1
|
Venkataraman M, Infante V, Sabat G, Sanos-Giles K, Ané JM, Pfleger BF. A Novel Membrane-Associated Protein Aids Bacterial Colonization of Maize. ACS Synth Biol 2024. [PMID: 39707987 DOI: 10.1021/acssynbio.4c00489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2024]
Abstract
The soil environment affected by plant roots and their exudates, termed the rhizosphere, significantly impacts crop health and is an attractive target for engineering desirable agricultural traits. Engineering microbes in the rhizosphere is one approach to improving crop yields that directly minimizes the number of genetic modifications made to plants. Soil microbes have the potential to assist with nutrient acquisition, heat tolerance, and drought response if they can persist in the rhizosphere in the correct numbers. Unfortunately, the mechanisms by which microbes adhere and persist on plant roots are poorly understood, limiting their application. This study examined the membrane proteome shift upon adherence to roots in two bacteria of interest, Klebsiella variicola and Pseudomonas putida. From this surface proteome data, we identified a novel membrane protein from a nonlaboratory isolate of P. putida that increases binding to maize roots using unlabeled proteomics. When this protein was moved from the environmental isolate to a common lab strain (P. putida KT2440), we observed increased binding capabilities of P. putida KT2440 to both abiotic mimic surfaces and maize roots. We observed a similar increased binding capability to maize roots when the protein was heterologously expressed in K. variicola and Stutzerimonas stutzeri. With the discovery of this novel binding protein, we outline a strategy for harnessing natural selection and wild isolates to build more persistent strains of bacteria for field applications and plant growth promotion.
Collapse
Affiliation(s)
- Maya Venkataraman
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| | - Valentina Infante
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| | - Grzegorz Sabat
- Biotechnology Center, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| | - Kai Sanos-Giles
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| | - Jean-Michel Ané
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
- Department of Plant and Agroecosystem Sciences, University of Wisconsin - Madison, Madison, Wisconsin 53705, United States
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| |
Collapse
|
2
|
Marasco R, Mosqueira MJ, Seferji KA, Al Romaih SM, Michoud G, Xu J, Bez C, Castillo Hernandez T, Venturi V, Blilou I, Daffonchio D. Desert-adapted plant growth-promoting pseudomonads modulate plant auxin homeostasis and mitigate salinity stress. Microb Biotechnol 2024; 17:e70043. [PMID: 39692704 DOI: 10.1111/1751-7915.70043] [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: 12/14/2023] [Accepted: 10/17/2024] [Indexed: 12/19/2024] Open
Abstract
By providing adaptive advantages to plants, desert microorganisms are emerging as promising solutions to mitigate the negative and abrupt effects of climate change in agriculture. Among these, pseudomonads, commonly found in soil and in association with plants' root system, have been shown to enhance plant tolerance to salinity and drought, primarily affecting root system architecture in various hosts. However, a comprehensive understanding of how these bacteria affect plant responses at the cellular, physiological and molecular levels is still lacking. In this study, we investigated the effects of two Pseudomonas spp. strains, E102 and E141, which were previously isolated from date palm roots and have demonstrated efficacy in promoting drought tolerance in their hosts. These strains colonize plant roots, influencing root architecture by inhibiting primary root growth while promoting root hair elongation and lateral root formation. Strains E102 and E141 increased auxin levels in Arabidopsis, whereas this effect was diminished in IAA-defective mutant strains, which exhibited reduced IAA production. In all cases, the effectiveness of the bacteria relies on the functioning of the plant auxin response and transport machinery. Notably, such physiological and morphological changes provide an adaptive advantage to the plant, specifically under stress conditions such as salinity. Collectively, this study demonstrates that by leveraging the host's auxin signalling machinery, strains E102 and E141 significantly improve plant resilience to abiotic stresses, positioning them as potential biopromoters/bioprotectors for crop production and ecosystem restoration in alignment with Nature-based Solution approaches.
Collapse
Affiliation(s)
- Ramona Marasco
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Maria J Mosqueira
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Kholoud A Seferji
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Sarah M Al Romaih
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Grégoire Michoud
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Jian Xu
- Plant Systems Physiology, Radboud University, Nijmegen, The Netherlands
| | - Cristina Bez
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Tatiana Castillo Hernandez
- Laboratory of Plant Cell and Developmental Biology, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
- African Genome Center, University Mohammed VI Polytechnic, Ben Guerir, Morocco
| | - Ikram Blilou
- Laboratory of Plant Cell and Developmental Biology, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Daniele Daffonchio
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| |
Collapse
|
3
|
Ni X, Li S, Yuan Y, Chang R, Liu Q, Liu Z, Li Z, Wang Y. Effect of siaD on Ag-8 to improve resistance to crown gall in grapes and related mechanisms. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 215:108869. [PMID: 39142011 DOI: 10.1016/j.plaphy.2024.108869] [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: 02/14/2024] [Revised: 06/18/2024] [Accepted: 06/20/2024] [Indexed: 08/16/2024]
Abstract
Crown gall caused by Agrobacterium vitis (A. vitis) is one of the crucial issues restricting the to grape industry. In this study, Agrobacterium tumefaciens (Ag-8) was separated from the soil that could prevent the occurrence of grape crown gall. By the mutagenesis of Ag-8 transposon, the siaD gene deletion strain (ΔsiaD) showed significantly lower efficacy in grape and tomato plants for controlling grape crown gall, but the relevant mechanism was not clear. The biofilm formation and motility of ΔsiaD were significantly decreased, and the colonization ability of ΔsiaD in tomato roots was significantly reduced. RNA-seq analysis showed that the expression of nemR significantly reduced in the ΔsiaD and that the expression of nemR showed a high correlation with biofilm and motility. Further studies showed that the nemR gene deletion strain of Ag-8 (ΔnemR) showed significantly reduced motility, biofilm formation and control of grape crown gall compared to Ag-8, and the nemR gene complementary strain of Ag-8 (ΔnemR-comp) recovered to Ag-8 wild-type levels. The inoculation experiments of preventive, curative or simultaneous treatment further showed that the preferential inoculation with Ag-8 reduced the incidence of grape crown gall on tomato plants, and studies showed that the mutation of siaD affected the site competition between Ag-8 and A. vitis, and that the mutation of nemR was consistent with the previous results. This study provides a new strategy for the prevention and control of grape crown gall, which is of great significance to the grape industry to increase production and income.
Collapse
Affiliation(s)
- Xuemei Ni
- Tianjin Agricultural University, College of Horticulture and Landscape Architecture, Tianjin, 300394, China
| | - Shiyu Li
- Tianjin Agricultural University, College of Horticulture and Landscape Architecture, Tianjin, 300394, China
| | - Yujin Yuan
- Tianjin Agricultural University, College of Horticulture and Landscape Architecture, Tianjin, 300394, China
| | - Ruokui Chang
- Tianjin Agricultural University, College of Engineering and Technology Architecture, Tianjin, 300394, China
| | - Quanyong Liu
- Tianjin Agricultural University, College of Horticulture and Landscape Architecture, Tianjin, 300394, China
| | - Zhenxing Liu
- Tianjin Agricultural University, College of Horticulture and Landscape Architecture, Tianjin, 300394, China
| | - Zhuoran Li
- Tianjin Agricultural University, College of Horticulture and Landscape Architecture, Tianjin, 300394, China.
| | - Yuanhong Wang
- Tianjin Agricultural University, College of Horticulture and Landscape Architecture, Tianjin, 300394, China.
| |
Collapse
|
4
|
Tienda S, Vida C, Villar-Moreno R, de Vicente A, Cazorla FM. Development of a Pseudomonas-based biocontrol consortium with effective root colonization and extended beneficial side effects for plants under high-temperature stress. Microbiol Res 2024; 285:127761. [PMID: 38761488 DOI: 10.1016/j.micres.2024.127761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 05/07/2024] [Accepted: 05/10/2024] [Indexed: 05/20/2024]
Abstract
The root microbiota plays a crucial role in plant performance. The use of microbial consortia is considered a very useful tool for studying microbial interactions in the rhizosphere of different agricultural crop plants. Thus, a consortium of 3 compatible beneficial rhizospheric Pseudomonas strains previously isolated from the avocado rhizosphere, was constructed. The consortium is composed of two compatible biocontrol P. chlororaphis strains (PCL1601 and PCL1606), and the biocontrol rhizobacterium Pseudomonas alcaligenes AVO110, which are all efficient root colonizers of avocado and tomato plants. These three strains were compatible with each other and reached stable levels both in liquid media and on plant roots. Bacterial strains were fluorescent tagged, and colonization-related traits were analyzed in vitro, revealing formation of mixed biofilm networks without exclusion of any of the strains. Additionally, bacterial colonization patterns compatible with the different strains were observed, with high survival traits on avocado and tomato roots. The bacteria composing the consortium shared the same root habitat and exhibited biocontrol activity against soil-borne fungal pathogens at similar levels to those displayed by the individual strains. As expected, because these strains were isolated from avocado roots, this Pseudomonas-based consortium had more stable bacterial counts on avocado roots than on tomato roots; however, inoculation of tomato roots with this consortium was shown to protect tomato plants under high-temperature stress. The results revealed that this consortium has side beneficial effect for tomato plants under high-temperature stress, thus improving the potential performance of the individual strains. We concluded that this rhizobacterial consortium do not improve the plant protection against soil-borne phytopathogenic fungi displayed by the single strains; however, its inoculation can show an specific improvement of plant performance on a horticultural non-host plant (such as tomato) when the plant was challenged by high temperature stress, thus extending the beneficial role of this bacterial consortium.
Collapse
Affiliation(s)
- Sandra Tienda
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Avda. Louis Pasteur 31, Málaga 29071, Spain; Grupo de Biología y Control de Enfermedades de Plantas, Área de Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Avda. Louis Pasteur 49, Málaga 29010, Spain
| | - Carmen Vida
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Avda. Louis Pasteur 31, Málaga 29071, Spain; Grupo de Biología y Control de Enfermedades de Plantas, Área de Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Avda. Louis Pasteur 49, Málaga 29010, Spain
| | - Rafael Villar-Moreno
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Avda. Louis Pasteur 31, Málaga 29071, Spain; Grupo de Biología y Control de Enfermedades de Plantas, Área de Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Avda. Louis Pasteur 49, Málaga 29010, Spain
| | - Antonio de Vicente
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Avda. Louis Pasteur 31, Málaga 29071, Spain; Grupo de Biología y Control de Enfermedades de Plantas, Área de Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Avda. Louis Pasteur 49, Málaga 29010, Spain
| | - Francisco M Cazorla
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Avda. Louis Pasteur 31, Málaga 29071, Spain; Grupo de Biología y Control de Enfermedades de Plantas, Área de Protección de Cultivos, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Avda. Louis Pasteur 49, Málaga 29010, Spain.
| |
Collapse
|
5
|
Rajewska M, Maciąg T, Narajczyk M, Jafra S. Carbon Source and Substrate Surface Affect Biofilm Formation by the Plant-Associated Bacterium Pseudomonas donghuensis P482. Int J Mol Sci 2024; 25:8351. [PMID: 39125921 PMCID: PMC11312691 DOI: 10.3390/ijms25158351] [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: 07/05/2024] [Revised: 07/25/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024] Open
Abstract
The ability of bacteria to colonize diverse environmental niches is often linked to their competence in biofilm formation. It depends on the individual characteristics of a strain, the nature of the colonized surface (abiotic or biotic), or the availability of certain nutrients. Pseudomonas donghuensis P482 efficiently colonizes the rhizosphere of various plant hosts, but a connection between plant tissue colonization and the biofilm formation ability of this strain has not yet been established. We demonstrate here that the potential of P482 to form biofilms on abiotic surfaces and the structural characteristics of the biofilm are influenced by the carbon source available to the bacterium, with glycerol promoting the process. Also, the type of substratum, polystyrene or glass, impacts the ability of P482 to attach to the surface. Moreover, P482 mutants in genes associated with motility or chemotaxis, the synthesis of polysaccharides, and encoding proteases or regulatory factors, which affect biofilm formation on glass, were fully capable of colonizing the root tissue of both tomato and maize hosts. Investigating the role of cellular factors in biofilm formation using these plant-associated bacteria shows that the ability of bacteria to form biofilm on abiotic surfaces does not necessarily mirror its ability to colonize plant tissues. Our research provides a broader perspective on the adaptation of these bacteria to various environments.
Collapse
Affiliation(s)
- Magdalena Rajewska
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland;
| | - Tomasz Maciąg
- Institute of Biology, Department of Botany, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland;
| | - Magdalena Narajczyk
- Laboratory of Electron Microscopy, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Sylwia Jafra
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland;
| |
Collapse
|
6
|
Blanco-Romero E, Garrido-Sanz D, Durán D, Rybtke M, Tolker-Nielsen T, Redondo-Nieto M, Rivilla R, Martín M. Role of extracellular matrix components in biofilm formation and adaptation of Pseudomonas ogarae F113 to the rhizosphere environment. Front Microbiol 2024; 15:1341728. [PMID: 38333580 PMCID: PMC10850567 DOI: 10.3389/fmicb.2024.1341728] [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: 11/20/2023] [Accepted: 01/11/2024] [Indexed: 02/10/2024] Open
Abstract
Regulating the transition of bacteria from motile to sessile lifestyles is crucial for their ability to compete effectively in the rhizosphere environment. Pseudomonas are known to rely on extracellular matrix (ECM) components for microcolony and biofilm formation, allowing them to adapt to a sessile lifestyle. Pseudomonas ogarae F113 possesses eight gene clusters responsible for the production of ECM components. These gene clusters are tightly regulated by AmrZ, a major transcriptional regulator that influences the cellular levels of c-di-GMP. The AmrZ-mediated transcriptional regulation of ECM components is primarily mediated by the signaling molecule c-di-GMP and the flagella master regulator FleQ. To investigate the functional role of these ECM components in P. ogarae F113, we performed phenotypic analyses using mutants in genes encoding these ECM components. These analyses included assessments of colony morphology, dye-staining, static attachment to abiotic surfaces, dynamic biofilm formation on abiotic surfaces, swimming motility, and competitive colonization assays of the rhizosphere. Our results revealed that alginate and PNAG polysaccharides, along with PsmE and the fimbrial low molecular weight protein/tight adherence (Flp/Tad) pilus, are the major ECM components contributing to biofilm formation. Additionally, we found that the majority of these components and MapA are needed for a competitive colonization of the rhizosphere in P. ogarae F113.
Collapse
Affiliation(s)
- Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Morten Rybtke
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| |
Collapse
|
7
|
Costa-Gutierrez SB, Raimondo EE, Vincent PA, de Cristóbal RE. Importance of biofilm formation for promoting plant growth under salt stress in Pseudomonas putida KT2440. J Basic Microbiol 2023; 63:1219-1232. [PMID: 37537345 DOI: 10.1002/jobm.202300215] [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: 04/18/2023] [Revised: 06/20/2023] [Accepted: 07/12/2023] [Indexed: 08/05/2023]
Abstract
An underutilized experimental design was employed to isolate adapted mutants of the model bacterium Pseudomonas putida KT2440. The design involved subjecting a random pool of mini-Tn5 mutants of P. putida KT2440 to multiple rounds of selection in the rhizosphere of soybean plants irrigated with a NaCl solution. The isolated adapted mutants, referred to as MutAd, exhibited a mutation in the gene responsible for encoding the membrane-binding protein LapA, which plays a role in the initial stages of biofilm formation on abiotic surfaces. Two MutAd bacteria, MutAd160 and MutAd185, along with a lapA deletion mutant, were selected for further investigation to examine the impact of this gene on salt tolerance, rhizosphere fitness, production of extracellular polymeric substances (EPS), and promotion of plant growth. Despite the mutants' inability to form biofilms, they were able to attach to soybean seeds and roots. The MutAd bacteria demonstrated an elevated production of EPS when cultivated under saline conditions, which likely compensated for the absence of biofilm formation. MutAd185 bacteria exhibited enhanced root attachment and promoted the growth of soybean plants in slightly saline soils. The proposed experimental design holds promise for expediting bacterial adaptation to the rhizosphere of plants under specific environmental conditions, identifying genetic mutations that enhance bacterial fitness in those conditions, and thereby increasing their capacity to promote plant growth.
Collapse
Affiliation(s)
- Stefanie Bernardette Costa-Gutierrez
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) e Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Tucumán, Argentina
| | - Enzo Emanuel Raimondo
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, San Miguel de Tucumán, Tucumán, Argentina
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Tucumán, Argentina
| | - Paula Andrea Vincent
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) e Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Tucumán, Argentina
| | - Ricardo Ezequiel de Cristóbal
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) e Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Tucumán, Argentina
| |
Collapse
|
8
|
Blanco-Romero E, Durán D, Garrido-Sanz D, Redondo-Nieto M, Martín M, Rivilla R. Adaption of Pseudomonas ogarae F113 to the Rhizosphere Environment-The AmrZ-FleQ Hub. Microorganisms 2023; 11:microorganisms11041037. [PMID: 37110460 PMCID: PMC10146422 DOI: 10.3390/microorganisms11041037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/10/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Motility and biofilm formation are two crucial traits in the process of rhizosphere colonization by pseudomonads. The regulation of both traits requires a complex signaling network that is coordinated by the AmrZ-FleQ hub. In this review, we describe the role of this hub in the adaption to the rhizosphere. The study of the direct regulon of AmrZ and the phenotypic analyses of an amrZ mutant in Pseudomonas ogarae F113 has shown that this protein plays a crucial role in the regulation of several cellular functions, including motility, biofilm formation, iron homeostasis, and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) turnover, controlling the synthesis of extracellular matrix components. On the other hand, FleQ is the master regulator of flagellar synthesis in P. ogarae F113 and other pseudomonads, but its implication in the regulation of multiple traits related with environmental adaption has been shown. Genomic scale studies (ChIP-Seq and RNA-Seq) have shown that in P. ogarae F113, AmrZ and FleQ are general transcription factors that regulate multiple traits. It has also been shown that there is a common regulon shared by the two transcription factors. Moreover, these studies have shown that AmrZ and FleQ form a regulatory hub that inversely regulate traits such as motility, extracellular matrix component production, and iron homeostasis. The messenger molecule c-di-GMP plays an essential role in this hub since its production is regulated by AmrZ and it is sensed by FleQ and required for its regulatory role. This regulatory hub is functional both in culture and in the rhizosphere, indicating that the AmrZ-FleQ hub is a main player of P. ogarae F113 adaption to the rhizosphere environment.
Collapse
Affiliation(s)
- Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| |
Collapse
|
9
|
Papadopoulou A, Matsi T, Kamou N, Avdouli D, Mellidou I, Karamanoli K. Decoding the potential of a new Pseudomonas putida strain for inducing drought tolerance of tomato (Solanum lycopersicum) plants through seed biopriming. JOURNAL OF PLANT PHYSIOLOGY 2022; 271:153658. [PMID: 35245824 DOI: 10.1016/j.jplph.2022.153658] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/08/2022] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
A total of 11 potential plant growth promoting rhizobacteria previously isolated from naturally stressed environments were evaluated for various traits of interest for a beneficial symbiosis with plants, including colonization ability, biofilm formation, motility, exopolysaccharide production and salt tolerance. The vast majority of the strains were found to possess multiple plant growth promoting traits. Nevertheless, the intensity varied among isolates, with those originated from tomato plants being more efficient colonizers. The strain SAESo11, genetically characterized as a Pseudomonas putida member was selected for further investigation of its potential to alleviate drought stress in tomato seedlings. Inoculation with SAESo11 mitigated the negative effects of drought stress as indicated by growth and photosynthetic indices. Furthermore, bacterial inoculation enhanced H2O2 content and malondialdehyde levels in colonized plants. Drought treatment did not further alter the oxidative status of these plants. Similarly, total phenolic content and antioxidant enzyme activity were induced in plant tissues in response to drought stress only at the absence of inoculum. These results indicated that inoculation with the selected strain imposed plants at a priming state, that enabled them to respond more robustly at the exposure to drought stress and efficiently attenuated the drought-induced injury. This state of plant alertness mediated by SAESo11 occurred at no cost to growth, highlighting its role as a potential plant priming agent.
Collapse
Affiliation(s)
- Anastasia Papadopoulou
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Theodora Matsi
- Laboratory of Soil Science, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nathalie Kamou
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Denisa Avdouli
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Ifigeneia Mellidou
- Institute of Plant Breeding and Genetic Resources, Hellenic Agricultural Organization DEMETER (ex NAGREF), Thermi, Greece.
| | - Katerina Karamanoli
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece.
| |
Collapse
|
10
|
Genome analysis of Pseudomonas sp. 14A reveals metabolic capabilities to support epiphytic behavior. World J Microbiol Biotechnol 2022; 38:49. [DOI: 10.1007/s11274-022-03238-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 01/19/2022] [Indexed: 11/26/2022]
|
11
|
Genome-wide identification of bacterial colonization and fitness determinants on the floating macrophyte, duckweed. Commun Biol 2022; 5:68. [PMID: 35046504 PMCID: PMC8770550 DOI: 10.1038/s42003-022-03014-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 12/23/2021] [Indexed: 11/08/2022] Open
Abstract
AbstractBacterial communities associated with aquatic macrophytes largely influence host primary production and nutrient cycling in freshwater environments; however, little is known about how specific bacteria migrate to and proliferate at this unique habitat. Here, we separately identified bacterial genes involved in the initial colonization and overall fitness on plant surface, using the genome-wide transposon sequencing (Tn-seq) of Aquitalea magnusonii H3, a plant growth-promoting bacterium of the floating macrophyte, duckweed. Functional annotation of identified genes indicated that initial colonization efficiency might be simply explained by motility and cell surface structure, while overall fitness was associated with diverse metabolic and regulatory functions. Genes involved in lipopolysaccharides and type-IV pili biosynthesis showed different contributions to colonization and fitness, reflecting their metabolic cost and profound roles in host association. These results provide a comprehensive genetic perspective on aquatic-plant-bacterial interactions, and highlight the potential trade-off between bacterial colonization and proliferation abilities on plant surface.
Collapse
|
12
|
Blanco-Romero E, Durán D, Garrido-Sanz D, Rivilla R, Martín M, Redondo-Nieto M. Transcriptomic analysis of Pseudomonas ogarae F113 reveals the antagonistic roles of AmrZ and FleQ during rhizosphere adaption. Microb Genom 2022; 8. [PMID: 35012704 PMCID: PMC8914362 DOI: 10.1099/mgen.0.000750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Rhizosphere colonization by bacteria involves molecular and cellular mechanisms, such as motility and chemotaxis, biofilm formation, metabolic versatility, or biosynthesis of secondary metabolites, among others. Nonetheless, there is limited knowledge concerning the main regulatory factors that drive the rhizosphere colonization process. Here we show the importance of the AmrZ and FleQ transcription factors for adaption in the plant growth-promoting rhizobacterium (PGPR) and rhizosphere colonization model Pseudomonas ogarae F113. RNA-Seq analyses of P. ogarae F113 grown in liquid cultures either in exponential and stationary growth phase, and rhizosphere conditions, revealed that rhizosphere is a key driver of global changes in gene expression in this bacterium. Regarding the genetic background, this work has revealed that a mutation in fleQ causes considerably more alterations in the gene expression profile of this bacterium than a mutation in amrZ under rhizosphere conditions. The functional analysis has revealed that in P. ogarae F113, the transcription factors AmrZ and FleQ regulate genes involved in diverse bacterial functions. Notably, in the rhizosphere, these transcription factors antagonistically regulate genes related to motility, biofilm formation, nitrogen, sulfur, and amino acid metabolism, transport, signalling, and secretion, especially the type VI secretion systems. These results define the regulon of two important bifunctional transcriptional regulators in pseudomonads during the process of rhizosphere colonization.
Collapse
Affiliation(s)
- Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain.,Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| |
Collapse
|
13
|
Santoyo G, Urtis-Flores CA, Loeza-Lara PD, Orozco-Mosqueda MDC, Glick BR. Rhizosphere Colonization Determinants by Plant Growth-Promoting Rhizobacteria (PGPR). BIOLOGY 2021; 10:biology10060475. [PMID: 34072072 PMCID: PMC8229920 DOI: 10.3390/biology10060475] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Plant growth-promoting rhizobacteria (PGPR) are an eco-friendly alternative to the use of chemicals in agricultural production and crop protection. However, the efficacy of PGPR as bioinoculants can be diminished by a low capacity to colonize spaces in the rhizosphere. In this work, we review pioneering and recent developments on several important functions that rhizobacteria exhibit in order to compete, colonize, and establish themselves in the plant rhizosphere. Therefore, the use of highly competitive strains in open field trials should be a priority, in order to have consistent and better results in agricultural production activities. Abstract The application of plant growth-promoting rhizobacteria (PGPR) in the field has been hampered by a number of gaps in the knowledge of the mechanisms that improve plant growth, health, and production. These gaps include (i) the ability of PGPR to colonize the rhizosphere of plants and (ii) the ability of bacterial strains to thrive under different environmental conditions. In this review, different strategies of PGPR to colonize the rhizosphere of host plants are summarized and the advantages of having highly competitive strains are discussed. Some mechanisms exhibited by PGPR to colonize the rhizosphere include recognition of chemical signals and nutrients from root exudates, antioxidant activities, biofilm production, bacterial motility, as well as efficient evasion and suppression of the plant immune system. Moreover, many PGPR contain secretion systems and produce antimicrobial compounds, such as antibiotics, volatile organic compounds, and lytic enzymes that enable them to restrict the growth of potentially phytopathogenic microorganisms. Finally, the ability of PGPR to compete and successfully colonize the rhizosphere should be considered in the development and application of bioinoculants.
Collapse
Affiliation(s)
- Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico;
- Correspondence:
| | - Carlos Alberto Urtis-Flores
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico;
| | - Pedro Damián Loeza-Lara
- Licenciatura en Genómica Alimentaria, Universidad de La Ciénega del Estado de Michoacán de Ocampo, Sahuayo 59103, Mexico;
| | - Ma. del Carmen Orozco-Mosqueda
- Facultad de Agrobiología “Presidente Juárez”, Universidad Michoacana de San Nicolás de Hidalgo, Melchor Ocampo, Uruapan 60170, Mexico;
| | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
| |
Collapse
|
14
|
Durán D, Bernal P, Vazquez-Arias D, Blanco-Romero E, Garrido-Sanz D, Redondo-Nieto M, Rivilla R, Martín M. Pseudomonas fluorescens F113 type VI secretion systems mediate bacterial killing and adaption to the rhizosphere microbiome. Sci Rep 2021; 11:5772. [PMID: 33707614 PMCID: PMC7970981 DOI: 10.1038/s41598-021-85218-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 02/26/2021] [Indexed: 02/06/2023] Open
Abstract
The genome of Pseudomonas fluorescens F113, a model rhizobacterium and a plant growth-promoting agent, encodes three putative type VI secretion systems (T6SSs); F1-, F2- and F3-T6SS. Bioinformatic analysis of the F113 T6SSs has revealed that they belong to group 3, group 1.1, and group 4a, respectively, similar to those previously described in Pseudomonas aeruginosa. In addition, in silico analyses allowed us to identify genes encoding a total of five orphan VgrG proteins and eight putative effectors (Tfe), some with their cognate immunity protein (Tfi) pairs. Genes encoding Tfe and Tfi are found in the proximity of P. fluorescens F113 vgrG, hcp, eagR and tap genes. RNA-Seq analyses in liquid culture and rhizosphere have revealed that F1- and F3-T6SS are expressed under all conditions, indicating that they are active systems, while F2-T6SS did not show any relevant expression under the tested conditions. The analysis of structural mutants in the three T6SSs has shown that the active F1- and F3-T6SSs are involved in interbacterial killing while F2 is not active in these conditions and its role is still unknown.. A rhizosphere colonization analysis of the double mutant affected in the F1- and F3-T6SS clusters showed that the double mutant was severely impaired in persistence in the rhizosphere microbiome, revealing the importance of these two systems for rhizosphere adaption.
Collapse
Affiliation(s)
- David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Patricia Bernal
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain.,Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida de la Reina Mercedes, 6, 41012, Sevilla, Spain
| | - David Vazquez-Arias
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain.
| |
Collapse
|
15
|
Zboralski A, Filion M. Genetic factors involved in rhizosphere colonization by phytobeneficial Pseudomonas spp. Comput Struct Biotechnol J 2020; 18:3539-3554. [PMID: 33304453 PMCID: PMC7711191 DOI: 10.1016/j.csbj.2020.11.025] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 12/13/2022] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) actively colonize the soil portion under the influence of plant roots, called the rhizosphere. Many plant-beneficial Pseudomonas spp. have been characterized as PGPR. They are ubiquitous rod-shaped motile Gram-negative bacteria displaying a high metabolic versatility. Their capacity to protect plants from pathogens and improve plant growth closely depends on their rhizosphere colonization abilities. Various molecular and cellular mechanisms are involved in this complex process, such as chemotaxis, biofilm formation, secondary metabolites biosynthesis, metabolic versatility, and evasion of plant immunity. The burst in Pseudomonas spp. genome sequencing in recent years has been crucial to better understand how they colonize the rhizosphere. In this review, we discuss the recent advances regarding these mechanisms and the underlying bacterial genetic factors required for successful rhizosphere colonization.
Collapse
Affiliation(s)
- Antoine Zboralski
- Department of Biology, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Martin Filion
- Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada
| |
Collapse
|
16
|
Latour X. The Evanescent GacS Signal. Microorganisms 2020; 8:microorganisms8111746. [PMID: 33172195 PMCID: PMC7695008 DOI: 10.3390/microorganisms8111746] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/18/2022] Open
Abstract
The GacS histidine kinase is the membrane sensor of the major upstream two-component system of the regulatory Gac/Rsm signal transduction pathway. This pathway governs the expression of a wide range of genes in pseudomonads and controls bacterial fitness and motility, tolerance to stress, biofilm formation, and virulence or plant protection. Despite the importance of these roles, the ligands binding to the sensor domain of GacS remain unknown, and their identification is an exciting challenge in this domain. At high population densities, the GacS signal triggers a switch from primary to secondary metabolism and a change in bacterial lifestyle. It has been suggested, based on these observations, that the GacS signal is a marker of the emergence of nutritional stress and competition. Biochemical investigations have yet to characterize the GacS signal fully. However, they portray this cue as a low-molecular weight, relatively simple and moderately apolar metabolite possibly resembling, but nevertheless different, from the aliphatic organic acids acting as quorum-sensing signaling molecules in other Proteobacteria. Significant progress in the development of metabolomic tools and new databases dedicated to Pseudomonas metabolism should help to unlock some of the last remaining secrets of GacS induction, making it possible to control the Gac/Rsm pathway.
Collapse
Affiliation(s)
- Xavier Latour
- Laboratory of Microbiology Signals and Microenvironment (LMSM EA 4312), Normandy University (University of Rouen Normandy), 55 rue Saint-Germain, 27000 Evreux, France;
- Research Federation NORVEGE Fed4277, Normandy University, F-76821 Mont-Saint-Aignan, France
| |
Collapse
|
17
|
Fabian BK, Tetu SG, Paulsen IT. Application of Transposon Insertion Sequencing to Agricultural Science. FRONTIERS IN PLANT SCIENCE 2020; 11:291. [PMID: 32256512 PMCID: PMC7093568 DOI: 10.3389/fpls.2020.00291] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 02/26/2020] [Indexed: 06/11/2023]
Abstract
Many plant-associated bacteria have the ability to positively affect plant growth and there is growing interest in utilizing such bacteria in agricultural settings to reduce reliance on pesticides and fertilizers. However, our capacity to utilize microbes in this way is currently limited due to patchy understanding of bacterial-plant interactions at a molecular level. Traditional methods of studying molecular interactions have sought to characterize the function of one gene at a time, but the slow pace of this work means the functions of the vast majority of bacterial genes remain unknown or poorly understood. New approaches to improve and speed up investigations into the functions of bacterial genes in agricultural systems will facilitate efforts to optimize microbial communities and develop microbe-based products. Techniques enabling high-throughput gene functional analysis, such as transposon insertion sequencing analyses, have great potential to be widely applied to determine key aspects of plant-bacterial interactions. Transposon insertion sequencing combines saturation transposon mutagenesis and high-throughput sequencing to simultaneously investigate the function of all the non-essential genes in a bacterial genome. This technique can be used for both in vitro and in vivo studies to identify genes involved in microbe-plant interactions, stress tolerance and pathogen virulence. The information provided by such investigations will rapidly accelerate the rate of bacterial gene functional determination and provide insights into the genes and pathways that underlie biotic interactions, metabolism, and survival of agriculturally relevant bacteria. This knowledge could be used to select the most appropriate plant growth promoting bacteria for a specific set of conditions, formulating crop inoculants, or developing crop protection products. This review provides an overview of transposon insertion sequencing, outlines how this approach has been applied to study plant-associated bacteria, and proposes new applications of these techniques for the benefit of agriculture.
Collapse
Affiliation(s)
- Belinda K. Fabian
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, Australia
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Sasha G. Tetu
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, Australia
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ian T. Paulsen
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, Australia
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| |
Collapse
|
18
|
Liu W, Huang L, Komorek R, Handakumbura PP, Zhou Y, Hu D, Engelhard MH, Jiang H, Yu XY, Jansson C, Zhu Z. Correlative surface imaging reveals chemical signatures for bacterial hotspots on plant roots. Analyst 2020; 145:393-401. [DOI: 10.1039/c9an01954e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A universal sample holder allows correlative imaging analysis of plant roots to reveal chemical signatures for bacterial hotspots.
Collapse
|
19
|
Noirot-Gros MF, Forrester S, Malato G, Larsen PE, Noirot P. CRISPR interference to interrogate genes that control biofilm formation in Pseudomonas fluorescens. Sci Rep 2019; 9:15954. [PMID: 31685917 PMCID: PMC6828691 DOI: 10.1038/s41598-019-52400-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 10/12/2019] [Indexed: 12/11/2022] Open
Abstract
Bacterial biofilm formation involves signaling and regulatory pathways that control the transition from motile to sessile lifestyle, production of extracellular polymeric matrix, and maturation of the biofilm 3D structure. Biofilms are extensively studied because of their importance in biomedical, ecological and industrial settings. Gene inactivation is a powerful approach for functional studies but it is often labor intensive, limiting systematic gene surveys to the most tractable bacterial hosts. Here, we adapted the CRISPR interference (CRISPRi) system for use in diverse strain isolates of P. fluorescens, SBW25, WH6 and Pf0-1. We found that CRISPRi is applicable to study complex phenotypes such as cell morphology, motility and biofilm formation over extended periods of time. In SBW25, CRISPRi-mediated silencing of genes encoding the GacA/S two-component system and regulatory proteins associated with the cylic di-GMP signaling messenger produced swarming and biofilm phenotypes similar to those obtained after gene inactivation. Combined with detailed confocal microscopy of biofilms, our study also revealed novel phenotypes associated with extracellular matrix biosynthesis as well as the potent inhibition of SBW25 biofilm formation mediated by the PFLU1114 operon. We conclude that CRISPRi is a reliable and scalable approach to investigate gene networks in the diverse P. fluorescens group.
Collapse
Affiliation(s)
| | - Sara Forrester
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States
| | - Grace Malato
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States
| | - Peter E Larsen
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States.,Department of Bioengineering, University of Illinois Chicago, Chicago, IL60607, United States
| | - Philippe Noirot
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States
| |
Collapse
|
20
|
Muriel C, Blanco-Romero E, Trampari E, Arrebola E, Durán D, Redondo-Nieto M, Malone JG, Martín M, Rivilla R. The diguanylate cyclase AdrA regulates flagellar biosynthesis in Pseudomonas fluorescens F113 through SadB. Sci Rep 2019; 9:8096. [PMID: 31147571 PMCID: PMC6543031 DOI: 10.1038/s41598-019-44554-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/14/2019] [Indexed: 11/23/2022] Open
Abstract
Flagellum mediated motility is an essential trait for rhizosphere colonization by pseudomonads. Flagella synthesis is a complex and energetically expensive process that is tightly regulated. In Pseudomonas fluorescens, the regulatory cascade starts with the master regulatory protein FleQ that is in turn regulated by environmental signals through the Gac/Rsm and SadB pathways, which converge in the sigma factor AlgU. AlgU is required for the expression of amrZ, encoding a FleQ repressor. AmrZ itself has been shown to modulate c-di-GMP levels through the control of many genes encoding enzymes implicated in c-di-GMP turnover. This cyclic nucleotide regulates flagellar function and besides, the master regulator of the flagellar synthesis signaling pathway, FleQ, has been shown to bind c-di-GMP. Here we show that AdrA, a diguanylate cyclase regulated by AmrZ participates in this signaling pathway. Epistasis analysis has shown that AdrA acts upstream of SadB, linking SadB with environmental signaling. We also show that SadB binds c-di-GMP with higher affinity than FleQ and propose that c-di-GMP produced by AdrA modulates flagella synthesis through SadB.
Collapse
Affiliation(s)
- Candela Muriel
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Esther Blanco-Romero
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Eleftheria Trampari
- Department of Molecular Microbiology, John Innes Centre. Colney Lane, Norwich, UK.,Quadram Institute, Norwich, UK
| | - Eva Arrebola
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain.,Department of Microbiology, University of Málaga, Málaga, Spain
| | - David Durán
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre. Colney Lane, Norwich, UK
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain.
| |
Collapse
|
21
|
Characterization of LuxI/LuxR and their regulation involved in biofilm formation and stress resistance in fish spoilers Pseudomonas fluorescens. Int J Food Microbiol 2018; 297:60-71. [PMID: 30884254 DOI: 10.1016/j.ijfoodmicro.2018.12.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 12/22/2022]
Abstract
Quorum sensing (QS) is crucial for adaption and development of foodborne bacteria in diverse environments. Pseudomonas fluorescens PF07 with QS mediated acylated homoserine lactones (AHLs) activity was isolated from spoiled large yellow croaker (Pseudosciaena crocea). In this study AHL-mediated QS system was characterized and their roles in biofilm formation, motility, stress response and spoilage of P. fluorescens were evaluated. A LuxI/LuxR homolog consisting of a conserved AHL synthase gene (luxI) and a transcriptional regulator gene (luxR) was identified in the strain. Two in-frame deletion mutants of luxI and luxR, ∆luxI and ∆luxR, were constructed to explore their QS signaling function in P. fluorescens. Three types of AHLs were detected in PF07 culture by LC-MS/MS, and N-butanoyl-l-homoserine lactone (C4-HSL) was a major signal molecule. The C4-HSL activities was almost abolished in ∆luxI, and decreased greatly in ∆luxR. Compared with wild type (WT) strain, both ∆luxI and ∆luxR showed the significant decrease of biofilm biomass and expolysaccharide production, resulting in thinner and incompact biofilm structure, but promoted swimming motility. The resistance of P. fluorescens to H2O2, heat, NaCl and crystal violet apparently declined in two mutants compared to WT. Spoilage factors, siderophore and protease, apparently attenuated due to deletion of luxI or luxR gene, while the growth and TVB-N production did not differ. Furthermore, the changes of the biofilm formation, motility and protease in ∆luxI strain were partially restored by the exogenous C4-HSL. In agreement with the effect of two mutants on various phenotypes, the transcriptions of alg, lapA, flgA, rpoS, and aprX were significantly down-regulated, and flgA was up-regulated in ∆luxI and ∆luxR. Therefore, the present study highlighted that the co-operation of LuxI/LuxR homolog was an important QS regulator in biofilm formation, motility and spoilage potential, and hinted its positive regulation of stress resistance with RpoS in P. fluorescens.
Collapse
|
22
|
Noirot-Gros MF, Shinde S, Larsen PE, Zerbs S, Korajczyk PJ, Kemner KM, Noirot PH. Dynamics of Aspen Roots Colonization by Pseudomonads Reveals Strain-Specific and Mycorrhizal-Specific Patterns of Biofilm Formation. Front Microbiol 2018; 9:853. [PMID: 29774013 PMCID: PMC5943511 DOI: 10.3389/fmicb.2018.00853] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/13/2018] [Indexed: 12/20/2022] Open
Abstract
Rhizosphere-associated Pseudomonas fluorescens are known plant growth promoting (PGP) and mycorrhizal helper bacteria (MHB) of many plants and ectomycorrhizal fungi. We investigated the spatial and temporal dynamics of colonization of mycorrhizal and non-mycorrhizal Aspen seedlings roots by the P. fluorescens strains SBW25, WH6, Pf0-1, and the P. protegens strain Pf-5. Seedlings were grown in laboratory vertical plates systems, inoculated with a fluorescently labeled Pseudomonas strain, and root colonization was monitored over a period of 5 weeks. We observed unexpected diversity of bacterial assemblies on seedling roots that changed over time and were strongly affected by root mycorrhization. P. fluorescens SBW25 and WH6 stains developed highly structured biofilms with internal void spaces forming channels. On mycorrhizal roots bacteria appeared encased in a mucilaginous substance in which they aligned side by side in parallel arrangements. The different phenotypic classes of bacterial assemblies observed for the four Pseudomonas strains were summarized in a single model describing transitions between phenotypic classes. Our findings also reveal that bacterial assembly phenotypes are driven by interactions with mucilaginous materials present at roots.
Collapse
Affiliation(s)
| | - Shalaka Shinde
- Biosciences Division, Argonne National Laboratory, Lemont, IL, United States
| | - Peter E Larsen
- Biosciences Division, Argonne National Laboratory, Lemont, IL, United States
| | - Sarah Zerbs
- Biosciences Division, Argonne National Laboratory, Lemont, IL, United States
| | - Peter J Korajczyk
- Biosciences Division, Argonne National Laboratory, Lemont, IL, United States
| | - Kenneth M Kemner
- Biosciences Division, Argonne National Laboratory, Lemont, IL, United States
| | - Philippe H Noirot
- Biosciences Division, Argonne National Laboratory, Lemont, IL, United States
| |
Collapse
|
23
|
Muriel C, Arrebola E, Redondo-Nieto M, Martínez-Granero F, Jalvo B, Pfeilmeier S, Blanco-Romero E, Baena I, Malone JG, Rivilla R, Martín M. AmrZ is a major determinant of c-di-GMP levels in Pseudomonas fluorescens F113. Sci Rep 2018; 8:1979. [PMID: 29386661 PMCID: PMC5792552 DOI: 10.1038/s41598-018-20419-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/18/2018] [Indexed: 01/17/2023] Open
Abstract
The transcriptional regulator AmrZ is a global regulatory protein conserved within the pseudomonads. AmrZ can act both as a positive and a negative regulator of gene expression, controlling many genes implicated in environmental adaption. Regulated traits include motility, iron homeostasis, exopolysaccharides production and the ability to form biofilms. In Pseudomonas fluorescens F113, an amrZ mutant presents a pleiotropic phenotype, showing increased swimming motility, decreased biofilm formation and very limited ability for competitive colonization of rhizosphere, its natural habitat. It also shows different colony morphology and binding of the dye Congo Red. The amrZ mutant presents severely reduced levels of the messenger molecule cyclic-di-GMP (c-di-GMP), which is consistent with the motility and biofilm formation phenotypes. Most of the genes encoding proteins with diguanylate cyclase (DGCs) or phosphodiesterase (PDEs) domains, implicated in c-di-GMP turnover in this bacterium, appear to be regulated by AmrZ. Phenotypic analysis of eight mutants in genes shown to be directly regulated by AmrZ and encoding c-di-GMP related enzymes, showed that seven of them were altered in motility and/or biofilm formation. The results presented here show that in P. fluorescens, AmrZ determines c-di-GMP levels through the regulation of a complex network of genes encoding DGCs and PDEs.
Collapse
Affiliation(s)
- Candela Muriel
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Eva Arrebola
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | | | - Blanca Jalvo
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Sebastian Pfeilmeier
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, NR47UH, Norwich, UK
| | - Esther Blanco-Romero
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Irene Baena
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, NR47UH, Norwich, UK
| | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain.
| |
Collapse
|
24
|
Martirani-Von Abercron SM, Marín P, Solsona-Ferraz M, Castañeda-Cataña MA, Marqués S. Naphthalene biodegradation under oxygen-limiting conditions: community dynamics and the relevance of biofilm-forming capacity. Microb Biotechnol 2017; 10:1781-1796. [PMID: 28840968 PMCID: PMC5658598 DOI: 10.1111/1751-7915.12842] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/21/2017] [Accepted: 07/25/2017] [Indexed: 11/27/2022] Open
Abstract
Toxic polycyclic aromatic hydrocarbons (PAHs) are frequently released into the environment from anthropogenic sources. PAH remediation strategies focus on biological processes mediated by bacteria. The availability of oxygen in polluted environments is often limited or absent, and only bacteria able to thrive in these conditions can be considered for bioremediation strategies. To identify bacterial strains able to degrade PAHs under oxygen‐limiting conditions, we set up enrichment cultures from samples of an oil‐polluted aquifer, using either anoxic or microaerophilic condition and with PAHs as the sole carbon source. Despite the presence of a significant community of nitrate‐reducing bacteria, the initial community, which was dominated by Betaproteobacteria, was incapable of PAH degradation under strict anoxic conditions, although a clear shift in the structure of the community towards an increase in the Alphaproteobacteria (Sphingomonadaceae), Actinobacteria and an uncultured group of Acidobacteria was observed in the enrichments. In contrast, growth under microaerophilic conditions with naphthalene as the carbon source evidenced the development of a biofilm structure around the naphthalene crystal. The enrichment process selected two co‐dominant groups which finally reached 97% of the bacterial communities: Variovorax spp. (54%, Betaproteobacteria) and Starkeya spp. (43%, Xanthobacteraceae). The two dominant populations were able to grow with naphthalene, although only Starkeya was able to reproduce the biofilm structure around the naphthalene crystal. The pathway for naphthalene degradation was identified, which included as essential steps dioxygenases with high affinity for oxygen, showing 99% identity with Xanthobacter polyaromaticivorans dbd cluster for PAH degradation. Our results suggest that the biofilm formation capacity of Starkeya provided a structure to allocate its cells at an appropriate distance from the toxic carbon source.
Collapse
Affiliation(s)
| | - Patricia Marín
- Estación Experimental del Zaidín, Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Marta Solsona-Ferraz
- Estación Experimental del Zaidín, Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Mayra-Alejandra Castañeda-Cataña
- Estación Experimental del Zaidín, Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Silvia Marqués
- Estación Experimental del Zaidín, Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Granada, Spain
| |
Collapse
|
25
|
Campilongo R, Fung RKY, Little RH, Grenga L, Trampari E, Pepe S, Chandra G, Stevenson CEM, Roncarati D, Malone JG. One ligand, two regulators and three binding sites: How KDPG controls primary carbon metabolism in Pseudomonas. PLoS Genet 2017; 13:e1006839. [PMID: 28658302 PMCID: PMC5489143 DOI: 10.1371/journal.pgen.1006839] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 05/26/2017] [Indexed: 12/04/2022] Open
Abstract
Effective regulation of primary carbon metabolism is critically important for bacteria to successfully adapt to different environments. We have identified an uncharacterised transcriptional regulator; RccR, that controls this process in response to carbon source availability. Disruption of rccR in the plant-associated microbe Pseudomonas fluorescens inhibits growth in defined media, and compromises its ability to colonise the wheat rhizosphere. Structurally, RccR is almost identical to the Entner-Doudoroff (ED) pathway regulator HexR, and both proteins are controlled by the same ED-intermediate; 2-keto-3-deoxy-6-phosphogluconate (KDPG). Despite these similarities, HexR and RccR control entirely different aspects of primary metabolism, with RccR regulating pyruvate metabolism (aceEF), the glyoxylate shunt (aceA, glcB, pntAA) and gluconeogenesis (pckA, gap). RccR displays complex and unusual regulatory behaviour; switching repression between the pyruvate metabolism and glyoxylate shunt/gluconeogenesis loci depending on the available carbon source. This regulatory complexity is enabled by two distinct pseudo-palindromic binding sites, differing only in the length of their linker regions, with KDPG binding increasing affinity for the 28 bp aceA binding site but decreasing affinity for the 15 bp aceE site. Thus, RccR is able to simultaneously suppress and activate gene expression in response to carbon source availability. Together, the RccR and HexR regulators enable the rapid coordination of multiple aspects of primary carbon metabolism, in response to levels of a single key intermediate. Here we show how Pseudomonas controls multiple different primary carbon metabolism pathways by sensing levels of KDPG, an Entner Doudoroff (ED) pathway intermediate. KDPG binds to two highly similar transcription factors; the ED regulator HexR and the previously uncharacterised protein RccR. RccR inversely controls the glyoxylate shunt, gluconeogenesis and pyruvate metabolism, suppressing the first two pathways as pyruvate metabolism genes are expressed, and vice versa. This complex regulation is enabled by two distinct RccR-binding consensus sequences in the RccR regulon promoters. KDPG binding simultaneously increases RccR affinity for the glyoxylate shunt and gluconeogenesis promoters, and releases repression of pyruvate metabolism. This elegant two-regulator circuit allows Pseudomonas to rapidly respond to carbon source availability by sensing a single key intermediate, KDPG.
Collapse
Affiliation(s)
- Rosaria Campilongo
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
- Istituto Pasteur- Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie ‘‘C. Darwin”, Sapienza Universita`di Roma, Roma, Italy
| | - Rowena K. Y. Fung
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
- University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Richard H. Little
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Lucia Grenga
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
- University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Eleftheria Trampari
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Simona Pepe
- Alma Mater Studiorum - University of Bologna, Department of Pharmacy and Biotechnology – FaBiT, Bologna, Italy
| | - Govind Chandra
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | | | - Davide Roncarati
- Alma Mater Studiorum - University of Bologna, Department of Pharmacy and Biotechnology – FaBiT, Bologna, Italy
| | - Jacob G. Malone
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
- University of East Anglia, Norwich Research Park, Norwich, United Kingdom
- * E-mail:
| |
Collapse
|
26
|
Vida C, Cazorla FM, de Vicente A. Characterization of biocontrol bacterial strains isolated from a suppressiveness-induced soil after amendment with composted almond shells. Res Microbiol 2017; 168:583-593. [PMID: 28373145 DOI: 10.1016/j.resmic.2017.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/21/2017] [Accepted: 03/24/2017] [Indexed: 12/16/2022]
Abstract
The improvement in soil quality of avocado crops through organic amendments with composted almond shells has a positive effect on crop yield and plant health, and enhances soil suppressiveness against the phytopathogenic fungus Rosellinia necatrix. In previous studies, induced soil suppressiveness against this pathogen was related to stimulation of Gammaproteobacteria, especially some members of Pseudomonas spp. with biocontrol-related activities. In this work, we isolated bacteria from this suppressiveness-induced amended soil using a selective medium for Pseudomonas-like microorganisms. We characterized the obtained bacterial collection to aid in identification, including metabolic profiles, antagonistic responses, hybridization to biosynthetic genes of antifungal compounds, production of lytic exoenzymatic activities and plant growth-promotion-related traits, and sequenced and compared amplified 16S rDNA genes from representative bacteria. The final selection of representative strains mainly belonged to the genus Pseudomonas, but also included the genera Serratia and Stenotrophomonas. Their biocontrol-related activities were assayed using the experimental avocado model, and results showed that all selected strains protected the avocado roots against R. necatrix. This work confirmed the biocontrol activity of these Gammaproteobacteria-related members against R. necatrix following specific stimulation in a suppressiveness-induced soil after a composted almond shell application.
Collapse
Affiliation(s)
- Carmen Vida
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain; Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Bulevar Louis Pasteur, 31, 29071 Málaga, Spain.
| | - Francisco M Cazorla
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain; Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Bulevar Louis Pasteur, 31, 29071 Málaga, Spain.
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain; Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Bulevar Louis Pasteur, 31, 29071 Málaga, Spain.
| |
Collapse
|
27
|
Barahona E, Navazo A, Garrido-Sanz D, Muriel C, Martínez-Granero F, Redondo-Nieto M, Martín M, Rivilla R. Pseudomonas fluorescens F113 Can Produce a Second Flagellar Apparatus, Which Is Important for Plant Root Colonization. Front Microbiol 2016; 7:1471. [PMID: 27713729 PMCID: PMC5031763 DOI: 10.3389/fmicb.2016.01471] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/02/2016] [Indexed: 12/30/2022] Open
Abstract
The genomic sequence of Pseudomonas fluorescens F113 has shown the presence of a 41 kb cluster of genes that encode the production of a second flagellar apparatus. Among 2,535 pseudomonads strains with sequenced genomes, these genes are only present in the genomes of F113 and other six strains, all but one belonging to the P. fluorescens cluster of species, in the form of a genetic island. The genes are homologous to the flagellar genes of the soil bacterium Azotobacter vinelandii. Regulation of these genes is mediated by the flhDC master operon, instead of the typical regulation in pseudomonads, which is through fleQ. Under laboratory conditions, F113 does not produce this flagellum and the flhDC operon is not expressed. However, ectopic expression of the flhDC operon is enough for its production, resulting in a hypermotile strain. This flagellum is also produced under laboratory conditions by the kinB and algU mutants. Genetic analysis has shown that kinB strongly represses the expression of the flhDC operon. This operon is activated by the Vfr protein probably in a c-AMP dependent way. The strains producing this second flagellum are all hypermotile and present a tuft of polar flagella instead of the single polar flagellum produced by the wild-type strain. Phenotypic variants isolated from the rhizosphere produce this flagellum and mutation of the genes encoding it, results in a defect in competitive colonization, showing its importance for root colonization.
Collapse
Affiliation(s)
- Emma Barahona
- Departamento de Biología, Universidad Autónoma de Madrid Madrid, Spain
| | - Ana Navazo
- Departamento de Biología, Universidad Autónoma de Madrid Madrid, Spain
| | | | - Candela Muriel
- Departamento de Biología, Universidad Autónoma de Madrid Madrid, Spain
| | | | | | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid Madrid, Spain
| |
Collapse
|
28
|
Lopes LD, Pereira E Silva MDC, Andreote FD. Bacterial Abilities and Adaptation Toward the Rhizosphere Colonization. Front Microbiol 2016; 7:1341. [PMID: 27610108 PMCID: PMC4997060 DOI: 10.3389/fmicb.2016.01341] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/15/2016] [Indexed: 11/13/2022] Open
Abstract
The rhizosphere harbors one of the most complex, diverse, and active plant-associated microbial communities. This community can be recruited by the plant host to either supply it with nutrients or to help in the survival under stressful conditions. Although selection for the rhizosphere community is evident, the specific bacterial traits that make them able to colonize this environment are still poorly understood. Thus, here we used a combination of community level physiological profile (CLPP) analysis and 16S rRNA gene quantification and sequencing (coupled with in silico analysis and metagenome prediction), to get insights on bacterial features and processes involved in rhizosphere colonization of sugarcane. CLPP revealed a higher metabolic activity in the rhizosphere compared to bulk soil, and suggested that D-galacturonic acid plays a role in bacterial selection by the plant roots (supported by results of metagenome prediction). Quantification of the 16S rRNA gene confirmed the higher abundance of bacteria in the rhizosphere. Sequence analysis showed that of the 252 classified families sampled, 24 were significantly more abundant in the bulk soil and 29 were more abundant in the rhizosphere. Furthermore, metagenomes predicted from the 16S rRNA gene sequences revealed a significant higher abundance of predicted genes associated with biofilm formation and with horizontal gene transfer (HGT) processes. In sum, this study identified major bacterial groups and their potential abilities to occupy the sugarcane rhizosphere, and indicated that polygalacturonase activity and HGT events may be important features for rhizosphere colonization.
Collapse
Affiliation(s)
- Lucas D Lopes
- Soil Microbiology Lab, Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo Piracicaba, Brazil
| | - Michele de Cássia Pereira E Silva
- Soil Microbiology Lab, Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo Piracicaba, Brazil
| | - Fernando D Andreote
- Soil Microbiology Lab, Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo Piracicaba, Brazil
| |
Collapse
|
29
|
Fox AR, Soto G, Valverde C, Russo D, Lagares A, Zorreguieta Á, Alleva K, Pascuan C, Frare R, Mercado-Blanco J, Dixon R, Ayub ND. Major cereal crops benefit from biological nitrogen fixation when inoculated with the nitrogen-fixing bacterium Pseudomonas protegens Pf-5 X940. Environ Microbiol 2016; 18:3522-3534. [PMID: 27198923 DOI: 10.1111/1462-2920.13376] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A main goal of biological nitrogen fixation research has been to expand the nitrogen-fixing ability to major cereal crops. In this work, we demonstrate the use of the efficient nitrogen-fixing rhizobacterium Pseudomonas protegens Pf-5 X940 as a chassis to engineer the transfer of nitrogen fixed by BNF to maize and wheat under non-gnotobiotic conditions. Inoculation of maize and wheat with Pf-5 X940 largely improved nitrogen content and biomass accumulation in both vegetative and reproductive tissues, and this beneficial effect was positively associated with high nitrogen fixation rates in roots. 15 N isotope dilution analysis showed that maize and wheat plants obtained substantial amounts of fixed nitrogen from the atmosphere. Pf-5 X940-GFP-tagged cells were always reisolated from the maize and wheat root surface but never from the inner root tissues. Confocal laser scanning microscopy confirmed root surface colonization of Pf-5 X940-GFP in wheat plants, and microcolonies were mostly visualized at the junctions between epidermal root cells. Genetic analysis using biofilm formation-related Pseudomonas mutants confirmed the relevance of bacterial root adhesion in the increase in nitrogen content, biomass accumulation and nitrogen fixation rates in wheat roots. To our knowledge, this is the first report of robust BNF in major cereal crops.
Collapse
Affiliation(s)
- Ana Romina Fox
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Gabriela Soto
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Claudio Valverde
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,LBMIBS, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Buenos Aires, Argentina
| | - Daniela Russo
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Fundación Instituto Leloir and IIBBA CONICET, Buenos Aires, Argentina
| | - Antonio Lagares
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,LBMIBS, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Buenos Aires, Argentina
| | - Ángeles Zorreguieta
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Fundación Instituto Leloir and IIBBA CONICET, Buenos Aires, Argentina
| | - Karina Alleva
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Departamento de Fisicomatemática, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cecilia Pascuan
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Romina Frare
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina
| | - Jesús Mercado-Blanco
- Department of Crop Protection, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Córdoba, Spain
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Nicolás Daniel Ayub
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cuidad Autónoma de Buenos Aires, Buenos Aires, Argentina. .,Instituto de Genética Ewald A. Favret (CICVyA-INTA), Buenos Aires, Argentina.
| |
Collapse
|
30
|
Acebo-Guerrero Y, Hernández-Rodríguez A, Vandeputte O, Miguélez-Sierra Y, Heydrich-Pérez M, Ye L, Cornelis P, Bertin P, El Jaziri M. Characterization of Pseudomonas chlororaphis from Theobroma cacao L. rhizosphere with antagonistic activity against Phytophthora palmivora (Butler). J Appl Microbiol 2016. [PMID: 26218193 DOI: 10.1111/jam.12910] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To isolate and characterize rhizobacteria from Theobroma cacao with antagonistic activity against Phytophthora palmivora, the causal agent of the black pod rot, which is one of the most important diseases of T. cacao. METHODS AND RESULTS Among 127 rhizobacteria isolated from cacao rhizosphere, three isolates (CP07, CP24 and CP30) identified as Pseudomonas chlororaphis, showed in vitro antagonistic activity against P. palmivora. Direct antagonism tested in cacao detached leaves revealed that the isolated rhizobacteria were able to reduce symptom severity upon infection with P. palmivora Mab1, with Ps. chlororaphis CP07 standing out as a potential biocontrol agent. Besides, reduced symptom severity on leaves was also observed in planta where cacao root system was pretreated with the isolated rhizobacteria followed by leaf infection with P. palmivora Mab1. The production of lytic enzymes, siderophores, biosurfactants and HCN, as well as the detection of genes encoding antibiotics, the formation of biofilm, and bacterial motility were also assessed for all three rhizobacterial strains. By using a mutant impaired in viscosin production, derived from CP07, it was found that this particular biosurfactant turned out to be crucial for both motility and biofilm formation, but not for the in vitro antagonism against Phytophthora, although it may contribute to the bioprotection of T. cacao. CONCLUSIONS In the rhizosphere of T. cacao, there are rhizobacteria, such as Ps. chlororaphis, able to protect plants against P. palmivora. SIGNIFICANCE AND IMPACT OF THE STUDY This study provides a theoretical basis for the potential use of Ps. chlororaphis CP07 as a biocontrol agent for the protection of cacao plants from P. palmivora infection.
Collapse
Affiliation(s)
- Y Acebo-Guerrero
- Laboratory of Microbial Ecology, Faculty of Biology, University of Havana, Plaza, Cuba
| | - A Hernández-Rodríguez
- Laboratory of Microbial Ecology, Faculty of Biology, University of Havana, Plaza, Cuba
| | - O Vandeputte
- Laboratory of Plant Biotechnology, Université Libre de Bruxelles, Gosselies, Belgium
| | | | - M Heydrich-Pérez
- Laboratory of Microbial Ecology, Faculty of Biology, University of Havana, Plaza, Cuba
| | - L Ye
- Department of Bioengineering Sciences, Research group Microbiology, Vrije Universiteit Brussel and VIB Structural Biology, Brussels, Belgium
| | - P Cornelis
- Department of Bioengineering Sciences, Research group Microbiology, Vrije Universiteit Brussel and VIB Structural Biology, Brussels, Belgium
| | - P Bertin
- Earth and Life Institute - Agronomy (ELI-A), Université Catholique de Louvain, Louvain, Belgium
| | - M El Jaziri
- Laboratory of Plant Biotechnology, Université Libre de Bruxelles, Gosselies, Belgium
| |
Collapse
|
31
|
Adaptive Remodeling of the Bacterial Proteome by Specific Ribosomal Modification Regulates Pseudomonas Infection and Niche Colonisation. PLoS Genet 2016; 12:e1005837. [PMID: 26845436 PMCID: PMC4741518 DOI: 10.1371/journal.pgen.1005837] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/11/2016] [Indexed: 12/17/2022] Open
Abstract
Post-transcriptional control of protein abundance is a highly important, underexplored regulatory process by which organisms respond to their environments. Here we describe an important and previously unidentified regulatory pathway involving the ribosomal modification protein RimK, its regulator proteins RimA and RimB, and the widespread bacterial second messenger cyclic-di-GMP (cdG). Disruption of rimK affects motility and surface attachment in pathogenic and commensal Pseudomonas species, with rimK deletion significantly compromising rhizosphere colonisation by the commensal soil bacterium P. fluorescens, and plant infection by the pathogens P. syringae and P. aeruginosa. RimK functions as an ATP-dependent glutamyl ligase, adding glutamate residues to the C-terminus of ribosomal protein RpsF and inducing specific effects on both ribosome protein complement and function. Deletion of rimK in P. fluorescens leads to markedly reduced levels of multiple ribosomal proteins, and also of the key translational regulator Hfq. In turn, reduced Hfq levels induce specific downstream proteomic changes, with significant increases in multiple ABC transporters, stress response proteins and non-ribosomal peptide synthetases seen for both ΔrimK and Δhfq mutants. The activity of RimK is itself controlled by interactions with RimA, RimB and cdG. We propose that control of RimK activity represents a novel regulatory mechanism that dynamically influences interactions between bacteria and their hosts; translating environmental pressures into dynamic ribosomal changes, and consequently to an adaptive remodeling of the bacterial proteome. Post-transcriptional control of protein abundance is a significant and underexplored regulatory process by which organisms respond to environmental change. We have discovered an important new mechanism for this control in bacteria, based on the covalent modification of a small ribosomal protein by the widespread enzyme RimK. Here we show that the activity of RimK has specific effects on the levels of ribosomal proteins in the cell, which in turn affects the abundance of the important translational regulator Hfq. RimK is itself controlled by binding to the small regulatory proteins RimA and RimB and the widespread signalling molecule cyclic-di-GMP. Deletion of rimK compromises motility, virulence and plant colonisation/infection in several different Pseudomonas species. We propose that changes in intracellular RimK activity enable Pseudomonas to respond to environmental pressures by changing the nature of their ribosomes, leading in turn to an adaptive phenotypic response to their surroundings. This promotes motility and virulence during the initial stages of plant contact, and phenotypes including attachment, metabolite transport and stress control during long-term environmental adaptation.
Collapse
|
32
|
Corral-Lugo A, De la Torre J, Matilla MA, Fernández M, Morel B, Espinosa-Urgel M, Krell T. Assessment of the contribution of chemoreceptor-based signalling to biofilm formation. Environ Microbiol 2016; 18:3355-3372. [PMID: 26662997 DOI: 10.1111/1462-2920.13170] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 11/30/2015] [Indexed: 12/01/2022]
Abstract
Although it is well established that one- and two-component regulatory systems participate in regulating biofilm formation, there also exists evidence suggesting that chemosensory pathways are also involved. However, little information exists about which chemoreceptors and signals modulate this process. Here we report the generation of the complete set of chemoreceptor mutants of Pseudomonas putida KT2440 and the identification of four mutants with significantly altered biofilm phenotypes. These receptors are a WspA homologue of Pseudomonas aeruginosa, previously identified to control biofilm formation by regulating c-di-GMP levels, and three uncharacterized chemoreceptors. One of these receptors, named McpU, was found to mediate chemotaxis towards different polyamines. The functional annotation of McpU was initiated by high-throughput thermal shift assays of the receptor ligand binding domain (LBD). Isothermal titration calorimetry showed that McpU-LBD specifically binds putrescine, cadaverine and spermidine, indicating that McpU represents a novel chemoreceptor type. Another uncharacterized receptor, named McpA, specifically binds 12 different proteinogenic amino acids and mediates chemotaxis towards these compounds. We also show that mutants in McpU and WspA-Pp have a significantly reduced ability to colonize plant roots. Data agree with other reports showing that polyamines are signal molecules involved in the regulation of bacteria-plant communication and biofilm formation.
Collapse
Affiliation(s)
- Andrés Corral-Lugo
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain
| | - Jesús De la Torre
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain
| | - Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain
| | - Matilde Fernández
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain
| | - Bertrand Morel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain
| | - Manuel Espinosa-Urgel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain.
| |
Collapse
|
33
|
Trampari E, Stevenson CEM, Little RH, Wilhelm T, Lawson DM, Malone JG. Bacterial rotary export ATPases are allosterically regulated by the nucleotide second messenger cyclic-di-GMP. J Biol Chem 2015; 290:24470-83. [PMID: 26265469 PMCID: PMC4591828 DOI: 10.1074/jbc.m115.661439] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Indexed: 01/03/2023] Open
Abstract
The widespread second messenger molecule cyclic di-GMP (cdG) regulates the transition from motile and virulent lifestyles to sessile, biofilm-forming ones in a wide range of bacteria. Many pathogenic and commensal bacterial-host interactions are known to be controlled by cdG signaling. Although the biochemistry of cyclic dinucleotide metabolism is well understood, much remains to be discovered about the downstream signaling pathways that induce bacterial responses upon cdG binding. As part of our ongoing research into the role of cdG signaling in plant-associated Pseudomonas species, we carried out an affinity capture screen for cdG binding proteins in the model organism Pseudomonas fluorescens SBW25. The flagella export AAA+ ATPase FliI was identified as a result of this screen and subsequently shown to bind specifically to the cdG molecule, with a KD in the low micromolar range. The interaction between FliI and cdG appears to be very widespread. In addition to FliI homologs from diverse bacterial species, high affinity binding was also observed for the type III secretion system homolog HrcN and the type VI ATPase ClpB2. The addition of cdG was shown to inhibit FliI and HrcN ATPase activity in vitro. Finally, a combination of site-specific mutagenesis, mass spectrometry, and in silico analysis was used to predict that cdG binds to FliI in a pocket of highly conserved residues at the interface between two FliI subunits. Our results suggest a novel, fundamental role for cdG in controlling the function of multiple important bacterial export pathways, through direct allosteric control of export ATPase proteins.
Collapse
Affiliation(s)
| | - Clare E M Stevenson
- the Biological Chemistry Department, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | | | - Thomas Wilhelm
- the Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, United Kingdom, and
| | - David M Lawson
- the Biological Chemistry Department, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Jacob G Malone
- From the Molecular Microbiology Department and the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| |
Collapse
|
34
|
Muriel C, Jalvo B, Redondo-Nieto M, Rivilla R, Martín M. Chemotactic Motility of Pseudomonas fluorescens F113 under Aerobic and Denitrification Conditions. PLoS One 2015; 10:e0132242. [PMID: 26161531 PMCID: PMC4498747 DOI: 10.1371/journal.pone.0132242] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/11/2015] [Indexed: 01/01/2023] Open
Abstract
The sequence of the genome of Pseudomonas fluorescens F113 has shown the presence of multiple traits relevant for rhizosphere colonization and plant growth promotion. Among these traits are denitrification and chemotactic motility. Besides aerobic growth, F113 is able to grow anaerobically using nitrate and nitrite as final electron acceptors. F113 is able to perform swimming motility under aerobic conditions and under anaerobic conditions when nitrate is used as the electron acceptor. However, nitrite can not support swimming motility. Regulation of swimming motility is similar under aerobic and anaerobic conditions, since mutants that are hypermotile under aerobic conditions, such as gacS, sadB, kinB, algU and wspR, are also hypermotile under anaerobic conditions. However, chemotactic behavior is different under aerobic and denitrification conditions. Unlike most pseudomonads, the F113 genome encode three complete chemotaxis systems, Che1, Che2 and Che3. Mutations in each of the cheA genes of the three Che systems has shown that the three systems are functional and independent. Mutation of the cheA1 gene completely abolished swimming motility both under aerobic and denitrification conditions. Mutation of the cheA2 gene, showed only a decrease in swimming motility under both conditions, indicating that this system is not essential for chemotactic motility but is necessary for optimal motility. Mutation of the cheA3 gene abolished motility under denitrification conditions but only produced a decrease in motility under aerobic conditions. The three Che systems proved to be implicated in competitive rhizosphere colonization, being the cheA1 mutant the most affected.
Collapse
Affiliation(s)
- Candela Muriel
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | - Blanca Jalvo
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail:
| |
Collapse
|
35
|
Zayda PMM, Elizabeth AAD, Thiago ASDO, Fernando PM, Leandro LL, Jorge TDS. Host and tissue preferences of Enterobacter cloacae and Bacillus amyloliquefaciens for endophytic colonization. ACTA ACUST UNITED AC 2015. [DOI: 10.5897/ajmr2015.7475] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
36
|
Comparative genomic analysis and phenazine production of Pseudomonas chlororaphis, a plant growth-promoting rhizobacterium. GENOMICS DATA 2015; 4:33-42. [PMID: 26484173 PMCID: PMC4535895 DOI: 10.1016/j.gdata.2015.01.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/13/2015] [Accepted: 01/15/2015] [Indexed: 11/22/2022]
Abstract
Pseudomonas chlororaphis HT66, a plant growth-promoting rhizobacterium that produces phenazine-1-carboxamide with high yield, was compared with three genomic sequenced P. chlororaphis strains, GP72, 30–84 and O6. The genome sizes of four strains vary from 6.66 to 7.30 Mb. Comparisons of predicted coding sequences indicated 4833 conserved genes in 5869–6455 protein-encoding genes. Phylogenetic analysis showed that the four strains are closely related to each other. Its competitive colonization indicates that P. chlororaphis can adapt well to its environment. No virulence or virulence-related factor was found in P. chlororaphis. All of the four strains could synthesize antimicrobial metabolites including different phenazines and insecticidal protein FitD. Some genes related to the regulation of phenazine biosynthesis were detected among the four strains. It was shown that P. chlororaphis is a safe PGPR in agricultural application and could also be used to produce some phenazine antibiotics with high-yield. The comparative genomic analysis showed that P. chlororaphis strains have 80% conserved genes. Its competitive colonization indicates that P. chlororaphis can adapt well to its environment. P. chlororaphis can synthesize different phenazine compounds and insecticidal proteins. The plant growth-promoting activities and lack of virulence factor make P. chlororaphis suitable for applications.
Collapse
Key Words
- 2-OH-PHZ, 2-hydroxyphenazine
- AAI, amino acid identity
- ACC, 1-aminocyclopropane-1-carboxylate
- Acr, achromobactin
- Anti-bacterial activity
- COGs, Clusters of Orthologous Groups
- Comparative genomics
- Fit, P. fluorescens insecticidal toxin
- GI, genomic island
- HCN, hydrogen cyanide
- HPR, 2-hexyl-5-propyl-alkylresorcinol
- IAA, indole-3-acetic acid
- MCP, methyl-accepting chemotaxis protein
- MLSA, multilocus sequence analysis
- Mcf, makes caterpillars floppy
- PAA, phenylacetic acid
- PCA, phenazine-1-carboxylic acid
- PCN, phenazine-1-carboxamide
- PGPR, plant growth-promoting rhizobacteria
- PQQ, pyrroloquinoline quinine
- Phenazines
- Prn, pyrrolnitrin
- Pseudomonas
- Pvd, pyoverdin
- Rhizosphere colonization
- Tad pili, type IVb tight adherence pili
- mGS, mGenomeSubtractor
Collapse
|
37
|
Ayub ND, Fox AR, García AN, Mozzicafreddo M, Cuccioloni M, Angeletti M, Pagano E, Soto G. Pseudomonas fluorescens Pf-5 genome-wide mutant screen for resistance to the antimicrobial peptide alfalfa snakin-1. FEMS Microbiol Lett 2014; 362:1-6. [PMID: 25670697 DOI: 10.1093/femsle/fnu006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Snakin-1, a peptide produced by higher plants, has broad-spectrum antibiotic activity, inhibiting organisms ranging from Bacteria to Eukaryotes. However, the mode of action against target organisms is poorly understood. As a first step to elucidate the mechanism, we screened a mutation library of Pseudomonas fluorescens Pf-5 in LB and agar medium supplemented with alfalfa snakin-1 (MsSN1). We identified three biofilm formation-related Pseudomonas mutants that showed increased resistance to MsSN1. Genetic, physiological and bioinformatics analysis validated the results of the mutant screens, indicating that bacterial adhesion protein lapA is probably the target of MsSN1. Collectively, these findings suggest that snakin-1 acts on microbial adhesion properties.
Collapse
Affiliation(s)
- Nicolás D Ayub
- Instituto de Genética Ewald A. Favret (CICVyA-INTA), De los reseros S/N, Castelar C25 (1712), Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avda. Rivadavia 1917, C1033AAJ, Cuidad Autónoma de Buenos Aires, Argentina
| | - Ana R Fox
- Instituto de Genética Ewald A. Favret (CICVyA-INTA), De los reseros S/N, Castelar C25 (1712), Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avda. Rivadavia 1917, C1033AAJ, Cuidad Autónoma de Buenos Aires, Argentina
| | - Araceli N García
- Instituto de Genética Ewald A. Favret (CICVyA-INTA), De los reseros S/N, Castelar C25 (1712), Buenos Aires, Argentina
| | - Matteo Mozzicafreddo
- School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino (MC), Italy
| | | | - Mauro Angeletti
- School of Biosciences and Biotechnology, University of Camerino, 62032 Camerino (MC), Italy
| | - Elba Pagano
- Instituto de Genética Ewald A. Favret (CICVyA-INTA), De los reseros S/N, Castelar C25 (1712), Buenos Aires, Argentina
| | - Gabriela Soto
- Instituto de Genética Ewald A. Favret (CICVyA-INTA), De los reseros S/N, Castelar C25 (1712), Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avda. Rivadavia 1917, C1033AAJ, Cuidad Autónoma de Buenos Aires, Argentina
| |
Collapse
|
38
|
Qiu M, Xu Z, Li X, Li Q, Zhang N, Shen Q, Zhang R. Comparative proteomics analysis of Bacillus amyloliquefaciens SQR9 revealed the key proteins involved in in situ root colonization. J Proteome Res 2014; 13:5581-91. [PMID: 25299960 DOI: 10.1021/pr500565m] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bacillus Amyloliquefaciens SQR9 is a well-investigated plant growth-promoting rhizobacteria with strong root colonization capability. To identify the key proteins involved in in situ root colonization and biofilm formation, the proteomic profiles of planktonic and root colonized SQR9 cells were compared. A total of 755 proteins were identified, of which 78 and 95 proteins were significantly increased and deceased, respectively, when SQR9 was colonized on the root. The proteins that were closely affiliated with the root colonization belonged to the functional categories of biocontrol, detoxification, biofilm formation, cell motility and chemotaxis, transport, and degradation of plant polysaccharides. A two-component system protein ResE was increased 100-fold when compared to the planktonic status; impairment of the resE gene postponed the formation of cell biofilm and decreased the root colonization capability, which may be regulated through the spo0A-sinI-yqxM pathway. The SQR9 proteomic data provide valuable clues for screening key proteins in the plant-rhizobacteria interaction.
Collapse
Affiliation(s)
- Meihua Qiu
- National Engineering Research Center for Organic-Based Fertilizers and Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University , Nanjing 210095, P.R. China
| | | | | | | | | | | | | |
Collapse
|
39
|
Pérez-Montaño F, Jiménez-Guerrero I, Del Cerro P, Baena-Ropero I, López-Baena FJ, Ollero FJ, Bellogín R, Lloret J, Espuny R. The symbiotic biofilm of Sinorhizobium fredii SMH12, necessary for successful colonization and symbiosis of Glycine max cv Osumi, is regulated by Quorum Sensing systems and inducing flavonoids via NodD1. PLoS One 2014; 9:e105901. [PMID: 25166872 PMCID: PMC4148318 DOI: 10.1371/journal.pone.0105901] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/25/2014] [Indexed: 11/18/2022] Open
Abstract
Bacterial surface components, especially exopolysaccharides, in combination with bacterial Quorum Sensing signals are crucial for the formation of biofilms in most species studied so far. Biofilm formation allows soil bacteria to colonize their surrounding habitat and survive common environmental stresses such as desiccation and nutrient limitation. This mode of life is often essential for survival in bacteria of the genera Mesorhizobium, Sinorhizobium, Bradyrhizobium, and Rhizobium. The role of biofilm formation in symbiosis has been investigated in detail for Sinorhizobium meliloti and Bradyrhizobium japonicum. However, for S. fredii this process has not been studied. In this work we have demonstrated that biofilm formation is crucial for an optimal root colonization and symbiosis between S. fredii SMH12 and Glycine max cv Osumi. In this bacterium, nod-gene inducing flavonoids and the NodD1 protein are required for the transition of the biofilm structure from monolayer to microcolony. Quorum Sensing systems are also required for the full development of both types of biofilms. In fact, both the nodD1 mutant and the lactonase strain (the lactonase enzyme prevents AHL accumulation) are defective in soybean root colonization. The impairment of the lactonase strain in its colonization ability leads to a decrease in the symbiotic parameters. Interestingly, NodD1 together with flavonoids activates certain quorum sensing systems implicit in the development of the symbiotic biofilm. Thus, S. fredii SMH12 by means of a unique key molecule, the flavonoid, efficiently forms biofilm, colonizes the legume roots and activates the synthesis of Nod factors, required for successfully symbiosis.
Collapse
Affiliation(s)
| | - Irene Jiménez-Guerrero
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Pablo Del Cerro
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Irene Baena-Ropero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | | | | | - Ramón Bellogín
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Javier Lloret
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Rosario Espuny
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| |
Collapse
|
40
|
D'aes J, Kieu NP, Léclère V, Tokarski C, Olorunleke FE, De Maeyer K, Jacques P, Höfte M, Ongena M. To settle or to move? The interplay between two classes of cyclic lipopeptides in the biocontrol strain Pseudomonas CMR12a. Environ Microbiol 2014; 16:2282-300. [PMID: 24673852 DOI: 10.1111/1462-2920.12462] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 02/14/2014] [Accepted: 02/15/2014] [Indexed: 12/15/2022]
Abstract
Pseudomonas CMR12a is a biocontrol strain that produces phenazine antibiotics and as yet uncharacterized cyclic lipopeptides (CLPs). The CLPs of CMR12a were studied by chemical structure analysis and in silico analysis of the gene clusters encoding the non-ribosomal peptide synthetases responsible for CLP biosynthesis. CMR12a produces two different classes of CLPs: orfamides B, D and E, whereby the latter two represent new derivatives of the orfamide family, and sessilins A-C. The orfamides are made up of a 10 amino acid peptide coupled to a β-hydroxydodecanoyl or β-hydroxytetradecanoyl fatty acid moiety, and are related to orfamides produced by biocontrol strain Pseudomonas protegens Pf-5. The sessilins consist of an 18-amino acid peptide linked to a β-hydroxyoctanoyl fatty acid and differ in one amino acid from tolaasins, toxins produced by the mushroom pathogen Pseudomonas tolaasii. CLP biosynthesis mutants were constructed and tested for biofilm formation and swarming motility. Orfamides appeared indispensable for swarming while sessilin mutants showed reduced biofilm formation, but enhanced swarming motility. The interplay between the two classes of CLPs fine tunes these processes. The presence of sessilins in wild type CMR12a interferes with swarming by hampering the release of orfamides and by co-precipitating orfamides to form a white line in agar.
Collapse
Affiliation(s)
- Jolien D'aes
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Fazli M, Almblad H, Rybtke ML, Givskov M, Eberl L, Tolker-Nielsen T. Regulation of biofilm formation in Pseudomonas and Burkholderia species. Environ Microbiol 2014; 16:1961-81. [PMID: 24592823 DOI: 10.1111/1462-2920.12448] [Citation(s) in RCA: 195] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/12/2014] [Accepted: 02/28/2014] [Indexed: 01/28/2023]
Abstract
In the present review, we describe and compare the molecular mechanisms that are involved in the regulation of biofilm formation by Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas aeruginosa and Burkholderia cenocepacia. Our current knowledge suggests that biofilm formation is regulated by cyclic diguanosine-5'-monophosphate (c-di-GMP), small RNAs (sRNA) and quorum sensing (QS) in all these bacterial species. The systems that employ c-di-GMP as a second messenger regulate the production of exopolysaccharides and surface proteins which function as extracellular matrix components in the biofilms formed by the bacteria. The systems that make use of sRNAs appear to regulate the production of exopolysaccharide biofilm matrix material in all these species. In the pseudomonads, QS regulates the production of extracellular DNA, lectins and biosurfactants which all play a role in biofilm formation. In B.cenocepacia QS regulates the expression of a large surface protein, lectins and extracellular DNA that all function as biofilm matrix components. Although the three regulatory systems all regulate the production of factors used for biofilm formation, the molecular mechanisms involved in transducing the signals into expression of the biofilm matrix components differ between the species. Under the conditions tested, exopolysaccharides appears to be the most important biofilm matrix components for P.aeruginosa, whereas large surface proteins appear to be the most important biofilm matrix components for P.putida, P.fluorescens, and B.cenocepacia.
Collapse
Affiliation(s)
- Mustafa Fazli
- Department of International Health, Immunology, and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Yeditepe University, Istanbul, Turkey
| | | | | | | | | | | |
Collapse
|
42
|
Martínez-Granero F, Redondo-Nieto M, Vesga P, Martín M, Rivilla R. AmrZ is a global transcriptional regulator implicated in iron uptake and environmental adaption in P. fluorescens F113. BMC Genomics 2014; 15:237. [PMID: 24670089 PMCID: PMC3986905 DOI: 10.1186/1471-2164-15-237] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 03/21/2014] [Indexed: 12/04/2022] Open
Abstract
Background AmrZ, a RHH transcriptional regulator, regulates motility and alginate production in pseudomonads. Expression of amrZ depends on the environmental stress sigma factor AlgU. amrZ and algU mutants have been shown to be impaired in environmental fitness in different pseudomonads with different lifestyles. Considering the importance of AmrZ for the ecological fitness of pseudomonads and taking advantage of the full sequencing and annotation of the Pseudomonas fluorescens F113 genome, we have carried out a ChIP-seq analysis from a pool of eight independent ChIP assays in order to determine the AmrZ binding sites and its implication in the regulation of genes involved in environmental adaption. Results 154 enriched regions (AmrZ binding sites) were detected in this analysis, being 76% of them located in putative promoter regions. 18 of these peaks were validated in an independent ChIP assay by qPCR. The 154 peaks were assigned to genes involved in several functional classes such as motility and chemotaxis, iron homeostasis, and signal transduction and transcriptional regulators, including genes encoding proteins implicated in the turn-over of c-diGMP. A putative AmrZ binding site was also observed by aligning the 154 regions with the MEME software. This motif was present in 75% of the peaks and was similar to that described in the amrZ and algD promoters in P. aeruginosa. We have analyzed the role of AmrZ in the regulation of iron uptake genes, to find that AmrZ represses their expression under iron limiting conditions. Conclusions The results presented here show that AmrZ is an important global transcriptional regulator involved in environmental sensing and adaption. It is also a new partner in the complex iron homeostasis regulation.
Collapse
Affiliation(s)
| | | | | | | | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, C/Darwin, 2, 28049 Madrid Spain.
| |
Collapse
|
43
|
Kim JS, Kim YH, Park JY, Anderson AJ, Kim YC. The global regulator GacS regulates biofilm formation in Pseudomonas chlororaphis O6 differently with carbon source. Can J Microbiol 2014; 60:133-8. [DOI: 10.1139/cjm-2013-0736] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
An aggressive root colonizer, Pseudomonas chlororaphis O6 produces various secondary metabolites that impact plant health. The sensor kinase GacS is a key regulator of the expression of biocontrol-related traits. Biofilm formation is one such trait because of its role in root surface colonization. This paper focuses on the effects of carbon source on biofilm formation. In comparison with the wild type, a gacS mutant formed biofilms at a reduced level with sucrose as the major carbon source but at much higher level with mannitol in the defined medium. Biofilm formation by the gacS mutant occurred without phenazine production and in the absence of normal levels of acyl homoserine lactones, which promote biofilms with other pseudomonads. Colonization of tomato roots was similar for the wild type and gacS mutant, showing that any differences in biofilm formation in the rhizosphere were not of consequence under the tested conditions. The reduced ability of the gacS mutant to induce systemic resistance against tomato leaf mold and tomato gray mold was consistent with a lack of production of effectors, such as phenazines. These results demonstrated plasticity in biofilm formation and root colonization in the rhizosphere by a beneficial pseudomonad.
Collapse
Affiliation(s)
- Ji Soo Kim
- Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju, South Korea
| | - Yong Hwan Kim
- Korea Institute of Planning & Evaluation for Technology on Food, Agriculture, Forestry & Fisheries, Anyang 431-060, South Korea
| | - Ju Yeon Park
- Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju, South Korea
| | | | - Young Cheol Kim
- Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju, South Korea
| |
Collapse
|
44
|
Martínez-Granero F, Navazo A, Barahona E, Redondo-Nieto M, González de Heredia E, Baena I, Martín-Martín I, Rivilla R, Martín M. Identification of flgZ as a flagellar gene encoding a PilZ domain protein that regulates swimming motility and biofilm formation in Pseudomonas. PLoS One 2014; 9:e87608. [PMID: 24504373 PMCID: PMC3913639 DOI: 10.1371/journal.pone.0087608] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 12/23/2013] [Indexed: 11/19/2022] Open
Abstract
Diguanylate cyclase and phosphodiesterase enzymatic activities control c-di-GMP levels modulating planktonic versus sessile lifestyle behavior in bacteria. The PilZ domain is described as a sensor of c-di-GMP intracellular levels and the proteins containing a PilZ domain represent the best studied class of c-di-GMP receptors forming part of the c-di-GMP signaling cascade. In P. fluorescens F113 we have found two diguanylate cyclases (WspR, SadC) and one phosphodiesterase (BifA) implicated in regulation of swimming motility and biofilm formation. Here we identify a flgZ gene located in a flagellar operon encoding a protein that contains a PilZ domain. Moreover, we show that FlgZ subcellular localization depends on the c-di-GMP intracellular levels. The overexpression analysis of flgZ in P. fluorescens F113 and P. putida KT2440 backgrounds reveal a participation of FlgZ in Pseudomonas swimming motility regulation. Besides, the epistasis of flgZ over wspR and bifA clearly shows that c-di-GMP intracellular levels produced by the enzymatic activity of the diguanylate cyclase WspR and the phosphodiesterase BifA regulates biofilm formation through FlgZ.
Collapse
Affiliation(s)
| | - Ana Navazo
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | - Emma Barahona
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | | | | | - Irene Baena
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail:
| |
Collapse
|
45
|
Pleiotropic effects of GacA on Pseudomonas fluorescens Pf0-1 in vitro and in soil. Appl Environ Microbiol 2013; 79:5405-10. [PMID: 23811507 DOI: 10.1128/aem.00819-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas species can exhibit phenotypic variation resulting from gacS or gacA mutation. P. fluorescens Pf0-1 is a gacA mutant and exhibits pleiotropic changes following the introduction of a functional allele. GacA enhances biofilm development while reducing dissemination in soil, suggesting that alternative Gac phenotypes enable Pseudomonas sp. to exploit varied environments.
Collapse
|
46
|
Barret M, Egan F, Moynihan J, Morrissey JP, Lesouhaitier O, O'Gara F. Characterization of the SPI-1 and Rsp type three secretion systems in Pseudomonas fluorescens F113. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:377-86. [PMID: 23754718 DOI: 10.1111/1758-2229.12039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 01/10/2013] [Indexed: 05/21/2023]
Abstract
Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) isolated from the sugar beet rhizosphere. The recent annotation of the F113 genome sequence has revealed that this strain encodes a wide array of secretion systems, including two complete type three secretion systems (T3SSs) belonging to the Hrp1 and SPI-1 families. While Hrp1 T3SSs are frequently encoded in other P. fluorescens strains, the presence of a SPI-1 T3SS in a plant-beneficial bacterial strain was unexpected. In this work, the genetic organization and expression of these two T3SS loci have been analysed by a combination of transcriptional reporter fusions and transcriptome analyses. Overexpression of two transcriptional activators has shown a number of genes encoding putative T3 effectors. In addition, the influence of these two T3SSs during the interaction of P. fluorescens F113 with some bacterial predators was also assessed. Our data revealed that the transcriptional activator hilA is induced by amoeba and that the SPI-1 T3SS could potentially be involved in resistance to amoeboid grazing.
Collapse
Affiliation(s)
- Matthieu Barret
- BIOMERIT Research Centre, University College Cork, Cork, Ireland
| | | | | | | | | | | |
Collapse
|
47
|
Kidarsa TA, Shaffer BT, Goebel NC, Roberts DP, Buyer JS, Johnson A, Kobayashi DY, Zabriskie TM, Paulsen I, Loper JE. Genes expressed by the biological control bacterium Pseudomonas protegens Pf-5 on seed surfaces under the control of the global regulators GacA and RpoS. Environ Microbiol 2013; 15:716-35. [PMID: 23297839 DOI: 10.1111/1462-2920.12066] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/20/2012] [Accepted: 11/22/2012] [Indexed: 12/12/2022]
Abstract
Gene expression profiles of the biological control strain Pseudomonas protegens Pf-5 inhabiting pea seed surfaces were revealed using a whole-genome oligonucleotide microarray. We identified genes expressed by Pf-5 under the control of two global regulators (GacA and RpoS) known to influence biological control and secondary metabolism. Transcript levels of 897 genes, including many with unknown functions as well as those for biofilm formation, cyclic diguanylate (c-di-GMP) signalling, iron homeostasis and secondary metabolism, were influenced by one or both regulators, providing evidence for expression of these genes by Pf-5 on seed surfaces. Comparison of the GacA and RpoS transcriptomes defined for Pf-5 grown on seed versus in broth culture overlapped, but most genes were regulated by GacA or RpoS under only one condition, likely due to differing levels of expression in the two conditions. We quantified secondary metabolites produced by Pf-5 and gacA and rpoS mutants on seed and in culture, and found that production profiles corresponded generally with biosynthetic gene expression profiles. Future studies evaluating biological control mechanisms can now focus on genes expressed by Pf-5 on seed surfaces, the habitat where the bacterium interacts with seed-infecting pathogens to suppress seedling diseases.
Collapse
Affiliation(s)
- Teresa A Kidarsa
- USDA-ARS Horticultural Crops Research Laboratory, Corvallis, OR, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Ping L, Birkenbeil J, Monajembashi S. Swimming behavior of the monotrichous bacterium Pseudomonas fluorescens SBW25. FEMS Microbiol Ecol 2013; 86:36-44. [PMID: 23346905 DOI: 10.1111/1574-6941.12076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/20/2013] [Accepted: 01/21/2013] [Indexed: 11/26/2022] Open
Abstract
Motility is an important trait for some bacteria living in nature and the analyses of it can provide important information on bacterial ecology. While the swimming behavior of peritrichous bacteria such as Escherichia coli has been extensively studied, the monotrichous bacteria such as the soil inhabiting and plant growth promoting bacterium Pseudmonas fluorescens is not very well characterized. Unlike E. coli that is propelled by a left-handed flagella bundle, P. fluorescens SBW25 swims several times faster by rotating a right-handed flagellum. Its swimming pattern is the most sophisticated known so far: it swims forward (run) and backward (backup); it can swiftly 'turn' the run directions or 'reorient' at run-backup transitions; it can 'flip' the cell body continuously or 'hover' in the milieu without translocation. The bacteria swam in circles near flat surfaces with reduced velocity and increased turn frequency. The viscous drag load due to wall effect potentially accounts for the circular motion and velocity change, but not the turn frequency. The flagellation and swimming behavior of P. fluorescens SBW25 show some similarity to Caulobacter, a fresh-water inhabitant, while the complex swimming pattern might be an adaptation to the geometrically restricted rhizo- and phyllospheres.
Collapse
Affiliation(s)
- Liyan Ping
- Max-Planck-Institute for Chemical Ecology, Jena, Germany
| | | | | |
Collapse
|
49
|
Redondo-Nieto M, Barret M, Morrissey J, Germaine K, Martínez-Granero F, Barahona E, Navazo A, Sánchez-Contreras M, Moynihan JA, Muriel C, Dowling D, O'Gara F, Martín M, Rivilla R. Genome sequence reveals that Pseudomonas fluorescens F113 possesses a large and diverse array of systems for rhizosphere function and host interaction. BMC Genomics 2013; 14:54. [PMID: 23350846 PMCID: PMC3570484 DOI: 10.1186/1471-2164-14-54] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 01/23/2013] [Indexed: 01/04/2023] Open
Abstract
Background Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) isolated from the sugar-beet rhizosphere. This bacterium has been extensively studied as a model strain for genetic regulation of secondary metabolite production in P. fluorescens, as a candidate biocontrol agent against phytopathogens, and as a heterologous host for expression of genes with biotechnological application. The F113 genome sequence and annotation has been recently reported. Results Comparative analysis of 50 genome sequences of strains belonging to the P. fluorescens group has revealed the existence of five distinct subgroups. F113 belongs to subgroup I, which is mostly composed of strains classified as P. brassicacearum. The core genome of these five strains is highly conserved and represents approximately 76% of the protein-coding genes in any given genome. Despite this strong conservation, F113 also contains a large number of unique protein-coding genes that encode traits potentially involved in the rhizocompetence of this strain. These features include protein coding genes required for denitrification, diterpenoids catabolism, motility and chemotaxis, protein secretion and production of antimicrobial compounds and insect toxins. Conclusions The genome of P. fluorescens F113 is composed of numerous protein-coding genes, not usually found together in previously sequenced genomes, which are potentially decisive during the colonisation of the rhizosphere and/or interaction with other soil organisms. This includes genes encoding proteins involved in the production of a second flagellar apparatus, the use of abietic acid as a growth substrate, the complete denitrification pathway, the possible production of a macrolide antibiotic and the assembly of multiple protein secretion systems.
Collapse
Affiliation(s)
- Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, c/Darwin, 2, Madrid, 28049, Spain
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Duggan PS, Thiel T, Adams DG. Symbiosis between the cyanobacterium Nostoc and the liverwort Blasia requires a CheR-type MCP methyltransferase. Symbiosis 2012. [DOI: 10.1007/s13199-012-0216-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|