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Guan Y, Bak F, Hennessy RC, Horn Herms C, Elberg CL, Dresbøll DB, Winding A, Sapkota R, Nicolaisen MH. The potential of Pseudomonas fluorescens SBW25 to produce viscosin enhances wheat root colonization and shapes root-associated microbial communities in a plant genotype-dependent manner in soil systems. mSphere 2024:e0029424. [PMID: 38904362 DOI: 10.1128/msphere.00294-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 05/15/2024] [Indexed: 06/22/2024] Open
Abstract
Microorganisms interact with plant roots through colonization of the root surface, i.e., the rhizoplane or the surrounding soil, i.e., the rhizosphere. Beneficial rhizosphere bacteria such as Pseudomonas spp. can promote plant growth and protect against pathogens by producing a range of bioactive compounds, including specialized metabolites like cyclic lipopeptides (CLPs) known for their biosurfactant and antimicrobial activities. However, the role of CLPs in natural soil systems during bacteria-plant interactions is underexplored. Here, Pseudomonas fluorescens SBW25, producing the CLP viscosin, was used to study the impact of viscosin on bacterial root colonization and microbiome assembly in two cultivars of winter wheat (Heerup and Sheriff). We inoculated germinated wheat seeds with SBW25 wild type or a viscosin-deficient mutant and grew the plants in agricultural soil. After 2 weeks, enhanced root colonization of SBW25 wild type compared to the viscosin-deficient mutant was observed, while no differences were observed between wheat cultivars. In contrast, the impact on root-associated microbial community structure was plant-genotype-specific, and SBW25 wild type specifically reduced the relative abundance of an unclassified oomycete and Phytophthora in Sheriff and Heerup, respectively. This study provides new insights into the natural role of viscosin and specifically highlights the importance of viscosin in wheat root colonization under natural soil conditions and in shaping the root microbial communities associated with different wheat cultivars. Furthermore, it pinpoints the significance of microbial microdiversity, plant genotype, and microbe-microbe interactions when studying colonization of plant roots. IMPORTANCE Understanding parameters governing microbiome assembly on plant roots is critical for successfully exploiting beneficial plant-microbe interactions for improved plant growth under low-input conditions. While it is well-known from in vitro studies that specialized metabolites are important for plant-microbe interactions, e.g., root colonization, studies on the ecological role under natural soil conditions are limited. This might explain the often-low translational power from laboratory testing to field performance of microbial inoculants. Here, we showed that viscosin synthesis potential results in a differential impact on the microbiome assembly dependent on wheat cultivar, unlinked to colonization potential. Overall, our study provides novel insights into factors governing microbial assembly on plant roots, and how this has a derived but differential effect on the bacterial and protist communities.
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Affiliation(s)
- Ying Guan
- Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Frederik Bak
- Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
- Bioresources Unit, AIT Austrian Institute of Technology, Tulln, Austria
| | | | - Courtney Horn Herms
- Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | | | - Dorte Bodin Dresbøll
- Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Anne Winding
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Rumakanta Sapkota
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
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2
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Pastora AB, Rzasa KM, O'Toole GA. Multiple pathways impact the swarming motility of Pseudomonas fluorescens Pf0-1. Microbiol Spectr 2024; 12:e0016624. [PMID: 38687073 DOI: 10.1128/spectrum.00166-24] [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: 01/17/2024] [Accepted: 04/20/2024] [Indexed: 05/02/2024] Open
Abstract
Swarming motility in pseudomonads typically requires both a functional flagellum and the production/secretion of a biosurfactant. Published work has shown that the wild-type Pseudomonas fluorescens Pf0-1 is swarming deficient due to a point mutation in the gacA gene, which until recently was thought to inactivate rather than attenuate the Gac/Rsm pathway. As a result, little is known about the underlying mechanisms that regulate swarming motility by P. fluorescens Pf0-1. Here, we demonstrate that a ΔrsmA ΔrsmE ΔrsmI mutant, which phenotypically mimics Gac/Rsm pathway overstimulation, is proficient at swarming motility. RsmA and RsmE appear to play a key role in this regulation. Transposon mutagenesis of the ΔrsmA ΔrsmE ΔrsmI mutant identified multiple factors that impact swarming motility, including pathways involved in flagellar synthesis and biosurfactant production/secretion. We find that loss of genes linked to biosurfactant Gacamide A biosynthesis or secretion impacts swarming motility, as does loss of the alternative sigma factor FliA, which results in a defect in flagellar function. Collectively, these findings provide evidence that P. fluorescens Pf0-1 can swarm if the Gac/Rsm pathway is activated, highlight the regulatory complexity of swarming motility in this strain, and demonstrate that the cyclic lipopeptide Gacamide A is utilized as a biosurfactant for swarming motility.IMPORTANCESwarming motility is a coordinated process that allows communities of bacteria to collectively move across a surface. For P. fluorescens Pf0-1, this phenotype is notably absent in the parental strain, and to date, little is known about the regulation of swarming in this strain. Here, we identify RsmA and RsmE as key repressors of swarming motility via modulating the levels of biosurfactant production/secretion. Using transposon mutagenesis and subsequent genetic analyses, we further identify potential regulatory mechanisms of swarming motility and link Gacamide A biosynthesis and transport machinery to swarming motility.
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Affiliation(s)
- Alexander B Pastora
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Kara M Rzasa
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, USA
| | - George A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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3
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Paliwal D, Rabiey M, Mauchline TH, Hassani-Pak K, Nauen R, Wagstaff C, Andrews S, Bass C, Jackson RW. Multiple toxins and a protease contribute to the aphid-killing ability of Pseudomonas fluorescens PpR24. Environ Microbiol 2024; 26:e16604. [PMID: 38561900 DOI: 10.1111/1462-2920.16604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 02/23/2024] [Indexed: 04/04/2024]
Abstract
Aphids are globally important pests causing damage to a broad range of crops. Due to insecticide resistance, there is an urgent need to develop alternative control strategies. In our previous work, we found Pseudomonas fluorescens PpR24 can orally infect and kill the insecticide-resistant green-peach aphid (Myzus persicae). However, the genetic basis of the insecticidal capability of PpR24 remains unclear. Genome sequencing of PpR24 confirmed the presence of various insecticidal toxins such as Tc (toxin complexes), Rhs (rearrangement hotspot) elements, and other insect-killing proteases. Upon aphids infection with PpR24, RNA-Seq analysis revealed 193 aphid genes were differentially expressed with down-regulation of 16 detoxification genes. In addition, 1325 PpR24 genes (542 were upregulated and 783 downregulated) were subject to differential expression, including genes responsible for secondary metabolite biosynthesis, the iron-restriction response, oxidative stress resistance, and virulence factors. Single and double deletion of candidate virulence genes encoding a secreted protease (AprX) and four toxin components (two TcA-like; one TcB-like; one TcC-like insecticidal toxins) showed that all five genes contribute significantly to aphid killing, particularly AprX. This comprehensive host-pathogen transcriptomic analysis provides novel insight into the molecular basis of bacteria-mediated aphid mortality and the potential of PpR24 as an effective biocontrol agent.
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Affiliation(s)
- Deepa Paliwal
- School of Biological Sciences, University of Reading, Reading, UK
| | - Mojgan Rabiey
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Tim H Mauchline
- Sustainable Soils and Crops, Rothamsted Research, Harpenden, UK
| | | | | | - Carol Wagstaff
- School of Chemistry, Food and Pharmacy, University of Reading, Reading, UK
| | - Simon Andrews
- School of Biological Sciences, University of Reading, Reading, UK
| | | | - Robert W Jackson
- School of Biological Sciences, University of Reading, Reading, UK
- School of Biosciences and Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
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4
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Wang X, Chi Y, Song S. Important soil microbiota's effects on plants and soils: a comprehensive 30-year systematic literature review. Front Microbiol 2024; 15:1347745. [PMID: 38591030 PMCID: PMC10999704 DOI: 10.3389/fmicb.2024.1347745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/11/2024] [Indexed: 04/10/2024] Open
Abstract
Clarifying the relationship between soil microorganisms and the plant-soil system is crucial for encouraging the sustainable development of ecosystems, as soil microorganisms serve a variety of functional roles in the plant-soil system. In this work, the influence mechanisms of significant soil microbial groups on the plant-soil system and their applications in environmental remediation over the previous 30 years were reviewed using a systematic literature review (SLR) methodology. The findings demonstrated that: (1) There has been a general upward trend in the number of publications on significant microorganisms, including bacteria, fungi, and archaea. (2) Bacteria and fungi influence soil development and plant growth through organic matter decomposition, nitrogen, phosphorus, and potassium element dissolution, symbiotic relationships, plant growth hormone production, pathogen inhibition, and plant resistance induction. Archaea aid in the growth of plants by breaking down low-molecular-weight organic matter, participating in element cycles, producing plant growth hormones, and suppressing infections. (3) Microorganism principles are utilized in soil remediation, biofertilizer production, denitrification, and phosphorus removal, effectively reducing environmental pollution, preventing soil pathogen invasion, protecting vegetation health, and promoting plant growth. The three important microbial groups collectively regulate the plant-soil ecosystem and help maintain its relative stability. This work systematically summarizes the principles of important microbial groups influence plant-soil systems, providing a theoretical reference for how to control soil microbes in order to restore damaged ecosystems and enhance ecosystem resilience in the future.
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Affiliation(s)
| | - Yongkuan Chi
- School of Karst Science, State Engineering Technology Institute for Karst Desertification Control, Guizhou Normal University, Guiyang, China
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5
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Santos BLP, Vieira IMM, Ruzene DS, Silva DP. Unlocking the potential of biosurfactants: Production, applications, market challenges, and opportunities for agro-industrial waste valorization. ENVIRONMENTAL RESEARCH 2024; 244:117879. [PMID: 38086503 DOI: 10.1016/j.envres.2023.117879] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/19/2023]
Abstract
Biosurfactants are eco-friendly compounds with unique properties and promising potential as sustainable alternatives to chemical surfactants. The current review explores the multifaceted nature of biosurfactant production and applications, highlighting key fermentative parameters and microorganisms able to convert carbon-containing sources into biosurfactants. A spotlight is given on biosurfactants' obstacles in the global market, focusing on production costs and the challenges of large-scale synthesis. Innovative approaches to valorizing agro-industrial waste were discussed, documenting the utilization of lignocellulosic waste, food waste, oily waste, and agro-industrial wastewater in the segment. This strategy strongly contributes to large-scale, cost-effective, and environmentally friendly biosurfactant production, while the recent advances in waste valorization pave the way for a sustainable society.
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Affiliation(s)
| | | | - Denise Santos Ruzene
- Northeastern Biotechnology Network, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil; Center for Exact Sciences and Technology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil; Graduate Program in Biotechnology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil
| | - Daniel Pereira Silva
- Northeastern Biotechnology Network, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil; Center for Exact Sciences and Technology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil; Graduate Program in Biotechnology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil; Graduate Program in Intellectual Property Science, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil.
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6
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Pastora AB, Rzasa KM, O’Toole GA. Multiple Pathways Impact Swarming Motility of Pseudomonas fluorescens Pf0-1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.576057. [PMID: 38293239 PMCID: PMC10827169 DOI: 10.1101/2024.01.17.576057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Swarming motility in pseudomonads typically requires both a functional flagellum and production/secretion of a biosurfactant. Published work has shown that the wild-type Pseudomonas fluorescens Pf0-1 is swarming-deficient due to a point mutation in the gacA gene, which until recently, was thought to inactivate rather than attenuate the Gac/Rsm pathway. As a result, little is known about the underlying mechanisms that regulate swarming motility by P. fluorescens Pf0-1. Here, we demonstrate that a ΔrsmA ΔrsmE ΔrsmI mutant, which phenotypically mimics Gac/Rsm pathway overstimulation, is proficient at swarming motility. RsmA and RsmE appear to play a key role in this regulation. Transposon mutagenesis of the ΔrsmA ΔrsmE ΔrsmI mutant identified multiple factors that impact swarming motility, including pathways involved in flagellar synthesis and biosurfactant production/secretion. We find that loss of genes linked to biosurfactant Gacamide A biosynthesis or secretion impact swarming motility, as does loss of the alternative sigma factor FliA, which results in a defect in flagellar function. Collectively, these findings provide evidence that P. fluorescens Pf0-1 can swarm if the Gac/Rsm pathway is activated, highlight the regulatory complexity of swarming motility in this strain, and demonstrate that the cyclic lipopeptide Gacamide A is utilized as a biosurfactant for swarming motility.
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Affiliation(s)
- Alexander B. Pastora
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Kara M. Rzasa
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, USA
| | - George A. O’Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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7
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Świątczak J, Kalwasińska A, Brzezinska MS. Plant growth-promoting rhizobacteria: Peribacillus frigoritolerans 2RO30 and Pseudomonas sivasensis 2RO45 for their effect on canola growth under controlled as well as natural conditions. FRONTIERS IN PLANT SCIENCE 2024; 14:1233237. [PMID: 38259930 PMCID: PMC10800854 DOI: 10.3389/fpls.2023.1233237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 12/15/2023] [Indexed: 01/24/2024]
Abstract
Even though canola is one of the most important industrial crops worldwide, it has high nutrient requirements and is susceptible to pests and diseases. Therefore, natural methods are sought to support the development of these plants. One of those methods could be a plant growth-promoting rhizobacteria (PGPR) that have a beneficial effect on plant development. The aim of this study was a genomic comparison of two PGPR strains chosen based on their effect on canola growth: Peribacillus frigoritolerans 2RO30, which stimulated canola growth only in sterile conditions, and Pseudomonas sivasensis 2RO45, which promoted canola growth in both sterile and non-sterile conditions. First of all, six bacterial strains: RO33 (Pseudomonas sp.), RO37 (Pseudomonas poae), RO45 (Pseudomonas kairouanensis), 2RO30 (Peribacillus frigoritolerans), 2RO45 (Pseudomonas sivasensis), and 3RO30 (Pseudomonas migulae), demonstrating best PGP traits in vitro, were studied for their stimulating effect on canola growth under sterile conditions. P. frigoritolerans 2RO30 and P. sivasensis 2RO45 showed the best promoting effect, significantly improving chlorophyll content index (CCI) and roots length compared to the non-inoculated control and to other inoculated seedlings. Under non-sterile conditions, only P. sivasensis 2RO45 promoted the canola growth, significantly increasing CCI compared to the untreated control and to other inoculants. Genome comparison revealed that the genome of P. sivasensis 2RO45 was enriched with additional genes responsible for ACC deaminase (acdA), IAA (trpF, trpG), and siderophores production (fbpA, mbtH, and acrB) compared to 2RO30. Moreover, P. sivasensis 2RO45 showed antifungal effect against all the tested phytopathogens and harbored six more biosynthetic gene clusters (BGC), namely, syringomycin, pyoverdin, viscosin, arylpolyene, lankacidin C, and enterobactin, than P. frigoritolerans 2RO30. These BGCs are well known as antifungal agents; therefore, it can be assumed that these BGCs were responsible for the antifungal activity of P. sivasensis 2RO45 against all plant pathogens. This study is the first report describing P. sivasensis 2RO45 as a canola growth promoter, both under controlled and natural conditions, thus suggesting its application in improving canola yield, by improving nutrient availability, enhancing stress tolerance, and reducing environmental impact of farming practices.
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Affiliation(s)
- Joanna Świątczak
- Department of Environmental Microbiology and Biotechnology, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | | | - Maria Swiontek Brzezinska
- Department of Environmental Microbiology and Biotechnology, Nicolaus Copernicus University in Toruń, Toruń, Poland
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8
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Das R, Hoysall C, Rao L. Unveiling the origin, fate, and remedial approaches for surfactants in sewage-fed foaming urban (Bellandur) Lake. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 339:122773. [PMID: 37858701 DOI: 10.1016/j.envpol.2023.122773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
Foam formation in surface water bodies has become a global phenomenon, but the solutions to this crisis are often insufficient. Foam formation in water bodies is attributed to surfactants and requires a comprehensive assessment of various sources of surfactants to evolve mitigation strategies. The study is focused on thoroughly analyzing surfactants in the water and foam fractions of a large waterbody in Bangalore (India) spanning around 1000 acres (400 ha), which has been foaming for two decades. Results revealed that the key surfactants originate predominantly from anthropogenic sources with a small component emerging from naturogenic sources. Anthropogenic surfactants were found to be predominant (96.5%), with linear alkylbenzene sulphonates (LAS) of various C-chain lengths 12-20 being the most prevalent. Naturogenic surfactants derived from bacterial genera Pseudomonas exhibited significant microbial diversity, accounting for over 19% of total bacterial population in both the water and organic sediments of the lake. Modelling studies and field validation efforts were carried out to understand the fate of LAS in the foaming lake. The results indicated that these surfactants donot degrade under the prevailing conditions and timeframe as wastewater traverses through the lake, and their presence was also observed in the organic sludge sediment. Modeling the underlying processes revealed that a minimum dissolved oxygen (DO) concentration of 3.5 mg/l enables the degradation of over 90% of surfactants within the residence time of 8-10 days in Lake. Additionally, the process of desludging could contribute to an additional increase to the overall efficiency of surfactant removal, simultaneously removing legacy sorbed surfactants to sediments.
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Affiliation(s)
- Reshmi Das
- Centre for Sustainable Technologies, Indian Institute of Science, Bangalore, India.
| | - Chanakya Hoysall
- Centre for Sustainable Technologies, Indian Institute of Science, Bangalore, India
| | - Lakshminarayana Rao
- Centre for Sustainable Technologies, Indian Institute of Science, Bangalore, India
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9
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Shepherd MJ, Pierce AP, Taylor TB. Evolutionary innovation through transcription factor rewiring in microbes is shaped by levels of transcription factor activity, expression, and existing connectivity. PLoS Biol 2023; 21:e3002348. [PMID: 37871011 PMCID: PMC10621929 DOI: 10.1371/journal.pbio.3002348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 11/02/2023] [Accepted: 09/25/2023] [Indexed: 10/25/2023] Open
Abstract
The survival of a population during environmental shifts depends on whether the rate of phenotypic adaptation keeps up with the rate of changing conditions. A common way to achieve this is via change to gene regulatory network (GRN) connections-known as rewiring-that facilitate novel interactions and innovation of transcription factors. To understand the success of rapidly adapting organisms, we therefore need to determine the rules that create and constrain opportunities for GRN rewiring. Here, using an experimental microbial model system with the soil bacterium Pseudomonas fluorescens, we reveal a hierarchy among transcription factors that are rewired to rescue lost function, with alternative rewiring pathways only unmasked after the preferred pathway is eliminated. We identify 3 key properties-high activation, high expression, and preexisting low-level affinity for novel target genes-that facilitate transcription factor innovation. Ease of acquiring these properties is constrained by preexisting GRN architecture, which was overcome in our experimental system by both targeted and global network alterations. This work reveals the key properties that determine transcription factor evolvability, and as such, the evolution of GRNs.
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Affiliation(s)
- Matthew J. Shepherd
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Aidan P. Pierce
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - Tiffany B. Taylor
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
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10
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Flanagan LM, Horton JS, Taylor TB. Mutational hotspots lead to robust but suboptimal adaptive outcomes in certain environments. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001395. [PMID: 37815519 PMCID: PMC10634368 DOI: 10.1099/mic.0.001395] [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: 05/27/2023] [Accepted: 09/19/2023] [Indexed: 10/11/2023]
Abstract
The observed mutational spectrum of adaptive outcomes can be constrained by many factors. For example, mutational biases can narrow the observed spectrum by increasing the rate of mutation at isolated sites in the genome. In contrast, complex environments can shift the observed spectrum by defining fitness consequences of mutational routes. We investigate the impact of different nutrient environments on the evolution of motility in Pseudomonas fluorescens Pf0-2x (an engineered non-motile derivative of Pf0-1) in the presence and absence of a strong mutational hotspot. Previous work has shown that this mutational hotspot can be built and broken via six silent mutations, which provide rapid access to a mutation that rescues swimming motility and confers the strongest swimming phenotype in specific environments. Here, we evolved a hotspot and non-hotspot variant strain of Pf0-2x for motility under nutrient-rich (LB) and nutrient-limiting (M9) environmental conditions. We observed the hotspot strain consistently evolved faster across all environmental conditions and its mutational spectrum was robust to environmental differences. However, the non-hotspot strain had a distinct mutational spectrum that changed depending on the nutrient environment. Interestingly, while alternative adaptive mutations in nutrient-rich environments were equal to, or less effective than, the hotspot mutation, the majority of these mutations in nutrient-limited conditions produced superior swimmers. Our competition experiments mirrored these findings, underscoring the role of environment in defining both the mutational spectrum and the associated phenotype strength. This indicates that while mutational hotspots working in concert with natural selection can speed up access to robust adaptive mutations (which can provide a competitive advantage in evolving populations), they can limit exploration of the mutational landscape, restricting access to potentially stronger phenotypes in specific environments.
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Affiliation(s)
| | - James S. Horton
- Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK
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11
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Shepherd MJ, Reynolds M, Pierce AP, Rice AM, Taylor TB. Transcription factor expression levels and environmental signals constrain transcription factor innovation. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001378. [PMID: 37584667 PMCID: PMC10482368 DOI: 10.1099/mic.0.001378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
Evolutionary innovation of transcription factors frequently drives phenotypic diversification and adaptation to environmental change. Transcription factors can gain or lose connections to target genes, resulting in novel regulatory responses and phenotypes. However the frequency of functional adaptation varies between different regulators, even when they are closely related. To identify factors influencing propensity for innovation, we utilise a Pseudomonas fluorescens SBW25 strain rendered incapable of flagellar mediated motility in soft-agar plates via deletion of the flagellar master regulator (fleQ ). This bacterium can evolve to rescue flagellar motility via gene regulatory network rewiring of an alternative transcription factor to rescue activity of FleQ. Previously, we have identified two members (out of 22) of the RpoN-dependent enhancer binding protein (RpoN-EBP) family of transcription factors (NtrC and PFLU1132) that are capable of innovating in this way. These two transcription factors rescue motility repeatably and reliably in a strict hierarchy – with NtrC the only route in a ∆fleQ background, and PFLU1132 the only route in a ∆fleQ ∆ntrC background. However, why other members in the same transcription factor family have not been observed to rescue flagellar activity is unclear. Previous work shows that protein homology cannot explain this pattern within the protein family (RpoN-EBPs), and mutations in strains that rescued motility suggested high levels of transcription factor expression and activation drive innovation. We predict that mutations that increase expression of the transcription factor are vital to unlock evolutionary potential for innovation. Here, we construct titratable expression mutant lines for 11 of the RpoN-EBPs in P. fluorescens . We show that in five additional RpoN-EBPs (FleR, HbcR, GcsR, DctD, AauR and PFLU2209), high expression levels result in different mutations conferring motility rescue, suggesting alternative rewiring pathways. Our results indicate that expression levels (and not protein homology) of RpoN-EBPs are a key constraining factor in determining evolutionary potential for innovation. This suggests that transcription factors that can achieve high expression through few mutational changes, or transcription factors that are active in the selective environment, are more likely to innovate and contribute to adaptive gene regulatory network evolution.
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Affiliation(s)
- Matthew J. Shepherd
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Mitchell Reynolds
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Aidan P. Pierce
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Alan M. Rice
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tiffany B. Taylor
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
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12
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Ibrahim E, Nasser R, Hafeez R, Ogunyemi SO, Abdallah Y, Khattak AA, Shou L, Zhang Y, Ahmed T, Atef Hatamleh A, Abdullah Al-Dosary M, M Ali H, Luo J, Li B. Biocontrol Efficacy of Endophyte Pseudomonas poae to Alleviate Fusarium Seedling Blight by Refining the Morpho-Physiological Attributes of Wheat. PLANTS (BASEL, SWITZERLAND) 2023; 12:2277. [PMID: 37375902 DOI: 10.3390/plants12122277] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 06/08/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023]
Abstract
Some endophyte bacteria can improve plant growth and suppress plant diseases. However, little is known about the potential of endophytes bacteria to promote wheat growth and suppress the Fusarium seedling blight pathogen Fusarium graminearum. This study was conducted to isolate and identify endophytic bacteria and evaluate their efficacy for the plant growth promotion and disease suppression of Fusarium seedling blight (FSB) in wheat. The Pseudomonas poae strain CO showed strong antifungal activity in vitro and under greenhouse conditions against F. graminearum strain PH-1. The cell-free supernatants (CFSs) of P. poae strain CO were able to inhibit the mycelium growth, the number of colonies forming, spore germination, germ tube length, and the mycotoxin production of FSB with an inhibition rate of 87.00, 62.25, 51.33, 69.29, and 71.08%, respectively, with the highest concentration of CFSs. The results indicated that P. poae exhibited multifarious antifungal properties, such as the production of hydrolytic enzymes, siderophores, and lipopeptides. In addition, compared to untreated seeds, wheat plants treated with the strain showed significant growth rates, where root and shoot length increased by about 33% and the weight of fresh roots, fresh shoots, dry roots, and dry shoots by 50%. In addition, the strain produced high levels of indole-3-acetic acid, phosphate solubilization, and nitrogen fixation. Finally, the strain demonstrated strong antagonistic properties as well as a variety of plant growth-promoting properties. Thus, this result suggest that this strain could be used as an alternate to synthetic chemicals, which can serve as an effective method of protecting wheat from fungal infection.
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Affiliation(s)
- Ezzeldin Ibrahim
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
- Department of Vegetable Diseases Research, Plant Pathology Research Institute, Agriculture Research Centre, Giza 12916, Egypt
| | - Raghda Nasser
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Zoology and Entomology Department, Faculty of Science, Minia University, Elminya 61519, Egypt
| | - Rahila Hafeez
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Solabomi Olaitan Ogunyemi
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Yasmine Abdallah
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Arif Ali Khattak
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Linfei Shou
- Station for the Plant Protection & Quarantine and Control of Agrochemicals Zhejiang Province, Hangzhou 310004, China
| | - Yang Zhang
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Temoor Ahmed
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Ashraf Atef Hatamleh
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Munirah Abdullah Al-Dosary
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Hayssam M Ali
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Jinyan Luo
- Department of Plant Quarantine, Shanghai Extension and Service Center of Agriculture Technology, Shanghai 201103, China
| | - Bin Li
- State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
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13
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Niem JM, Billones-Baaijens R, Stodart BJ, Reveglia P, Savocchia S. Biocontrol Potential of an Endophytic Pseudomonas poae Strain against the Grapevine Trunk Disease Pathogen Neofusicoccum luteum and Its Mechanism of Action. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12112132. [PMID: 37299111 DOI: 10.3390/plants12112132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/11/2023] [Accepted: 05/21/2023] [Indexed: 06/12/2023]
Abstract
Grapevine trunk diseases (GTDs) impact the sustainability of vineyards worldwide and management options are currently limited. Biological control agents (BCAs) may offer a viable alternative for disease control. With an aim to develop an effective biocontrol strategy against the GTD pathogen Neofusicoccum luteum, this study investigated the following: (1) the efficacy of the strains in suppressing the BD pathogen N. luteum in detached canes and potted vines; (2) the ability of a strain of Pseudomonas poae (BCA17) to colonize and persist within grapevine tissues; and (3) the mode of action of BCA17 to antagonize N. luteum. Co-inoculations of the antagonistic bacterial strains with N. luteum revealed that one strain of P. poae (BCA17) suppressed infection by 100% and 80% in detached canes and potted vines, respectively. Stem inoculations of a laboratory-generated rifampicin-resistant strain of BCA17 in potted vines (cv. Shiraz) indicated the bacterial strain could colonize and persist in the grapevine tissues, potentially providing some protection against GTDs for up to 6 months. The bioactive diffusible compounds secreted by BCA17 significantly reduced the spore germination and fungal biomass of N. luteum and the other representative GTD pathogens. Complementary analysis via MALDI-TOF revealed the presence of an unknown cyclic lipopeptide in the bioactive diffusible compounds, which was absent in a non-antagonistic strain of P. poae (JMN13), suggesting this novel lipopeptide may be responsible for the biocontrol activity of the BCA17. Our study provided evidence that P. poae BCA17 is a potential BCA to combat N. luteum, with a potential novel mode of action.
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Affiliation(s)
- Jennifer Millera Niem
- Gulbali Institute, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
- Faculty of Science and Health, School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
- UPLB Museum of Natural History, University of the Philippines Los Baños, College, Los Baños 4031, Laguna, Philippines
- Institute of Weed Science, Entomology, and Plant Pathology, College of Agriculture and Food Science, University of the Philippines Los Baños, College, Los Baños 4031, Laguna, Philippines
| | | | - Benjamin J Stodart
- Gulbali Institute, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
- Faculty of Science and Health, School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
| | - Pierluigi Reveglia
- Gulbali Institute, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
- Faculty of Science and Health, School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
- Institute for Sustainable Agriculture, CSIC, 14004 Córdoba, Spain
| | - Sandra Savocchia
- Gulbali Institute, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
- Faculty of Science and Health, School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
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14
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Horton JS, Ali SUP, Taylor TB. Transient mutation bias increases the predictability of evolution on an empirical genotype-phenotype landscape. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220043. [PMID: 37004722 PMCID: PMC10067260 DOI: 10.1098/rstb.2022.0043] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 01/25/2023] [Indexed: 04/04/2023] Open
Abstract
Predicting how a population will likely navigate a genotype-phenotype landscape requires consideration of selection in combination with mutation bias, which can skew the likelihood of following a particular trajectory. Strong and persistent directional selection can drive populations to ascend toward a peak. However, with a greater number of peaks and more routes to reach them, adaptation inevitably becomes less predictable. Transient mutation bias, which operates only on one mutational step, can influence landscape navigability by biasing the mutational trajectory early in the adaptive walk. This sets an evolving population upon a particular path, constraining the number of accessible routes and making certain peaks and routes more likely to be realized than others. In this work, we employ a model system to investigate whether such transient mutation bias can reliably and predictably place populations on a mutational trajectory to the strongest selective phenotype or usher populations to realize inferior phenotypic outcomes. For this we use motile mutants evolved from ancestrally non-motile variants of the microbe Pseudomonas fluorescens SBW25, of which one trajectory exhibits significant mutation bias. Using this system, we elucidate an empirical genotype-phenotype landscape, where the hill-climbing process represents increasing strength of the motility phenotype, to reveal that transient mutation bias can facilitate rapid and predictable ascension to the strongest observed phenotype in place of equivalent and inferior trajectories. This article is part of the theme issue 'Interdisciplinary approaches to predicting evolutionary biology'.
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Affiliation(s)
- James S. Horton
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Shani U. P. Ali
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tiffany B. Taylor
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
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15
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Adnan M, Siddiqui AJ, Noumi E, Hannachi S, Ashraf SA, Awadelkareem AM, Snoussi M, Badraoui R, Bardakci F, Sachidanandan M, Patel M, Patel M. Integrating Network Pharmacology Approaches to Decipher the Multi-Target Pharmacological Mechanism of Microbial Biosurfactants as Novel Green Antimicrobials against Listeriosis. Antibiotics (Basel) 2022; 12:antibiotics12010005. [PMID: 36671206 PMCID: PMC9854906 DOI: 10.3390/antibiotics12010005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Listeria monocytogenes (L. monocytogenes) is a serious food-borne pathogen that can cause listeriosis, an illness caused by eating food contaminated with this pathogen. Currently, the treatment or prevention of listeriosis is a global challenge due to the resistance of bacteria against multiple commonly used antibiotics, thus necessitating the development of novel green antimicrobials. Scientists are increasingly interested in microbial surfactants, commonly known as "biosurfactants", due to their antimicrobial properties and eco-friendly nature, which make them an ideal candidate to combat a variety of bacterial infections. Therefore, the present study was designed to use a network pharmacology approach to uncover the active biosurfactants and their potential targets, as well as the signaling pathway(s) involved in listeriosis treatment. In the framework of this study, 15 biosurfactants were screened out for subsequent studies. Among 546 putative targets of biosurfactants and 244 targets of disease, 37 targets were identified as potential targets for treatment of L. monocytogenes infection, and these 37 targets were significantly enriched in a Gene Ontology (GO) analysis, which aims to identify those biological processes, cellular locations, and molecular functions that are impacted in the condition studied. The obtained results revealed several important biological processes, such as positive regulation of MAP kinase activity, protein kinase B signaling, ERK1 and ERK2 cascade, ERBB signaling pathway, positive regulation of protein serine/threonine kinase activity, and regulation of caveolin-mediated endocytosis. Several important KEGG pathways, such as the ERBBB signaling pathway, TH17 cell differentiation, HIF-1 signaling pathway, Yersinia infection, Shigellosis, and C-type lectin receptor signaling pathways, were identified. The protein-protein interaction analysis yielded 10 core targets (IL2, MAPK1, EGFR, PTPRC, TNF, ITGB1, IL1B, ERBB2, SRC, and mTOR). Molecular docking was used in the latter part of the study to verify the effectiveness of the active biosurfactants against the potential targets. Lastly, we found that a few highly active biosurfactants, namely lichenysin, iturin, surfactin, rhamnolipid, subtilisin, and polymyxin, had high binding affinities towards IL2, MAPK1, EGFR, PTPRC, TNF, ITGB1, IL1B, ERBB2, SRC, and mTOR, which may act as potential therapeutic targets for listeriosis. Overall, based on the integrated network pharmacology and docking analysis, we found that biosurfactants possess promising anti-listeriosis properties and explored the pharmacological mechanisms behind their effect, laying the groundwork for further research and development.
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Affiliation(s)
- Mohd Adnan
- Department of Biology, College of Science, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Arif Jamal Siddiqui
- Department of Biology, College of Science, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Emira Noumi
- Department of Biology, College of Science, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Sami Hannachi
- Department of Biology, College of Science, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Syed Amir Ashraf
- Department of Clinical Nutrition, College of Applied Medial Sciences, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Amir Mahgoub Awadelkareem
- Department of Clinical Nutrition, College of Applied Medial Sciences, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Mejdi Snoussi
- Department of Biology, College of Science, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Riadh Badraoui
- Department of Biology, College of Science, University of Hail, Hail P.O. Box 2440, Saudi Arabia
- Section of Histology-Cytology, Medicine Faculty of Tunis, University of Tunis El Manar, La Rabta 1007, Tunis, Tunisia
| | - Fevzi Bardakci
- Department of Biology, College of Science, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Manojkumar Sachidanandan
- Department of Oral Radiology, College of Dentistry, University of Hail, Hail P.O. Box 2440, Saudi Arabia
| | - Mirav Patel
- Department of Biotechnology, Parul Institute of Applied Sciences and Centre of Research for Development, Parul University, Vadodara 391760, India
| | - Mitesh Patel
- Department of Biotechnology, Parul Institute of Applied Sciences and Centre of Research for Development, Parul University, Vadodara 391760, India
- Correspondence:
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16
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Characterization and Assessment of 2, 4-Diacetylphloroglucinol (DAPG)-Producing Pseudomonas fluorescens VSMKU3054 for the Management of Tomato Bacterial Wilt Caused by Ralstonia solanacearum. Microorganisms 2022; 10:microorganisms10081508. [PMID: 35893565 PMCID: PMC9330548 DOI: 10.3390/microorganisms10081508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 12/04/2022] Open
Abstract
Microbial bio-products are becoming an appealing and viable alternative to chemical pesticides for effective management of crop diseases. These bio-products are known to have potential to minimize agrochemical applications without losing crop yield and also restore soil fertility and productivity. In this study, the inhibitory efficacy of 2,4-diacetylphloroglucinol (DAPG) produced by Pseudomonas fluorescens VSMKU3054 against Ralstonia solanacearum was assessed. Biochemical and functional characterization study revealed that P. fluorescens produced hydrogen cyanide (HCN), siderophore, indole acetic acid (IAA) and hydrolytic enzymes such as amylase, protease, cellulase and chitinase, and had the ability to solubilize phosphate. The presence of the key antimicrobial encoding gene in the biosynthesis of 2,4-diacetylphloroglucinol (DAPG) was identified by PCR. The maximum growth and antimicrobial activity of P. fluorescens was observed in king’s B medium at pH 7, 37 °C and 36 h of growth. Glucose and tryptone were found to be the most suitable carbon and nitrogen sources, respectively. DAPG was separated by silica column chromatography and identified by various methods such as UV-Vis, FT-IR, GC-MS and NMR spectroscopy. When R. solanacearum cells were exposed to DAPG at 90 µg/mL, the cell viability was decreased, reactive oxygen species (ROS) were increased and chromosomal DNA was damaged. Application of P. fluorescens and DAPG significantly reduced the bacterial wilt incidence. In addition, P. fluorescens was also found effective in promoting the growth of tomato seedlings. It is concluded that the indigenous isolate P. fluorescens VSMKU3054 could be used as a suitable biocontrol agent against bacterial wilt disease of tomato.
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17
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Shepherd MJ, Horton JS, Taylor TB. A near-deterministic mutational hotspot in Pseudomonas fluorescens is constructed by multiple interacting genomic features. Mol Biol Evol 2022; 39:msac132. [PMID: 35707979 PMCID: PMC9234803 DOI: 10.1093/molbev/msac132] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/27/2022] [Accepted: 06/06/2022] [Indexed: 01/12/2023] Open
Abstract
Mutation - whilst stochastic - is frequently biased toward certain loci. When combined with selection this results in highly repeatable and predictable evolutionary outcomes. Immotile variants of the bacterium Pseudomonas fluorescens (SBW25) possess a 'mutational hotspot' that facilitates repeated occurrences of an identical de novo single nucleotide polymorphism when re-evolving motility, where ≥95% independent lines fix the mutation ntrB A289C. Identifying hotspots of similar potency in other genes and genomic backgrounds would prove valuable for predictive evolutionary models, but to do so we must understand the genomic features that enable such a hotspot to form. Here we reveal that genomic location, local nucleotide sequence, gene strandedness and presence of mismatch repair proteins operate in combination to facilitate the formation of this mutational hotspot. Our study therefore provides a framework for utilising genomic features to predict and identify hotspot positions capable of enforcing near-deterministic evolution.
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Affiliation(s)
- M J Shepherd
- Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - J S Horton
- Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - T B Taylor
- Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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18
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Styczynski M, Biegniewski G, Decewicz P, Rewerski B, Debiec-Andrzejewska K, Dziewit L. Application of Psychrotolerant Antarctic Bacteria and Their Metabolites as Efficient Plant Growth Promoting Agents. Front Bioeng Biotechnol 2022; 10:772891. [PMID: 35284420 PMCID: PMC8907978 DOI: 10.3389/fbioe.2022.772891] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 02/07/2022] [Indexed: 01/04/2023] Open
Abstract
Iron is the fourth most abundant element on earth. However, its low bioavailability is a key plant-growth limiting factor. Bacteria play an important role in plant growth promotion since they produce specific secondary metabolites that may increase macro- and micronutrient accessibility in soil. Therefore, bacterial-derived iron chelators, as well as surface-active compounds, are recognised as essential to plant welfare. In this study, three cold-active Antarctic bacterial strains, i.e. Pseudomonas sp. ANT_H12B, Psychrobacter sp. ANT_H59 and Bacillus sp. ANT_WA51, were analysed. The physiological and genomic characterisation of these strains revealed their potential for plant growth promotion, reflected in the production of various biomolecules, including biosurfactants (that may lower the medium surface tension of even up to 53%) and siderophores (including ANT_H12B-produced mixed-type siderophore that demonstrated the highest production, reaching the concentration of up to 1.065 mM), increasing the availability of nutrients in the environment and neutralising fungal pathogens. Tested bacteria demonstrated an ability to promote the growth of a model plant, alfalfa, increasing shoots’ length and fresh biomass even up to 26 and 46% respectively; while their metabolites increased the bioavailability of iron in soil up to 40%. It was also revealed that the introduced strains did not disrupt physicochemical conditions and indigenous soil microbial composition, which suggests that they are promising amendments preserving the natural biodiversity of soil and increasing its fertility.
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Affiliation(s)
- Michal Styczynski
- Institute of Microbiology, Department of Environmental Microbiology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Gabriel Biegniewski
- Institute of Microbiology, Department of Environmental Microbiology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Przemyslaw Decewicz
- Institute of Microbiology, Department of Environmental Microbiology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Bartosz Rewerski
- Institute of Microbiology, Department of Geomicrobiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Klaudia Debiec-Andrzejewska
- Institute of Microbiology, Department of Environmental Microbiology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Lukasz Dziewit
- Institute of Microbiology, Department of Environmental Microbiology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- *Correspondence: Lukasz Dziewit,
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19
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Pacheco-Moreno A, Stefanato FL, Ford JJ, Trippel C, Uszkoreit S, Ferrafiat L, Grenga L, Dickens R, Kelly N, Kingdon AD, Ambrosetti L, Nepogodiev SA, Findlay KC, Cheema J, Trick M, Chandra G, Tomalin G, Malone JG, Truman AW. Pan-genome analysis identifies intersecting roles for Pseudomonas specialized metabolites in potato pathogen inhibition. eLife 2021; 10:71900. [PMID: 34792466 PMCID: PMC8719888 DOI: 10.7554/elife.71900] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/16/2021] [Indexed: 11/29/2022] Open
Abstract
Agricultural soil harbors a diverse microbiome that can form beneficial relationships with plants, including the inhibition of plant pathogens. Pseudomonas spp. are one of the most abundant bacterial genera in the soil and rhizosphere and play important roles in promoting plant health. However, the genetic determinants of this beneficial activity are only partially understood. Here, we genetically and phenotypically characterize the Pseudomonas fluorescens population in a commercial potato field, where we identify strong correlations between specialized metabolite biosynthesis and antagonism of the potato pathogens Streptomyces scabies and Phytophthora infestans. Genetic and chemical analyses identified hydrogen cyanide and cyclic lipopeptides as key specialized metabolites associated with S. scabies inhibition, which was supported by in planta biocontrol experiments. We show that a single potato field contains a hugely diverse and dynamic population of Pseudomonas bacteria, whose capacity to produce specialized metabolites is shaped both by plant colonization and defined environmental inputs. Potato scab and blight are two major diseases which can cause heavy crop losses. They are caused, respectively, by the bacterium Streptomyces scabies and an oomycete (a fungus-like organism) known as Phytophthora infestans. Fighting these disease-causing microorganisms can involve crop management techniques – for example, ensuring that a field is well irrigated helps to keep S. scabies at bay. Harnessing biological control agents can also offer ways to control disease while respecting the environment. Biocontrol bacteria, such as Pseudomonas, can produce compounds that keep S. scabies and P. infestans in check. However, the identity of these molecules and how irrigation can influence Pseudomonas population remains unknown. To examine these questions, Pacheco-Moreno et al. sampled and isolated hundreds of Pseudomonas strains from a commercial potato field, closely examining the genomes of 69 of these. Comparing the genetic information of strains based on whether they could control the growth of S. scabies revealed that compounds known as cyclic lipopeptides are key to controlling the growth of S. scabies and P. infestans. Whether the field was irrigated also had a large impact on the strains forming the Pseudomonas population. Working out how Pseudomonas bacteria block disease could speed up the search for biological control agents. The approach developed by Pacheco-Moreno et al. could help to predict which strains might be most effective based on their genetic features. Similar experiments could also work for other combinations of plants and diseases.
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Affiliation(s)
- Alba Pacheco-Moreno
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jonathan J Ford
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Christine Trippel
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Simon Uszkoreit
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Laura Ferrafiat
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Lucia Grenga
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Ruth Dickens
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Nathan Kelly
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Alexander Dh Kingdon
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Liana Ambrosetti
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Sergey A Nepogodiev
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich, United Kingdom
| | - Kim C Findlay
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Jitender Cheema
- Department of Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Martin Trick
- Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Andrew W Truman
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
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20
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Sharma J, Sundar D, Srivastava P. Biosurfactants: Potential Agents for Controlling Cellular Communication, Motility, and Antagonism. Front Mol Biosci 2021; 8:727070. [PMID: 34708073 PMCID: PMC8542798 DOI: 10.3389/fmolb.2021.727070] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/02/2021] [Indexed: 12/29/2022] Open
Abstract
Biosurfactants are surface-active molecules produced by microorganisms, either on the cell surface or secreted extracellularly. They form a thin film on the surface of microorganisms and help in their detachment or attachment to other cell surfaces. They are involved in regulating the motility of bacteria and quorum sensing. Here, we describe the various types of biosurfactants produced by microorganisms and their role in controlling motility, antagonism, virulence, and cellular communication.
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Affiliation(s)
- Jyoti Sharma
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - Durai Sundar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - Preeti Srivastava
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
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21
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Horton JS, Flanagan LM, Jackson RW, Priest NK, Taylor TB. A mutational hotspot that determines highly repeatable evolution can be built and broken by silent genetic changes. Nat Commun 2021; 12:6092. [PMID: 34667151 PMCID: PMC8526746 DOI: 10.1038/s41467-021-26286-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/28/2021] [Indexed: 11/08/2022] Open
Abstract
Mutational hotspots can determine evolutionary outcomes and make evolution repeatable. Hotspots are products of multiple evolutionary forces including mutation rate heterogeneity, but this variable is often hard to identify. In this work, we reveal that a near-deterministic genetic hotspot can be built and broken by a handful of silent mutations. We observe this when studying homologous immotile variants of the bacteria Pseudomonas fluorescens, AR2 and Pf0-2x. AR2 resurrects motility through highly repeatable de novo mutation of the same nucleotide in >95% lines in minimal media (ntrB A289C). Pf0-2x, however, evolves via a number of mutations meaning the two strains diverge significantly during adaptation. We determine that this evolutionary disparity is owed to just 6 synonymous variations within the ntrB locus, which we demonstrate by swapping the sites and observing that we are able to both break (>95% to 0%) and build (0% to 80%) a deterministic mutational hotspot. Our work reveals a key role for silent genetic variation in determining adaptive outcomes.
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Affiliation(s)
- James S Horton
- Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Louise M Flanagan
- Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Robert W Jackson
- School of Biosciences and Birmingham Institute of Forest Research (BIFoR), University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Nicholas K Priest
- Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Tiffany B Taylor
- Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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22
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Mishra S, Lin Z, Pang S, Zhang Y, Bhatt P, Chen S. Biosurfactant is a powerful tool for the bioremediation of heavy metals from contaminated soils. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126253. [PMID: 34119972 DOI: 10.1016/j.jhazmat.2021.126253] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/26/2021] [Accepted: 05/26/2021] [Indexed: 05/05/2023]
Abstract
Heavy metal toxicity has become a pressing ecological problem that affects the ecosystems through bioaccumulation, representing a serious public health hazard. Many conventional strategies have been developed and applied to decontaminate and restore metal-contaminated areas. However, these conventional approaches are not very suitable and environmentally safe for heavy metal remediation because of their high operational costs, high energy requirements, post-waste disposal problems, and secondary pollutant generation. Thus, biosurfactant-based bioremediation of heavy metals is a sustainable and promising approach because of its biodegradation capability, economic effectiveness, and ecofriendly nature. Pseudomonas sp., Bacillus sp., Citrobacter freundii, and Candida tropicalis have been isolated as potential sources of biosurfactants and produce compounds such as surfactin, rhamnolipids, and sophorolipids. Owing to the severity of heavy metal pollution in certain parts of the environment, biosurfactants have garnered great interest and attention as an emerging multi-functional technology of the new century for successful removal of heavy metal pollutants. The present study describes the role of biosurfactants in the bioremediation of heavy metals from contaminated environments. Moreover, the interaction mechanism underlying biosurfactant-metal complexation and metal remediation are discussed. Based on the review of the literature, further research is warranted to elucidate the mechanistic roles and explore the structural characterization and gene regulation of biosurfactants to improve their productivity and expand their applicability in bioremediation.
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Affiliation(s)
- Sandhya Mishra
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Ziqiu Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Shimei Pang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Yuming Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Pankaj Bhatt
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China.
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23
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Kumar A, Singh SK, Kant C, Verma H, Kumar D, Singh PP, Modi A, Droby S, Kesawat MS, Alavilli H, Bhatia SK, Saratale GD, Saratale RG, Chung SM, Kumar M. Microbial Biosurfactant: A New Frontier for Sustainable Agriculture and Pharmaceutical Industries. Antioxidants (Basel) 2021; 10:1472. [PMID: 34573103 PMCID: PMC8469275 DOI: 10.3390/antiox10091472] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 11/16/2022] Open
Abstract
In the current scenario of changing climatic conditions and the rising global population, there is an urgent need to explore novel, efficient, and economical natural products for the benefit of humankind. Biosurfactants are one of the latest explored microbial synthesized biomolecules that have been used in numerous fields, including agriculture, pharmaceuticals, cosmetics, food processing, and environment-cleaning industries, as a source of raw materials, for the lubrication, wetting, foaming, emulsions formulations, and as stabilizing dispersions. The amphiphilic nature of biosurfactants have shown to be a great advantage, distributing themselves into two immiscible surfaces by reducing the interfacial surface tension and increasing the solubility of hydrophobic compounds. Furthermore, their eco-friendly nature, low or even no toxic nature, durability at higher temperatures, and ability to withstand a wide range of pH fluctuations make microbial surfactants preferable compared to their chemical counterparts. Additionally, biosurfactants can obviate the oxidation flow by eliciting antioxidant properties, antimicrobial and anticancer activities, and drug delivery systems, further broadening their applicability in the food and pharmaceutical industries. Nowadays, biosurfactants have been broadly utilized to improve the soil quality by improving the concentration of trace elements and have either been mixed with pesticides or applied singly on the plant surfaces for plant disease management. In the present review, we summarize the latest research on microbial synthesized biosurfactant compounds, the limiting factors of biosurfactant production, their application in improving soil quality and plant disease management, and their use as antioxidant or antimicrobial compounds in the pharmaceutical industries.
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Affiliation(s)
- Ajay Kumar
- Agriculture Research Organization, Volcani Center, Department of Postharvest Science, Rishon Lezzion 50250, Israel; (A.K.); (A.M.); (S.D.)
| | - Sandeep Kumar Singh
- Centre of Advance Study in Botany, Banaras Hindu University, Varanasi 221005, India; (S.K.S.); (D.K.); (P.P.S.)
| | - Chandra Kant
- Department of Botany, Dharma Samaj College, Aligarh 202001, India;
| | - Hariom Verma
- Department of Botany, B.R.D. Government Degree College, Sonbhadra, Duddhi 231218, India;
| | - Dharmendra Kumar
- Centre of Advance Study in Botany, Banaras Hindu University, Varanasi 221005, India; (S.K.S.); (D.K.); (P.P.S.)
| | - Prem Pratap Singh
- Centre of Advance Study in Botany, Banaras Hindu University, Varanasi 221005, India; (S.K.S.); (D.K.); (P.P.S.)
| | - Arpan Modi
- Agriculture Research Organization, Volcani Center, Department of Postharvest Science, Rishon Lezzion 50250, Israel; (A.K.); (A.M.); (S.D.)
| | - Samir Droby
- Agriculture Research Organization, Volcani Center, Department of Postharvest Science, Rishon Lezzion 50250, Israel; (A.K.); (A.M.); (S.D.)
| | - Mahipal Singh Kesawat
- Department of Genetics and Plant Breeding, Faculty of Agriculture, Sri Sri University, Cuttack 754006, India;
| | - Hemasundar Alavilli
- Department of Bioresources Engineering, Sejong University, Seoul 05006, Korea;
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Korea;
| | | | - Rijuta Ganesh Saratale
- Research Institute of Biotechnology and Medical Converged Science, Dongguk University, Seoul 10326, Korea;
| | - Sang-Min Chung
- Department of Life Science, College of Life Science and Biotechnology, Dongguk University, Seoul 10326, Korea;
| | - Manu Kumar
- Department of Life Science, College of Life Science and Biotechnology, Dongguk University, Seoul 10326, Korea;
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24
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Han Y, Liu S, Chen F, Deng X, Miao Z, Wu Z, Ye BC. Characteristics of plant growth-promoting rhizobacteria SCPG-7 and its effect on the growth of Capsicum annuum L. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:11323-11332. [PMID: 33118066 DOI: 10.1007/s11356-020-11388-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
The strain SCPG-7 was isolated from saline soil in a cotton field. It is confirmed that the strain SCPG-7 is Pseudomonas sp. by means of the analysis of its phenotypic features and 16S rRNA sequence. SCPG-7 was capable of dissolving mineral tri-calcium phosphate (Ca3(PO4)2) and tri-magnesium phosphate (Mg3(PO4)2). In contrast, no showing iron phosphate (FePO4) or aluminum phosphate (AlPO4) solubilizing activities were detected by this experimental approach. The ratio of the dissolved P diameter to the colony diameter was 1.86. To study the phosphate dissolving mechanisms of the strain, we analyzed the changes of the pH value, the soluble phosphate content, the concentration of alkaline phosphatase, and the production of organic acid in the insoluble phosphate liquid medium. 2-keto-D-gluconicacid, α-ketoglutaric acid, succinic acid, etc. were characterized by LC-MS/MS in NBRIP medium. The concentration of 2-keto-D-gluconicacid increased to 88.6 mg/L after being cultured for 216 h. The strain decreased the pH value of the medium from 7.4 to 4.7 and the released soluble phosphate up to 516 mg/L, which proved the production of organic acids and alkaline phosphatase to be mechanism for solubilizing P. Under low phosphorus stress, Pseudomonas global regulatory protein PhoB regulates the transcription of the alkaline phosphatase gene. IAA and siderophore were secreted by SCPG-7. After treatment with SCPG-7, the individual plant height and dry weight of pepper increased by 23.3 and 31.2%, respectively, compared to the control group. The results show that the strain SCPG-7 has the potential to convert insoluble inorganic phosphorus to plant-available phosphorus. It can enhance soil phosphorus release through biological pathways, thereby increasing crop yield, and providing germplasm resources for the development of biological fertilizers.
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Affiliation(s)
- Yajie Han
- School of Chemistry and Chemical Engineering/The Key Lab. for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Shihezi, 832003, People's Republic of China
- College of Life Science, Shihezi University, Shihezi, 832003, People's Republic of China
| | - Shengxue Liu
- Analysis and Testing Center, Shihezi University, Shihezi, 832003, China
| | - Fulong Chen
- College of Life Science, Shihezi University, Shihezi, 832003, People's Republic of China
| | - Xiaolin Deng
- Teachers College, Shihezi University, Shihezi, 832003, People's Republic of China
| | - Zhuang Miao
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Zhansheng Wu
- School of Environmental and Chemical Engineering, Xi'an Polytechnic University, Xi'an, 710048, China.
| | - Bang-Ce Ye
- School of Chemistry and Chemical Engineering/The Key Lab. for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Shihezi, 832003, People's Republic of China.
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Goswami M, Deka S. Isolation of a novel rhizobacteria having multiple plant growth promoting traits and antifungal activity against certain phytopathogens. Microbiol Res 2020; 240:126516. [DOI: 10.1016/j.micres.2020.126516] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 10/24/2022]
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26
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Grenga L, Little RH, Chandra G, Woodcock SD, Saalbach G, Morris RJ, Malone JG. Control of mRNA translation by dynamic ribosome modification. PLoS Genet 2020; 16:e1008837. [PMID: 32584816 PMCID: PMC7343187 DOI: 10.1371/journal.pgen.1008837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/08/2020] [Accepted: 05/07/2020] [Indexed: 01/28/2023] Open
Abstract
Control of mRNA translation is a crucial regulatory mechanism used by bacteria to respond to their environment. In the soil bacterium Pseudomonas fluorescens, RimK modifies the C-terminus of ribosomal protein RpsF to influence important aspects of rhizosphere colonisation through proteome remodelling. In this study, we show that RimK activity is itself under complex, multifactorial control by the co-transcribed phosphodiesterase trigger enzyme (RimA) and a polyglutamate-specific protease (RimB). Furthermore, biochemical experimentation and mathematical modelling reveal a role for the nucleotide second messenger cyclic-di-GMP in coordinating these activities. Active ribosome regulation by RimK occurs by two main routes: indirectly, through changes in the abundance of the global translational regulator Hfq and directly, with translation of surface attachment factors, amino acid transporters and key secreted molecules linked specifically to RpsF modification. Our findings show that post-translational ribosomal modification functions as a rapid-response mechanism that tunes global gene translation in response to environmental signals.
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Affiliation(s)
- Lucia Grenga
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
| | | | - Govind Chandra
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | | | - Gerhard Saalbach
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | - Richard James Morris
- Computational and Systems Biology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | - Jacob George Malone
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
- * E-mail:
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27
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Koza A, Jerdan R, Cameron S, Spiers AJ. Three biofilm types produced by a model pseudomonad are differentiated by structural characteristics and fitness advantage. MICROBIOLOGY-SGM 2020; 166:707-716. [PMID: 32520698 DOI: 10.1099/mic.0.000938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Model bacterial biofilm systems suggest that bacteria produce one type of biofilm, which is then modified by environmental and physiological factors, although the diversification of developing populations might result in the appearance of adaptive mutants producing altered structures with improved fitness advantage. Here we compare the air-liquid (A-L) interface viscous mass (VM) biofilm produced by Pseudomonas fluorescens SBW25 and the wrinkly spreader (WS) and complementary biofilm-forming strain (CBFS) biofilm types produced by adaptive SBW25 mutants in order to better understand the link between these physical structures and the fitness advantage they provide in experimental microcosms. WS, CBFS and VM biofilms can be differentiated by strength, attachment levels and rheology, as well as by strain characteristics associated with biofilm formation. Competitive fitness assays demonstrate that they provide similar advantages under static growth conditions but respond differently to increasing levels of physical disturbance. Pairwise competitions between biofilms suggest that these strains must be competing for at least two growth-limiting resources at the A-L interface, most probably O2 and nutrients, although VM and CBFS cells located lower down in the liquid column might provide an additional fitness advantage through the colonization of a less competitive zone below the biofilm. Our comparison of different SBW25 biofilm types illustrates more generally how varied biofilm characteristics and fitness advantage could become among adaptive mutants arising from an ancestral biofilm-forming strain and raises the question of how significant these changes might be in a range of medical, biotechnological and industrial contexts where diversification and change may be problematic.
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Affiliation(s)
- Anna Koza
- School of Applied Sciences, Abertay University, Bell Street, Dundee DD1 1HG, UK
| | - Robyn Jerdan
- School of Applied Sciences, Abertay University, Bell Street, Dundee DD1 1HG, UK
| | - Scott Cameron
- School of Applied Sciences, Abertay University, Bell Street, Dundee DD1 1HG, UK
| | - Andrew J Spiers
- School of Applied Sciences, Abertay University, Bell Street, Dundee DD1 1HG, UK
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28
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Characterization of Antimicrobial Effects of Plasma-Treated Water (PTW) Produced by Microwave-Induced Plasma (MidiPLexc) on Pseudomonas fluorescens Biofilms. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10093118] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
For the decontamination of surfaces in the food production industry, plasma-generated compounds such as plasma-treated water or plasma-processed air offer many promising possibilities for future applications. Therefore, the antimicrobial effect of water treated with microwave-induced plasma (MidiPLexc) on Pseudomonas fluorescens biofilms was investigated. A total of 10 mL deionized water was treated with the MidiPLexc plasma source for 100, 300 and 900 s (pretreatment time) and the bacterial biofilms were exposed to the plasma-treated water for 1, 3 and 5 min (post-treatment time). To investigate the influence of plasma-treated water on P. fluorescens biofilms, microbiological assays (colony-forming units, fluorescence and XTT assay) and imaging techniques (fluorescence microscopy, confocal laser scanning microscopy, and atomic force microscopy) were used. The colony-forming units showed a maximum reduction of 6 log10 by using 300 s pretreated plasma water for 5 min. Additionally, a maximum reduction of 81% for the viability of the cells and a 92% reduction in the metabolic activity of the cells were achieved by using 900 s pretreated plasma water for 5 min. The microscopic images showed evident microbial inactivation within the biofilm even at the shortest pretreatment (100 s) and post-treatment (1 min) times. Moreover, reduction of the biofilm thickness and increased cluster formation within the biofilm was detected. Morphologically, the fusion of cell walls into a uniform dense cell mass was detectable. The findings correlated with a decrease in the pH value of the plasma-treated water, which forms the basis for the chemically active components of plasma-treated water and its antimicrobial effects. These results provide valuable insights into the mechanisms of inactivation of biofilms by plasma-generated compounds such as plasma-treated water and thus allow for further parameter adjustment for applications in food industry.
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29
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De Vleeschouwer M, Van Kersavond T, Verleysen Y, Sinnaeve D, Coenye T, Martins JC, Madder A. Identification of the Molecular Determinants Involved in Antimicrobial Activity of Pseudodesmin A, a Cyclic Lipopeptide From the Viscosin Group. Front Microbiol 2020; 11:646. [PMID: 32373092 PMCID: PMC7187754 DOI: 10.3389/fmicb.2020.00646] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 03/20/2020] [Indexed: 12/24/2022] Open
Abstract
Cyclic lipo(depsi)peptides (CLiPs) from Pseudomonas constitute a class of natural products involved in a broad range of biological functions for their producers. They also display interesting antimicrobial potential including activity against Gram-positive bacteria. Literature has indicated that these compounds can induce membrane permeabilization, possibly through pore-formation, leading to the general view that the cellular membrane constitutes the primary target in their mode of action. In support of this view, we previously demonstrated that the enantiomer of pseudodesmin A, a member of the viscosin group of CLiPs, shows identical activity against a test panel of six Gram-positive bacterial strains. Here, a previously developed total organic synthesis route is used and partly adapted to generate 20 novel pseudodesmin A analogs in an effort to derive links between molecular constitution, structure and activity. From these, the importance of a macrocycle closed by an ester bond as well as a critical length of β-OH fatty acid chain capping the N-terminus is conclusively demonstrated, providing further evidence for the importance of peptide-membrane interactions in the mode of action. Moreover, an alanine scan is used to unearth the contribution of specific amino acid residues to biological activity. Subsequent interpretation in terms of a structural model describing the location and orientation of pseudodesmin A in a membrane environment, allows first insight in the peptide-membrane interactions involved. The biological screening also identified residue positions that appear less sensitive to conservative modifications, allowing the introduction of a non-perturbing tryptophan residue which will pave the way toward biophysical studies using fluorescence spectroscopy.
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Affiliation(s)
- Matthias De Vleeschouwer
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium.,NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Tim Van Kersavond
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium.,NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Yentl Verleysen
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium.,NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Davy Sinnaeve
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Department of Pharmaceutical Analysis, Ghent University, Ghent, Belgium
| | - José C Martins
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Annemieke Madder
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
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30
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Ye X, Li Z, Luo X, Wang W, Li Y, Li R, Zhang B, Qiao Y, Zhou J, Fan J, Wang H, Huang Y, Cao H, Cui Z, Zhang R. A predatory myxobacterium controls cucumber Fusarium wilt by regulating the soil microbial community. MICROBIOME 2020; 8:49. [PMID: 32252828 PMCID: PMC7137222 DOI: 10.1186/s40168-020-00824-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 03/05/2020] [Indexed: 05/19/2023]
Abstract
BACKGROUND Myxobacteria are micropredators in the soil ecosystem with the capacity to move and feed cooperatively. Some myxobacterial strains have been used to control soil-borne fungal phytopathogens. However, interactions among myxobacteria, plant pathogens, and the soil microbiome are largely unexplored. In this study, we aimed to investigate the behaviors of the myxobacterium Corallococcus sp. strain EGB in the soil and its effect on the soil microbiome after inoculation for controlling cucumber Fusarium wilt caused by Fusarium oxysporum f. sp. cucumerinum (FOC). RESULTS A greenhouse and a 2-year field experiment demonstrated that the solid-state fermented strain EGB significantly reduced the cucumber Fusarium wilt by 79.6% (greenhouse), 66.0% (2015, field), and 53.9% (2016, field). Strain EGB adapted to the soil environment well and decreased the abundance of soil-borne FOC efficiently. Spatiotemporal analysis of the soil microbial community showed that strain EGB migrated towards the roots and root exudates of the cucumber plants via chemotaxis. Cooccurrence network analysis of the soil microbiome indicated a decreased modularity and community number but an increased connection number per node after the application of strain EGB. Several predatory bacteria, such as Lysobacter, Microvirga, and Cupriavidus, appearing as hubs or indicators, showed intensive connections with other bacteria. CONCLUSION The predatory myxobacterium Corallococcus sp. strain EGB controlled cucumber Fusarium wilt by migrating to the plant root and regulating the soil microbial community. This strain has the potential to be developed as a novel biological control agent of soil-borne Fusarium wilt. Video abstract.
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Affiliation(s)
- Xianfeng Ye
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Zhoukun Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Xue Luo
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Wenhui Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Yongkai Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Rui Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Bo Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Yan Qiao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Jie Zhou
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Jiaqin Fan
- Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture and Rural Affairs, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Hui Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Yan Huang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Hui Cao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Science of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
- Key Laboratory of plant immunity, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
| | - Ruifu Zhang
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China.
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Lesson from Ecotoxicity: Revisiting the Microbial Lipopeptides for the Management of Emerging Diseases for Crop Protection. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17041434. [PMID: 32102264 PMCID: PMC7068399 DOI: 10.3390/ijerph17041434] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 11/17/2022]
Abstract
Microorganisms area treasure in terms of theproduction of various bioactive compounds which are being explored in different arenas of applied sciences. In agriculture, microbes and their bioactive compounds are being utilized in growth promotion and health promotion withnutrient fortification and its acquisition. Exhaustive explorations are unraveling the vast diversity of microbialcompounds with their potential usage in solving multiferous problems incrop production. Lipopeptides are one of such microbial compounds which havestrong antimicrobial properties against different plant pathogens. These compounds are reported to be produced by bacteria, cyanobacteria, fungi, and few other microorganisms; however, genus Bacillus alone produces a majority of diverse lipopeptides. Lipopeptides are low molecular weight compounds which havemultiple industrial roles apart from being usedas biosurfactants and antimicrobials. In plant protection, lipopeptides have wide prospects owing totheirpore-forming ability in pathogens, siderophore activity, biofilm inhibition, and dislodging activity, preventing colonization bypathogens, antiviral activity, etc. Microbes with lipopeptides that haveall these actions are good biocontrol agents. Exploring these antimicrobial compounds could widen the vistasof biological pest control for existing and emerging plant pathogens. The broader diversity and strong antimicrobial behavior of lipopeptides could be a boon for dealing withcomplex pathosystems and controlling diseases of greater economic importance. Understanding which and how these compounds modulate the synthesis and production of defense-related biomolecules in the plants is a key question—the answer of whichneeds in-depth investigation. The present reviewprovides a comprehensive picture of important lipopeptides produced by plant microbiome, their isolation, characterization, mechanisms of disease control, behavior against phytopathogens to understand different aspects of antagonism, and potential prospects for future explorations as antimicrobial agents. Understanding and exploring the antimicrobial lipopeptides from bacteria and fungi could also open upan entire new arena of biopesticides for effective control of devastating plant diseases.
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Jerdan R, Kuśmierska A, Petric M, Spiers AJ. Penetrating the air-liquid interface is the key to colonization and wrinkly spreader fitness. MICROBIOLOGY-SGM 2020; 165:1061-1074. [PMID: 31436522 DOI: 10.1099/mic.0.000844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In radiating populations of Pseudomonas fluorescens SBW25, adaptive wrinkly spreader (WS) mutants are able to gain access to the air-liquid (A-L) interface of static liquid microcosms and achieve a significant competitive fitness advantage over other non-biofilm-forming competitors. Aerotaxis and flagella-based swimming allows SBW25 cells to move into the high-O2 region located at the top of the liquid column and maintain their position by countering the effects of random cell diffusion, convection and disturbance (i.e. physical displacement). However, wild-type cells showed significantly lower levels of enrichment in this region compared to the archetypal WS, indicating that WS cells employ an additional mechanism to transfer to the A-L interface where displacement is no longer an issue and a biofilm can develop at the top of the liquid column. Preliminary experiments suggest that this might be achieved through the expression of an as yet unidentified surface active agent that is weakly associated with WS cells and alters liquid surface tension, as determined by quantitative tensiometry. The effect of physical displacement on the colonization of the high-O2 region and A-L interface was reduced through the addition of agar or polyethylene glycol to increase liquid viscosity, and under these conditions the competitive fitness of the WS was significantly reduced. These observations suggest that the ability to transfer to the A-L interface from the high-O2 region and remain there without further expenditure of energy (through, for example, the deployment of flagella) is a key evolutionary innovation of the WS, as it allows subsequent biofilm development and significant population increase, thereby affording these adaptive mutants a competitive fitness advantage over non-biofilm-forming competitors located within the liquid column.
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Affiliation(s)
- Robyn Jerdan
- School of Applied Sciences, Abertay University, Dundee DD1 1HG, UK
| | - Anna Kuśmierska
- Department of Industrial Microbiology and Biotechnology, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland.,School of Applied Sciences, Abertay University, Dundee DD1 1HG, UK
| | - Marija Petric
- School of Applied Sciences, Abertay University, Dundee DD1 1HG, UK
| | - Andrew J Spiers
- School of Applied Sciences, Abertay University, Dundee DD1 1HG, UK
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Ait Kaki A, Smargiasso N, Ongena M, Kara Ali M, Moula N, De Pauw E, Kacem Chaouche N. Characterization of New Fengycin Cyclic Lipopeptide Variants Produced by Bacillus amyloliquefaciens (ET) Originating from a Salt Lake of Eastern Algeria. Curr Microbiol 2020; 77:443-451. [PMID: 31894376 DOI: 10.1007/s00284-019-01855-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/19/2019] [Indexed: 11/27/2022]
Abstract
Fengycin antibiotic displays a strong antifungal activity and inhibits the growth of a wide range of plant pathogens especially filamentous fungi. The main objective of the present study is to characterize fengycin variants produced by B. amyloliquefaciens strain (ET). LC-MS analysis of fengycin extracts has shown several molecular ion peaks corresponding to conventional fengycin homologues (MH + : m/z 1463.9; 1491.9; 1506) and some new ones (MH + : m/z 1433; 1447; 1461; and 1477). Further characterization of these precursor ions was carried out by LC-MS.MS analysis. Reporter fragment ions were observed (named A and B), they correspond to the cleavage of Orn2-Tyr3 (A), Glu1-Orn2 (B), and used for identifying fengycin variants. The reporter fragment couple ions [A/B] at [m/z 966.5/1080.5] and [m/z 994.4 /1108.5] represent fengycin A and B, respectively. The diagnostic ions at ([m/z 980/1094]) may correspond to fengycin C3, D, S or B2. Interestingly, unknown diagnostic product ions at [m/z 951/1065] and [m/z 979/1093] were detected for the first time in this study which prove that they correspond to new fengycin variants, named fengycin X and fengycin Y, respectively. The fengycin X results from a substitution of the glutamine amino acid (Q), at position 8 of the fengycin A peptide part, by an isoleucine (I) or a leucine (L) residue. This mutation should be the same in fengycin Y but compared to fengycin B.
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Affiliation(s)
- Asma Ait Kaki
- Faculty of Sciences, Department of Biology, University of M'Hamed Bougara, 35000, Boumerdès, Algeria. .,Bioindustries Unit, Gembloux Agrobiotech, University of Liege, Passage of the Deportees 2, 5030, Gembloux, Belgium. .,Laboratory of Mycology, Biology and Biotechnology, Faculty of Natural and Life Sciences, Department of Applied Biology, University of Mentouri 1, 25000, Constantine, Algeria.
| | - Nicolas Smargiasso
- Mass Spectrometry Laboratory, Molecular Systems Research Unit, University of Liege, B6C, B 400, Liege, Belgium
| | - Marc Ongena
- Bioindustries Unit, Gembloux Agrobiotech, University of Liege, Passage of the Deportees 2, 5030, Gembloux, Belgium
| | - Mounira Kara Ali
- Laboratory of Mycology, Biology and Biotechnology, Faculty of Natural and Life Sciences, Department of Applied Biology, University of Mentouri 1, 25000, Constantine, Algeria
| | - Nassim Moula
- Department of Animal Productions, Faculty of Veterinary Medicine, University of Liege, Colonster Boulevard 20, 4000, Liege, Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, Molecular Systems Research Unit, University of Liege, B6C, B 400, Liege, Belgium
| | - Noreddine Kacem Chaouche
- Laboratory of Mycology, Biology and Biotechnology, Faculty of Natural and Life Sciences, Department of Applied Biology, University of Mentouri 1, 25000, Constantine, Algeria
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Causes and Biophysical Consequences of Cellulose Production by Pseudomonas fluorescens SBW25 at the Air-Liquid Interface. J Bacteriol 2019; 201:JB.00110-19. [PMID: 31085696 PMCID: PMC6707908 DOI: 10.1128/jb.00110-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/29/2019] [Indexed: 12/20/2022] Open
Abstract
This work reveals a hitherto unrecognized behavior that manifests at the air-liquid interface that depends on production of cellulose and hints at undiscovered dimensions to bacterial life at surfaces. Additionally, the study links activation of known diguanylate cyclase-encoding pathways to cellulose expression and to signals encountered at the meniscus. Further significance stems from recognition of the consequences of fluid instabilities arising from surface production of cellulose for transport of water-soluble products over large distances. Cellulose-overproducing wrinkly spreader mutants of Pseudomonas fluorescens SBW25 have been the focus of much investigation, but conditions promoting the production of cellulose in ancestral strain SBW25 and its effects and consequences have escaped in-depth investigation through lack of an in vitro phenotype. Here, using a custom-built device, we reveal that in static broth microcosms, ancestral SBW25 encounters environmental signals at the air-liquid interface that activate, via three diguanylate cyclase-encoding pathways (Wsp, Aws, and Mws), production of cellulose. Secretion of the polymer at the meniscus leads to modification of the environment and growth of numerous microcolonies that extend from the surface. Accumulation of cellulose and associated microbial growth leads to Rayleigh-Taylor instability resulting in bioconvection and rapid transport of water-soluble products over tens of millimeters. Drawing upon data, we built a mathematical model that recapitulates experimental results and captures the interactions between biological, chemical and physical processes. IMPORTANCE This work reveals a hitherto unrecognized behavior that manifests at the air-liquid interface that depends on production of cellulose and hints at undiscovered dimensions to bacterial life at surfaces. Additionally, the study links activation of known diguanylate cyclase-encoding pathways to cellulose expression and to signals encountered at the meniscus. Further significance stems from recognition of the consequences of fluid instabilities arising from surface production of cellulose for transport of water-soluble products over large distances.
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Geudens N, Kovács B, Sinnaeve D, Oni FE, Höfte M, Martins JC. Conformation and Dynamics of the Cyclic Lipopeptide Viscosinamide at the Water-Lipid Interface. Molecules 2019; 24:E2257. [PMID: 31213011 PMCID: PMC6630293 DOI: 10.3390/molecules24122257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 12/19/2022] Open
Abstract
Cyclic lipodepsipeptides or CLiPs from Pseudomonas are secondary metabolites that mediate a wide range of biological functions for their producers, and display antimicrobial and anticancer activities. Direct interaction of CLiPs with the cellular membranes is presumed to be essential in causing these. To understand the processes involved at the molecular level, knowledge of the conformation and dynamics of CLiPs at the water-lipid interface is required to guide the interpretation of biophysical investigations in model membrane systems. We used NMR and molecular dynamics to study the conformation, location and orientation of the Pseudomonas CLiP viscosinamide in a water/dodecylphosphocholine solution. In the process, we demonstrate the strong added value of combining uniform, isotope-enriched viscosinamide and protein NMR methods. In particular, the use of techniques to determine backbone dihedral angles and detect and identify long-lived hydrogen bonds, establishes that the solution conformation previously determined in acetonitrile is maintained in water/dodecylphosphocholine solution. Paramagnetic relaxation enhancements pinpoint viscosinamide near the water-lipid interface, with its orientation dictated by the amphipathic distribution of hydrophobic and hydrophilic residues. Finally, the experimental observations are supported by molecular dynamics simulations. Thus a firm structural basis is now available for interpreting biophysical and bioactivity data relating to this class of compounds.
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Affiliation(s)
- Niels Geudens
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
| | - Benjámin Kovács
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
| | - Davy Sinnaeve
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
| | - Feyisara Eyiwumi Oni
- Laboratory of Phytopathology, Department of Plants and Crops, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
| | - Monica Höfte
- Laboratory of Phytopathology, Department of Plants and Crops, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
| | - José C Martins
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
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Araújo HWC, Andrade RFS, Montero-Rodríguez D, Rubio-Ribeaux D, Alves da Silva CA, Campos-Takaki GM. Sustainable biosurfactant produced by Serratia marcescens UCP 1549 and its suitability for agricultural and marine bioremediation applications. Microb Cell Fact 2019; 18:2. [PMID: 30609918 PMCID: PMC6318876 DOI: 10.1186/s12934-018-1046-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/12/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Biosurfactants are surface-active agents produced by microorganisms that have higher efficiency and stability, lower toxicity and higher biocompatibility and biodegradability than chemical surfactants. Despite its properties and potential application in a wide range of environmental and industrial processes, biosurfactants are still not cost-competitive when compared to their synthetic counterparts. Cost effective technologies and renewable raw substrates as agro-industrial and regional waste from northeast of Brazil as cassava flour wastewater, supplemented with lactose and corn oil are mainly the chemically media for growing microorganism and in turn the production of the biosurfactant of quality. This study aimed to obtained biosurfactant by Serratia marcescens UCP 1549 containing cassava flour wastewater (CWW), by application of a full-factorial design, as sustainable practices in puts the production process in promising formulation medium. The characterization of the biomolecule was carried out, as well as the determination of its stability and toxicity for cabbage seeds. In addition, its ability to stimulate seed germination for agriculture application and oil spill bioremediation were investigated. RESULTS Serratia marcescens showed higher reduction of surface tension (25.92 mN/m) in the new medium containing 0.2% lactose, 6% cassava flour wastewater and 5% corn waste oil, after 72 h of fermentation at 28 °C and 150 rpm. The substrate cassava flour wastewater showed a promising source of nutrients for biosurfactant production. The isolate biosurfactant exhibited a CMC of 1.5% (w/v) and showed an anionic and polymeric structure, confirmed by infrared spectra. The biomolecule demonstrated high stability under different temperatures, salinity and pH values and non-toxicity against to cabbage seeds. Thus, exploring biosurfactant their potential role in seeds germinations and the promotion and agricultural applications was investigated. In addition, the effectiveness of biosurfactant for removal burned motor oil adsorbed in sand was verified. CONCLUSIONS The use of medium containing CWW not only reduces the cost of process of biosurfactant production, but also the environmental pollution due to the inappropriate disposal of this residue. This fact, added to the high stability and non-toxicity of the biosurfactant produced by S. marcescens UCP 1549, confirms its high environmental compatibility, make it a sustainable biocompound that can be replace chemical surfactants in diverse industries. In addition, the effectiveness of biosurfactant for stimulate seed germination and removing burned motor oil from sand, suggests its suitability for agriculture and bioremediation applications.
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Affiliation(s)
- Hélvia W C Araújo
- Chemistry Department, State University of Paraíba, Campina Grande, PB, 58429-500, Brazil
| | - Rosileide F S Andrade
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, PE, 50050-590, Brazil
| | - Dayana Montero-Rodríguez
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, PE, 50050-590, Brazil
| | - Daylin Rubio-Ribeaux
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, PE, 50050-590, Brazil
- Center of Biosciences, Federal University of Pernambuco, Recife, PE, 50670-420, Brazil
| | - Carlos A Alves da Silva
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, PE, 50050-590, Brazil
| | - Galba M Campos-Takaki
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, PE, 50050-590, Brazil.
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ROSA ENDAH, MARDHIAH BATUBARA UMMI, SUPARJO SUPARJO. Chemotactic Motility and Growth of Pseudomonas fluorescens Towards Glucose Concentration. MICROBIOLOGY INDONESIA 2019. [DOI: 10.5454/mi.13.2.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Re-programming of Pseudomonas syringae pv. actinidiae gene expression during early stages of infection of kiwifruit. BMC Genomics 2018; 19:822. [PMID: 30442113 PMCID: PMC6238374 DOI: 10.1186/s12864-018-5197-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/23/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pseudomonas syringae is a widespread bacterial species complex that includes a number of significant plant pathogens. Amongst these, P. syringae pv. actinidiae (Psa) initiated a worldwide pandemic in 2008 on cultivars of Actinidia chinensis var. chinensis. To gain information about the expression of genes involved in pathogenicity we have carried out transcriptome analysis of Psa during the early stages of kiwifruit infection. RESULTS Gene expression in Psa was investigated during the first five days after infection of kiwifruit plantlets, using RNA-seq. Principal component and heatmap analyses showed distinct phases of gene expression during the time course of infection. The first phase was an immediate transient peak of induction around three hours post inoculation (HPI) that included genes that code for a Type VI Secretion System and nutrient acquisition (particularly phosphate). This was followed by a significant commitment, between 3 and 24 HPI, to the induction of genes encoding the Type III Secretion System (T3SS) and Type III Secreted Effectors (T3SE). Expression of these genes collectively accounted for 6.3% of the bacterial transcriptome at this stage. There was considerable variation in the expression levels of individual T3SEs but all followed the same temporal expression pattern, with the exception of hopAS1, which peaked later in expression at 48 HPI. As infection progressed over the time course of five days, there was an increase in the expression of genes with roles in sugar, amino acid and sulfur transport and the production of alginate and colanic acid. These are both polymers that are major constituents of extracellular polysaccharide substances (EPS) and are involved in biofilm production. Reverse transcription-quantitative PCR (RT-qPCR) on an independent infection time course experiment showed that the expression profile of selected bacterial genes at each infection phase correlated well with the RNA-seq data. CONCLUSIONS The results from this study indicate that there is a complex remodeling of the transcriptome during the early stages of infection, with at least three distinct phases of coordinated gene expression. These include genes induced during the immediate contact with the host, those involved in the initiation of infection, and finally those responsible for nutrient acquisition.
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Adeniji AA, Aremu OS, Babalola OO. Selecting lipopeptide-producing, Fusarium-suppressing Bacillus spp.: Metabolomic and genomic probing of Bacillus velezensis NWUMFkBS10.5. Microbiologyopen 2018; 8:e00742. [PMID: 30358165 PMCID: PMC6562122 DOI: 10.1002/mbo3.742] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/03/2018] [Accepted: 09/10/2018] [Indexed: 12/29/2022] Open
Abstract
The results of this study indicate that the maize rhizosphere remains a reservoir for microbial strains with unique beneficial properties. The study sought to provide an indigenous Bacillus strain with a bioprotective potential to alleviate maize fusariosis in South Africa. We selected seven Bacillus isolates (MORWBS1.1, MARBS2.7, VERBS5.5, MOREBS6.3, MOLBS8.5, MOLBS8.6, and NWUMFkBS10.5) with biosuppressive effects against two maize fungal pathogens (Fusarium graminearum and Fusarium culmorum) based on 16S rDNA gene characterization and lipopeptide gene analysis. The PCR analysis revealed that lipopeptide genes encoding the synthesis of iturin, surfactin, and fengycin might be responsible for their antifungal activities. Few of the isolates also showed possible biosurfactant capability, and their susceptibility to known antibiotics is indicative of their eco‐friendly attributes. In addition, in silico genomic analysis of our best isolate (Bacillus velezensis NWUMFkBS10.5) and characterization of its active metabolite with FTIR, NMR, and ESI‐Micro‐Tof MS confirmed the presence of valuable genes clusters and metabolic pathways. The versatile genomic potential of our Bacillus isolate emphasizes the continued relevance of Bacillus spp. in biological management of plant diseases.
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Affiliation(s)
- Adetomiwa Ayodele Adeniji
- Department of Biological Sciences, Faculty of Natural and Agriculture Science, North-West University, Mmabatho, South Africa.,Food Security and Safety Niche Area, Faculty of Natural and Agriculture Science, North-West University, Mmabatho, South Africa
| | - Oluwole Samuel Aremu
- Department of Chemistry, Faculty of Natural and Agriculture Science, North-West University, Mmabatho, South Africa
| | - Olubukola Oluranti Babalola
- Department of Biological Sciences, Faculty of Natural and Agriculture Science, North-West University, Mmabatho, South Africa.,Food Security and Safety Niche Area, Faculty of Natural and Agriculture Science, North-West University, Mmabatho, South Africa
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Patel S, Homaei A, Patil S, Daverey A. Microbial biosurfactants for oil spill remediation: pitfalls and potentials. Appl Microbiol Biotechnol 2018; 103:27-37. [DOI: 10.1007/s00253-018-9434-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/02/2018] [Accepted: 10/02/2018] [Indexed: 12/11/2022]
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Koskella B, Taylor TB. Multifaceted Impacts of Bacteriophages in the Plant Microbiome. ANNUAL REVIEW OF PHYTOPATHOLOGY 2018; 56:361-380. [PMID: 29958076 DOI: 10.1146/annurev-phyto-080417-045858] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Plant-associated bacteria face multiple selection pressures within their environments and have evolved countless adaptations that both depend on and shape bacterial phenotype and their interaction with plant hosts. Explaining bacterial adaptation and evolution therefore requires considering each of these forces independently as well as their interactions. In this review, we examine how bacteriophage viruses (phages) can alter the ecology and evolution of plant-associated bacterial populations and communities. This includes influencing a bacterial population's response to both abiotic and biotic selection pressures and altering ecological interactions within the microbiome and between the bacteria and host plant. We outline specific ways in which phages can alter bacterial phenotype and discuss when and how this might impact plant-microbe interactions, including for plant pathogens. Finally, we highlight key open questions in phage-bacteria-plant research and offer suggestions for future study.
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Affiliation(s)
- Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, California 94720, USA;
| | - Tiffany B Taylor
- The Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom;
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Geudens N, Martins JC. Cyclic Lipodepsipeptides From Pseudomonas spp. - Biological Swiss-Army Knives. Front Microbiol 2018; 9:1867. [PMID: 30158910 PMCID: PMC6104475 DOI: 10.3389/fmicb.2018.01867] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/25/2018] [Indexed: 12/20/2022] Open
Abstract
Cyclic lipodepsipeptides produced by Pseudomonas spp. (Ps-CLPs) are biosurfactants that constitute a diverse class of versatile bioactive natural compounds with promising application potential. While chemically diverse, they obey a common structural blue-print, allowing the definition of 14 distinct groups with multiple structurally homologous members. In addition to antibacterial and antifungal properties the reported activity profile of Ps-CLPs includes their effect on bacterial motility, biofilm formation, induced defense responses in plants, their insecticidal activity and anti-proliferation effects on human cancer cell-lines. To further validate their status of potential bioactive substances, we assessed the results of 775 biological tests on 51 Ps-CLPs available from literature. From this, a fragmented view emerges. Taken as a group, Ps-CLPs present a broad activity profile. However, reports on individual Ps-CLPs are often much more limited in the scope of organisms that are challenged or activities that are explored. As a result, our analysis shows that the available data is currently too sparse to allow biological function to be correlated to a particular group of Ps-CLPs. Consequently, certain generalizations that appear in literature with respect to the biological activities of Ps-CLPs should be nuanced. This notwithstanding, the data for the two most extensively studied Ps-CLPs does indicate they can display activities against various biological targets. As the discovery of novel Ps-CLPs accelerates, current challenges to complete and maintain a useful overview of biological activity are discussed.
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Affiliation(s)
- Niels Geudens
- NMR and Structure Analysis Unit, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - José C Martins
- NMR and Structure Analysis Unit, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
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LeTourneau MK, Marshall MJ, Cliff JB, Bonsall RF, Dohnalkova AC, Mavrodi DV, Devi SI, Mavrodi OV, Harsh JB, Weller DM, Thomashow LS. Phenazine‐1‐carboxylic acid and soil moisture influence biofilm development and turnover of rhizobacterial biomass on wheat root surfaces. Environ Microbiol 2018; 20:2178-2194. [DOI: 10.1111/1462-2920.14244] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 04/15/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Melissa K. LeTourneau
- Department of Crop & Soil SciencesWashington State UniversityPullmanWA 99164‐6420 USA
| | - Matthew J. Marshall
- Earth & Biological Sciences DirectoratePacific Northwest National LaboratoryRichlandWA 99352 USA
| | - John B. Cliff
- Environmental Molecular Sciences LaboratoryPacific Northwest National LaboratoryRichlandWA 99352 USA
| | - Robert F. Bonsall
- Department of Plant PathologyWashington State UniversityPullmanWA 99164‐6420 USA
| | - Alice C. Dohnalkova
- Environmental Molecular Sciences LaboratoryPacific Northwest National LaboratoryRichlandWA 99352 USA
| | - Dmitri V. Mavrodi
- Department of Biological SciencesUniversity of Southern MississippiHattiesburgMS 39406‐0001 USA
| | - S. Indira Devi
- Institute of Bioresources and Sustainable DevelopmentTakyelpat ManipurImphal 795001 India
| | - Olga V. Mavrodi
- Department of Biological SciencesUniversity of Southern MississippiHattiesburgMS 39406‐0001 USA
| | - James B. Harsh
- Department of Crop & Soil SciencesWashington State UniversityPullmanWA 99164‐6420 USA
| | - David M. Weller
- United States Department of Agriculture – Agricultural Research ServiceWheat Health, Genetics, and Quality Research UnitPullmanWA 99164‐6430 USA
| | - Linda S. Thomashow
- United States Department of Agriculture – Agricultural Research ServiceWheat Health, Genetics, and Quality Research UnitPullmanWA 99164‐6430 USA
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Yendyo S, G C R, Pandey BR. Evaluation of Trichoderma spp., Pseudomonasfluorescens and Bacillus subtilis for biological control of Ralstonia wilt of tomato. F1000Res 2018; 6:2028. [PMID: 29560253 PMCID: PMC5854981 DOI: 10.12688/f1000research.12448.3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/20/2018] [Indexed: 11/20/2022] Open
Abstract
Background:Ralstonia spp. is a major pathogenic microbe for tomato, which invades the roots of diverse plant hosts and colonizes xylem vessels causing wilt, especially in tropical, subtropical and warm-temperate regions. Ralstonia spp. produces several virulence factors helping it to invade the plant's natural defense mechanism. Native isolates of Trichoderma spp., Pseudomonas fluorescens and Bacillus subtilis can be used as biocontrol agents to control the bacterial wilt and combined application of these beneficial microbes can give better results. Methods: Bacterial wilt infection in the field was identified by field experts and the infected plant part was used to isolate Ralstonia spp. in CPG media and was positively identified. Subsequently, the efficacy of the biocontrol agents was tested and documented using agar well diffusion technique and digital microscopy. 2ml of the microbial concentrate (10 9 cells/ml) was mixed in one liter of water and was applied in the plant root at the rate of 100 ml per plant as a treatment method. Results: It was observed that the isolated Trichoderma spp. AA2 and Pseudomonas fluorescens PFS were most potent in inhibiting the growth of Ralstonia spp. , showing ZOI 20.67 mm and 22.33 mm, respectively. Digital microscopy showed distinct inhibitory effect on the growth and survival of Ralstonia spp . The results from the field data indicated that Trichoderma spp. and Pseudomonas fluorescens alone were able to prevent 92% and 96% of the infection and combination of both were more effective, preventing 97% of infection. Chemical control methods prevented 94% of infection. Bacillus subtilis could only prevent 84 % of the infection. Conclusions: Antagonistic effect against Ralstonia spp. shown by native isolates of Trichoderma spp. and P. fluorescens manifested the promising potential as biocontrol agents. Combined application gave better results. Results shown by Bacillus subtilis were not significant.
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Affiliation(s)
- Shiva Yendyo
- Kishan Call Center, Bharatpur-4, Chitwan, 44207, Nepal
| | - Ramesh G C
- Department of Quality Control, Agricare Nepal Pvt. Ltd., Bharatpur-4, Chitwan, 44207, Nepal
| | - Binayak Raj Pandey
- Department of Quality Control, Agricare Nepal Pvt. Ltd., Bharatpur-4, Chitwan, 44207, Nepal
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Hassen W, Neifar M, Cherif H, Najjari A, Chouchane H, Driouich RC, Salah A, Naili F, Mosbah A, Souissi Y, Raddadi N, Ouzari HI, Fava F, Cherif A. Pseudomonas rhizophila S211, a New Plant Growth-Promoting Rhizobacterium with Potential in Pesticide-Bioremediation. Front Microbiol 2018; 9:34. [PMID: 29527191 PMCID: PMC5829100 DOI: 10.3389/fmicb.2018.00034] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/09/2018] [Indexed: 11/18/2022] Open
Abstract
A number of Pseudomonas strains function as inoculants for biocontrol, biofertilization, and phytostimulation, avoiding the use of pesticides and chemical fertilizers. Here, we present a new metabolically versatile plant growth-promoting rhizobacterium, Pseudomonas rhizophila S211, isolated from a pesticide contaminated artichoke field that shows biofertilization, biocontrol and bioremediation potentialities. The S211 genome was sequenced, annotated and key genomic elements related to plant growth promotion and biosurfactant (BS) synthesis were elucidated. S211 genome comprises 5,948,515 bp with 60.4% G+C content, 5306 coding genes and 215 RNA genes. The genome sequence analysis confirmed the presence of genes involved in plant-growth promoting and remediation activities such as the synthesis of ACC deaminase, putative dioxygenases, auxin, pyroverdin, exopolysaccharide levan and rhamnolipid BS. BS production by P. rhizophila S211 grown on olive mill wastewater based media was effectively optimized using a central-composite experimental design and response surface methodology (RSM). The optimum conditions for maximum BS production yield (720.80 ± 55.90 mg/L) were: 0.5% (v/v) inoculum size, 15% (v/v) olive oil mill wastewater (OMWW) and 40°C incubation temperature at pH 6.0 for 8 days incubation period. Biochemical and structural characterization of S211 BS by chromatography and spectroscopy studies suggested the glycolipid nature of the BS. P. rhizophila rhamnolipid was stable over a wide range of temperature (40-90°C), pH (6-10), and salt concentration (up to 300 mM NaCl). Due to its low-cost production, emulsification activities and high performance in solubilization enhancement of chemical pesticides, the indigenous BS-producing PGPR S211 could be used as a promising agent for environmental bioremediation of pesticide-contaminated agricultural soils.
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Affiliation(s)
- Wafa Hassen
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
- Laboratory of Microorganisms and Active Biomolecules, MBA-LR03ES03, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Mohamed Neifar
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Hanene Cherif
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Afef Najjari
- Laboratory of Microorganisms and Active Biomolecules, MBA-LR03ES03, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Habib Chouchane
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Rim C. Driouich
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Asma Salah
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Fatma Naili
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Amor Mosbah
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Yasmine Souissi
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
| | - Noura Raddadi
- Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Bologna, Italy
| | - Hadda I. Ouzari
- Laboratory of Microorganisms and Active Biomolecules, MBA-LR03ES03, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Fabio Fava
- Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Bologna, Italy
| | - Ameur Cherif
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
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Yendyo S, G.C. R, Pandey BR. Evaluation of Trichoderma spp., Pseudomonasfluorescens and Bacillus subtilis for biological control of Ralstonia wilt of tomato. F1000Res 2017; 6:2028. [PMID: 29560253 PMCID: PMC5854981 DOI: 10.12688/f1000research.12448.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/20/2018] [Indexed: 08/13/2023] Open
Abstract
Background:Ralstonia spp. is a major pathogenic microbe for tomato, which invades the roots of diverse plant hosts and colonizes xylem vessels causing wilt, especially in tropical, subtropical and warm-temperate regions. Ralstonia spp. produces several virulence factors helping it to invade the plant's natural defense mechanism. Native isolates of Trichoderma spp., Pseudomonas fluorescens and Bacillus subtilis can be used as biocontrol agents to control the bacterial wilt and combined application of these beneficial microbes can give better results. Methods: Bacterial wilt infection in the field was identified by field experts and the infected plant part was used to isolate Ralstonia spp. in CPG media and was positively identified. Subsequently, the efficacy of the biocontrol agents was tested and documented using agar well diffusion technique and digital microscopy. 2ml of the microbial concentrate (10 9 cells/ml) was mixed in one liter of water and was applied in the plant root at the rate of 100 ml per plant as a treatment method. Results: It was observed that the isolated Trichoderma spp. AA2 and Pseudomonas fluorescens PFS were most potent in inhibiting the growth of Ralstonia spp. , showing ZOI 20.67 mm and 22.33 mm, respectively. Digital microscopy showed distinct inhibitory effect on the growth and survival of Ralstonia spp . The results from the field data indicated that Trichoderma spp. and Pseudomonas fluorescens alone were able to prevent 92% and 96% of the infection and combination of both were more effective, preventing 97% of infection. Chemical control methods prevented 94% of infection. Bacillus subtilis could only prevent 84 % of the infection. Conclusions: Antagonistic effect against Ralstonia spp. shown by native isolates of Trichoderma spp. and P. fluorescens manifested the promising potential as biocontrol agents. Combined application gave better results. Results shown by Bacillus subtilis were not significant.
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Affiliation(s)
- Shiva Yendyo
- Kishan Call Center, Bharatpur-4, Chitwan, 44207, Nepal
| | - Ramesh G.C.
- Department of Quality Control, Agricare Nepal Pvt. Ltd., Bharatpur-4, Chitwan, 44207, Nepal
| | - Binayak Raj Pandey
- Department of Quality Control, Agricare Nepal Pvt. Ltd., Bharatpur-4, Chitwan, 44207, Nepal
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Poly-γ-glutamic acid productivity of Bacillus subtilis BsE1 has positive function in motility and biocontrol against Fusarium graminearum. J Microbiol 2017; 55:554-560. [PMID: 28664519 DOI: 10.1007/s12275-017-6589-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 04/05/2017] [Accepted: 04/18/2017] [Indexed: 10/19/2022]
Abstract
In this study, we investigate the relationship between γ-PGA productivity and biocontrol capacity of Bacillus subtilis BsE1; one bacterial isolate displayed 62.14% biocontrol efficacy against Fusarium root rot. The γ-PGA yield assay, motility assay, wheat root colonization assay, and biological control assay were analysed in different γ-PGA yield mutants of BsE1. The pgsB (PGA-synthase-CapB gene) deleted mutant of BsE1 reduced γ-PGA yield and exhibited apparent decline of in vitro motile ability. Deletion of pgsB impaired colonizing capacity of BsE1 on wheat root in 30 days, also lowered biocontrol efficacies from 62.08% (wild type BsE1) to 14.22% in greenhouse experiment against Fusarium root rot. The knockout of pgdS and ggt (genes relate to two γ-PGA degrading enzymes) on BsE1, leads to a considerable improvement in polymer yield and biocontrol efficacy, which attains higher level compared with wild type BsE1. Compared with ΔpgsB mutant, defense genes related to reactive oxygen species (ROS) and phytoalexin expressed changes by notable levels on wheat roots treated with BsE1, demonstrating the functional role γ-PGA plays in biocontrol against Fusarium root rot. γ-PGA is not only important to the motile and plant root colonization ability of BsE1, but also essential to the biological control performed by BsE1 against Fusarium root rot. Our goal in this study is to reveals a new perspective of BCAs screening on bacterial isolates, without good performance during pre-assays of antagonism ability.
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Mauchline TH, Malone JG. Life in earth – the root microbiome to the rescue? Curr Opin Microbiol 2017; 37:23-28. [DOI: 10.1016/j.mib.2017.03.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/22/2017] [Indexed: 01/10/2023]
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Hölscher T, Kovács ÁT. Sliding on the surface: bacterial spreading without an active motor. Environ Microbiol 2017; 19:2537-2545. [PMID: 28370801 DOI: 10.1111/1462-2920.13741] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/20/2017] [Accepted: 03/23/2017] [Indexed: 11/28/2022]
Abstract
Bacteria are able to translocate over surfaces using different types of active and passive motility mechanisms. Sliding is one of the passive types of movement since it is powered by the pushing force of dividing cells and additional factors facilitating the expansion over surfaces. In this review, we describe the sliding proficient bacteria that were previously investigated in details highlighting the sliding facilitating compounds and the regulation of sliding motility. Besides surfactants that reduce the friction between cells and substratum, other compounds including exopolysaccharides, hydrophobic proteins, or glycopeptidolipids where discovered to promote sliding. Therefore, we present the sliding bacteria in three groups depending on the additional compound required for sliding. Despite recent accomplishments in sliding research there are still many open questions about the mechanisms underlying sliding motility and its regulation in diverse bacterial species.
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Affiliation(s)
- Theresa Hölscher
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Ákos T Kovács
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
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50
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Geudens N, Nasir MN, Crowet JM, Raaijmakers JM, Fehér K, Coenye T, Martins JC, Lins L, Sinnaeve D, Deleu M. Membrane Interactions of Natural Cyclic Lipodepsipeptides of the Viscosin Group. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:331-339. [DOI: 10.1016/j.bbamem.2016.12.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 12/12/2016] [Accepted: 12/16/2016] [Indexed: 11/16/2022]
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