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Schlechter RO, Marti E, Remus-Emsermann MNP, Drissner D, Gekenidis MT. Correlation of in vitro biofilm formation capacity with persistence of antibiotic-resistant Escherichia coli on gnotobiotic lamb's lettuce. Appl Environ Microbiol 2025; 91:e0029925. [PMID: 40293242 DOI: 10.1128/aem.00299-25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2025] [Accepted: 03/31/2025] [Indexed: 04/30/2025] Open
Abstract
Bacterial contamination of fresh produce is a growing concern for food safety, as apart from human pathogens, antibiotic-resistant bacteria (ARB) can persist on fresh leafy produce. A prominent persistence trait in bacteria is biofilm formation, as it provides increased tolerance to stressful conditions. We screened a comprehensive collection of 174 antibiotic-susceptible and -resistant Escherichia coli originating from fresh leafy produce and its production environment. We tested the ability of these strains to produce biofilms, ranging from none or weak to extreme biofilm-forming bacteria. Next, we tested the ability of selected antibiotic-resistant isolates to colonize gnotobiotic lamb's lettuce (Valerianella locusta) plants. We hypothesized that a higher in vitro biofilm formation capacity correlates with increased colonization of gnotobiotic plant leaves. Despite a marked difference in the ability to form in vitro biofilms for a number of E. coli strains, in vitro biofilm formation was not associated with increased survival on gnotobiotic V. locusta leaf surfaces. However, all tested strains persisted for at least 21 days, highlighting potential food safety risks through unwanted ingestion of resistant bacteria. Population densities of biofilm-forming E. coli exhibited a complex pattern, with subpopulations more successful in colonizing gnotobiotic V. locusta leaves. These findings emphasize the complex behavior of ARB on leaf surfaces and their implications for human safety.IMPORTANCEEach raw food contains a collection of microorganisms, including bacteria. This is of special importance for fresh produce such as leafy salads or herbs, as these foods are usually consumed raw or after minimal processing, whereby higher loads of living bacteria are ingested than with a food that is heated before consumption. A common bacterial lifestyle involves living in large groups embedded in secreted protective substances. Such bacterial assemblies, so-called biofilms, confer high persistence and resistance of bacteria to external harsh conditions. In our research, we investigated whether stronger in vitro biofilm formation by antibiotic-resistant Escherichia coli correlates with better survival on lamb's lettuce leaves. Although no clear correlation was observed between biofilm formation capacity and population density on the salad, all tested isolates could survive for at least 3 weeks with no significant decline over time, highlighting a potential food safety risk independently of in vitro biofilm formation.
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Affiliation(s)
- Rudolf O Schlechter
- Institute of Microbiology, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Elisabet Marti
- Research Group Microbiological Food Safety, Agroscope, Bern, Switzerland
| | - Mitja N P Remus-Emsermann
- Institute of Microbiology, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - David Drissner
- Department of Life Sciences, Albstadt-Sigmaringen University, Sigmaringen, Germany
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Manninen J, Saarenpää M, Roslund M, Galitskaya P, Sinkkonen A. Microbial communities on dry natural rocks are richer and less stressed than those on man-made playgrounds. Microbiol Spectr 2025; 13:e0193024. [PMID: 40202313 PMCID: PMC12054085 DOI: 10.1128/spectrum.01930-24] [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: 08/12/2024] [Accepted: 03/11/2025] [Indexed: 04/10/2025] Open
Abstract
In modern urbanized societies, the incidence of major immune-mediated diseases is several times higher than before World War II. A potential explanation is that these diseases are triggered by limited possibilities to be exposed to rich environmental microbiota. This requires that the urban environment hosts less and poorer microbiota than the natural environment. The current study was designed to test the assumption that urban man-made environments host less and poorer environmental microbiota, compared to natural habitats. We selected two types of dry environments, natural rocks and playground rubber mats, both of which were used daily and extensively by children. In quantitative PCR and next-generation sequencing, bacterial abundance and richness were higher on the natural rocks than the rubber mats. Altogether, 67 amplicon sequence variants (ASVs) belonging mostly to Actinobacteria and Proteobacteria were indicative of rock microbiota, while three ASVs were indicative of rubber mats. Interestingly, bacteria formed more complex networks on rubber mats than natural rocks. Based on the literature, this indicates that the studied artificial dry environment is more challenging and stressful for bacterial communities than dry natural rocks. The results support the hypothesis that urban man-made environments host poor microbial communities, which is in accordance with the biodiversity hypothesis of immune-mediated diseases.IMPORTANCEThe current study provides new evidence that artificial urban play environments host poor microbial communities and provide a stressful environment for microbes, as compared to dry natural rocks. Through this, the current study underlines the need to enhance microbial diversity in urban areas, especially in outdoor play environments, which have a crucial role in providing essential microbial exposure for the development of children's immune system. This research can potentially offer guidance for urban planning and public health strategies that support planetary health.
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Affiliation(s)
- J. Manninen
- Faculty of Biological and Environmental Sciences, Ecosystems and Environment Research programme, University of Helsinki, Helsinki, Finland
| | - M. Saarenpää
- Faculty of Biological and Environmental Sciences, Ecosystems and Environment Research programme, University of Helsinki, Helsinki, Finland
| | - M. Roslund
- Natural Resources Institute Finland Luke, Helsinki, Finland
| | - P. Galitskaya
- Research Institute for Environmental Studies, Parede, Portugal
| | - A. Sinkkonen
- Natural Resources Institute Finland Luke, Helsinki, Finland
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3
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Cowles KN, Iyer AS, McConnell I, Guillemette EG, Nellore D, Zaacks SC, Barak JD. Established Pseudomonas syringae pv. tomato infection disrupts immigration of leaf surface bacteria to the apoplast. Front Microbiol 2025; 16:1546411. [PMID: 39963495 PMCID: PMC11830748 DOI: 10.3389/fmicb.2025.1546411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2024] [Accepted: 01/21/2025] [Indexed: 02/20/2025] Open
Abstract
Bacterial disease alters the infection court creating new niches. The apoplast is an oasis from the hardships of the leaf surface and is generally inaccessible to nonpathogenic members of the phyllosphere bacterial community. Previously, we demonstrated that Salmonella enterica serovar Typhimurium (S. Typhimurium) immigrants to the leaf surface can both enter the apoplast and replicate due to conditions created by an established Xanthomonas hortorum pv. gardneri (Xhg) infection in tomato. Here, we have expanded our investigation of how infection changes the host by examining the effects of another water-soaking pathogen, Pseudomonas syringae pv. tomato (Pst), on immigrating bacteria. We discovered that, despite causing macroscopically similar symptoms as Xhg, Pst infection disrupts S. Typhimurium colonization of the apoplast. To determine if these effects were broadly applicable to phyllosphere bacteria, we examined the fates of immigrant Xhg and Pst arriving on an infected leaf. We found that this effect is not specific to S. Typhimurium, but that immigrating Xhg or Pst also struggled to fully join the infecting Pst population established in the apoplast. To identify the mechanisms underlying these results, we quantified macroscopic infection symptoms, examined stomata as a pinch point of bacterial entry, and characterized aspects of interbacterial competition. While it may be considered common knowledge that hosts are fundamentally altered following infection, the mechanisms that drive these changes remain poorly understood. Here, we investigated these pathogens to reach a deeper understanding of how infection alters a host from a rarely accessible, inhabitable environment to an obtainable, habitable niche.
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Affiliation(s)
- Kimberly N. Cowles
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Arjun S. Iyer
- Data Science Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Iain McConnell
- Data Science Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Ellie G. Guillemette
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Dharshita Nellore
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Sonia C. Zaacks
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jeri D. Barak
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
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Schlechter RO, Remus‐Emsermann MNP. Differential Responses of Methylobacterium and Sphingomonas Species to Multispecies Interactions in the Phyllosphere. Environ Microbiol 2025; 27:e70025. [PMID: 39792582 PMCID: PMC11722692 DOI: 10.1111/1462-2920.70025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Revised: 11/06/2024] [Accepted: 11/29/2024] [Indexed: 01/12/2025]
Abstract
The leaf surface, known as the phylloplane, presents an oligotrophic and heterogeneous environment due to its topography and uneven distribution of resources. Although it is a challenging environment, leaves support abundant bacterial communities that are spatially structured. However, the factors influencing these spatial distribution patterns are not well understood. To study the changes in population density and spatial distribution of bacteria in synthetic communities, the behaviour of two common bacterial groups in the Arabidopsis thaliana leaf microbiota-Methylobacterium (methylobacteria) and Sphingomonas (sphingomonads)-was examined. Using synthetic communities consisting of two or three species, the hypothesis was tested that the presence of a third species affects the density and spatial interaction of the other two species. Results indicated that methylobacteria exhibit greater sensitivity to changes in population densities and spatial patterns, with higher intra-genus competition and lower densities and aggregation compared to sphingomonads. Pairwise comparisons were insufficient to explain the shifts observed in three-species communities, suggesting that higher-order interactions influence the structuring of complex communities. This emphasises the role of multispecies interactions in determining spatial patterns and community dynamics on the phylloplane.
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Affiliation(s)
- R. O. Schlechter
- Institute of Microbiology and Dahlem Centre of Plant Sciences, Department of Biology, Chemistry, PharmacyFreie Universität BerlinBerlinGermany
- School of Biological Sciences and Biomolecular Interaction Centre and Bioprotection Research CoreUniversity of CanterburyChristchurchNew Zealand
| | - M. N. P. Remus‐Emsermann
- Institute of Microbiology and Dahlem Centre of Plant Sciences, Department of Biology, Chemistry, PharmacyFreie Universität BerlinBerlinGermany
- School of Biological Sciences and Biomolecular Interaction Centre and Bioprotection Research CoreUniversity of CanterburyChristchurchNew Zealand
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5
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Idris AL, Fan X, Li W, Pei H, Muhammad MH, Guan X, Huang T. Galactose-1-phosphate uridylyltransferase GalT promotes biofilm formation and enhances UV-B resistance of Bacillus thuringiensis. World J Microbiol Biotechnol 2024; 40:383. [PMID: 39551829 DOI: 10.1007/s11274-024-04195-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/06/2024] [Indexed: 11/19/2024]
Abstract
Ultraviolet radiation (UV) is a major abiotic stress resulting in relative short duration of Bacillus thuringiensis (Bt) biopesticides in the field, which is expected to be solved by formation of Bt biofilm with higher UV resistance. Therefore, one of the important prerequisite works is to clarify the functions of biofilm-associated genes on biofilm formation and UV resistance of Bt. In this study, comparative genomics and bioinformatic analysis indicated that BTXL6_19475 gene involved in biofilm formation of Bt XL6 was likely to encode a galactose-1-phosphate uridylyltransferase (GalT, E.C. 2.7.7.12). Heterologous expression of the BTXL6_19475 gene in Escherichia coli and detection of its GalT enzyme activity in vitro proved that the gene did encode GalT. Comparing the wild type Bt strain XL6 with galT gene knockout mutant Bt XL6ΔgalT and its complementary strain Bt XL6ΔgalT::19,475, GalT promoted the biofilm formation and enhanced the UV-B resistance of Bt XL6 likely by increasing its D-ribose production and reducing its alanine aryldamidase activity. GalT did not affect the growth and the cell motility of Bt XL6. A regulation map had been proposed to elucidate how GalT promoted biofilm formation and enhanced UV-B resistance of Bt XL6 by the cross-talk between Leloir pathway, Embden-Meyerhof glycolysis pathway and pentose phosphate pathway. Our finding provides a theoretical basis for the efficient use of biofilm genes to improve the UV resistance of Bt biofilms and thus extend field duration of Bt formulations based on biofilm engineering.
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Affiliation(s)
- Aisha Lawan Idris
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Biopesticide Research Center, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xiao Fan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Biopesticide Research Center, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wen Li
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Biopesticide Research Center, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Hankun Pei
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Biopesticide Research Center, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Musa Hassan Muhammad
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Biopesticide Research Center, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xiong Guan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Biopesticide Research Center, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Tianpei Huang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Biopesticide Research Center, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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Sreepadmanabh M, Ganesh M, Sanjenbam P, Kurzthaler C, Agashe D, Bhattacharjee T. Cell shape affects bacterial colony growth under physical confinement. Nat Commun 2024; 15:9561. [PMID: 39516204 PMCID: PMC11549454 DOI: 10.1038/s41467-024-53989-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 10/28/2024] [Indexed: 11/16/2024] Open
Abstract
Evidence from homogeneous liquid or flat-plate cultures indicates that biochemical cues are the primary modes of bacterial interaction with their microenvironment. However, these systems fail to capture the effect of physical confinement on bacteria in their natural habitats. Bacterial niches like the pores of soil, mucus, and infected tissues are disordered microenvironments with material properties defined by their internal pore sizes and shear moduli. Here, we use three-dimensional matrices that match the viscoelastic properties of gut mucus to test how altering the physical properties of their microenvironment influences the growth of bacteria under confinement. We find that low aspect ratio (spherical) bacteria form compact, spherical colonies under confinement while high aspect ratio (rod-shaped) bacteria push their progenies further outwards to create elongated colonies with a higher surface area, enabling increased access to nutrients. As a result, the population growth of high aspect ratio bacteria is, under the tested conditions, more robust to increased physical confinement compared to that of low aspect ratio bacteria. Thus, our experimental evidence supports that environmental physical constraints can play a selective role in bacterial growth based on cell shape.
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Affiliation(s)
- M Sreepadmanabh
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Meenakshi Ganesh
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
- Indian Institute of Science Education and Research, Mohali, India
| | - Pratibha Sanjenbam
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Christina Kurzthaler
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
- Physics of Life, TU Dresden, Dresden, Germany
| | - Deepa Agashe
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Tapomoy Bhattacharjee
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India.
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7
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Maguvu TE, Frias RJ, Hernandez-Rosas AI, Shipley E, Dardani G, Nouri MT, Yaghmour MA, Trouillas FP. Pathogenicity, phylogenomic, and comparative genomic study of Pseudomonas syringae sensu lato affecting sweet cherry in California. Microbiol Spectr 2024; 12:e0132424. [PMID: 39225473 PMCID: PMC11448091 DOI: 10.1128/spectrum.01324-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 07/13/2024] [Indexed: 09/04/2024] Open
Abstract
To gain insights into the diversity of Pseudomonas syringae sensu lato affecting sweet cherry in California, we sequenced and analyzed the phylogenomic and genomic architecture of 86 fluorescent pseudomonads isolated from symptomatic and asymptomatic cherry tissues. Fifty-eight isolates were phylogenetically placed within the P. syringae species complex and taxonomically classified into five genomospecies: P. syringae pv. syringae, P. syringae, Pseudomonas cerasi, Pseudomonas viridiflava, and A. We annotated components of the type III secretion system and phytotoxin-encoding genes and correlated the data with pathogenicity phenotypes. Intact probable regulatory protein HrpR was annotated in the genomic sequences of all isolates of P. syringae pv. syringae, P. syringae, P. cerasi, and A. Isolates of P. viridiflava had atypical probable regulatory protein HrpR. Syringomycin and syringopeptin-encoding genes were annotated in isolates of all genomospecies except for A and P. viridiflava. All isolates of P. syringae pv. syringae caused cankers, leaf spots, and fruit lesions in the field. In contrast, all isolates of P. syringae and P. cerasi and some isolates of P. viridiflava caused only cankers. Isolates of genomospecies A could not cause any symptoms suggesting phytotoxins are essential for pathogenicity. On detached immature cherry fruit pathogenicity assays, isolates of all five genomospecies produced symptoms (black-dark brown lesions). However, symptoms of isolates of genomospecies A were significantly (P < 0.01) less severe than those of other genomospecies. We also mined for genes conferring resistance to copper and kasugamycin and correlated these data with in vitro antibiotic sensitivity tests. IMPORTANCE Comprehensive identification of phytopathogens and an in-depth understanding of their genomic architecture, particularly virulence determinants and antibiotic-resistant genes, are critical for several practical reasons. These include disease diagnosis, improved knowledge of disease epidemiology, pathogen diversity, and determination of the best possible management strategies. In this study, we provide the first report of the presence and pathogenicity of genomospecies Pseudomonas cerasi and Pseudomonas viridiflava in California sweet cherry. More importantly, we report a relatively high level of resistance to copper among the population of Pseudomonas syringae pv. syringae (47.5%). This implies copper cannot be effectively used to control bacterial blast and bacterial canker of sweet cherries. On the other hand, no isolates were resistant to kasugamycin, an indication that kasugamycin could be effectively used for the control of bacterial blast and bacterial canker. Our findings are important to improve the management of bacterial blast and bacterial canker of sweet cherries in California.
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Affiliation(s)
- Tawanda E. Maguvu
- Department of Plant Pathology, University of California, Davis, California, USA
- Department of Plant Pathology, Kearney Agricultural Research and Extension Center, Parlier, California, USA
| | - Rosa J. Frias
- Department of Plant Pathology, University of California, Davis, California, USA
| | | | - Erin Shipley
- Department of Plant Pathology, Kearney Agricultural Research and Extension Center, Parlier, California, USA
| | - Greta Dardani
- Department of Plant Pathology, Kearney Agricultural Research and Extension Center, Parlier, California, USA
- Department of Agricultural, Forest and Food Science, University of Torino, Torino, Italy
| | - Mohamed T. Nouri
- Department of Plant Pathology, University of California Cooperative Extension, San Joaquin County, Stockton, California, USA
| | - Mohammad A. Yaghmour
- University of California Cooperative Extension, Kern County, Bakersfield, California, USA
| | - Florent P. Trouillas
- Department of Plant Pathology, University of California, Davis, California, USA
- Department of Plant Pathology, Kearney Agricultural Research and Extension Center, Parlier, California, USA
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8
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Thomas G, Kay WT, Fones HN. Life on a leaf: the epiphyte to pathogen continuum and interplay in the phyllosphere. BMC Biol 2024; 22:168. [PMID: 39113027 PMCID: PMC11304629 DOI: 10.1186/s12915-024-01967-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 08/01/2024] [Indexed: 08/11/2024] Open
Abstract
Epiphytic microbes are those that live for some or all of their life cycle on the surface of plant leaves. Leaf surfaces are a topologically complex, physicochemically heterogeneous habitat that is home to extensive, mixed communities of resident and transient inhabitants from all three domains of life. In this review, we discuss the origins of leaf surface microbes and how different biotic and abiotic factors shape their communities. We discuss the leaf surface as a habitat and microbial adaptations which allow some species to thrive there, with particular emphasis on microbes that occupy the continuum between epiphytic specialists and phytopathogens, groups which have considerable overlap in terms of adapting to the leaf surface and between which a single virulence determinant can move a microbial strain. Finally, we discuss the recent findings that the wheat pathogenic fungus Zymoseptoria tritici spends a considerable amount of time on the leaf surface, and ask what insights other epiphytic organisms might provide into this pathogen, as well as how Z. tritici might serve as a model system for investigating plant-microbe-microbe interactions on the leaf surface.
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Affiliation(s)
| | - William T Kay
- Department of Plant Sciences, University of Oxford, Oxford, UK
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9
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Samgane G, Karaçam S, Tunçer Çağlayan S. Unveiling the synergistic potency of chlorhexidine and azithromycin in combined action. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:5975-5987. [PMID: 38376540 PMCID: PMC11329591 DOI: 10.1007/s00210-024-03010-0] [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: 08/25/2023] [Accepted: 02/12/2024] [Indexed: 02/21/2024]
Abstract
The growing challenge of antibiotic resistance necessitates novel approaches for combating bacterial infections. This study explores the distinctive synergy between chlorhexidine, an antiseptic and disinfectant agent, and azithromycin, a macrolide antibiotic, in their impact on bacterial growth and virulence factors using Escherichia coli strain Crooks (ATCC 8739) as a model. Our findings reveal that the chlorhexidine and azithromycin combination demonstrates enhanced anti-bacterial effects compared to individual treatments. Intriguingly, the combination induced oxidative stress, decreased flagellin expression, impaired bacterial motility, and enhanced bacterial autoaggregation. Notably, the combined treatment also demonstrated a substantial reduction in bacterial adherence to colon epithelial cells and downregulated NF-κB in the epithelial cells. In conclusion, these results shed light on the potential of the chlorhexidine and azithromycin synergy as a compelling strategy to address the rising challenge of antibiotic resistance and may pave the way for innovative therapeutic interventions in tackling bacterial infections.
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Affiliation(s)
- Gizem Samgane
- Department of Biotechnology, Bilecik Şeyh Edebali University, Bilecik, 11100, Turkey
| | - Sevinç Karaçam
- Department of Biotechnology, Bilecik Şeyh Edebali University, Bilecik, 11100, Turkey
- Central Research and Application Laboratory, Bilecik Şeyh Edebali University, Bilecik, 11100, Turkey
| | - Sinem Tunçer Çağlayan
- Department of Medical Services and Techniques, Vocational School of Health Services, Bilecik Şeyh Edebali University, Pelitözü Mah. Fatih Sultan Mehmet Bulvarı No:27, Bilecik, 11100, Turkey.
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10
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Wang L, Huang J, Chen S, Su X, Zhang X, Wang L, Zhang W, Wang Z, Zeng Q, Wang Q, Li Y. Endogenous cell wall degrading enzyme LytD is important for the biocontrol activity of Bacillus subtilis. FRONTIERS IN PLANT SCIENCE 2024; 15:1381018. [PMID: 38660441 PMCID: PMC11039861 DOI: 10.3389/fpls.2024.1381018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/14/2024] [Indexed: 04/26/2024]
Abstract
Autolysins are endogenous cell wall degrading enzymes (CWDEs) in bacteria that remodel the peptidoglycan layer of its own cell wall. In the Bacillus subtilis genome, at least 35 autolysin genes have been identified. However, the study of their roles in bacterial physiology has been hampered by their complexity and functional redundancy. B. subtilis GLB191 is an effective biocontrol strain against grape downy mildew disease, the biocontrol effect of which results from both direct effect against the pathogen and stimulation of the plant defense. In this study, we show that the autolysin N-acetylglucosaminidase LytD, a major autolysin of vegetative growth in B. subtilis, plays an important role in its biocontrol activity against grape downy mildew. Disruption of lytD resulted in reduced suppression of the pathogen Plasmopara viticola and stimulation of the plant defense. LytD is also shown to affect the biofilm formation and colonization of B. subtilis on grape leaves. This is the first report that demonstrates the role of an endogenous CWDE in suppressing plant disease infection of a biological control microorganism. These findings not only expand our knowledge on the biological function of autolysins but also provide a new target to promote the biocontrol activity of B. subtilis.
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Affiliation(s)
- Luotao Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jianquan Huang
- The Research Institute of Forestry and Pomology, Tianjin Academy of Agricultural Sciences, Tianjin, China
| | - Si Chen
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xin Su
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xun Zhang
- Airport Research Institute, China Academy of Civil Aviation Science and Technology, Beijing, China
| | - Lujun Wang
- Weinan Grapevine Research Institute, Weinan, China
| | - Wei Zhang
- Weinan Grapevine Research Institute, Weinan, China
| | - Zhenshuo Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qingchao Zeng
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qi Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yan Li
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
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11
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Mohaimin AZ, Krishnamoorthy S, Shivanand P. A critical review on bioaerosols-dispersal of crop pathogenic microorganisms and their impact on crop yield. Braz J Microbiol 2024; 55:587-628. [PMID: 38001398 PMCID: PMC10920616 DOI: 10.1007/s42770-023-01179-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
Bioaerosols are potential sources of pathogenic microorganisms that can cause devastating outbreaks of global crop diseases. Various microorganisms, insects and viroids are known to cause severe crop diseases impeding global agro-economy. Such losses threaten global food security, as it is estimated that almost 821 million people are underfed due to global crisis in food production. It is estimated that global population would reach 10 billion by 2050. Hence, it is imperative to substantially increase global food production to about 60% more than the existing levels. To meet the increasing demand, it is essential to control crop diseases and increase yield. Better understanding of the dispersive nature of bioaerosols, seasonal variations, regional diversity and load would enable in formulating improved strategies to control disease severity, onset and spread. Further, insights on regional and global bioaerosol composition and dissemination would help in predicting and preventing endemic and epidemic outbreaks of crop diseases. Advanced knowledge of the factors influencing disease onset and progress, mechanism of pathogen attachment and penetration, dispersal of pathogens, life cycle and the mode of infection, aid the development and implementation of species-specific and region-specific preventive strategies to control crop diseases. Intriguingly, development of R gene-mediated resistant varieties has shown promising results in controlling crop diseases. Forthcoming studies on the development of an appropriately stacked R gene with a wide range of resistance to crop diseases would enable proper management and yield. The article reviews various aspects of pathogenic bioaerosols, pathogen invasion and infestation, crop diseases and yield.
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Affiliation(s)
- Abdul Zul'Adly Mohaimin
- Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Bandar Seri Begawan, BE1410, Brunei Darussalam
| | - Sarayu Krishnamoorthy
- Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Bandar Seri Begawan, BE1410, Brunei Darussalam
| | - Pooja Shivanand
- Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Bandar Seri Begawan, BE1410, Brunei Darussalam.
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12
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Kostešić E, Mitrović M, Kajan K, Marković T, Hausmann B, Orlić S, Pjevac P. Microbial Diversity and Activity of Biofilms from Geothermal Springs in Croatia. MICROBIAL ECOLOGY 2023; 86:2305-2319. [PMID: 37209180 PMCID: PMC10640420 DOI: 10.1007/s00248-023-02239-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/07/2023] [Indexed: 05/22/2023]
Abstract
Hot spring biofilms are stable, highly complex microbial structures. They form at dynamic redox and light gradients and are composed of microorganisms adapted to the extreme temperatures and fluctuating geochemical conditions of geothermal environments. In Croatia, a large number of poorly investigated geothermal springs host biofilm communities. Here, we investigated the microbial community composition of biofilms collected over several seasons at 12 geothermal springs and wells. We found biofilm microbial communities to be temporally stable and highly dominated by Cyanobacteria in all but one high-temperature sampling site (Bizovac well). Of the physiochemical parameters recorded, temperature had the strongest influence on biofilm microbial community composition. Besides Cyanobacteria, the biofilms were mainly inhabited by Chloroflexota, Gammaproteobacteria, and Bacteroidota. In a series of incubations with Cyanobacteria-dominated biofilms from Tuhelj spring and Chloroflexota- and Pseudomonadota-dominated biofilms from Bizovac well, we stimulated either chemoorganotrophic or chemolithotrophic community members, to determine the fraction of microorganisms dependent on organic carbon (in situ predominantly produced via photosynthesis) versus energy derived from geochemical redox gradients (here simulated by addition of thiosulfate). We found surprisingly similar levels of activity in response to all substrates in these two distinct biofilm communities, and observed microbial community composition and hot spring geochemistry to be poor predictors of microbial activity in the study systems.
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Affiliation(s)
- Ema Kostešić
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Maja Mitrović
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Katarina Kajan
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
- Center of Excellence for Science and Technology-Integration of Mediterranean Region (STIM), Split, Croatia
| | | | - Bela Hausmann
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Sandi Orlić
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
- Center of Excellence for Science and Technology-Integration of Mediterranean Region (STIM), Split, Croatia
| | - Petra Pjevac
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria.
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria.
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13
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Fiegna F, Pande S, Peitz H, Velicer GJ. Widespread density dependence of bacterial growth under acid stress. iScience 2023; 26:106952. [PMID: 37332671 PMCID: PMC10275722 DOI: 10.1016/j.isci.2023.106952] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 01/27/2023] [Accepted: 05/22/2023] [Indexed: 06/20/2023] Open
Abstract
Many microbial phenotypes are density-dependent, including group-level phenotypes emerging from cooperation. However, surveys for the presence of a particular form of density dependence across diverse species are rare, as are direct tests for the Allee effect, i.e., positive density dependence of fitness. Here, we test for density-dependent growth under acid stress in five diverse bacterial species and find the Allee effect in all. Yet social protection from acid stress appears to have evolved by multiple mechanisms. In Myxococcus xanthus, a strong Allee effect is mediated by pH-regulated secretion of a diffusible molecule by high-density populations. In other species, growth from low density under acid stress was not enhanced by high-density supernatant. In M. xanthus, high cell density may promote predation on other microbes that metabolically acidify their environment, and acid-mediated density dependence may impact the evolution of fruiting-body development. More broadly, high density may protect most bacterial species against acid stress.
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Affiliation(s)
- Francesca Fiegna
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Samay Pande
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | | | - Gregory J. Velicer
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Department of Biology, Indiana University, Bloomington, IN, USA
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14
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Herpell JB, Alickovic A, Diallo B, Schindler F, Weckwerth W. Phyllosphere symbiont promotes plant growth through ACC deaminase production. THE ISME JOURNAL 2023:10.1038/s41396-023-01428-7. [PMID: 37264153 DOI: 10.1038/s41396-023-01428-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 04/24/2023] [Accepted: 04/28/2023] [Indexed: 06/03/2023]
Abstract
Plant growth promoting bacteria can confer resistance to various types of stress and increase agricultural yields. The mechanisms they employ are diverse. One of the most important genes associated with the increase in plant biomass and stress resistance is acdS, which encodes a 1-aminocyclopropane-1-carboxylate- or ACC-deaminase. The non-proteinogenic amino acid ACC is the precursor and means of long-distance transport of ethylene, a plant hormone associated with growth arrest. Expression of acdS reduces stress induced ethylene levels and the enzyme is abundant in rhizosphere colonizers. Whether ACC hydrolysis plays a role in the phyllosphere, both as assembly cue and in growth promotion, remains unclear. Here we show that Paraburkholderia dioscoreae Msb3, a yam phyllosphere symbiont, colonizes the tomato phyllosphere and promotes plant growth by action of its ACC deaminase. We found that acdS is required for improved plant growth but not for efficient leaf colonization. Strain Msb3 readily proliferates on the leaf surface of tomato, only occasionally spreading to the leaf endosphere through stomata. The strain can also colonize the soil or medium around the roots but only spreads into the root if the plant is wounded. Our results indicate that the degradation of ACC is not just an important trait of plant growth promoting rhizobacteria but also one of leaf dwelling phyllosphere bacteria. Manipulation of the leaf microbiota by means of spray inoculation may be more easily achieved than that of the soil. Therefore, the application of ACC deaminase containing bacteria to the phyllosphere may be a promising strategy to increasing plant stress resistance, pathogen control, and harvest yields.
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Affiliation(s)
- Johannes B Herpell
- Molecular Systems Biology Division, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Ajtena Alickovic
- Molecular Systems Biology Division, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Bocar Diallo
- Molecular Systems Biology Division, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Florian Schindler
- Molecular Systems Biology Division, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Wolfram Weckwerth
- Molecular Systems Biology Division, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
- Vienna Metabolomics Center, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
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15
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Amato P, Mathonat F, Nuñez Lopez L, Péguilhan R, Bourhane Z, Rossi F, Vyskocil J, Joly M, Ervens B. The aeromicrobiome: the selective and dynamic outer-layer of the Earth's microbiome. Front Microbiol 2023; 14:1186847. [PMID: 37260685 PMCID: PMC10227452 DOI: 10.3389/fmicb.2023.1186847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/24/2023] [Indexed: 06/02/2023] Open
Abstract
The atmosphere is an integral component of the Earth's microbiome. Abundance, viability, and diversity of microorganisms circulating in the air are determined by various factors including environmental physical variables and intrinsic and biological properties of microbes, all ranging over large scales. The aeromicrobiome is thus poorly understood and difficult to predict due to the high heterogeneity of the airborne microorganisms and their properties, spatially and temporally. The atmosphere acts as a highly selective dispersion means on large scales for microbial cells, exposing them to a multitude of physical and chemical atmospheric processes. We provide here a brief critical review of the current knowledge and propose future research directions aiming at improving our comprehension of the atmosphere as a biome.
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Affiliation(s)
- Pierre Amato
- Université Clermont Auvergne, CNRS, Institut de Chimie de Clermont-Ferrand (ICCF), Clermont-Ferrand, France
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16
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Cao Z, Zuo W, Wang L, Chen J, Qu Z, Jin F, Dai L. Spatial profiling of microbial communities by sequential FISH with error-robust encoding. Nat Commun 2023; 14:1477. [PMID: 36932092 PMCID: PMC10023729 DOI: 10.1038/s41467-023-37188-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 03/06/2023] [Indexed: 03/19/2023] Open
Abstract
Spatial analysis of microbiomes at single cell resolution with high multiplexity and accuracy has remained challenging. Here we present spatial profiling of a microbiome using sequential error-robust fluorescence in situ hybridization (SEER-FISH), a highly multiplexed and accurate imaging method that allows mapping of microbial communities at micron-scale. We show that multiplexity of RNA profiling in microbiomes can be increased significantly by sequential rounds of probe hybridization and dissociation. Combined with error-correction strategies, we demonstrate that SEER-FISH enables accurate taxonomic identification in complex microbial communities. Using microbial communities composed of diverse bacterial taxa isolated from plant rhizospheres, we apply SEER-FISH to quantify the abundance of each taxon and map microbial biogeography on roots. At micron-scale, we identify clustering of microbial cells from multiple species on the rhizoplane. Under treatment of plant metabolites, we find spatial re-organization of microbial colonization along the root and alterations in spatial association among microbial taxa. Taken together, SEER-FISH provides a useful method for profiling the spatial ecology of complex microbial communities in situ.
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Affiliation(s)
- Zhaohui Cao
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenlong Zuo
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Lanxiang Wang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Junyu Chen
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Zepeng Qu
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Fan Jin
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Dai
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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17
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Engelhart-Straub S, Cavelius P, Hölzl F, Haack M, Awad D, Brueck T, Mehlmer N. Effects of Light on Growth and Metabolism of Rhodococcus erythropolis. Microorganisms 2022; 10:microorganisms10081680. [PMID: 36014097 PMCID: PMC9416670 DOI: 10.3390/microorganisms10081680] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/16/2022] Open
Abstract
Rhodococcus erythropolis is resilient to various stressors. However, the response of R. erythropolis towards light has not been evaluated. In this study, R. erythropolis was exposed to different wavelengths of light. Compared to non-illuminated controls, carotenoid levels were significantly increased in white (standard warm white), green (510 nm) and blue light (470 nm) illuminated cultures. Notably, blue light (455, 425 nm) exhibited anti-microbial effects. Interestingly, cellular lipid composition shifted under light stress, increasing odd chain fatty acids (C15:0, C17:1) cultured under white (standard warm white) and green (510 nm) light. When exposed to blue light (470, 455, 425 nm), fatty acid profiles shifted to more saturated fatty acids (C16:1 to C16:0). Time-resolved proteomics analysis revealed several oxidative stress-related proteins to be upregulated under light illumination.
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18
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Dynamic character displacement among a pair of bacterial phyllosphere commensals in situ. Nat Commun 2022; 13:2836. [PMID: 35595740 PMCID: PMC9123166 DOI: 10.1038/s41467-022-30469-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 05/03/2022] [Indexed: 11/09/2022] Open
Abstract
Differences between species promote stable coexistence in a resource-limited environment. These differences can result from interspecies competition leading to character shifts, a process referred to as character displacement. While character displacement is often interpreted as a consequence of genetically fixed trait differences between species, it can also be mediated by phenotypic plasticity in response to the presence of another species. Here, we test whether phenotypic plasticity leads to a shift in proteome allocation during co-occurrence of two bacterial species from the abundant, leaf-colonizing families Sphingomonadaceae and Rhizobiaceae in their natural habitat. Upon mono-colonizing of the phyllosphere, both species exhibit specific and shared protein functions indicating a niche overlap. During co-colonization, quantitative differences in the protein repertoire of both bacterial populations occur as a result of bacterial coexistence in planta. Specifically, the Sphingomonas strain produces enzymes for the metabolization of xylan, while the Rhizobium strain reprograms its metabolism to beta-oxidation of fatty acids fueled via the glyoxylate cycle and adapts its biotin acquisition. We demonstrate the conditional relevance of cross-species facilitation by mutagenesis leading to loss of fitness in competition in planta. Our results show that dynamic character displacement and niche facilitation mediated by phenotypic plasticity can contribute to species coexistence. In this study, the concept of dynamic character displacement among interacting bacterial species from leaf-colonizing families was empirically tested using a proteomics approach. A phenotypic shift towards the utilization of alternative carbon sources was observed during coexistence, thereby minimizing niche overlap.
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19
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Fessia A, Barra P, Barros G, Nesci A. Could Bacillus biofilms enhance the effectivity of biocontrol strategies in the phyllosphere? J Appl Microbiol 2022; 133:2148-2166. [PMID: 35476896 DOI: 10.1111/jam.15596] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/13/2022] [Accepted: 04/21/2022] [Indexed: 11/30/2022]
Abstract
Maize (Zea mays L.), a major crop in Argentina and a staple food around the world, is affected by the emergence and re-emergence of foliar diseases. Agrochemicals are the main control strategy nowadays, but they can cause resistance in insects and microbial pathogens and have negative effects on the environment and human health. An emerging alternative is the use of living organisms, i.e. microbial biocontrol agents, to suppress plant pathogen populations. This is a risk-free approach when the organisms acting as biocontrol agents come from the same ecosystem as the foliar pathogens they are meant to antagonize. Some epiphytic microorganisms may form biofilm by becoming aggregated and attached to a surface, as is the case of spore-forming bacteria from the genus Bacillus. Their ability to sporulate and their tolerance to long storage periods make them a frequently used biocontrol agent. Moreover, the biofilm that they create protects them against different abiotic and biotic factors and helps them to acquire nutrients, which ensures their survival on the plants they protect. This review analyzes the interactions that the phyllosphere-inhabiting Bacillus genus establishes with its environment through biofilm, and how this lifestyle could serve to design effective biological control strategies.
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Affiliation(s)
- Aluminé Fessia
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
| | - Paula Barra
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
| | - Germán Barros
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
| | - Andrea Nesci
- Laboratorio de Ecología Microbiana, Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ruta Nacional 36, Km 601, X5804ZAB Río Cuarto, Córdoba, Argentina
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20
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Lin Y, Xu X, Maróti G, Strube ML, Kovács ÁT. Adaptation and phenotypic diversification of Bacillus thuringiensis biofilm are accompanied by fuzzy spreader morphotypes. NPJ Biofilms Microbiomes 2022; 8:27. [PMID: 35418164 PMCID: PMC9007996 DOI: 10.1038/s41522-022-00292-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 03/19/2022] [Indexed: 11/12/2022] Open
Abstract
Bacillus cereus group (Bacillus cereus sensu lato) has a diverse ecology, including various species that produce biofilms on abiotic and biotic surfaces. While genetic and morphological diversification enables the adaptation of multicellular communities, this area remains largely unknown in the Bacillus cereus group. In this work, we dissected the experimental evolution of Bacillus thuringiensis 407 Cry- during continuous recolonization of plastic beads. We observed the evolution of a distinct colony morphotype that we named fuzzy spreader (FS) variant. Most multicellular traits of the FS variant displayed higher competitive ability versus the ancestral strain, suggesting an important role for diversification in the adaptation of B. thuringiensis to the biofilm lifestyle. Further genetic characterization of FS variant revealed the disruption of a guanylyltransferase gene by an insertion sequence (IS) element, which could be similarly observed in the genome of a natural isolate. The evolved FS and the deletion mutant in the guanylyltransferase gene (Bt407ΔrfbM) displayed similarly altered aggregation and hydrophobicity compared to the ancestor strain, suggesting that the adaptation process highly depends on the physical adhesive forces.
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Affiliation(s)
- Yicen Lin
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, 2800, Lyngby, Denmark
| | - Xinming Xu
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, 2800, Lyngby, Denmark
| | - Gergely Maróti
- Institute of Plant Biology, Biological Research Center, ELKH, 6726, Szeged, Hungary
| | - Mikael Lenz Strube
- Bacterial Ecophysiology and Biotechnology Group, DTU Bioengineering, Technical University of Denmark, 2800, Lyngby, Denmark
| | - Ákos T Kovács
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, 2800, Lyngby, Denmark.
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21
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Huddling together to survive: Population density as a survival strategy of non-spore forming bacteria under nutrient starvation and desiccation at solid-air interfaces. Microbiol Res 2022; 258:126997. [DOI: 10.1016/j.micres.2022.126997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 01/16/2022] [Accepted: 02/24/2022] [Indexed: 11/19/2022]
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22
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Šantl-Temkiv T, Amato P, Casamayor EO, Lee PKH, Pointing SB. OUP accepted manuscript. FEMS Microbiol Rev 2022; 46:6524182. [PMID: 35137064 PMCID: PMC9249623 DOI: 10.1093/femsre/fuac009] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/31/2022] [Accepted: 02/06/2022] [Indexed: 11/30/2022] Open
Abstract
The atmosphere connects habitats across multiple spatial scales via airborne dispersal of microbial cells, propagules and biomolecules. Atmospheric microorganisms have been implicated in a variety of biochemical and biophysical transformations. Here, we review ecological aspects of airborne microorganisms with respect to their dispersal, activity and contribution to climatic processes. Latest studies utilizing metagenomic approaches demonstrate that airborne microbial communities exhibit pronounced biogeography, driven by a combination of biotic and abiotic factors. We quantify distributions and fluxes of microbial cells between surface habitats and the atmosphere and place special emphasis on long-range pathogen dispersal. Recent advances have established that these processes may be relevant for macroecological outcomes in terrestrial and marine habitats. We evaluate the potential biological transformation of atmospheric volatile organic compounds and other substrates by airborne microorganisms and discuss clouds as hotspots of microbial metabolic activity in the atmosphere. Furthermore, we emphasize the role of microorganisms as ice nucleating particles and their relevance for the water cycle via formation of clouds and precipitation. Finally, potential impacts of anthropogenic forcing on the natural atmospheric microbiota via emission of particulate matter, greenhouse gases and microorganisms are discussed.
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Affiliation(s)
- Tina Šantl-Temkiv
- Department of Biology, Aarhus University, DK-8000 Aarhus, Denmark
- Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus, Denmark
| | - Pierre Amato
- Institut de Chimie de Clermont-Ferrand, SIGMA Clermont, CNRS, Université Clermont Auvergne, 63178, Clermont-Ferrand, France
| | - Emilio O Casamayor
- Centre for Advanced Studies of Blanes, Spanish Council for Research (CSIC), 17300, Blanes, Spain
| | - Patrick K H Lee
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China
| | - Stephen B Pointing
- Corresponding author: Yale-NUS College, National University of Singapore, 16 College Avenue West, Singapore 138527. Tel: +65 6601 1000; E-mail:
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23
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Alsanius BW, Vaas L, Gharaie S, Karlsson ME, Rosberg AK, Wohanka W, Khalil S, Windstam S. Dining in Blue Light Impairs the Appetite of Some Leaf Epiphytes. Front Microbiol 2021; 12:725021. [PMID: 34733247 PMCID: PMC8558677 DOI: 10.3389/fmicb.2021.725021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/10/2021] [Indexed: 11/13/2022] Open
Abstract
Background: The phyllosphere is subjected to fluctuating abiotic conditions. This study examined the phenotypic plasticity (PP) of four selected non-phototrophic phyllosphere bacteria [control strain: Pseudomonas sp. DR 5-09; Pseudomonas agarici, Bacillus thuringiensis serovar israeliensis (Bti), and Streptomyces griseoviridis (SG)] regarding their respiration patterns and surfactant activity as affected by light spectrum and nutrient supply. Methods: The PP of the strains was examined under four light regimes [darkness (control); monochromatic light-emitting diodes (LED) at 460 nm (blue) and 660 nm (red); continuously polychromatic white LEDs], in the presence of 379 substrates and conditions. Results: Light treatment affected the studied bacterial strains regarding substrate utilization (Pseudomonas strains > SG > Bti). Blue LEDs provoked the most pronounced impact on the phenotypic reaction norms of the Pseudomonas strains and Bti. The two Gram-positive strains Bti and SG, respectively, revealed inconsistent biosurfactant formation in all cases. Biosurfactant formation by both Pseudomonas strains was supported by most substrates incubated in darkness, and blue LED exposure altered the surface activity profoundly. Blue and white LEDs enhanced biofilm formation in PA in highly utilized C-sources. Putative blue light receptor proteins were found in both Pseudomonas strains, showing 91% similarity with the sequence from NCBI accession number WP_064119393. Conclusion: Light quality–nutrient interactions affect biosurfactant activity and biofilm formation of some non-phototrophic phyllosphere bacteria and are, thus, crucial for dynamics of the phyllosphere microbiome.
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Affiliation(s)
- Beatrix W Alsanius
- Microbial Horticulture Unit, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Lea Vaas
- Fraunhofer IME, Computational Biology, Screening Port, Hamburg, Germany
| | - Samareh Gharaie
- Microbial Horticulture Unit, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Maria E Karlsson
- Microbial Horticulture Unit, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Anna Karin Rosberg
- Microbial Horticulture Unit, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Walter Wohanka
- Department of Phytomedicine, Geisenheim University, Geisenheim, Germany
| | - Sammar Khalil
- Microbial Horticulture Unit, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Sofia Windstam
- Microbial Horticulture Unit, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Lomma, Sweden
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24
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Lin Y, Alstrup M, Pang JKY, Maróti G, Er-Rafik M, Tourasse N, Økstad OA, Kovács ÁT. Adaptation of Bacillus thuringiensis to Plant Colonization Affects Differentiation and Toxicity. mSystems 2021; 6:e0086421. [PMID: 34636664 PMCID: PMC8510532 DOI: 10.1128/msystems.00864-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/27/2021] [Indexed: 01/11/2023] Open
Abstract
The Bacillus cereus group (Bacillus cereus sensu lato) has a diverse ecology, including various species that are vertebrate or invertebrate pathogens. Few isolates from the B. cereus group have however been demonstrated to benefit plant growth. Therefore, it is crucial to explore how bacterial development and pathogenesis evolve during plant colonization. Herein, we investigated Bacillus thuringiensis (Cry-) adaptation to the colonization of Arabidopsis thaliana roots and monitored changes in cellular differentiation in experimentally evolved isolates. Isolates from two populations displayed improved iterative ecesis on roots and increased virulence against insect larvae. Molecular dissection and recreation of a causative mutation revealed the importance of a nonsense mutation in the rho transcription terminator gene. Transcriptome analysis revealed how Rho impacts various B. thuringiensis genes involved in carbohydrate metabolism and virulence. Our work suggests that evolved multicellular aggregates have a fitness advantage over single cells when colonizing plants, creating a trade-off between swimming and multicellularity in evolved lineages, in addition to unrelated alterations in pathogenicity. IMPORTANCE Biologicals-based plant protection relies on the use of safe microbial strains. During application of biologicals to the rhizosphere, microbes adapt to the niche, including genetic mutations shaping the physiology of the cells. Here, the experimental evolution of Bacillus thuringiensis lacking the insecticide crystal toxins was examined on the plant root to reveal how adaptation shapes the differentiation of this bacterium. Interestingly, evolution of certain lineages led to increased hemolysis and insect larva pathogenesis in B. thuringiensis driven by transcriptional rewiring. Further, our detailed study reveals how inactivation of the transcription termination protein Rho promotes aggregation on the plant root in addition to altered differentiation and pathogenesis in B. thuringiensis.
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Affiliation(s)
- Yicen Lin
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Monica Alstrup
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Janet Ka Yan Pang
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Gergely Maróti
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Mériem Er-Rafik
- National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Lyngby, Denmark
| | - Nicolas Tourasse
- Université Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, Bordeaux, France
| | - Ole Andreas Økstad
- Centre for Integrative Microbial Evolution, University of Oslo, Oslo, Norway
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Ákos T. Kovács
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, Lyngby, Denmark
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25
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Dewangan NK, Tran N, Wang-Reed J, Conrad JC. Bacterial aggregation assisted by anionic surfactant and calcium ions. SOFT MATTER 2021; 17:8474-8482. [PMID: 34586147 DOI: 10.1039/d1sm00479d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We identify factors leading to aggregation of bacteria in the presence of a surfactant using absorbance and microscopy. Two marine bacteria, Marinobacter hydrocarbonoclasticus SP17 and Halomonas titanicae Bead 10BA, formed aggregates of a broad size distribution in synthetic sea water in the presence of an anionic surfactant, dioctyl sodium sulfosuccinate (DOSS). Both DOSS at high concentrations and calcium ions were necessary for aggregate formation, but DOSS micelles were not required for aggregation. Addition of proteinase K but not DNase1 eliminated aggregate formation over two hours. Finally, swimming motility also enhanced aggregate formation.
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Affiliation(s)
- Narendra K Dewangan
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, 77204-4004, USA.
| | - Nhi Tran
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, 77204-4004, USA.
| | - Jing Wang-Reed
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, 77204-4004, USA.
| | - Jacinta C Conrad
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, 77204-4004, USA.
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26
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Nadarajah K, Abdul Rahman NSN. Plant-Microbe Interaction: Aboveground to Belowground, from the Good to the Bad. Int J Mol Sci 2021; 22:ijms221910388. [PMID: 34638728 PMCID: PMC8508622 DOI: 10.3390/ijms221910388] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 02/06/2023] Open
Abstract
Soil health and fertility issues are constantly addressed in the agricultural industry. Through the continuous and prolonged use of chemical heavy agricultural systems, most agricultural lands have been impacted, resulting in plateaued or reduced productivity. As such, to invigorate the agricultural industry, we would have to resort to alternative practices that will restore soil health and fertility. Therefore, in recent decades, studies have been directed towards taking a Magellan voyage of the soil rhizosphere region, to identify the diversity, density, and microbial population structure of the soil, and predict possible ways to restore soil health. Microbes that inhabit this region possess niche functions, such as the stimulation or promotion of plant growth, disease suppression, management of toxicity, and the cycling and utilization of nutrients. Therefore, studies should be conducted to identify microbes or groups of organisms that have assigned niche functions. Based on the above, this article reviews the aboveground and below-ground microbiomes, their roles in plant immunity, physiological functions, and challenges and tools available in studying these organisms. The information collected over the years may contribute toward future applications, and in designing sustainable agriculture.
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27
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Debray R, Herbert RA, Jaffe AL, Crits-Christoph A, Power ME, Koskella B. Priority effects in microbiome assembly. Nat Rev Microbiol 2021; 20:109-121. [PMID: 34453137 DOI: 10.1038/s41579-021-00604-w] [Citation(s) in RCA: 200] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2021] [Indexed: 11/09/2022]
Abstract
Advances in next-generation sequencing have enabled the widespread measurement of microbiome composition across systems and over the course of microbiome assembly. Despite substantial progress in understanding the deterministic drivers of community composition, the role of historical contingency remains poorly understood. The establishment of new species in a community can depend on the order and/or timing of their arrival, a phenomenon known as a priority effect. Here, we review the mechanisms of priority effects and evidence for their importance in microbial communities inhabiting a range of environments, including the mammalian gut, the plant phyllosphere and rhizosphere, soil, freshwaters and oceans. We describe approaches for the direct testing and prediction of priority effects in complex microbial communities and illustrate these with re-analysis of publicly available plant and animal microbiome datasets. Finally, we discuss the shared principles that emerge across study systems, focusing on eco-evolutionary dynamics and the importance of scale. Overall, we argue that predicting when and how current community state impacts the success of newly arriving microbial taxa is crucial for the management of microbiomes to sustain ecological function and host health. We conclude by discussing outstanding conceptual and practical challenges that are faced when measuring priority effects in microbiomes.
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Affiliation(s)
- Reena Debray
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA.
| | - Robin A Herbert
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA. .,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Alexander L Jaffe
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | | | - Mary E Power
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
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28
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Leaf-FISH: In Situ Hybridization Method for Visualizing Bacterial Taxa on Plant Surfaces. Methods Mol Biol 2021. [PMID: 33576986 DOI: 10.1007/978-1-0716-1115-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
High-resolution, spatial characterization of microbial communities is critical for the accurate understanding of microbe-microbe and microbe-plant interactions in leaf surfaces (phyllosphere). However, leaves are specially challenging surfaces for imaging methods due to their high autofluorescence. In this chapter we describe the Leaf-FISH method. Leaf-FISH is a fluorescence in situ hybridization (FISH) method specially adapted to the requirements of plant tissues. Leaf-FISH uses a combination of leaf pretreatments coupled with spectral imaging confocal microscopy and image post-processing to visualize bacterial taxa on a structural-informed context recreated from the residual background autofluorescence of the tissues. Leaf-FISH is suitable for simultaneous identification of multiple bacterial taxa using multiple taxon-specific fluorescently labeled oligonucleotide probes (combinatorial labeling).
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29
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Chaudhry V, Runge P, Sengupta P, Doehlemann G, Parker JE, Kemen E. Shaping the leaf microbiota: plant-microbe-microbe interactions. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:36-56. [PMID: 32910810 PMCID: PMC8210630 DOI: 10.1093/jxb/eraa417] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 09/07/2020] [Indexed: 05/28/2023]
Abstract
The aerial portion of a plant, namely the leaf, is inhabited by pathogenic and non-pathogenic microbes. The leaf's physical and chemical properties, combined with fluctuating and often challenging environmental factors, create surfaces that require a high degree of adaptation for microbial colonization. As a consequence, specific interactive processes have evolved to establish a plant leaf niche. Little is known about the impact of the host immune system on phyllosphere colonization by non-pathogenic microbes. These organisms can trigger plant basal defenses and benefit the host by priming for enhanced resistance to pathogens. In most disease resistance responses, microbial signals are recognized by extra- or intracellular receptors. The interactions tend to be species specific and it is unclear how they shape leaf microbial communities. In natural habitats, microbe-microbe interactions are also important for shaping leaf communities. To protect resources, plant colonizers have developed direct antagonistic or host manipulation strategies to fight competitors. Phyllosphere-colonizing microbes respond to abiotic and biotic fluctuations and are therefore an important resource for adaptive and protective traits. Understanding the complex regulatory host-microbe-microbe networks is needed to transfer current knowledge to biotechnological applications such as plant-protective probiotics.
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Affiliation(s)
- Vasvi Chaudhry
- Department of Microbial Interactions, IMIT/ZMBP, University of
Tübingen, Tübingen, Germany
| | - Paul Runge
- Department of Microbial Interactions, IMIT/ZMBP, University of
Tübingen, Tübingen, Germany
- Max Planck Institute for Plant Breeding Research, Köln, Germany
| | - Priyamedha Sengupta
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences
(CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne,
Germany
| | - Gunther Doehlemann
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences
(CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne,
Germany
| | - Jane E Parker
- Max Planck Institute for Plant Breeding Research, Köln, Germany
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences
(CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne,
Germany
| | - Eric Kemen
- Department of Microbial Interactions, IMIT/ZMBP, University of
Tübingen, Tübingen, Germany
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30
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Xiang Q, Lott AA, Assmann SM, Chen S. Advances and perspectives in the metabolomics of stomatal movement and the disease triangle. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 302:110697. [PMID: 33288010 DOI: 10.1016/j.plantsci.2020.110697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 05/20/2023]
Abstract
Crops are continuously exposed to microbial pathogens that cause tremendous yield losses worldwide. Stomatal pores formed by pairs of specialized guard cells in the leaf epidermis represent a major route of pathogen entry. Guard cells have an essential role as a first line of defense against pathogens. Metabolomics is an indispensable systems biology tool that has facilitated discovery and functional studies of metabolites that regulate stomatal movement in response to pathogens and other environmental factors. Guard cells, pathogens and environmental factors constitute the "stomatal disease triangle". The aim of this review is to highlight recent advances toward understanding the stomatal disease triangle in the context of newly discovered signaling molecules, hormone crosstalk, and consequent molecular changes that integrate pathogens and environmental sensing into stomatal immune responses. Future perspectives on emerging single-cell studies, multiomics and molecular imaging in the context of stomatal defense are discussed. Advances in this important area of plant biology will inform rational crop engineering and breeding for enhanced stomatal defense without disruption of other pathways that impact crop yield.
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Affiliation(s)
- Qingyuan Xiang
- Department of Biology, University of Florida Genetics Institute, Gainesville, FL, USA
| | - Aneirin A Lott
- Department of Biology, University of Florida Genetics Institute, Gainesville, FL, USA; Plant Molecular and Cellular Biology Program, University of Florida, FL, USA
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, State College, PA, USA
| | - Sixue Chen
- Department of Biology, University of Florida Genetics Institute, Gainesville, FL, USA; Plant Molecular and Cellular Biology Program, University of Florida, FL, USA; Proteomics and Mass Spectrometry Facility, University of Florida, FL, USA.
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31
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Steinberg S, Grinberg M, Beitelman M, Peixoto J, Orevi T, Kashtan N. Two-way microscale interactions between immigrant bacteria and plant leaf microbiota as revealed by live imaging. ISME JOURNAL 2020; 15:409-420. [PMID: 32963344 DOI: 10.1038/s41396-020-00767-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/27/2020] [Indexed: 12/31/2022]
Abstract
The phyllosphere - the aerial parts of plants - is an important microbial habitat that is home to diverse microbial communities. The spatial organization of bacterial cells on leaf surfaces is non-random, and correlates with leaf microscopic features. Yet, the role of microscale interactions between bacterial cells therein is not well understood. Here, we ask how interactions between immigrant bacteria and resident microbiota affect the spatial organization of the combined community. By means of live imaging in a simplified in vitro system, we studied the spatial organization, at the micrometer scale, of the biocontrol agent Pseudomonas fluorescens A506 and the plant pathogen P. syringae B728a when introduced to pear and bean leaf microbiota (the corresponding native plants of these strains). We found significant co-localization of immigrant and resident microbial cells at distances of a few micrometers, for both strains. Interestingly, this co-localization was in part due to preferential attachment of microbiota cells near newly formed P. fluorescens aggregates. Our results indicate that two-way immigrant bacteria - resident microbiota interactions affect the microscale spatial organization of leaf microbiota, and possibly that of other surface-related microbial communities.
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Affiliation(s)
- Shifra Steinberg
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, 76100, Rehovot, Israel
| | - Maor Grinberg
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, 76100, Rehovot, Israel
| | - Michael Beitelman
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, 76100, Rehovot, Israel
| | - Julianna Peixoto
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, 76100, Rehovot, Israel.,Laboratory of Enzymology, Department of Cellular Biology, Biological Sciences Institute, University of Brasilia, Brasilia, DF, 70910-900, Brazil
| | - Tomer Orevi
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, 76100, Rehovot, Israel
| | - Nadav Kashtan
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, 76100, Rehovot, Israel.
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32
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Zhang L, Okabe S. Ecological niche differentiation among anammox bacteria. WATER RESEARCH 2020; 171:115468. [PMID: 31926373 DOI: 10.1016/j.watres.2020.115468] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 12/03/2019] [Accepted: 01/02/2020] [Indexed: 05/05/2023]
Abstract
Anaerobic ammonium oxidizing (anammox) bacteria can directly convert ammonium and nitrite to nitrogen gas anaerobically and were responsible for a substantial part of the fixed nitrogen loss and re-oxidation of nitrite to nitrate in freshwater and marine ecosystems. Although a wide variety of studies have been undertaken to investigate the abundance and biodiversity of anammox bacteria so far, ecological niche differentiation of anammox bacteria is still not fully understood. To assess their growth behavior and consequent population dynamics at a given environment, the Monod model is often used. Here, we summarize the Monod kinetic parameters such as the maximum specific growth rate (μmax) and the half-saturation constant for nitrite (KNO2-) and ammonium (KNH4+) of five known candidatus genera of anammox bacteria. We also discuss potential pivotal environmental factors and metabolic flexibility that influence the community compositions of anammox bacteria. Particularly biodiversity of the genus "Scalindua" might have been largely underestimated. Several anammox bacteria have been successfully enriched from various source of biomass. We reevaluate their enrichment methods and culture medium compositions to gain a clue of niche differentiation of anammox bacteria. Furthermore, we formulate the current issues that must be addressed. Overall this review re-emphasizes the importance of enrichment cultures (preferably pure cultures), physiological characterization and direct microbial competition studies using enrichment cultures in laboratories.
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Affiliation(s)
- Lei Zhang
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Sapporo, Hokkaido, 060-8628, Japan
| | - Satoshi Okabe
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Sapporo, Hokkaido, 060-8628, Japan.
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33
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Greffe VRG, Michiels J. Desiccation-induced cell damage in bacteria and the relevance for inoculant production. Appl Microbiol Biotechnol 2020; 104:3757-3770. [PMID: 32170388 DOI: 10.1007/s00253-020-10501-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/18/2020] [Accepted: 02/26/2020] [Indexed: 12/21/2022]
Abstract
Plant growth-promoting bacteria show great potential for use in agriculture although efficient application remains challenging to achieve. Cells often lose viability during inoculant production and application, jeopardizing the efficacy of the inoculant. Since desiccation has been documented to be the primary stress factor affecting the decrease in survival, obtaining xerotolerance in plant growth-promoting bacteria is appealing. The molecular damage that occurs by drying bacteria has been broadly investigated, although a complete view is still lacking due to the complex nature of the process. Mechanic, structural, and metabolic changes that occur as a result of water depletion may potentially afflict lethal damage to membranes, DNA, and proteins. Bacteria respond to these harsh conditions by increasing production of exopolysaccharides, changing composition of the membrane, improving the stability of proteins, reducing oxidative stress, and repairing DNA damage. This review provides insight into the complex nature of desiccation stress in bacteria in order to facilitate strategic choices to improve survival and shelf life of newly developed inoculants. KEY POINTS: Desiccation-induced damage affects most major macromolecules in bacteria. Most bacteria are not xerotolerant despite multiple endogenous adaption mechanisms. Sensitivity to drying severely hampers inoculant quality.
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Affiliation(s)
- Vincent Robert Guy Greffe
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,VIB Center for Microbiology, Flanders Institute for Biotechnology, Leuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium. .,VIB Center for Microbiology, Flanders Institute for Biotechnology, Leuven, Belgium.
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34
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Abstract
Microscopic water films allow bacteria to survive the seemingly dry surface of plant leaves.
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Affiliation(s)
- Robin Tecon
- Department of Environmental Systems Science, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
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35
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Heinz J, Waajen AC, Airo A, Alibrandi A, Schirmack J, Schulze-Makuch D. Bacterial Growth in Chloride and Perchlorate Brines: Halotolerances and Salt Stress Responses of Planococcus halocryophilus. ASTROBIOLOGY 2019; 19:1377-1387. [PMID: 31386567 PMCID: PMC6818489 DOI: 10.1089/ast.2019.2069] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/26/2019] [Indexed: 06/10/2023]
Abstract
Extraterrestrial environments encompass physicochemical conditions and habitats that are unknown on Earth, such as perchlorate-rich brines that can be at least temporarily stable on the martian surface. To better understand the potential for life in these cold briny environments, we determined the maximum salt concentrations suitable for growth (MSCg) of six different chloride and perchlorate salts at 25°C and 4°C for the extremotolerant cold- and salt-adapted bacterial strain Planococcus halocryophilus. Growth was measured through colony-forming unit (CFU) counts, while cellular and colonial phenotypic stress responses were observed through visible light, fluorescence, and scanning electron microscopy. Our data show the following: (1) The tolerance to high salt concentrations can be increased through a stepwise inoculation toward higher concentrations. (2) Ion-specific factors are more relevant for the growth limitation of P. halocryophilus in saline solutions than single physicochemical parameters like ionic strength or water activity. (3) P. halocryophilus shows the highest microbial sodium perchlorate tolerance described so far. However, (4) MSCg values are higher for all chlorides compared to perchlorates. (5) The MSCg for calcium chloride was increased by lowering the temperature from 25°C to 4°C, while sodium- and magnesium-containing salts can be tolerated at 25°C to higher concentrations than at 4°C. (6) Depending on salt type and concentration, P. halocryophilus cells show distinct phenotypic stress responses such as novel types of colony morphology on agar plates and biofilm-like cell clustering, encrustation, and development of intercellular nanofilaments. This study, taken in context with previous work on the survival of extremophiles in Mars-like environments, suggests that high-concentrated perchlorate brines on Mars might not be habitable to any present organism on Earth, but extremophilic microorganisms might be able to evolve thriving in such environments.
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Affiliation(s)
- Jacob Heinz
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Annemiek C. Waajen
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - Alessandro Airo
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Armando Alibrandi
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Janosch Schirmack
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Dirk Schulze-Makuch
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
- School of the Environment, Washington State University, Pullman, Washington, USA
- GFZ German Center for Geoscience, Section Geomicrobiology, Potsdam, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Department of Experimental Limnology, Stechlin, Germany
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36
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Kiplimo D, Mugweru J, Kituyi S, Kipnyargis A, Mwirichia R. Diversity of esterase and lipase producing haloalkaliphilic bacteria from Lake Magadi in Kenya. J Basic Microbiol 2019; 59:1173-1184. [PMID: 31621083 DOI: 10.1002/jobm.201900353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/11/2019] [Accepted: 09/29/2019] [Indexed: 11/10/2022]
Abstract
Lipids are hydrocarbons comprised of long-chain fatty acids and are found in all living things. In the environment, microorganisms degrade them to obtain energy using esterases and lipases. These enzymes are nowadays used in different industrial applications. We report isolation of 24 bacteria with esteresic and lipolytic activity from Lake Magadi, Kenya. The isolates were characterised using morphological, biochemical, and molecular methods. Isolates grew at an optimum salt concentration of 5-8% (w/v), pH range of 8.0-9.0, and temperature range of 35-40°C. The isolates were positive for esterase and lipase assay as well as other extracellular enzymes. Phylogenetic analysis of the 16S ribosomal RNA gene showed that the isolates were affiliated to the genus Bacillus, Alkalibacterium, Staphylococcus, Micrococcus, Halomonas, and Alkalilimnicola. None of the bacterial isolates produced antimicrobial agents, and all of them were resistant to trimethoprim and nalidixic acid but susceptible to streptomycin, amoxillin, chloramphenicol, and cefotaxime. Growth at elevated pH, salt, and temperature is an indicator that the enzymes from these organisms could function well under haloalkaline conditions. Therefore, Lake Magadi could be a good source of isolates with the potential to produce unique biocatalysts for the biotechnology industry.
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Affiliation(s)
- Denis Kiplimo
- Department of Biological Sciences, University of Embu, Embu, Kenya
| | - Julius Mugweru
- Department of Biological Sciences, University of Embu, Embu, Kenya
| | - Sarah Kituyi
- Department of Biological Sciences, University of Embu, Embu, Kenya
| | - Alex Kipnyargis
- Department of Biological Sciences, University of Embu, Embu, Kenya
| | - Romano Mwirichia
- Department of Biological Sciences, University of Embu, Embu, Kenya
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37
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Grinberg M, Orevi T, Steinberg S, Kashtan N. Bacterial survival in microscopic surface wetness. eLife 2019; 8:e48508. [PMID: 31610846 PMCID: PMC6824842 DOI: 10.7554/elife.48508] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/20/2019] [Indexed: 01/06/2023] Open
Abstract
Plant leaves constitute a huge microbial habitat of global importance. How microorganisms survive the dry daytime on leaves and avoid desiccation is not well understood. There is evidence that microscopic surface wetness in the form of thin films and micrometer-sized droplets, invisible to the naked eye, persists on leaves during daytime due to deliquescence - the absorption of water until dissolution - of hygroscopic aerosols. Here, we study how such microscopic wetness affects cell survival. We show that, on surfaces drying under moderate humidity, stable microdroplets form around bacterial aggregates due to capillary pinning and deliquescence. Notably, droplet-size increases with aggregate-size, and cell survival is higher the larger the droplet. This phenomenon was observed for 13 bacterial species, two of which - Pseudomonas fluorescens and P. putida - were studied in depth. Microdroplet formation around aggregates is likely key to bacterial survival in a variety of unsaturated microbial habitats, including leaf surfaces.
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Affiliation(s)
- Maor Grinberg
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
| | - Tomer Orevi
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
| | - Shifra Steinberg
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
| | - Nadav Kashtan
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
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Hernandez MN, Lindow SE. Pseudomonas syringae Increases Water Availability in Leaf Microenvironments via Production of Hygroscopic Syringafactin. Appl Environ Microbiol 2019; 85:e01014-19. [PMID: 31285194 PMCID: PMC6715840 DOI: 10.1128/aem.01014-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 06/27/2019] [Indexed: 01/26/2023] Open
Abstract
The epiphytic bacterium Pseudomonas syringae strain B728a produces the biosurfactant syringafactin, which is hygroscopic. The water-absorbing potential of syringafactin is high. Syringafactin attracts 250% of its weight in water at high relative humidities but is less hygroscopic at lower relative humidities. This finding suggests that the benefit of syringafactin to the producing cells is strongly context dependent. The contribution of syringafactin to the water availability around cells on different matrices was assessed by examining the water stress exhibited by biosensor strains expressing gfp via the water-stress-activated proU promoter. Wild-type cells exhibited significantly less green fluorescent protein (GFP) fluorescence than a syringafactin-deficient strain on dry filters in atmospheres of high water saturation, as well as on leaf surfaces, indicating greater water availability. When infiltrated into the leaf apoplast, wild-type cells also subsequently exhibited less GFP fluorescence than the syringafactin-deficient strain. These results suggest that the apoplast is a dry but humid environment and that, just as on dry but humid leaf surfaces, syringafactin increases liquid water availability and reduces the water stress experienced by P. syringaeIMPORTANCE Many microorganisms, including the plant pathogen Pseudomonas syringae, produce amphiphilic compounds known as biosurfactants. While biosurfactants are known to disperse hydrophobic compounds and to reduce water tension, they have other properties that can benefit the cells that produce them. Leaf-colonizing bacteria experience frequent water stress, since liquid water is present only transiently on or in leaf sites that they colonize. The demonstration that syringafactin, a biosurfactant produced by P. syringae, is sufficiently hygroscopic to increase water availability to cells, thus relieving water stress, reveals that P. syringae can modify its local habitat both on leaf surfaces and in the leaf apoplast. Such habitat modification may be a common role for biosurfactants produced by other bacterial species that colonize habitats (such as soil) that are not always water saturated.
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Affiliation(s)
- Monica N Hernandez
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Steven E Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
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Schlechter RO, Miebach M, Remus-Emsermann MN. Driving factors of epiphytic bacterial communities: A review. J Adv Res 2019; 19:57-65. [PMID: 31341670 PMCID: PMC6630024 DOI: 10.1016/j.jare.2019.03.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 12/29/2022] Open
Abstract
Bacteria establish complex, compositionally consistent communities on healthy leaves. Ecological processes such as dispersal, diversification, ecological drift, and selection as well as leaf surface physicochemistry and topology impact community assembly. Since the leaf surface is an oligotrophic environment, species interactions such as competition and cooperation may be major contributors to shape community structure. Furthermore, the plant immune system impacts on microbial community composition, as plant cells respond to bacterial molecules and shape their responses according to the mixture of molecules present. Such tunability of the plant immune network likely enables the plant host to differentiate between pathogenic and non-pathogenic colonisers, avoiding costly immune responses to non-pathogenic colonisers. Plant immune responses are either systemically distributed or locally confined, which in turn affects the colonisation pattern of the associated microbiota. However, how each of these factors impacts the bacterial community is unclear. To better understand this impact, bacterial communities need to be studied at a micrometre resolution, which is the scale that is relevant to the members of the community. Here, current insights into the driving factors influencing the assembly of leaf surface-colonising bacterial communities are discussed, with a special focus on plant host immunity as an emerging factor contributing to bacterial leaf colonisation.
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Affiliation(s)
- Rudolf O. Schlechter
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| | - Moritz Miebach
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Mitja N.P. Remus-Emsermann
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
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Barcarolo MV, Garavaglia BS, Thomas L, Marondedze C, Gehring C, Gottig N, Ottado J. Proteome changes and physiological adaptations of the phytopathogen Xanthomonas citri subsp. citri under salt stress and their implications for virulence. FEMS Microbiol Ecol 2019; 95:5509571. [DOI: 10.1093/femsec/fiz081] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/30/2019] [Indexed: 12/17/2022] Open
Affiliation(s)
- María Victoria Barcarolo
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-CONICET) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR). Ocampo y Esmeralda, Rosario, 2000, Argentina
| | - Betiana S Garavaglia
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-CONICET) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR). Ocampo y Esmeralda, Rosario, 2000, Argentina
| | - Ludivine Thomas
- HM.Clause, rue Louis Saillant, 26801 Portes-lès-Valence, France
| | - Claudius Marondedze
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CEA/DRF/BIG, INRA UMR1417, CNRS UMR5168, 38054 Grenoble Cedex 9, France
| | - Chris Gehring
- Department of Chemistry, Biology & Biotechnology, University of Perugia,
06121 Perugia, Italy
| | - Natalia Gottig
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-CONICET) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR). Ocampo y Esmeralda, Rosario, 2000, Argentina
| | - Jorgelina Ottado
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-CONICET) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR). Ocampo y Esmeralda, Rosario, 2000, Argentina
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Survival and ice nucleation activity of Pseudomonas syringae strains exposed to simulated high-altitude atmospheric conditions. Sci Rep 2019; 9:7768. [PMID: 31123327 PMCID: PMC6533367 DOI: 10.1038/s41598-019-44283-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 05/07/2019] [Indexed: 12/01/2022] Open
Abstract
Pseudomonas syringae produces highly efficient biological ice nuclei (IN) that were proposed to influence precipitation by freezing water in clouds. This bacterium may be capable of dispersing through the atmosphere, having been reported in rain, snow, and cloud water samples. This study assesses its survival and maintenance of IN activity under stressing conditions present at high altitudes, such as UV radiation within clouds. Strains of the pathovars syringae and garcae were compared to Escherichia coli. While UV-C effectively inactivated these cells, the Pseudomonas were much more tolerant to UV-B. The P. syringae strains were also more resistant to radiation from a solar simulator, composed of UV-A and UV-B, while only one of them suffered a decline in IN activity at −5 °C after long exposures. Desiccation at different relative humidity values also affected the IN, but some activity at −5 °C was always maintained. The pathovar garcae tended to be more resistant than the pathovar syringae, particularly to desiccation, though its IN were found to be generally more sensitive. Compared to E. coli, the P. syringae strains appear to be better adapted to survival under conditions present at high altitudes and in clouds.
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Srinivasan S, Vladescu ID, Koehler SA, Wang X, Mani M, Rubinstein SM. Matrix Production and Sporulation in Bacillus subtilis Biofilms Localize to Propagating Wave Fronts. Biophys J 2019; 114:1490-1498. [PMID: 29590605 DOI: 10.1016/j.bpj.2018.02.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 12/31/2022] Open
Abstract
Bacterial biofilms are surface-attached microbial communities encased in self-produced extracellular polymeric substances. Here we demonstrate that during the development of Bacillus subtilis biofilms, matrix production is localized to an annular front propagating at the periphery and sporulation to a second front at a fixed distance at the interior. We show that within these fronts, cells switch off matrix production and transition to sporulation after a set time delay of ∼100 min. Correlation analyses of fluctuations in fluorescence reporter activity reveal that the fronts emerge from a pair of gene-expression waves of matrix production and sporulation. The localized expression waves travel across cells that are immobilized in the biofilm matrix in contrast to active cell migration or horizontal colony spreading. Our results suggest that front propagation arises via a local developmental program occurring at the level of individual bacterial cells, likely driven by nutrient depletion and metabolic by-product accumulation. A single-length scale and timescale couples the spatiotemporal propagation of both fronts throughout development. As a result, gene expression patterns within the advancing fronts collapse to self-similar expression profiles. Our findings highlight the key role of the localized cellular developmental program associated with the propagating front in describing biofilm growth.
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Affiliation(s)
- Siddarth Srinivasan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts.
| | - Ioana D Vladescu
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts
| | - Stephan A Koehler
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts
| | - Xiaoling Wang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts; School of Mechanical Engineering, University of Science and Technology Beijing, Beijing, China
| | - Madhav Mani
- Department of Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois
| | - Shmuel M Rubinstein
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts; School of Engineering and Applied Sciences and Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, Massachusetts.
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Amato P, Besaury L, Joly M, Penaud B, Deguillaume L, Delort AM. Metatranscriptomic exploration of microbial functioning in clouds. Sci Rep 2019; 9:4383. [PMID: 30867542 PMCID: PMC6416334 DOI: 10.1038/s41598-019-41032-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 02/27/2019] [Indexed: 01/19/2023] Open
Abstract
Clouds constitute the uppermost layer of the biosphere. They host diverse communities whose functioning remains obscure, although biological activity potentially participates to atmospheric chemical and physical processes. In order to gain information on the metabolic functioning of microbial communities in clouds, we conducted coordinated metagenomics/metatranscriptomics profiling of cloud water microbial communities. Samples were collected from a high altitude atmospheric station in France and examined for biological content after untargeted amplification of nucleic acids. Living microorganisms, essentially bacteria, maintained transcriptional and translational activities and expressed many known complementary physiological responses intended to fight oxidants, osmotic variations and cold. These included activities of oxidant detoxification and regulation, synthesis of osmoprotectants/cryoprotectants, modifications of membranes, iron uptake. Consistently these energy-demanding processes were fueled by central metabolic routes involved in oxidative stress response and redox homeostasis management, such as pentose phosphate and glyoxylate pathways. Elevated binding and transmembrane ion transports demonstrated important interactions between cells and their cloud droplet chemical environments. In addition, polysaccharides, potentially beneficial for survival like exopolysaccharides, biosurfactants and adhesins, were synthesized. Our results support a biological influence on cloud physical and chemical processes, acting notably on the oxidant capacity, iron speciation and availability, amino-acids distribution and carbon and nitrogen fates.
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Affiliation(s)
- Pierre Amato
- Université Clermont Auvergne, CNRS, SIGMA Clermont, ICCF, F-63000, Clermont-Ferrand, France.
| | - Ludovic Besaury
- Université Clermont Auvergne, CNRS, SIGMA Clermont, ICCF, F-63000, Clermont-Ferrand, France
| | - Muriel Joly
- Université Clermont Auvergne, CNRS, SIGMA Clermont, ICCF, F-63000, Clermont-Ferrand, France
| | - Benjamin Penaud
- Université Clermont Auvergne, CNRS, SIGMA Clermont, ICCF, F-63000, Clermont-Ferrand, France
| | | | - Anne-Marie Delort
- Université Clermont Auvergne, CNRS, SIGMA Clermont, ICCF, F-63000, Clermont-Ferrand, France
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Grinberg M, Orevi T, Kashtan N. Bacterial surface colonization, preferential attachment and fitness under periodic stress. PLoS Comput Biol 2019; 15:e1006815. [PMID: 30835727 PMCID: PMC6420035 DOI: 10.1371/journal.pcbi.1006815] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/15/2019] [Accepted: 01/23/2019] [Indexed: 12/31/2022] Open
Abstract
Early bacterial surface colonization is not a random process wherein cells arbitrarily attach to surfaces and grow; but rather, attachment events, movement and cellular interactions induce non-random spatial organization. We have only begun to understand how the apparent self-organization affects the fitness of the population. A key factor contributing to fitness is the tradeoff between solitary-planktonic and aggregated surface-attached biofilm lifestyles. Though planktonic cells typically grow faster, bacteria in aggregates are more resistant to stress such as desiccation, antibiotics and predation. Here we ask if and to what extent informed surface-attachments improve fitness during early surface colonization under periodic stress conditions. We use an individual-based modeling approach to simulate foraging planktonic cells colonizing a surface under alternating wet-dry cycles. Such cycles are common in the largest terrestrial microbial habitats–soil, roots, and leaf surfaces–that are not constantly saturated with water and experience daily periods of desiccation stress. We compared different surface-attachment strategies, and analyzed the emerging spatio-temporal dynamics of surface colonization and population yield as a measure of fitness. We demonstrate that a simple strategy of preferential attachment (PA), biased to dense sites, carries a large fitness advantage over any random attachment across a broad range of environmental conditions–particularly under periodic stress. A vast portion of bacterial life on Earth takes place on surfaces. In many of these surfaces cells collectively organize into biofilms that are known to provide them protection from various environmental stresses. Early bacterial colonization of surfaces, prior to the development of mature biofilm, is a critical stage during which cells attempt to establish a sustainable population. It is not a random process wherein cells arbitrarily attach to surfaces and grow to form micro-colonies. Rather, surface-attachments, movement and cellular interactions take place to yield non-random organization. Using computer simulations, based on individual-based modeling, we demonstrate that simple attachment strategies, where planktonic cells preferentially attach to existing surface-attached aggregates, may confer fitness advantage over random attachment. The advantage of preferential attachment is particularly substantial under periodic stress–a common characteristic of many natural microbial habitats. This is due to a more efficient recruitment of planktonic cells that accelerates the formation of stress-protected aggregates.
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Affiliation(s)
- Maor Grinberg
- The department of Plant Pathology and Microbiology, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tomer Orevi
- The department of Plant Pathology and Microbiology, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Nadav Kashtan
- The department of Plant Pathology and Microbiology, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
- * E-mail:
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Santana JO, Gramacho KP, de Souza Eduvirgens Ferreira KT, Rezende RP, Mangabeira PAO, Dias RPM, Couto FM, Pirovani CP. Witches' broom resistant genotype CCN51 shows greater diversity of symbiont bacteria in its phylloplane than susceptible genotype catongo. BMC Microbiol 2018; 18:194. [PMID: 30470193 PMCID: PMC6251189 DOI: 10.1186/s12866-018-1339-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 11/14/2018] [Indexed: 12/26/2022] Open
Abstract
Background Theobroma cacao L. (cacao) is a perennial tropical tree, endemic to rainforests of the Amazon Basin. Large populations of bacteria live on leaf surfaces and these phylloplane microorganisms can have important effects on plant health. In recent years, the advent of high-throughput sequencing techniques has greatly facilitated studies of the phylloplane microbiome. In this study, we characterized the bacterial microbiome of the phylloplane of the catongo genotype (susceptible to witch’s broom) and CCN51 (resistant). Bacterial microbiome was determined by sequencing the V3-V4 region of the bacterial 16S rRNA gene. Results After the pre-processing, a total of 1.7 million reads were considered. In total, 106 genera of bacteria were characterized. Proteobacteria was the predominant phylum in both genotypes. The exclusive genera of Catongo showed activity in the protection against UV radiation and in the transport of substrates. CCN51 presented genus that act in the biological control and inhibition in several taxonomic groups. Genotype CCN51 presented greater diversity of microorganisms in comparison to the Catongo genotype and the total community was different between both. Scanning electron microscopy analysis of leaves revealed that on the phylloplane, many bacterial occur in large aggregates in several regions of the surface and isolated nearby to the stomata. Conclusions We describe for the first time the phylloplane bacterial communities of T. cacao. The Genotype CCN51, resistant to the witch’s broom, has a greater diversity of bacterial microbioma in comparison to Catongo and a greater amount of exclusive microorganisms in the phylloplane with antagonistic action against phytopathogens. Electronic supplementary material The online version of this article (10.1186/s12866-018-1339-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Rachel Passos Rezende
- Department of Biological Science, State University of Santa Cruz, Ilhéus, Bahia, Brazil
| | | | - Ricardo Pedro Moreira Dias
- BioISI: Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Francisco M Couto
- LaSIGE, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
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Cowles KN, Groves RL, Barak JD. Leafhopper-Induced Activation of the Jasmonic Acid Response Benefits Salmonella enterica in a Flagellum-Dependent Manner. Front Microbiol 2018; 9:1987. [PMID: 30190716 PMCID: PMC6115507 DOI: 10.3389/fmicb.2018.01987] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 08/07/2018] [Indexed: 11/29/2022] Open
Abstract
Enteric human pathogens such as Salmonella enterica are typically studied in the context of their animal hosts, but it has become apparent that these bacteria spend a significant portion of their life cycle on plants. S. enterica survives the numerous stresses common to a plant niche, including defense responses, water and nutrient limitation, and exposure to UV irradiation leading to an increased potential for human disease. In fact, S. enterica is estimated to cause over one million cases of foodborne illness each year in the United States with 20% of those cases resulting from consumption of contaminated produce. Although S. enterica successfully persists in the plant environment, phytobacterial infection by Pectobacterium carotovorum or Xanthomonas spp. increases S. enterica survival and infrequently leads to growth on infected plants. The co-association of phytophagous insects, such as the Aster leafhopper, Macrosteles quadrilineatus, results in S. enterica populations that persist at higher levels for longer periods of time when compared to plants treated with S. enterica alone. We hypothesized that leafhoppers increase S. enterica persistence by altering the plant defense response to the benefit of the bacteria. Leafhopper infestation activated the jasmonic acid (JA) defense response while S. enterica colonization triggered the salicylic acid (SA) response. In tomato plants co-treated with S. enterica and leafhoppers, both JA- and SA-inducible genes were activated, suggesting that the presence of leafhoppers may affect the crosstalk that occurs between the two immune response pathways. To rule out the possibility that leafhoppers provide additional benefits to S. enterica, plants were treated with a chemical JA analog to activate the immune response in the absence of leafhoppers. Although bacterial populations continue to decline over time, analog treatment significantly increased bacterial persistence on the leaf surface. Bacterial mutant analysis determined that the bacterial flagellum, whether functional or not, was required for increased S. enterica survival after analog treatment. By investigating the interaction between this human pathogen, a common phytophagous insect, and their plant host, we hope to elucidate the mechanisms promoting S. enterica survival on plants and provide information to be used in the development of new food safety intervention strategies.
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Affiliation(s)
- Kimberly N Cowles
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Russell L Groves
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jeri D Barak
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
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Wright KM, Holden NJ. Quantification and colonisation dynamics of Escherichia coli O157:H7 inoculation of microgreens species and plant growth substrates. Int J Food Microbiol 2018; 273:1-10. [DOI: 10.1016/j.ijfoodmicro.2018.02.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 02/23/2018] [Accepted: 02/27/2018] [Indexed: 02/02/2023]
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Straub C, Colombi E, Li L, Huang H, Templeton MD, McCann HC, Rainey PB. The ecological genetics ofPseudomonas syringaefrom kiwifruit leaves. Environ Microbiol 2018. [DOI: 10.1111/1462-2920.14092] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christina Straub
- New Zealand Institute for Advanced Study, Massey UniversityAuckland New Zealand
| | - Elena Colombi
- New Zealand Institute for Advanced Study, Massey UniversityAuckland New Zealand
| | - Li Li
- Key Laboratory of Plant Germplasm Enhancement and Specialty AgricultureWuhan Botanical Garden, Chinese Academy of SciencesWuhan People's Republic of China
| | - Hongwen Huang
- Key Laboratory of Plant Germplasm Enhancement and Specialty AgricultureWuhan Botanical Garden, Chinese Academy of SciencesWuhan People's Republic of China
- Key Laboratory of Plant Resources Conservation and Sustainable UtilizationSouth China Botanical Garden, Chinese Academy of SciencesGuangzhou People's Republic of China
| | | | - Honour C. McCann
- New Zealand Institute for Advanced Study, Massey UniversityAuckland New Zealand
| | - Paul B. Rainey
- New Zealand Institute for Advanced Study, Massey UniversityAuckland New Zealand
- Max Planck Institute for Evolutionary Biology, Department of Microbial Population BiologyPlön Germany
- École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris Tech), Laboratoire de Génétique de l'EvolutionParis France
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Benforte FC, Colonnella MA, Ricardi MM, Solar Venero EC, Lizarraga L, López NI, Tribelli PM. Novel role of the LPS core glycosyltransferase WapH for cold adaptation in the Antarctic bacterium Pseudomonas extremaustralis. PLoS One 2018; 13:e0192559. [PMID: 29415056 PMCID: PMC5802925 DOI: 10.1371/journal.pone.0192559] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 01/25/2018] [Indexed: 11/19/2022] Open
Abstract
Psychrotroph microorganisms have developed cellular mechanisms to cope with cold stress. Cell envelopes are key components for bacterial survival. Outer membrane is a constituent of Gram negative bacterial envelopes, consisting of several components, such as lipopolysaccharides (LPS). In this work we investigated the relevance of envelope characteristics for cold adaptation in the Antarctic bacterium Pseudomonas extremaustralis by analyzing a mini Tn5 wapH mutant strain, encoding a core LPS glycosyltransferase. Our results showed that wapH strain is impaired to grow under low temperature but not for cold survival. The mutation in wapH, provoked a strong aggregative phenotype and modifications of envelope nanomechanical properties such as lower flexibility and higher turgor pressure, cell permeability and surface area to volume ratio (S/V). Changes in these characteristics were also observed in the wild type strain grown at different temperatures, showing higher cell flexibility but lower turgor pressure under cold conditions. Cold shock experiments indicated that an acclimation period in the wild type is necessary for cell flexibility and S/V ratio adjustments. Alteration in cell-cell interaction capabilities was observed in wapH strain. Mixed cells of wild type and wapH strains, as well as those of the wild type strain grown at different temperatures, showed a mosaic pattern of aggregation. These results indicate that wapH mutation provoked marked envelope alterations showing that LPS core conservation appears as a novel essential feature for active growth under cold conditions.
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Affiliation(s)
- Florencia C. Benforte
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Maria A. Colonnella
- Centro de Investigaciones en Bionanociencias, CONICET, Buenos Aires, Argentina
| | - Martiniano M. Ricardi
- Instituto de Fisiología, Biología Molecular y Neurociencias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Leonardo Lizarraga
- Centro de Investigaciones en Bionanociencias, CONICET, Buenos Aires, Argentina
| | - Nancy I. López
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- IQUIBICEN, CONICET, Buenos Aires, Argentina
- * E-mail: (NIL); (PMT)
| | - Paula M. Tribelli
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- IQUIBICEN, CONICET, Buenos Aires, Argentina
- * E-mail: (NIL); (PMT)
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50
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Peredo EL, Simmons SL. Leaf-FISH: Microscale Imaging of Bacterial Taxa on Phyllosphere. Front Microbiol 2018; 8:2669. [PMID: 29375531 PMCID: PMC5767230 DOI: 10.3389/fmicb.2017.02669] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/21/2017] [Indexed: 11/13/2022] Open
Abstract
Molecular methods for microbial community characterization have uncovered environmental and plant-associated factors shaping phyllosphere communities. Variables undetectable using bulk methods can play an important role in shaping plant-microbe interactions. Microscale analysis of bacterial dynamics in the phyllosphere requires imaging techniques specially adapted to the high autoflouresence and 3-D structure of the leaf surface. We present an easily-transferable method (Leaf-FISH) to generate high-resolution tridimensional images of leaf surfaces that allows simultaneous visualization of multiple bacterial taxa in a structurally informed context, using taxon-specific fluorescently labeled oligonucleotide probes. Using a combination of leaf pretreatments coupled with spectral imaging confocal microscopy, we demonstrate the successful imaging bacterial taxa at the genus level on cuticular and subcuticular leaf areas. Our results confirm that different bacterial species, including closely related isolates, colonize distinct microhabitats in the leaf. We demonstrate that highly related Methylobacterium species have distinct colonization patterns that could not be predicted by shared physiological traits, such as carbon source requirements or phytohormone production. High-resolution characterization of microbial colonization patterns is critical for an accurate understanding of microbe-microbe and microbe-plant interactions, and for the development of foliar bacteria as plant-protective agents.
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Affiliation(s)
- Elena L Peredo
- Marine Biological Laboratory, Josephine Bay Paul Center, Woods Hole, MA, United States
| | - Sheri L Simmons
- Marine Biological Laboratory, Josephine Bay Paul Center, Woods Hole, MA, United States
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