate that bacteria with the potential to respire under microoxic conditions are phylogenetically diverse and intriguingly widespread in nature. We explore the implications of these findings by highlighting the importance of microaerobic metabolism in host-associated bacteria related to health and disease.
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