1
|
Xu L, Yue XL, Li HZ, Jian SL, Shu WS, Cui L, Xu XW. Aerobic Anoxygenic Phototrophic Bacteria in the Marine Environments Revealed by Raman/Fluorescence-Guided Single-Cell Sorting and Targeted Metagenomics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:7087-7098. [PMID: 38651173 DOI: 10.1021/acs.est.4c02881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Aerobic anoxygenic phototrophic bacteria (AAPB) contribute profoundly to the global carbon cycle. However, most AAPB in marine environments are uncultured and at low abundance, hampering the recognition of their functions and molecular mechanisms. In this study, we developed a new culture-independent method to identify and sort AAPB using single-cell Raman/fluorescence spectroscopy. Characteristic Raman and fluorescent bands specific to bacteriochlorophyll a (Bchl a) in AAPB were determined by comparing multiple known AAPB with non-AAPB isolates. Using these spectroscopic biomarkers, AAPB in coastal seawater, pelagic seawater, and hydrothermal sediment samples were screened, sorted, and sequenced. 16S rRNA gene analysis and functional gene annotations of sorted cells revealed novel AAPB members and functional genes, including one species belonging to the genus Sphingomonas, two genera affiliated to classes Betaproteobacteria and Gammaproteobacteria, and function genes bchCDIX, pucC2, and pufL related to Bchl a biosynthesis and photosynthetic reaction center assembly. Metagenome-assembled genomes (MAGs) of sorted cells from pelagic seawater and deep-sea hydrothermal sediment belonged to Erythrobacter sanguineus that was considered as an AAPB and genus Sphingomonas, respectively. Moreover, multiple photosynthesis-related genes were annotated in both MAGs, and comparative genomic analysis revealed several exclusive genes involved in amino acid and inorganic ion metabolism and transport. This study employed a new single-cell spectroscopy method to detect AAPB, not only broadening the taxonomic and genetic contents of AAPB in marine environments but also revealing their genetic mechanisms at the single-genomic level.
Collapse
Affiliation(s)
- Lin Xu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, P. R. China
- Collge of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Xiao-Lan Yue
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, P. R. China
- School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, P. R. China
| | - Hong-Zhe Li
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P. R. China
| | - Shu-Ling Jian
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, P. R. China
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P. R. China
| | - Wen-Sheng Shu
- Institute of Ecological Science, School of Life Science, South China Normal University, Guangzhou 510631, P. R. China
| | - Li Cui
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P. R. China
| | - Xue-Wei Xu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, P. R. China
- School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, P. R. China
| |
Collapse
|
2
|
Bains W, Petkowski JJ, Seager S. Venus' Atmospheric Chemistry and Cloud Characteristics Are Compatible with Venusian Life. ASTROBIOLOGY 2024; 24:371-385. [PMID: 37306952 DOI: 10.1089/ast.2022.0113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Venus is Earth's sister planet, with similar mass and density but an uninhabitably hot surface, an atmosphere with a water activity 50-100 times lower than anywhere on Earths' surface, and clouds believed to be made of concentrated sulfuric acid. These features have been taken to imply that the chances of finding life on Venus are vanishingly small, with several authors describing Venus' clouds as "uninhabitable," and that apparent signs of life there must therefore be abiotic, or artefactual. In this article, we argue that although many features of Venus can rule out the possibility that Earth life could live there, none rule out the possibility of all life based on what we know of the physical principle of life on Earth. Specifically, there is abundant energy, the energy requirements for retaining water and capturing hydrogen atoms to build biomass are not excessive, defenses against sulfuric acid are conceivable and have terrestrial precedent, and the speculative possibility that life uses concentrated sulfuric acid as a solvent instead of water remains. Metals are likely to be available in limited supply, and the radiation environment is benign. The clouds can support a biomass that could readily be detectable by future astrobiology-focused space missions from its impact on the atmosphere. Although we consider the prospects for finding life on Venus to be speculative, they are not absent. The scientific reward from finding life in such an un-Earthlike environment justifies considering how observations and missions should be designed to be capable of detecting life if it is there.
Collapse
Affiliation(s)
- William Bains
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
| | - Janusz J Petkowski
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- JJ Scientific, Warsaw, Poland
| | - Sara Seager
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| |
Collapse
|
3
|
Palberg D, Kaszecki E, Dhanjal C, Kisiała A, Morrison EN, Stock N, Emery RJN. Impact of glyphosate and glyphosate-based herbicides on phyllospheric Methylobacterium. BMC PLANT BIOLOGY 2024; 24:119. [PMID: 38369476 PMCID: PMC10875822 DOI: 10.1186/s12870-024-04818-x] [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: 10/08/2023] [Accepted: 02/12/2024] [Indexed: 02/20/2024]
Abstract
Symbiotic Methylobacterium comprise a significant portion of the phyllospheric microbiome, and are known to benefit host plant growth, development, and confer tolerance to stress factors. The near ubiquitous use of the broad-spectrum herbicide, glyphosate, in farming operations globally has necessitated a more expansive evaluation of the impacts of the agent itself and formulations containing glyphosate on important components of the plant phyllosphere, including Methylobacterium.This study provides an investigation of the sensitivity of 18 strains of Methylobacterium to glyphosate and two commercially available glyphosate-based herbicides (GBH). Nearly all strains of Methylobacterium showed signs of sensitivity to the popular GBH formulations WeatherMax® and Transorb® in a modified Kirby Bauer experiment. However, exposure to pure forms of glyphosate did not show a significant effect on growth for any strain in both the Kirby Bauer test and in liquid broth, until polysorbate-20 (Tween20) was added as a surfactant. Artificially increasing membrane permeability through the introduction of polysorbate-20 caused a 78-84% reduction in bacterial cell biomass relative to controls containing glyphosate or high levels of surfactant only (0-9% and 6-37% reduction respectively). Concentrations of glyphosate as low as 0.05% w/v (500 µg/L) from both commercial formulations tested, inhibited the culturability of Methylobacterium on fresh nutrient-rich medium.To better understand the compatibility of important phyllospheric bacteria with commercial glyphosate-based herbicides, this study endeavours to characterize sensitivity in multiple strains of Methylobacterium, and explore possible mechanisms by which toxicity may be induced.
Collapse
Affiliation(s)
- Daniel Palberg
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Emma Kaszecki
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Chetan Dhanjal
- Department of Biological Sciences, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA, 15213, USA
| | - Anna Kisiała
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Erin N Morrison
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Naomi Stock
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
- Water Quality Centre, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - R J Neil Emery
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada.
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada.
| |
Collapse
|
4
|
Tinguely C, Paulméry M, Terrettaz C, Gonzalez D. Diurnal cycles drive rhythmic physiology and promote survival in facultative phototrophic bacteria. ISME COMMUNICATIONS 2023; 3:125. [PMID: 38001234 PMCID: PMC10674011 DOI: 10.1038/s43705-023-00334-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 11/02/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023]
Abstract
Bacteria have evolved many strategies to spare energy when nutrients become scarce. One widespread such strategy is facultative phototrophy, which helps heterotrophs supplement their energy supply using light. Our knowledge of the impact that such behaviors have on bacterial fitness and physiology is, however, still limited. Here, we study how a representative of the genus Porphyrobacter, in which aerobic anoxygenic phototrophy is ancestral, responds to different light regimes under nutrient limitation. We show that bacterial survival in stationary phase relies on functional reaction centers and varies depending on the light regime. Under dark-light alternance, our bacterial model presents a diphasic life history dependent on phototrophy: during dark phases, the cells inhibit DNA replication and part of the population lyses and releases nutrients, while subsequent light phases allow for the recovery and renewed growth of the surviving cells. We correlate these cyclic variations with a pervasive pattern of rhythmic transcription which reflects global changes in diurnal metabolic activity. Finally, we demonstrate that, compared to either a phototrophy mutant or a bacteriochlorophyll a overproducer, the wild type strain is better adapted to natural environments, where regular dark-light cycles are interspersed with additional accidental dark episodes. Overall, our results highlight the importance of light-induced biological rhythms in a new model of aerobic anoxygenic phototroph representative of an ecologically important group of environmental bacteria.
Collapse
Affiliation(s)
- Camille Tinguely
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Mélanie Paulméry
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Céline Terrettaz
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Diego Gonzalez
- Laboratory of Microbiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
| |
Collapse
|
5
|
Kuzyk SB, Messner K, Plouffe J, Ma X, Wiens K, Yurkov V. Diverse aerobic anoxygenic phototrophs synthesize bacteriochlorophyll in oligotrophic rather than copiotrophic conditions, suggesting ecological niche. Environ Microbiol 2023; 25:2653-2665. [PMID: 37604501 DOI: 10.1111/1462-2920.16482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 08/01/2023] [Indexed: 08/23/2023]
Abstract
While investigating aerobic anoxygenic phototrophs (AAP) from Lake Winnipeg's bacterial community, over 500 isolates were obtained. Relatives of 20 different species were examined simultaneously, identifying conditions for optimal growth or pigment production to determine features that may unify this group of phototrophs. All were distributed among assorted α-Proteobacterial families including Erythrobacteraceae, Sphingomonadaceae, Sphingosinicellaceae, Acetobacteraceae, Methylobacteriaceae, and Rhodobacteraceae. Major phenotypic characteristics matched phylogenetic association, including pigmentation, morphology, metal transformations, tolerances, lipid configurations, and enzyme activities, which distinctly separated each taxonomic family. While varying pH and temperature had a limited independent impact on pigment production, bacteriochlorophyll synthesis was distinctly promoted under low nutrient conditions, whereas copiotrophy repressed its production but enhanced carotenoid yield. New AAP diversity was also reported by revealing strains related to non-phototrophic Rubellimicrobium and Sphingorhabdus, as well as spread throughout Roseomonas, Sphingomonas, and Methylobacterium/Methylorubrum, which previously only had a few known photosynthetic members. This study exemplified the overwhelming diversity of AAP in a single aquatic environment, confirming cultivation continues to be of importance in microbial ecology to discover functionality in both new and previously reported cohorts of bacteria as specific laboratory conditions were required to promote aerobic bacteriochlorophyll production.
Collapse
Affiliation(s)
- Steven B Kuzyk
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Katia Messner
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jocelyn Plouffe
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Xiao Ma
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kaitlyn Wiens
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Vladimir Yurkov
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| |
Collapse
|
6
|
Avontuur JR, Wilken PM, Palmer M, Coetzee MPA, Stępkowski T, Venter SN, Steenkamp ET. Complex evolutionary history of photosynthesis in Bradyrhizobium. Microb Genom 2023; 9:001105. [PMID: 37676703 PMCID: PMC10569730 DOI: 10.1099/mgen.0.001105] [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: 05/16/2023] [Accepted: 08/28/2023] [Indexed: 09/08/2023] Open
Abstract
Bradyrhizobium comprises a diverse group of bacteria with various lifestyles. Although best known for their nodule-based nitrogen-fixation in symbiosis with legumes, a select group of bradyrhizobia are also capable of photosynthesis. This ability seems to be rare among rhizobia, and its origin and evolution in these bacteria remain a subject of substantial debate. Therefore, our aim here was to investigate the distribution and evolution of photosynthesis in Bradyrhizobium using comparative genomics and representative genomes from closely related taxa in the families Nitrobacteraceae, Methylobacteriaceae, Boseaceae and Paracoccaceae . We identified photosynthesis gene clusters (PGCs) in 25 genomes belonging to three different Bradyrhizobium lineages, notably the so-called Photosynthetic, B. japonicum and B. elkanii supergroups. Also, two different PGC architectures were observed. One of these, PGC1, was present in genomes from the Photosynthetic supergroup and in three genomes from a species in the B. japonicum supergroup. The second cluster, PGC2, was also present in some strains from the B. japonicum supergroup, as well as in those from the B. elkanii supergroup. PGC2 was largely syntenic to the cluster found in Rhodopseudomonas palustris and Tardiphaga . Bayesian ancestral state reconstruction unambiguously showed that the ancestor of Bradyrhizobium lacked a PGC and that it was acquired horizontally by various lineages. Maximum-likelihood phylogenetic analyses of individual photosynthesis genes also suggested multiple acquisitions through horizontal gene transfer, followed by vertical inheritance and gene losses within the different lineages. Overall, our findings add to the existing body of knowledge on Bradyrhizobium ’s evolution and provide a meaningful basis from which to explore how these PGCs and the photosynthesis itself impact the physiology and ecology of these bacteria.
Collapse
Affiliation(s)
- Juanita R. Avontuur
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - P. Markus Wilken
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Marike Palmer
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Martin P. A. Coetzee
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Tomasz Stępkowski
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Warszawa, Poland
| | - Stephanus N. Venter
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Emma T. Steenkamp
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| |
Collapse
|
7
|
Tanabe Y, Yamaguchi H, Yoshida M, Kai A, Okazaki Y. Characterization of a bloom-associated alphaproteobacterial lineage, 'Candidatus Phycosocius': insights into freshwater algal-bacterial interactions. ISME COMMUNICATIONS 2023; 3:20. [PMID: 36906708 PMCID: PMC10008586 DOI: 10.1038/s43705-023-00228-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/23/2023] [Accepted: 03/01/2023] [Indexed: 03/13/2023]
Abstract
Marine bacterial lineages associated with algal blooms, such as the Roseobacter clade, have been well characterized in ecological and genomic contexts, yet such lineages have rarely been explored in freshwater blooms. This study performed phenotypic and genomic analyses of an alphaproteobacterial lineage 'Candidatus Phycosocius' (denoted the CaP clade), one of the few lineages ubiquitously associated with freshwater algal blooms, and described a novel species: 'Ca. Phycosocius spiralis.' Phylogenomic analyses indicated that the CaP clade is a deeply branching lineage in the Caulobacterales. Pangenome analyses revealed characteristic features of the CaP clade: aerobic anoxygenic photosynthesis and essential vitamin B auxotrophy. Genome size varies widely among members of the CaP clade (2.5-3.7 Mb), likely a result of independent genome reductions at each lineage. This includes a loss of tight adherence pilus genes (tad) in 'Ca. P. spiralis' that may reflect its adoption of a unique spiral cell shape and corkscrew-like burrowing activity at the algal surface. Notably, quorum sensing (QS) proteins showed incongruent phylogenies, suggesting that horizontal transfers of QS genes and QS-involved interactions with specific algal partners might drive CaP clade diversification. This study elucidates the ecophysiology and evolution of proteobacteria associated with freshwater algal blooms.
Collapse
Affiliation(s)
- Yuuhiko Tanabe
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, 305-8506, Japan.
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan.
| | - Haruyo Yamaguchi
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, 305-8506, Japan
| | - Masaki Yoshida
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Atsushi Kai
- Algae Biomass and Energy System R&D Center, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Yusuke Okazaki
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
| |
Collapse
|
8
|
Kuzyk SB, Ma X, Yurkov V. Seasonal Dynamics of Lake Winnipeg’s Microbial Communities Reveal Aerobic Anoxygenic Phototrophic Populations Coincide with Sunlight Availability. Microorganisms 2022; 10:microorganisms10091690. [PMID: 36144291 PMCID: PMC9501198 DOI: 10.3390/microorganisms10091690] [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: 07/14/2022] [Revised: 08/12/2022] [Accepted: 08/19/2022] [Indexed: 11/30/2022] Open
Abstract
In this first comprehensive study of Lake Winnipeg’s microbial communities, limnetic and littoral euphotic zones were examined during each season from 2016 through 2020. Classical cultivation and modern high-throughput sequencing techniques provided quantification and identification of key phototrophic populations, including aerobic anoxygenic phototrophs (AAP). Annual dynamics found total heterotrophs reached 4.23 × 106 CFU/g in littoral sands, and 7.69 × 104 CFU/mL in summer littoral waters on oligotrophic media, higher counts than for copiotrophic compositions. Limnetic numbers inversely dipped to 4.34 × 103 CFU/mL midsummer. Cultured AAP did not follow heterotrophic trends, instead peaking during the spring in both littoral and limnetic waters as 19.1 and 4.7% of total copiotrophs, or 3.9 and 4.9% of oligotrophs, decreasing till autumn each year. Complementary observations came from environmental 16S V4 rRNA gene analysis, as AAP made up 1.49 and 1.02% of the littoral and limnetic sequenced communities in the spring, declining with seasonal progression. Spatial and temporal fluctuations of microbes compared to environmental factors exposed photosynthetic populations to independently and regularly fluctuate in the ecosystem. Oxygenic phototrophic numbers expectantly matched the midsummer peak of Chl a and b, oxygenic photosynthesis related carbon fixation, and water temperature. Independently, AAP particularly colonized spring littoral areas more than limnetic, and directly corresponded to habitat conditions that specifically promoted growth: the requirement of light and organic material.
Collapse
|
9
|
Leducq JB, Sneddon D, Santos M, Condrain-Morel D, Bourret G, Cecilia Martinez-Gomez N, Lee JA, Foster JA, Stolyar S, Jesse Shapiro B, Kembel SW, Sullivan JM, Marx CJ. Comprehensive phylogenomics of Methylobacterium reveals four evolutionary distinct groups and underappreciated phyllosphere diversity. Genome Biol Evol 2022; 14:6652236. [PMID: 35906926 PMCID: PMC9364378 DOI: 10.1093/gbe/evac123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Methylobacterium is a group of methylotrophic microbes associated with soil, fresh water, and particularly the phyllosphere, the aerial part of plants that has been well-studied in terms of physiology but whose evolutionary history and taxonomy are unclear. Recent work has suggested that Methylobacterium is much more diverse than thought previously, questioning its status as an ecologically and phylogenetically coherent taxonomic genus. However, taxonomic and evolutionary studies of Methylobacterium have mostly been restricted to model species, often isolated from habitats other than the phyllosphere, and have yet to utilize comprehensive phylogenomic methods to examine gene trees, gene content, or synteny. By analyzing 189 Methylobacterium genomes from a wide range of habitats, including the phyllosphere, we inferred a robust phylogenetic tree while explicitly accounting for the impact of horizontal gene transfer. We showed that Methylobacterium contains four evolutionarily distinct groups of bacteria (namely A, B, C, D), characterized by different genome size, GC content, gene content and genome architecture, revealing the dynamic nature of Methylobacterium genomes. In addition to recovering 59 described species, we identified 45 candidate species, mostly phyllosphere-associated, stressing the significance of plants as a reservoir of Methylobacterium diversity. We inferred an ancient transition from a free-living lifestyle to association with plant roots in Methylobacteriaceae ancestor, followed by phyllosphere association of three of the major groups (A, B, D), whose early branching in Methylobacterium history has been heavily obscured by HGT. Together, our work lays the foundations for a thorough redefinition of Methylobacterium taxonomy, beginning with the abandonment of Methylorubrum.
Collapse
Affiliation(s)
- Jean-Baptiste Leducq
- Université Laval - Quebec City (QC) Canada.,University of Idaho - Moscow (ID) US
| | | | | | | | | | | | | | | | | | - B Jesse Shapiro
- Université de Montréal - Montreal (QC) Canada.,McGill University - Montreal (QC) Canada
| | | | | | | |
Collapse
|
10
|
Zeng Y, Nupur, Wu N, Madsen AM, Chen X, Gardiner AT, Koblížek M. Gemmatimonas groenlandica sp. nov. Is an Aerobic Anoxygenic Phototroph in the Phylum Gemmatimonadetes. Front Microbiol 2021; 11:606612. [PMID: 33519753 PMCID: PMC7844134 DOI: 10.3389/fmicb.2020.606612] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/08/2020] [Indexed: 12/18/2022] Open
Abstract
The bacterial phylum Gemmatimonadetes contains members capable of performing bacteriochlorophyll-based phototrophy (chlorophototrophy). However, only one strain of chlorophototrophic Gemmatimonadetes bacteria (CGB) has been isolated to date, hampering our further understanding of their photoheterotrophic lifestyle and the evolution of phototrophy in CGB. By combining a culturomics strategy with a rapid screening technique for chlorophototrophs, we report the isolation of a new member of CGB, Gemmatimonas (G.) groenlandica sp. nov., from the surface water of a stream in the Zackenberg Valley in High Arctic Greenland. Distinct from the microaerophilic G. phototrophica strain AP64T, G. groenlandica strain TET16T is a strictly aerobic anoxygenic phototroph, lacking many oxygen-independent enzymes while possessing an expanded arsenal for coping with oxidative stresses. Its pigment composition and infra-red absorption properties are also different from G. phototrophica, indicating that it possesses a different photosystem apparatus. The complete genome sequence of G. groenlandica reveals unique and conserved features in the photosynthesis gene clusters of CGB. We further analyzed metagenome-assembled genomes of CGB obtained from soil and glacier metagenomes from Northeast Greenland, revealing a wide distribution pattern of CGB beyond the stream water investigated.
Collapse
Affiliation(s)
- Yonghui Zeng
- Department of Environmental Science, Aarhus University, Roskilde, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
| | - Nupur
- Centre Algatech, Institute of Microbiology CAS, Třeboň, Czechia
| | - Naicheng Wu
- Department of Geography and Spatial Information Techniques, Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo, China
| | - Anne Mette Madsen
- The National Research Centre for the Working Environment, Copenhagen, Denmark
| | - Xihan Chen
- Department of Engineering, Aarhus University, Aarhus, Denmark
| | | | - Michal Koblížek
- Centre Algatech, Institute of Microbiology CAS, Třeboň, Czechia
| |
Collapse
|
11
|
Consiglieri E, Xu QZ, Zhao KH, Gärtner W, Losi A. The first molecular characterisation of blue- and red-light photoreceptors from Methylobacterium radiotolerans. Phys Chem Chem Phys 2020; 22:12434-12446. [PMID: 32458860 DOI: 10.1039/d0cp02014a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Methylobacteria are facultative methylotrophic phytosymbionts of great industrial and agronomical interest, and they are considered as opportunistic pathogens posing a health threat to humans. So far only a few reports mention photoreceptor coding sequences in Methylobacteria genomes, but no investigation at the molecular level has been performed yet. We here present comprehensive in silico research into potential photoreceptors in this bacterial phylum and report the photophysical and photochemical characterisation of two representatives of the most widespread photoreceptor classes, a blue-light sensing LOV (light, oxygen, voltage) protein and a red/far red light sensing BphP (biliverdin-binding bacterial phytochrome) from M. radiotolerans JCM 2831. Overall, both proteins undergo the expected light-triggered reactions, but peculiar features were also identified. The LOV protein Mr4511 has an extremely long photocycle and lacks a tryptophan conserved in ca. 75% of LOV domains. Mutation I37V accelerates the photocycle by one order of magnitude, while the Q112W change underscores the ability of tryptophan in this position to perform efficient energy transfer to the flavin chromophore. Time-resolved photoacoustic experiments showed that Mr4511 has a higher triplet quantum yield than other LOV domains and that the formation of the photoproduct results in a volume expansion, in sharp contrast to other LOV proteins. Mr4511 was found to be astonishingly resistant to denaturation by urea, still showing light-triggered reactions after incubation in urea for more than 20 h. The phytochrome MrBphP1 exhibits the so far most red-shifted absorption maxima for its Pr- and Pfr forms (λmax = 707 nm and 764 nm for the Pr and Pfr forms). The light-driven conversions in both directions occur with relatively high quantum yields of 0.2. Transient ns absorption spectroscopy (μs-ms time range) identifies the decay of the instantaneously formed lumi-intermediate, followed by only one additional intermediate before the formation of the respective final photoproducts for Pr-to-Pfr or Pfr-to-Pr photoconversion, in contrast to other BphPs. The relatively simple photoconversion patterns suggest the absence of the shunt pathways reported for other bacterial phytochromes.
Collapse
Affiliation(s)
- Eleonora Consiglieri
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy.
| | - Qian-Zhao Xu
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany and State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Kai-Hong Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Wolfgang Gärtner
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany
| | - Aba Losi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy.
| |
Collapse
|
12
|
The effect of wheat seedling density on photosynthesis may be associated with the phyllosphere microorganisms. Appl Microbiol Biotechnol 2020; 104:10265-10277. [PMID: 33026496 DOI: 10.1007/s00253-020-10934-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/18/2020] [Accepted: 09/23/2020] [Indexed: 10/23/2022]
Abstract
Wheat seedlings are significantly impacted by the presence of bacteria. However, bacteria are unavoidably growing together with wheat. The study aimed to reveal wheat photosynthesis, phyllosphere bacterial community composition, and a shift in the bacterial community following different density treatments in a closed artificial ecosystem. Here, we report the relationship between photosynthesis and bacterial community in wheat seedlings for different planting densities. In this closed artificial ecosystem, a total of 30 phyla were detected, with 17 of them were simultaneously present in four treatments, under high light intensity and carbon dioxide growth environment. The key phyla detected include Firmicutes, Proteobacteria, and Bacteroidetes. We found that planting densities significantly impacted the photosynthetic characteristics of wheat and bacterial genetic biodiversity, but not on species composition of the bacterial community. Network analysis shows that the phyllosphere bacteria network structures were characterized by the clustering coefficient and modularity. Network for the 1000 plants/m2 treatment group exhibits the highest levels of average clustering coefficient but lowest modularity and number of modules, among all plant densities tested. In addition, the network for the 1200 plants/m2 treatment group exhibits the best characteristics in terms of net photosynthesis rate and intrinsic water use efficiency, higher complex phyllosphere community network structures, higher abundance of Corynebacterium, and more function of "Amino acid metabolism", which encourages the plants to grow better. The findings presented in this work elucidated the role of plant density in the growth of phyllosphere bacteria during wheat seedlings and provided theoretical support for reasonable wheat density cultivation in closed artificial ecosystems and wheat field production.
Collapse
|
13
|
Baldi P, La Porta N. Molecular Approaches for Low-Cost Point-of-Care Pathogen Detection in Agriculture and Forestry. FRONTIERS IN PLANT SCIENCE 2020; 11:570862. [PMID: 33193502 PMCID: PMC7655913 DOI: 10.3389/fpls.2020.570862] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/29/2020] [Indexed: 05/14/2023]
Abstract
Early detection of plant diseases is a crucial factor to prevent or limit the spread of a rising infection that could cause significant economic loss. Detection test on plant diseases in the laboratory can be laborious, time consuming, expensive, and normally requires specific technical expertise. Moreover, in the developing countries, it is often difficult to find laboratories equipped for this kind of analysis. Therefore, in the past years, a high effort has been made for the development of fast, specific, sensitive, and cost-effective tests that can be successfully used in plant pathology directly in the field by low-specialized personnel using minimal equipment. Nucleic acid-based methods have proven to be a good choice for the development of detection tools in several fields, such as human/animal health, food safety, and water analysis, and their application in plant pathogen detection is becoming more and more common. In the present review, the more recent nucleic acid-based protocols for point-of-care (POC) plant pathogen detection and identification are described and analyzed. All these methods have a high potential for early detection of destructive diseases in agriculture and forestry, they should help make molecular detection for plant pathogens accessible to anyone, anywhere, and at any time. We do not suggest that on-site methods should replace lab testing completely, which remains crucial for more complex researches, such as identification and classification of new pathogens or the study of plant defense mechanisms. Instead, POC analysis can provide a useful, fast, and efficient preliminary on-site screening that is crucial in the struggle against plant pathogens.
Collapse
Affiliation(s)
- Paolo Baldi
- IASMA Research and Innovation Centre, Fondazione Edmund Mach, Trento, Italy
- *Correspondence: Paolo Baldi,
| | - Nicola La Porta
- IASMA Research and Innovation Centre, Fondazione Edmund Mach, Trento, Italy
- The EFI Project Centre on Mountain Forests (MOUNTFOR), San Michele a/Adige, Trento, Italy
| |
Collapse
|