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Kumari S, Kumar A, Lepcha A, Kumar R. Cold-adapted Exiguobacterium sibiricum K1 as a potential bioinoculant in cold regions: Physiological and genomic elucidation of biocontrol and plant growth promotion. Gene 2024; 916:148439. [PMID: 38583819 DOI: 10.1016/j.gene.2024.148439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/22/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
The scarcity of soil nutrient availability under cold conditions of Himalayan regions needs a sustainable approach for better crop yields. The cold-adapted bacteria, Exiguobacterium sibiricum K1, with the potential to produce several plant growth-promoting (PGP) attributes, nitrogen fixation, indole acetic acid production, phosphate and potassium solubilization at 10 °C can provide an opportunity to promote crop yield improvement in an eco-friendly way under cold conditions. The bacterium also exhibited biocontrol activity against two phytopathogens and produced siderophore (53.0 ± 0.5 % psu). The strain's PGP properties were investigated using a spinach-based bioassay under controlled conditions. The bacterized seeds showed a notable increase in germination rate (23.2 %), shoot length (65.3 %), root length (56.6 %), leaf area (73.7 %), number of leaflets (65.2 %), and dry matter (65.2 %). Additionally, the leaf analysis indicated elevated chlorophyll pigments, i.e., chlorophyll a (55.5 %), chlorophyll b (42.8 %), carotenoids (35.2 %), percentage radical scavenging activity (47.4 %), and leaf nutrient uptake such as nitrogen (23.4 %), calcium (60.8 %), potassium (62.3 %), and magnesium (28.9 %). Moreover, the whole-genome sequencing and genome mining endorsed various biofertilisation-related genes, including genes for potassium and phosphate solubilization, iron and nitrogen acquisition, carbon dioxide fixation, and biocontrol ability of Exiguobacterium sibiricum K1. Overall, this study highlights the role of Exiguobacterium sibiricum K1 as a potential bioinoculant for improving crop yield under cold environments.
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Affiliation(s)
- Sareeka Kumari
- High Altitude Microbiology Laboratory (HAM-LAB), Biotechnology Division, CSIR -Institute of Himalayan and Bioresource Technology, Palampur, H.P. 176061, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Anil Kumar
- High Altitude Microbiology Laboratory (HAM-LAB), Biotechnology Division, CSIR -Institute of Himalayan and Bioresource Technology, Palampur, H.P. 176061, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Ayush Lepcha
- High Altitude Microbiology Laboratory (HAM-LAB), Biotechnology Division, CSIR -Institute of Himalayan and Bioresource Technology, Palampur, H.P. 176061, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Rakshak Kumar
- High Altitude Microbiology Laboratory (HAM-LAB), Biotechnology Division, CSIR -Institute of Himalayan and Bioresource Technology, Palampur, H.P. 176061, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India; Department of Molecular Biology & Bioinformatics, Tripura University (A Central University), Suryamaninagar, Tripura, 799022, India.
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Fan D, Schwinghamer T, Liu S, Xia O, Ge C, Chen Q, Smith DL. Characterization of endophytic bacteriome diversity and associated beneficial bacteria inhabiting a macrophyte Eichhornia crassipes. FRONTIERS IN PLANT SCIENCE 2023; 14:1176648. [PMID: 37404529 PMCID: PMC10316030 DOI: 10.3389/fpls.2023.1176648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/24/2023] [Indexed: 07/06/2023]
Abstract
Introduction The endosphere of a plant is an interface containing a thriving community of endobacteria that can affect plant growth and potential for bioremediation. Eichhornia crassipes is an aquatic macrophyte, adapted to estuarine and freshwater ecosystems, which harbors a diverse bacterial community. Despite this, we currently lack a predictive understanding of how E. crassipes taxonomically structure the endobacterial community assemblies across distinct habitats (root, stem, and leaf). Methods In the present study, we assessed the endophytic bacteriome from different compartments using 16S rRNA gene sequencing analysis and verified the in vitro plant beneficial potential of isolated bacterial endophytes of E. crassipes. Results and discussion Plant compartments displayed a significant impact on the endobacterial community structures. Stem and leaf tissues were more selective, and the community exhibited a lower richness and diversity than root tissue. The taxonomic analysis of operational taxonomic units (OTUs) showed that the major phyla belonged to Proteobacteria and Actinobacteriota (> 80% in total). The most abundant genera in the sampled endosphere was Delftia in both stem and leaf samples. Members of the family Rhizobiaceae, such as in both stem and leaf samples. Members of the family Rhizobiaceae, such as Allorhizobium- Neorhizobium-Pararhizobium-Rhizobium were mainly associated with leaf tissue, whereas the genera Nannocystis and Nitrospira from the families Nannocystaceae and Nitrospiraceae, respectively, were statistically significantly associated with root tissue. Piscinibacter and Steroidobacter were putative keystone taxa of stem tissue. Most of the endophytic bacteria isolated from E. crassipes showed in vitro plant beneficial effects known to stimulate plant growth and induce plant resistance to stresses. This study provides new insights into the distribution and interaction of endobacteria across different compartments of E. crassipes Future study of endobacterial communities, using both culture-dependent and -independent techniques, will explore the mechanisms underlying the wide-spread adaptability of E. crassipesto various ecosystems and contribute to the development of efficient bacterial consortia for bioremediation and plant growth promotion.
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Affiliation(s)
- Di Fan
- School of Biology, Food and Environment, Hefei University, Hefei, China
| | - Timothy Schwinghamer
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - Shuaitong Liu
- School of Biology, Food and Environment, Hefei University, Hefei, China
| | - Ouyuan Xia
- School of Biology, Food and Environment, Hefei University, Hefei, China
| | - Chunmei Ge
- School of Biology, Food and Environment, Hefei University, Hefei, China
| | - Qun Chen
- School of Biology, Food and Environment, Hefei University, Hefei, China
| | - Donald L. Smith
- Department of Plant Science, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
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Marfetán JA, Gallo AL, Farias ME, Vélez ML, Pescuma M, Ordoñez OF. Exiguobacterium sp. as a bioinoculant for plant-growth promotion and Selenium biofortification strategies in horticultural plants. World J Microbiol Biotechnol 2023; 39:134. [PMID: 36961610 DOI: 10.1007/s11274-023-03571-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/07/2023] [Indexed: 03/25/2023]
Abstract
Plant growth-promoting rhizobacteria (PGPR) have a positive effect on plant development and being a promising way to enhance crop productivity and as substitution of chemical fertilizers. Selenium (Se) is an important trace element and its intake is usually lower than the daily minimum amount required for humans; hence, there is a demand on the design of Se biofortification strategies. Here, the genetic traits known to be associated with Plant-Growth Promotion (PGP) and Se biotransformation of Exiguobacterium sp. S17 were evaluated through genome analysis. Its growth-promoting capacity was tested through plant-growth promotion assays in laboratory and field conditions, using Brassica juncea (indian mustard), Beta vulgaris (chard), and Lactuca sativa (lettuce). Additionally, the Se biotransformation ability of Exiguobacterium sp. S17 was evaluated and the obtained selenized bacteria were tested in mustard plants. The sequenced bacteria genome revealed the presence of multiple genes involved in important functions regarding soil and plant colonization, PGP and Se biotransformation. Moreover, it was demonstrated that Exiguobacterium sp. S17 enhanced plant growth and could be useful to produce Se accumulation and biofortification in accumulator plants such as mustard. Thereby, Exiguobacterium sp. S17 might be used for developing new, sustainable, and environmentally friendly agro-technological strategies.
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Affiliation(s)
- Jorge A Marfetán
- Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), Esquel, Chubut, Argentina
- CONICET Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Ana L Gallo
- Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), Esquel, Chubut, Argentina
- Agencia Nacional de Promoción de la Investigación, El Desarrollo Tecnológico y la Innovación (Agencia I+D+I), Buenos Aires, Argentina
| | - Maria E Farias
- PROIMI Planta Piloto de Procesos Industriales Microbiológicos Av. Belgrano y Pasaje Caseros -(4000) - LIMLA Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas Tucumán, Argentina, CONICET Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucuman, Argentina
- PUNABIO SRL. Tucumán, Buenos Aires, Argentina
| | - Maria L Vélez
- Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), Esquel, Chubut, Argentina.
- CONICET Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
- Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), Esquel, Chubut, Argentina.
| | - Micaela Pescuma
- Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), Esquel, Chubut, Argentina
- CONICET Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Omar F Ordoñez
- Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), Esquel, Chubut, Argentina.
- CONICET Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
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Shi Y, Chen C, Wu X, Han Z, Zhang S, Chen K, Qiu X. Exposure to amitriptyline induces persistent gut damages and dysbiosis of the gut microbiota in zebrafish (Danio rerio). Comp Biochem Physiol C Toxicol Pharmacol 2022; 260:109417. [PMID: 35872240 DOI: 10.1016/j.cbpc.2022.109417] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/27/2022] [Accepted: 07/17/2022] [Indexed: 11/30/2022]
Abstract
Amitriptyline (AMI), the most commonly prescribed tricyclic antidepressant, is widely detected in water environments. Exposure to AMI may lead to diverse adverse effects on aquatic organisms, but little is known about the effect of short-term exposure to AMI on the gut microbiota of aquatic organisms and their recovery characteristics. In the present study, adult zebrafish (Danio rerio) were exposed to AMI (0, 2.5, 10, and 40 μg/L) for seven days, and then allowed to recover in AMI-free culture water for 21 days. The exposure caused gut damages in all the AMI treated groups of zebrafish, which became more severe after recovery compared to the control group. AMI exposure also disturbed the microbiota of zebrafish guts and rearing water even after the 21-day recovery period. Furthermore, AMI exposure affected microbes involved in the substance and energy metabolic functions in zebrafish guts and tended to increase the abundance of microbial genera associated with opportunistic pathogens. In addition, the microbial predicted metabolic functions in AMI-exposed guts of zebrafish were significantly altered after the 21-day recovery period, explaining the persistent effects of short-term exposure to AMI. The results of this study suggest that acute exposure to AMI may have persistent impacts on the gut histomorphology and the gut microbiota in aquatic organisms.
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Affiliation(s)
- Yanhong Shi
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Chen Chen
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Xiangyang Wu
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Ziming Han
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Shanshuo Zhang
- Henan Division GRG Metrology and Test Co., Ltd, Zhengzhou 450001, China
| | - Kun Chen
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Xuchun Qiu
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, China.
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Wu F, Ding Y, Nie Y, Wang XJ, An YQ, Roessner U, Walker R, Du B, Bai JG. Plant metabolomics integrated with transcriptomics and rhizospheric bacterial community indicates the mitigation effects of Klebsiella oxytoca P620 on p-hydroxybenzoic acid stress in cucumber. JOURNAL OF HAZARDOUS MATERIALS 2021; 415:125756. [PMID: 34088210 DOI: 10.1016/j.jhazmat.2021.125756] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/04/2021] [Accepted: 03/20/2021] [Indexed: 06/12/2023]
Abstract
Accumulation of p-hydroxybenzoic acid (PHBA) in soil causes autotoxicity stress in cucumber. When the stress is mitigated by PHBA-degrading bacteria, plant metabolites have not been detected. To explore mechanisms underlining the mitigation, plant metabolites have not been combined with rhizospheric microbes, antioxidant and soil enzymes. In this study, a strain P620 of Klebsiella decomposed PHBA to acetyl CoA. Cucumber was sown into soil supplemented with P620 and/or PHBA. After addition with P620, P620 colonization and the enriched bacterial genera were observed in rhizosphere. Compared to PHBA stress alone, the combination of P620 application and PHBA stress improved plant growth, decreased PHBA concentration in soil, and increased the activities of five soil enzymes and eight antioxidant enzymes in leaves. Metabolomic and transcriptomic analysis highlighted that P620 application decreased the intensities of MAG(18:3) isomer 4, MAG(18:3) isomer 2, lysoPC 18:3 (2n isomer), 2'-deoxyadenosine-5'-monophosphate, pyridoxine, and glucarate O-phosphoric acid in PHBA-stressed leaves and down-regulated the expression of genes related to these metabolites. We propose a mechanism that P620 application alters microbial communities in PHBA-contaminated soil. Thus, the application reduces PHBA concentration in soil, activates antioxidant and soil enzymes, and also influences metabolites in leaves by affecting plant transcriptome, mitigating PHBA stress in cucumber.
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Affiliation(s)
- Fenghui Wu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China; Shandong Provincial Key Laboratory of Plant Stress, College of life Sciences, Shandong Normal University, Ji'nan, Shandong 250014, PR China
| | - Yanqin Ding
- Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Yongxin Nie
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Xiu-Juan Wang
- Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Yan-Qiu An
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Ute Roessner
- School of BioSciences, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Robert Walker
- School of BioSciences, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Binghai Du
- Shandong Engineering Research Center of Plant-Microbial Restoration for Saline-alkali Land, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China
| | - Ji-Gang Bai
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
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Liu B, Eltanahy EE, Liu H, Chua ET, Thomas-Hall SR, Wass TJ, Pan K, Schenk PM. Growth-promoting bacteria double eicosapentaenoic acid yield in microalgae. BIORESOURCE TECHNOLOGY 2020; 316:123916. [PMID: 32768998 DOI: 10.1016/j.biortech.2020.123916] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 05/26/2023]
Abstract
High-yielding microalgae present an important commodity to sustainably satisfy burgeoning food, feed and biofuel demands. Because algae-associated bacteria can significantly enhance or reduce yields, we isolated, identified and selected highly-effective "probiotic" bacterial strains associated with Nannochloropsis oceanica, a high-yielding microalga rich in eicosapentaenoic acid (EPA). Xenic algae growth was significantly enhanced by co-cultivation with ten isolated bacteria that improved culture density and biomass by 2.2- and 1.56-fold, respectively (1.39 × 108 cells mL-1; 0.82 g L-1). EPA contents increased up to 2.25-fold (to 39.68% of total fatty acids). Added probiotic bacteria possessed multiple growth-stimulating characteristics, including atmospheric nitrogen fixation, growth hormone production and phosphorous solubilization. Core N. oceanica-dominant bacterial microbiomes at different cultivation scales included Sphingobacteria, Flavobacteria (Bacteroidetes), and α, γ-Proteobacteria, and added probiotic bacteria could be maintained. We conclude that the supplementation with probiotic algae-associated bacteria can significantly enhance biomass and EPA production of N. oceanica.
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Affiliation(s)
- Bingli Liu
- Laboratory of Applied Microalgae Biology, Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China; Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Eladl E Eltanahy
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia; Phycology Laboratory, Botany Department, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
| | - Hongwei Liu
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - Elvis T Chua
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Skye R Thomas-Hall
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Taylor J Wass
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Kehou Pan
- Laboratory of Applied Microalgae Biology, Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Peer M Schenk
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
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Evaluation of Candida tropicalis (NCIM 3321) extracellular phytase having plant growth promoting potential and process development. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2018. [DOI: 10.1016/j.bcab.2017.12.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Kasana RC, Pandey CB. Exiguobacterium: an overview of a versatile genus with potential in industry and agriculture. Crit Rev Biotechnol 2017; 38:141-156. [DOI: 10.1080/07388551.2017.1312273] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - C. B. Pandey
- ICAR-Central Arid Zone Research Institute, Jodhpur, India
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In-situ Adsorption-Biological Combined Technology Treating Sediment Phosphorus in all Fractions. Sci Rep 2016; 6:29725. [PMID: 27418242 PMCID: PMC4945969 DOI: 10.1038/srep29725] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 06/22/2016] [Indexed: 12/23/2022] Open
Abstract
The removal efficiency of sediment phosphorus (P) in all fractions with in-situ adsorption-biological combined technology was studied in West Lake, Hangzhou, China. The removal amounts of sediment Ca-P, Fe/Al-P, IP, OP and TP by the combined effect of PCFM (Porous ceramic filter media) and V. spiralis was 61 mg/kg, 249 mg/kg, 318 mg/kg, 85 mg/kg and 416 mg/kg, respectively, and the corresponding removing rate reached 10.5%, 44.6%, 27.5%, 30.6% and 29.2%. This study suggested that the combination of PCFM and V. spiralis could achieve a synergetic sediment P removal because the removal rates of the combinations were higher than the sum of that of PCFM and macrophytes used separately. From analysis of sediment microbial community and predicted function, we found that the combined PCFM and V. spiralis enhanced the function of P metabolism by increasing specific genus that belong to phylum Firmicutes and Nitrospirae. Thus it can be seen the in-situ adsorption-biological combined technology could be further applied to treat internal P loading in eutrophic waters.
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Tang J, Zhang Y, Cui Y, Ma J. Effects of a rhizobacterium on the growth of and chromium remediation by Lemna minor. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:9686-93. [PMID: 25631740 DOI: 10.1007/s11356-015-4138-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/15/2015] [Indexed: 05/13/2023]
Abstract
Duckweed has shown great potential for both energy and environmental applications, particularly in wastewater treatment and fuel ethanol production. A rhizobacterium, Exiguobacterium sp. MH3, has been reported to associate with the duckweed Lemna minor for symbiotic growth. The aim of this work is to study the effects of rhizobacterium MH3 on L. minor growth and chromium (Cr) remediation. It appeared to have a synergism between the rhizobacterium MH3 and duckweed; the presence of strain MH3 promoted the growth of duckweeds by increasing both the frond number and dry weight of duckweed by more than 30%, while duckweed in turn provided essential carbon source and energy for the growth of rhizobacterium MH3. Under Cr(VI) exposure, particularly at higher Cr(VI) concentrations, Exiguobacterium sp. MH3 significantly alleviated the harmful effects of the stress on the duckweed by promoting duckweed growth and preventing duckweed from excessive uptake of Cr. Potential mechanisms were also discussed in light of the genome sequence of strain MH3, and it was speculated that siderophores and indole-3-acetic acid (IAA) secreted by strain MH3 might contribute to promoting duckweed growth.
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Affiliation(s)
- Jie Tang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
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Bharti N, Yadav D, Barnawal D, Maji D, Kalra A. Exiguobacterium oxidotolerans, a halotolerant plant growth promoting rhizobacteria, improves yield and content of secondary metabolites in Bacopa monnieri (L.) Pennell under primary and secondary salt stress. World J Microbiol Biotechnol 2012; 29:379-87. [PMID: 23085953 DOI: 10.1007/s11274-012-1192-1] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 10/10/2012] [Indexed: 02/01/2023]
Abstract
Brahmi (Bacopa monnieri), an integral component of Indian Ayurvedic medicine system, is facing a threat of extinction owing to the depletion of its natural populations. The present study investigates the prospective of exploitation of halotolerant plant growth promoting rhizobacteria (PGPR) in utilising the salt stressed soils for cultivation of B. monnieri. The effects of two salt tolerant PGPR, Bacillus pumilus (STR2) and Exiguobacterium oxidotolerans (STR36) on the growth and content of bacoside-A, an important pharmaceutical compound in B. monnieri, were investigated under primary and secondary salinity conditions. The herb yields of un-inoculated plants decreased by 48 % under secondary salinization and 60 % under primary salinization than the non salinised plants. Among the rhizobacteria treated plants, E. oxidotolerans recorded 109 and 138 %, higher herb yield than non-inoculated plants subjected to primary and secondary salinity respectively. E. oxidotolerans inoculated plants recorded 36 and 76 % higher bacoside-A content under primary and secondary salinity respectively. Higher levels of proline content and considerably lower levels of lipid peroxidation were noticed when the plants were inoculated with PGPR under all salinity regimes. From the results of this investigation, it can be concluded that, the treatments with salt tolerant PGPR can be a useful strategy in the enhancement of biomass yield and saponin contents in B. monnieri, as besides being an eco-friendly approach; it can also be instrumental in cultivation of B. monnieri in salt stressed environments.
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Affiliation(s)
- Nidhi Bharti
- Microbial Technology and Entomology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow 226015, India
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