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de Sousa RDSDR, Lima GVS, Garcias JT, Gomes GDO, Mateus JR, Madeira LDPDS, Seldin L, Rogez HLG, Marques JM. The Microbial Community Structure in the Rhizosphere of Theobroma cacao L. and Euterpe oleracea Mart. Is Influenced by Agriculture System in the Brazilian Amazon. Microorganisms 2024; 12:398. [PMID: 38399802 PMCID: PMC10892126 DOI: 10.3390/microorganisms12020398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 12/26/2023] [Accepted: 12/27/2023] [Indexed: 02/25/2024] Open
Abstract
This study tested the hypothesis that cocoa monoculture (MS) and cocoa-açai agroforestry systems (AFS) may influence the microbial community structure and populations of plant growth-promoting bacteria (PGPR). Accordingly, the aim was to analyze the microbial community structure and PGPR populations in different agroecosystems in the Brazilian Amazon. To achieve this, the rhizosphere microbial community of cocoa and açai plants in both Amazonian seasons (dry and rainy) was analyzed using culture-dependent (PGPR screening) and -independent methods [PCR-DGGE based on rrs, alp, nifH gene, and intergenic region (ITS) of fungi]. Concerning PGPR screening, out of 48 isolated bacterial strains, 25% were capable of siderophore production, 29% of mineralized organic phosphate, 8% of inorganic phosphate solubilization, and 4% of indole acetic acid production. Moreover, 17% of isolates could inhibit the growth of various phytopathogenic fungi. Statistical analyses of DGGE fingerprints (p < 0.05) showed that bacterial and fungal community structures in the rhizosphere were influenced by the seasons, supporting the results of the physicochemical analysis of the environment. Furthermore, as hypothesized, microbial communities differed statistically when comparing the MS and AFS. These findings provide important insights into the influence of climate and cultivation systems on soil microbial communities to guide the development of sustainable agricultural practices.
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Affiliation(s)
- Rosiane do Socorro dos Reis de Sousa
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil; (R.d.S.d.R.d.S.); (G.V.S.L.); (J.T.G.); (G.d.O.G.); (L.D.P.d.S.M.); (H.L.G.R.)
| | - Giulia Victória Silva Lima
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil; (R.d.S.d.R.d.S.); (G.V.S.L.); (J.T.G.); (G.d.O.G.); (L.D.P.d.S.M.); (H.L.G.R.)
| | - Josinete Torres Garcias
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil; (R.d.S.d.R.d.S.); (G.V.S.L.); (J.T.G.); (G.d.O.G.); (L.D.P.d.S.M.); (H.L.G.R.)
| | - Graziane de Oliveira Gomes
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil; (R.d.S.d.R.d.S.); (G.V.S.L.); (J.T.G.); (G.d.O.G.); (L.D.P.d.S.M.); (H.L.G.R.)
| | - Jackeline Rossetti Mateus
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Rio de Janeiro, Brazil; (J.R.M.); (L.S.)
| | - Lucimar Di Paula dos Santos Madeira
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil; (R.d.S.d.R.d.S.); (G.V.S.L.); (J.T.G.); (G.d.O.G.); (L.D.P.d.S.M.); (H.L.G.R.)
| | - Lucy Seldin
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Rio de Janeiro, Brazil; (J.R.M.); (L.S.)
| | - Hervé Louis Ghislain Rogez
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil; (R.d.S.d.R.d.S.); (G.V.S.L.); (J.T.G.); (G.d.O.G.); (L.D.P.d.S.M.); (H.L.G.R.)
| | - Joana Montezano Marques
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil; (R.d.S.d.R.d.S.); (G.V.S.L.); (J.T.G.); (G.d.O.G.); (L.D.P.d.S.M.); (H.L.G.R.)
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Rio de Janeiro, Brazil; (J.R.M.); (L.S.)
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Patowary R, Jain P, Malakar C, Devi A. Biodegradation of carbofuran by Pseudomonas aeruginosa S07: biosurfactant production, plant growth promotion, and metal tolerance. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:115185-115198. [PMID: 37878173 DOI: 10.1007/s11356-023-30466-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 10/10/2023] [Indexed: 10/26/2023]
Abstract
Pesticides are an indispensable part of modern farming as it aids in controlling pests and hence increase crop yield. But, unmanaged use of pesticides is a growing concern for safety and conservation of the environment. In the present study, a novel biosurfactant-producing bacterium, Pseudomonas aeruginosa S07, was utilized to degrade carbofuran pesticide, and it was obtained at 150 mg/L concentration; 89.2% degradation was achieved on the 5th day of incubation in in vitro culture condition. GC-MS (gas chromatography and mass spectrometry) and LC-MS (liquid chromatography and mass spectrometry) analyses revealed the presence of several degradation intermediates such as hydroxycarbofurnan, ketocarbofuran, and hydroxybenzofuran, in the degradation process. The bacterium was found to exhibit tolerance towards several heavy metals: Cu, Co, Zn, Ni, and Cd, where maximum and least tolerance were obtained against Co and Ni, respectively. Additionally, the bacterium also possesses plant growth-promoting activity showing positive results in nitrogen fixation, phosphate solubilising, ammonia production, and potassium solubilizing assays. Thus, from the study, it can be assumed that the bacterium can be useful in the production of bioformulation for remediation and rejuvenation of pesticide-contaminated sites in the coming days.
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Affiliation(s)
- Rupshikha Patowary
- Department of Biotechnology, The Assam Royal Global University, Betkuchi, Guwahati, Assam, 781035, India
- Environmental Chemistry Laboratory, Life Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati, Assam, 781 035, India
| | - Prerna Jain
- Environmental Chemistry Laboratory, Life Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati, Assam, 781 035, India
| | - Chandana Malakar
- Microbial Biotechnology and Protein Research Laboratory, Life Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati, Assam, 781 035, India
| | - Arundhuti Devi
- Environmental Chemistry Laboratory, Life Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati, Assam, 781 035, India.
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Pallavi, Mishra RK, Sahu PK, Mishra V, Jamal H, Varma A, Tripathi S. Isolation and characterization of halotolerant plant growth promoting rhizobacteria from mangrove region of Sundarbans, India for enhanced crop productivity. FRONTIERS IN PLANT SCIENCE 2023; 14:1122347. [PMID: 37152133 PMCID: PMC10158646 DOI: 10.3389/fpls.2023.1122347] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/24/2023] [Indexed: 12/07/2023]
Abstract
Halotolerant plant growth promoting rhizobacteria (PGPR) are beneficial microorganisms utilized to mitigate the biotic and abiotic stresses in plants. The areas of Sundarban mangroves of West Bengal, India have been reported to be rich in halotolerant microflora, yet major area remains unexplored. The present study, therefore, aims to map down the region-specific native microbial community potent of salt tolerance, plant growth promoting (PGP) activity and antagonistic activity against fungal pathogens. Bacterial samples were isolated from the saline soil of the Sundarban mangroves. A total of 156 bacterial samples were isolated and 20 were screened for their salt tolerance potential. These isolates were characterised using morphological, biochemical, and molecular approaches. Based on 16s rRNA sequencing, they were classified into 4 different genera, including Arthrobacter sp. (01 isolate), Pseudomonas plecoglossicida (01 isolate), Kocuria rosea (01 isolate), and Bacillus (17 isolates). The halotolerant isolates which possessed plant growth promoting traits including phosphate, and zinc solubilization, indole acetic acid production, siderophore, and ammonia generation were selected. Further, the effect of two halotolerant isolates GN-5 and JR-12 which showed most prominent PGP activities was evaluated in pea plant under high salinity conditions. The isolates improved survival by promoting germination (36 to 43%) and root-shoot growth and weight of pea plant in comparison to non-inoculated control plants. In a subsequent dual culture confrontation experiment, both these halo-tolerant isolates showed antagonistic activities against the aggressive root rot disease-causing Macrophomina phaseolina (Tassi) Goid NAIMCC-F-02902. The identified isolates could be used as potential bioagents for saline soils, with potential antagonistic effect on root rot disease. However, further studies at the physiological and molecular level would help to delineate a detail mechanistic understanding of broad-spectrum defence against salinity and potential biotic pathogen.
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Affiliation(s)
- Pallavi
- Amity Institute of Microbial Technology, Amity University, Noida, India
- Department of Microbiology, Indian Council of Agricultural Research – National Bureau of Agriculturally Important Microorganism, Kushmaur, Mau, Uttar Pradesh, India
| | - Rohit Kumar Mishra
- Centre of Science and Society, University of Allahabad, Prayagraj, Uttar Pradesh, India
| | - Pramod Kumar Sahu
- Department of Microbiology, Indian Council of Agricultural Research – National Bureau of Agriculturally Important Microorganism, Kushmaur, Mau, Uttar Pradesh, India
| | - Vani Mishra
- Nanotechnology Application Centre, University of Allahabad, Prayagraj, Uttar Pradesh, India
| | - Hafiza Jamal
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University, Noida, India
| | - Swati Tripathi
- Amity Institute of Microbial Technology, Amity University, Noida, India
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Sritongon N, Boonlue S, Mongkolthanaruk W, Jogloy S, Riddech N. The combination of multiple plant growth promotion and hydrolytic enzyme producing rhizobacteria and their effect on Jerusalem artichoke growth improvement. Sci Rep 2023; 13:5917. [PMID: 37041302 PMCID: PMC10090049 DOI: 10.1038/s41598-023-33099-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 04/07/2023] [Indexed: 04/13/2023] Open
Abstract
Rhizobacteria are well recognized for their beneficial multifunctions as key promoters of plant development, suppressing pathogens, and improving soil health. In this study, experiments focused on characterizing the plant growth promotion (PGP) and extracellular hydrolase production traits of rhizobacteria, and their impact on Jerusalem artichoke growth. A total of 50 isolates proved capable of either direct PGP or hydrolase-producing traits. Two promising strains (Enterobacter cloacae S81 and Pseudomonas azotoformans C2-114) showed potential on phosphate and potassium solubilization, IAA production, and 1-aminocyclopropane-1-carboxylic acid deaminase activity and hydrolase production. A hydrolase-producing strain (Bacillus subtilis S42) was able to generate cellulase, protease, amylase, β-glucosidase, and phosphatase. These three selected strains also gave positive results for indirect PGP traits such as siderophore, ammonia, oxalate oxidase, polyamine, exopolysaccharide, biofilm, motility, and tolerance to salinity and drought stress. Colonization was observed using a scanning electron microscope and rhizobacteria appeared at the root surface. Interestingly, inoculation with consortia strains (S42, S81, and C2-114) significantly increased all plant parameters, including height, biomass, root (length, surface, diameter, and volume), and tuber fresh weight. Therefore, we recommend that potential consortia of PGP and hydrolase-producing rhizobacteria be employed as a biofertilizer to improve soil and boost crop productivity.
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Affiliation(s)
- Natthawat Sritongon
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Sophon Boonlue
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Wiyada Mongkolthanaruk
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Sanun Jogloy
- Department of Agronomy, Faculty of Agriculture, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Nuntavun Riddech
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand.
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Wang G, Zhang L, Zhang S, Li B, Li J, Wang X, Zhang J, Guan C, Ji J. The combined use of a plant growth promoting Bacillus sp. strain and GABA promotes the growth of rice under salt stress by regulating antioxidant enzyme system, enhancing photosynthesis and improving soil enzyme activities. Microbiol Res 2023; 266:127225. [DOI: 10.1016/j.micres.2022.127225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/16/2022] [Accepted: 10/06/2022] [Indexed: 11/05/2022]
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New Bacillus subtilis Strains Isolated from Prosopis glandulosa Rhizosphere for Suppressing Fusarium Spp. and Enhancing Growth of Gossypium hirsutum L. BIOLOGY 2022; 12:biology12010073. [PMID: 36671765 PMCID: PMC9855134 DOI: 10.3390/biology12010073] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/27/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023]
Abstract
Rhizobacteria from desert plants can alleviate biotic stress and suppress plant diseases, and consequently can enhance plant growth. Therefore, the current study was performed to isolate and identify Prosopis glandulosa-associating rhizobacteria based on their antagonistic activity against Fusarium species and plant growth-promoting properties. Three bacterial isolates were identified as Bacillus subtilis: LDA-1, LDA-2, and LDA-3. The molecular analysis suggests the biosynthesis of the bacteriocins subtilisin and subtilosin, as well as the lipopeptide iturin, by these strains. In addition, the antagonistic study by dual-culture assay showed a high efficacy of all B. subtilis strains against phytopathogenic fungi (Fusarium nygamai, F. equisseti, F. solani, F. solani ICADL1, and F. oxysporum ICADL2) with inhibition percentages ranging from 43.3 to 83.5% in comparison to the control. Moreover, atomic force microscopy (AFM) analysis showed significant differences in the cell wall topography of the F. solani ICADL1 among the treated mycelia and untreated control. As a result, these three B. subtilis strains were used as bioinoculants for cotton seedlings infected by F. solani ICADL1 in pot trials, and the results revealed that the bacterial inoculations as an individual or combined with F. solani ICADL1 significantly improved cotton root and stem length, lateral roots, indole acetic acid (IAA), and gibberellic acid (GA3) contents, as well as increased antioxidants, flavonoids, and phenols in comparison to those obtained from healthy and infected control plants. In conclusion, the three bacterial strains of B. subtilis (i.e., LDA-1, LDA-2, and LDA-3) are considered promising tools as biocontrol agents for F. solani and cotton growth promoters, and consequently can be used as bio-ertilizer in sustainable agriculture systems.
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Sinha T, Malakar C, Talukdar NC. Mustard seed–associated endophytes suppress Sclerotinia sclerotiorum causing Sclerotinia rot in mustard crop. Int Microbiol 2022:10.1007/s10123-022-00314-0. [PMID: 36542232 DOI: 10.1007/s10123-022-00314-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 12/24/2022]
Abstract
Mustard-rapeseed cultivation is affected by Sclerotinia sclerotiorum resulting in loss of oil yield and degradation of crop quality. This study adopted an environment friendly biocontrol approach of screening mustard endophytes against the pathogen. Two bacterial isolates, Bacillus safensis (TS46 bac4) and Bacillus australimaris (SM2) showed potential biocontrol activity under both in vitro and in vivo conditions. Dual culture assay reported 90% inhibition of fungal growth. The bacterial cell free supernatant of isolate SM2 showed 52.89% inhibition and the other isolate TS46 bac4 showed 57.97% inhibition. The crude (10 mg/ml) and purified (10 mg/ml) metabolite extract of SM2 showed 100% and 97% inhibition respectively. Both crude (10 mg/ml) and purified (7.5 mg/ml) metabolite extract of TS46 bac4 exhibited 99% inhibition of the pathogen. Antifungal lipopeptides: surfactin, iturin and fengycin were identified in bacterial metabolite extract of the isolates. Both strains promoted healthy germination and prevented the formation of any disease symptoms in seedling. The selected Bacillus strains applied by spray method showed better results against fungal infection on mustard leaf and stem. Microscopic studies revealed degradation of fungal mycelial growth by both isolates. These findings support the employment of the bacterial strains as potential biocontrol agents to reduce the effects of S. sclerotiorum in mustard-rapeseed.
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Hoque MN, Imran S, Hannan A, Paul NC, Mahamud MA, Chakrobortty J, Sarker P, Irin IJ, Brestic M, Rhaman MS. Organic Amendments for Mitigation of Salinity Stress in Plants: A Review. Life (Basel) 2022; 12:life12101632. [PMID: 36295067 PMCID: PMC9605495 DOI: 10.3390/life12101632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/14/2022] [Accepted: 10/14/2022] [Indexed: 11/20/2022] Open
Abstract
Natural and/or human-caused salinization of soils has become a growing problem in the world, and salinization endangers agro-ecosystems by causing salt stress in most cultivated plants, which has a direct effect on food quality and quantity. Several techniques, as well as numerous strategies, have been developed in recent years to help plants cope with the negative consequences of salt stress and mitigate the impacts of salt stress on agricultural plants. Some of them are not environmentally friendly. In this regard, it is crucial to develop long-term solutions that boost saline soil productivity while also protecting the ecosystem. Organic amendments, such as vermicompost (VC), vermiwash (VW), biochar (BC), bio-fertilizer (BF), and plant growth promoting rhizobacteria (PGPR) are gaining attention in research. The organic amendment reduces salt stress and improves crops growth, development and yield. The literature shows that organic amendment enhances salinity tolerance and improves the growth and yield of plants by modifying ionic homeostasis, photosynthetic apparatus, antioxidant machineries, and reducing oxidative damages. However, the positive regulatory role of organic amendments in plants and their stress mitigation mechanisms is not reviewed adequately. Therefore, the present review discusses the recent reports of organic amendments in plants under salt stress and how stress is mitigated by organic amendments. The current assessment also analyzes the limitations of applying organic amendments and their future potential.
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Affiliation(s)
- Md. Najmol Hoque
- Department of Biochemistry and Molecular Biology, Khulna Agricultural University, Khulna 9100, Bangladesh
| | - Shahin Imran
- Department of Agronomy, Khulna Agricultural University, Khulna 9100, Bangladesh
| | - Afsana Hannan
- Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Newton Chandra Paul
- Department of Agronomy, Khulna Agricultural University, Khulna 9100, Bangladesh
| | - Md. Asif Mahamud
- Department of Agricultural Chemistry, Khulna Agricultural University, Khulna 9100, Bangladesh
| | | | - Prosenjit Sarker
- Department of Crop Botany, Khulna Agricultural University, Khulna 9100, Bangladesh
| | - Israt Jahan Irin
- Department of Agronomy, Khulna Agricultural University, Khulna 9100, Bangladesh
| | - Marian Brestic
- Department of Botany and Plant Physiology, Czech University of Life Sciences, Kamycka 129, 16500 Prague, Czech Republic
- Institute of Plant and Environmental Studies, Slovak University of Agriculture, A. Hlinku 2, 94976 Nitra, Slovakia
- Correspondence: (M.B.); (M.S.R.)
| | - Mohammad Saidur Rhaman
- Department of Seed Science and Technology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
- Correspondence: (M.B.); (M.S.R.)
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Contrasting genome patterns of two pseudomonas strains isolated from the date palm rhizosphere to assess survival in a hot arid environment. World J Microbiol Biotechnol 2022; 38:207. [PMID: 36008694 DOI: 10.1007/s11274-022-03392-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 08/13/2022] [Indexed: 10/15/2022]
Abstract
The plant growth-promoting rhizobacteria (PGPRs) improve plant growth and fitness by multiple direct (nitrogen fixation and phosphate solubilization) and indirect (inducing systematic resistance against phytopathogens, soil nutrient stabilization, and maintenance) mechanisms. Nevertheless, the mechanisms by which PGPRs promote plant growth in hot and arid environments remain poorly recorded. In this study, a comparative genome analysis of two phosphate solubilizing bacteria, Pseudomonas atacamensis SM1 and Pseudomonas toyotomiensis SM2, isolated from the rhizosphere of date palm was performed. The abundance of genes conferring stress tolerance (chaperones, heat shock genes, and chemotaxis) and supporting plant growth (plant growth hormone, root colonization, nitrogen fixation, and phosphate solubilization) were compared among the two isolates. This study further evaluated their functions, metabolic pathways, and evolutionary relationship. Results show that both bacterial strains have gene clusters required for plant growth promotion (phosphate solubilization and root colonization), but it is more abundant in P. atacamensis SM1 than in P. toyotomiensis SM2. Genes involved in stress tolerance (mcp, rbs, wsp, and mot), heat shock, and chaperones (hslJ and hslR) were also more common in P. atacamensis SM1. These findings suggest that P. atacamensis SM1could have better adaptability to the hot and arid environment owing to a higher abundance of chaperone genes and heat shock proteins. It may promote plant growth owing to a higher load of root colonization and phosphate solubilization genes and warrants further in vitro study.
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Ke T, Zhang J, Tao Y, Zhang C, Zhang Y, Xu Y, Chen L. Individual and combined application of Cu-tolerant Bacillus spp. enhance the Cu phytoextraction efficiency of perennial ryegrass. CHEMOSPHERE 2021; 263:127952. [PMID: 32828058 DOI: 10.1016/j.chemosphere.2020.127952] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/30/2020] [Accepted: 08/08/2020] [Indexed: 05/27/2023]
Abstract
Forage grasses have recently received a remarkable amount of attention as promising candidates for decontaminating metal-polluted soils, but this strategy is time-consuming and inefficient. The present study aimed to address the beneficial effects of screened plant growth-promoting rhizobacteria (PGPR) strains Bacillus sp. EhS5 and EhS7 on perennial ryegrass and tall fescue. Single or combined inoculation considerably increased the biomass yield and Cu content of inoculated ryegrass compared with uninoculated plants, thereby enhancing the extraction efficiency at different Cu contamination levels. Bioaugmentation did not show a positive impact on the improvement of fescue's phytoextraction efficiency. Principal component analysis (PCA) and Pearson correlation coefficient results identified root development and photosynthesis as the key variables influencing ryegrass biomass. Antioxidant activities and Cu bioavailability are the key variables influencing Cu accumulation. The inoculated ryegrass showed improved photosynthetic status as the photosystem II system efficiency parameters increased and energy dissipation in the form of heat (DIo/RC) decreased with the help of PGPR. The root length, diameter, surface area, and forks of inoculated ryegrass increased remarkably. The levels of scavengers of reactive oxygen species were enhanced in these plants. Moreover, PGPR significantly increased soil Cu bioavailability by secreting siderophores and organic acid and by increasing soil organic carbon content. Dual inoculation showed better results than individual inoculation in improving ryegrass growth and Cu translocation under high Cu contamination level according to PCA. This study systematically explored the effects and mechanisms of the Bacillus-ryegrass combined remediation and provided a novel method for cleaning Cu-contaminated sites.
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Affiliation(s)
- Tan Ke
- School of Resource & Environmental Sciences, Hubei Key Laboratory of Biomass Resource Chemistry and Environmental Biotechnology, Hubei Research Center of Environment Remediation Technology, Wuhan University, Wuhan, 430079, PR China
| | - Jin Zhang
- School of Resource & Environmental Sciences, Hubei Key Laboratory of Biomass Resource Chemistry and Environmental Biotechnology, Hubei Research Center of Environment Remediation Technology, Wuhan University, Wuhan, 430079, PR China
| | - Yue Tao
- School of Resource & Environmental Sciences, Hubei Key Laboratory of Biomass Resource Chemistry and Environmental Biotechnology, Hubei Research Center of Environment Remediation Technology, Wuhan University, Wuhan, 430079, PR China
| | - Chao Zhang
- School of Resource & Environmental Sciences, Hubei Key Laboratory of Biomass Resource Chemistry and Environmental Biotechnology, Hubei Research Center of Environment Remediation Technology, Wuhan University, Wuhan, 430079, PR China
| | - Yurui Zhang
- School of Resource & Environmental Sciences, Hubei Key Laboratory of Biomass Resource Chemistry and Environmental Biotechnology, Hubei Research Center of Environment Remediation Technology, Wuhan University, Wuhan, 430079, PR China
| | - Yanhong Xu
- National Central City Research Institute, Zhengzhou Normal University, Zhengzhou, 450044, PR China
| | - Lanzhou Chen
- School of Resource & Environmental Sciences, Hubei Key Laboratory of Biomass Resource Chemistry and Environmental Biotechnology, Hubei Research Center of Environment Remediation Technology, Wuhan University, Wuhan, 430079, PR China.
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