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Ben Abdallah M, Chamkha M, Karray F, Sayadi S. Microbial diversity in polyextreme salt flats and their potential applications. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:11371-11405. [PMID: 38180652 DOI: 10.1007/s11356-023-31644-9] [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: 08/30/2023] [Accepted: 12/17/2023] [Indexed: 01/06/2024]
Abstract
Recent geological, hydrochemical, and mineralogical studies performed on hypersaline salt flats have given insights into similar geo-morphologic features on Mars. These salt-encrusted depressions are widely spread across the Earth, where they are characterized by high salt concentrations, intense UV radiation, high evaporation, and low precipitation. Their surfaces are completely dry in summer; intermittent flooding occurs in winter turning them into transitory hypersaline lakes. Thanks to new approaches such as culture-dependent, culture-independent, and metagenomic-based methods, it is important to study microbial life under polyextreme conditions and understand what lives in these dynamic ecosystems and how they function. Regarding these particular features, new halophilic microorganisms have been isolated from some salt flats and identified as excellent producers of primary and secondary metabolites and granules such as halocins, enzymes, carotenoids, polyhydroxyalkanoates, and exopolysaccharides. Additionally, halophilic microorganisms are implemented in heavy metal bioremediation and hypersaline wastewater treatment. As a result, there is a growing interest in the distribution of halophilic microorganisms around the world that can be looked upon as good models to develop sustainable biotechnological processes for all fields. This review provides insights into diversity, ecology, metabolism, and genomics of halophiles in hypersaline salt flats worldwide as well as their potential uses in biotechnology.
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Affiliation(s)
- Manel Ben Abdallah
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, BP 1177, 3018, Sfax, Tunisia.
| | - Mohamed Chamkha
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, BP 1177, 3018, Sfax, Tunisia
| | - Fatma Karray
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, BP 1177, 3018, Sfax, Tunisia
| | - Sami Sayadi
- Biotechnology Program, Center for Sustainable Development, College of Arts and Sciences, Qatar University, 2713, Doha, Qatar
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Amiour S, Chekroud K, Font-Verdera F, Anver S, Liébana R, Hafdi O, Viver T. Overview of the Diversity of Extremely Saline Soils from a Semi-Arid Region Using 16S rRNA Gene Sequencing: A Case Study of the Sebkhas in Algerian High Plateaus. Microbiology (Reading) 2022. [DOI: 10.1134/s0026261722100472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Khan AL, Lopes LD, Bilal S, Asaf S, Crawford KM, Balan V, Al-Rawahi A, Al-Harrasi A, Schachtman DP. Microbiome Variation Across Populations of Desert Halophyte Zygophyllum qatarensis. FRONTIERS IN PLANT SCIENCE 2022; 13:841217. [PMID: 35432394 PMCID: PMC9009292 DOI: 10.3389/fpls.2022.841217] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/17/2022] [Indexed: 06/14/2023]
Abstract
Microbial symbionts play a significant role in plant health and stress tolerance. However, few studies exist that address rare species of core-microbiome function during abiotic stress. In the current study, we compared the microbiome composition of succulent dwarf shrub halophyte Zygophyllum qatarensis Hadidi across desert populations. The results showed that rhizospheric and endosphere microbiome greatly varied due to soil texture (sandy and gravel). No specific bacterial amplicon sequence variants were observed in the core-microbiome of bulk soil and rhizosphere, however, bacterial genus Alcaligenes and fungal genus Acidea were abundantly distributed across root and shoot endospheres. We also analyzed major nutrients such as silicon (Si), magnesium, and calcium across different soil textures and Z. qatarensis populations. The results showed that the rhizosphere and root parts had significantly higher Si content than the bulk soil and shoot parts. The microbiome variation can be attributed to markedly higher Si - suggesting that selective microbes are contributing to the translocation of soluble Si to root. In conclusion, low core-microbiome species abundance might be due to the harsh growing conditions in the desert - making Z. qatarensis highly selective to associate with microbial communities. Utilizing rare microbial players from plant microbiomes may be vital for increasing crop stress tolerance and productivity during stresses.
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Affiliation(s)
- Abdul Latif Khan
- Department of Engineering Technology, College of Technology, University of Houston, Sugar Land, TX, United States
- Natural and Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
| | - Lucas Dantas Lopes
- Department of Agronomy and Horticulture, Centre for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Saqib Bilal
- Natural and Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
| | - Sajjad Asaf
- Natural and Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
| | - Kerri M. Crawford
- Department of Biology and Biochemistry, College of Natural Science and Mathematics, University of Houston, Houston, TX, United States
| | - Venkatesh Balan
- Department of Engineering Technology, College of Technology, University of Houston, Sugar Land, TX, United States
| | - Ahmed Al-Rawahi
- Natural and Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
| | - Ahmed Al-Harrasi
- Natural and Medical Sciences Research Centre, University of Nizwa, Nizwa, Oman
| | - Daniel P. Schachtman
- Department of Agronomy and Horticulture, Centre for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, United States
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Meier DV, Greve AJ, Chennu A, van Erk MR, Muthukrishnan T, Abed RMM, Woebken D, de Beer D. Limitation of Microbial Processes at Saturation-Level Salinities in a Microbial Mat Covering a Coastal Salt Flat. Appl Environ Microbiol 2021; 87:e0069821. [PMID: 34160273 PMCID: PMC8357274 DOI: 10.1128/aem.00698-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/16/2021] [Indexed: 12/18/2022] Open
Abstract
Hypersaline microbial mats are dense microbial ecosystems capable of performing complete element cycling and are considered analogs of early Earth and hypothetical extraterrestrial ecosystems. We studied the functionality and limits of key biogeochemical processes, such as photosynthesis, aerobic respiration, and sulfur cycling, in salt crust-covered microbial mats from a tidal flat at the coast of Oman. We measured light, oxygen, and sulfide microprofiles as well as sulfate reduction rates at salt saturation and in flood conditions and determined fine-scale stratification of pigments, biomass, and microbial taxa in the resident microbial community. The salt crust did not protect the mats against irradiation or evaporation. Although some oxygen production was measurable at salinities of ≤30% (wt/vol) in situ, at saturation-level salinity (40%), oxygenic photosynthesis was completely inhibited and only resumed 2 days after reducing the porewater salinity to 12%. Aerobic respiration and active sulfur cycling occurred at low rates under salt saturation and increased strongly upon salinity reduction. Apart from high relative abundances of Chloroflexi, photoheterotrophic Alphaproteobacteria, Bacteroidetes, and Archaea, the mat contained a distinct layer harboring filamentous Cyanobacteria, which is unusual for such high salinities. Our results show that the diverse microbial community inhabiting this salt flat mat ultimately depends on periodic salt dilution to be self-sustaining and is rather adapted to merely survive salt saturation than to thrive under the salt crust. IMPORTANCE Due to their abilities to survive intense radiation and low water availability, hypersaline microbial mats are often suggested to be analogs of potential extraterrestrial life. However, even the limitations imposed on microbial processes by saturation-level salinity found on Earth have rarely been studied in situ. While abundance and diversity of microbial life in salt-saturated environments are well documented, most of our knowledge on process limitations stems from culture-based studies, few in situ studies, and theoretical calculations. In particular, oxygenic photosynthesis has barely been explored beyond 5 M NaCl (28% wt/vol). By applying a variety of biogeochemical and molecular methods, we show that despite abundance of photoautotrophic microorganisms, oxygenic photosynthesis is inhibited in salt-crust-covered microbial mats at saturation salinities, while rates of other energy generation processes are decreased several-fold. Hence, the complete element cycling required for self-sustaining microbial communities only occurs at lower salt concentrations.
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Affiliation(s)
- Dimitri V. Meier
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | | | - Arjun Chennu
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | | | | | - Raeid M. M. Abed
- Biology Department, College of Science, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Dagmar Woebken
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Dirk de Beer
- Max Planck Institute for Marine Microbiology, Bremen, Germany
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Fisher A, Wangpraseurt D, Larkum AWD, Johnson M, Kühl M, Chen M, Wong HL, Burns BP. Correlation of bio-optical properties with photosynthetic pigment and microorganism distribution in microbial mats from Hamelin Pool, Australia. FEMS Microbiol Ecol 2019; 95:5151331. [PMID: 30380056 DOI: 10.1093/femsec/fiy219] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/30/2018] [Indexed: 11/14/2022] Open
Abstract
Microbial mats and stromatolites are widespread in Hamelin Pool, Shark Bay, however the phototrophic capacity of these systems is unknown. This study has determined the optical properties and light-harvesting potential of these mats with light microsensors. These characteristics were linked via a combination of 16S rDNA sequencing, pigment analyses and hyperspectral imaging. Local scalar irradiance was elevated over the incident downwelling irradiance by 1.5-fold, suggesting light trapping and strong scattering by the mats. Visible light (400-700 nm) penetrated to a depth of 2 mm, whereas near-infrared light (700-800 nm) penetrated to at least 6 mm. Chlorophyll a and bacteriochlorophyll a (Bchl a) were found to be the dominant photosynthetic pigments present, with BChl a peaking at the subsurface (2-4 mm). Detailed 16S rDNA analyses revealed the presence of putative Chl f-containing Halomicronema sp. and photosynthetic members primarily decreased from the mat surface down to a depth of 6 mm. Data indicated high abundances of some pigments and phototrophic organisms in deeper layers of the mats (6-16 mm). It is proposed that the photosynthetic bacteria present in this system undergo unique adaptations to lower light conditions below the mat surface, and that phototrophic metabolisms are major contributors to ecosystem function.
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Affiliation(s)
- Amy Fisher
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia.,Australian Centre for Astrobiology, University of New South Wales, Sydney 2052, Australia
| | - Daniel Wangpraseurt
- Marine Biological Section, University of Copenhagen, Copenhagen 1017, Denmark.,Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.,Scripps Institution of Oceanography, University of California, San Diego 92037, CA, USA
| | - Anthony W D Larkum
- Climate Change Cluster, University of Technology, Sydney 2007, Australia
| | - Michael Johnson
- Climate Change Cluster, University of Technology, Sydney 2007, Australia
| | - Michael Kühl
- Marine Biological Section, University of Copenhagen, Copenhagen 1017, Denmark.,Climate Change Cluster, University of Technology, Sydney 2007, Australia
| | - Min Chen
- School of Life and Environmental Sciences, University of Sydney, Sydney 2006, Australia
| | - Hon Lun Wong
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia.,Australian Centre for Astrobiology, University of New South Wales, Sydney 2052, Australia
| | - Brendan P Burns
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia.,Australian Centre for Astrobiology, University of New South Wales, Sydney 2052, Australia
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McGonigle JM, Bernau JA, Bowen BB, Brazelton WJ. Robust Archaeal and Bacterial Communities Inhabit Shallow Subsurface Sediments of the Bonneville Salt Flats. mSphere 2019; 4:e00378-19. [PMID: 31462415 PMCID: PMC6714890 DOI: 10.1128/msphere.00378-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/12/2019] [Indexed: 12/31/2022] Open
Abstract
We report the first census of natural microbial communities of the Bonneville Salt Flats (BSF), a perennial salt pan at the Utah-Nevada border. Environmental DNA sequencing of archaeal and bacterial 16S rRNA genes was conducted on samples from multiple evaporite sediment layers collected from the upper 30 cm of the surface salt crust. Our results show that at the time of sampling (September 2016), BSF hosted a robust microbial community dominated by diverse halobacteria and Salinibacter species. Sequences identical to Geitlerinema sp. strain PCC 9228, an anoxygenic cyanobacterium that uses sulfide as the electron donor for photosynthesis, are also abundant in many samples. We identified taxonomic groups enriched in each layer of the salt crust sediment and revealed that the upper gypsum sediment layer found immediately under the uppermost surface halite contains a robust microbial community. In these sediments, we found an increased presence of Thermoplasmatales, Hadesarchaeota, Nanoarchaeaeota, Acetothermia, Desulfovermiculus, Halanaerobiales, Bacteroidetes, and Rhodovibrio This study provides insight into the diversity, spatial heterogeneity, and geologic context of a surprisingly complex microbial ecosystem within this macroscopically sterile landscape.IMPORTANCE Pleistocene Lake Bonneville, which covered a third of Utah, desiccated approximately 13,000 years ago, leaving behind the Bonneville Salt Flats (BSF) in the Utah West Desert. The potash salts that saturate BSF basin are extracted and sold as an additive for agricultural fertilizers. The salt crust is a well-known recreational and economic commodity, but the biological interactions with the salt crust have not been studied. This study is the first geospatial analysis of microbially diverse populations at this site using cultivation-independent environmental DNA sequencing methods. Identification of the microbes present within this unique, dynamic, and valued sedimentary evaporite environment is an important step toward understanding the potential consequences of perturbations to the microbial ecology on the surrounding landscape and ecosystem.
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Affiliation(s)
- Julia M McGonigle
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Jeremiah A Bernau
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, USA
| | - Brenda B Bowen
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, USA
| | - William J Brazelton
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
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Kacimov AR, Obnosov YV, Or D. Evaporation-Induced Capillary Siphoning Through Hydraulically Connected Porous Domains: The Vedernikov–Bouwer Model Revisited. Transp Porous Media 2019. [DOI: 10.1007/s11242-019-01285-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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8
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Mogany T, Swalaha FM, Allam M, Mtshali PS, Ismail A, Kumari S, Bux F. Phenotypic and genotypic characterisation of an unique indigenous hypersaline unicellular cyanobacterium, Euhalothece sp.nov. Microbiol Res 2018; 211:47-56. [PMID: 29705205 DOI: 10.1016/j.micres.2018.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 02/16/2018] [Accepted: 04/02/2018] [Indexed: 11/28/2022]
Abstract
A novel halotolerant species of cyanobacterium of the order Chroococcales was isolated from hypersaline estuary in Kwa-Zulu Natal, South Africa. A comprehensive polyphasic approach viz., cell morphology, pigment composition and complete genome sequence analysis was conducted to elucidate the taxonomic position of the isolated strain. The blue-green oval to rod-shaped cells were 14-18 μm in size, and contained a high amount of phycocyanin pigments. The strain was moderate thermotolerant/alkalitolerant halophile with the optimum conditions for growth at 35 °C, pH 8.5 and 120 g/l of NaCl. Based on 16S rRNA gene sequence phylogeny, the strain was related to members of the 'Euhalothece' subcluster (99%). The whole genome sequence was determined, and the annotated genes showed a 90% sequence similarity to the gas-vacuolate, spindle-shaped Dactylococcopsis salina PCC 8305. The size of the genome was determined to be 5,113,178 bp and contained 4332 protein-coding genes and 69 RNA genes with a G + C content of 46.7%. Genes encoding osmoregulation, oxidative stress, heat shock, persister cells, and UV-absorbing secondary metabolites, among others, were identified. Based on the phylogenetic analysis of the 16S rRNA gene sequences, physiological data, pigment compositions and genomic data, the strain is considered to represent a novel species of Euhalothece.
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Affiliation(s)
- Trisha Mogany
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Feroz M Swalaha
- Department of Biotechnology and Food Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Mushal Allam
- Sequencing Core Facility, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham, 2192, Johannesburg, South Africa
| | - Phillip Senzo Mtshali
- Sequencing Core Facility, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham, 2192, Johannesburg, South Africa
| | - Arshad Ismail
- Sequencing Core Facility, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham, 2192, Johannesburg, South Africa
| | - Sheena Kumari
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Faizal Bux
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa.
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Griko YV, Rask JC, Raychev R. Advantage of Animal Models with Metabolic Flexibility for Space Research Beyond Low Earth Orbit. ACTA ACUST UNITED AC 2017. [DOI: 10.1089/space.2016.0024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yuri V. Griko
- Space Biosciences Division, NASA-Ames Research Center, Moffett Field, California
| | - Jon C. Rask
- Space Biosciences Division, NASA-Ames Research Center, Moffett Field, California
- KBRwyle, Moffett Field, California
| | - Raycho Raychev
- Space Challenges Program, EnduroSat, Inc., Sofia, Bulgaria
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