1
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Goetsch AG, Ufearo D, Keiser G, Heiss C, Azadi P, Hershey DM. An exopolysaccharide pathway from a freshwater Sphingomonas isolate. J Bacteriol 2024:e0016924. [PMID: 39007563 DOI: 10.1128/jb.00169-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 06/17/2024] [Indexed: 07/16/2024] Open
Abstract
Bacteria embellish their cell envelopes with a variety of specialized polysaccharides. Biosynthesis pathways for these glycans are complex, and final products vary greatly in their chemical structures, physical properties, and biological activities. This tremendous diversity comes from the ability to arrange complex pools of monosaccharide building blocks into polymers with many possible linkage configurations. Due to the complex chemistry of bacterial glycans, very few biosynthetic pathways have been defined in detail. As part of an initiative to characterize novel polysaccharide biosynthesis enzymes, we isolated a bacterium from Lake Michigan called Sphingomonas sp. LM7 that is proficient in exopolysaccharide (EPS) production. We identified genes that contribute to EPS biosynthesis in LM7 by screening a transposon mutant library for colonies displaying altered colony morphology. A gene cluster was identified that appears to encode a complete wzy/wzx-dependent polysaccharide assembly pathway. Deleting individual genes in this cluster caused a non-mucoid phenotype and a corresponding loss of EPS secretion, confirming the role of this gene cluster in polysaccharide production. We extracted EPS from LM7 cultures and determined that it contains a linear chain of 3- and 4-linked glucose, galactose, and glucuronic acid residues. Finally, we show that the EPS pathway in Sphingomonas sp. LM7 diverges from that of sphingan-family EPSs and adhesive polysaccharides such as the holdfast that are present in other Alphaproteobacteria. Our approach of characterizing complete biosynthetic pathways holds promise for engineering polysaccharides with valuable properties. IMPORTANCE Bacteria produce complex polysaccharides that serve a range of biological functions. These polymers often have properties that make them attractive for industrial applications, but they remain woefully underutilized. In this work, we studied a novel polysaccharide called promonan that is produced by Sphingomonas sp. LM7, a bacterium we isolated from Lake Michigan. We extracted promonan from LM7 cultures and identified which sugars are present in the polymer. We also identified the genes responsible for polysaccharide production. Comparing the promonan genes to those of other bacteria showed that promonan is distinct from previously characterized polysaccharides. We conclude by discussing how the promonan pathway could be used to produce new polysaccharides through genetic engineering.
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Affiliation(s)
- Alexandra G Goetsch
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Daniel Ufearo
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Griffin Keiser
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Christian Heiss
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - David M Hershey
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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2
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Zhou N, Li X, Zheng Z, Liu J, Downie JA, Xie F. RinRK1 enhances NF receptors accumulation in nanodomain-like structures at root-hair tip. Nat Commun 2024; 15:3568. [PMID: 38670968 PMCID: PMC11053012 DOI: 10.1038/s41467-024-47794-4] [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: 03/09/2023] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Legume-rhizobia root-nodule symbioses involve the recognition of rhizobial Nod factor (NF) signals by NF receptors, triggering both nodule organogenesis and rhizobial infection. RinRK1 is induced by NF signaling and is essential for infection thread (IT) formation in Lotus japonicus. However, the precise mechanism underlying this process remains unknown. Here, we show that RinRK1 interacts with the extracellular domains of NF receptors (NFR1 and NFR5) to promote their accumulation at root hair tips in response to rhizobia or NFs. Furthermore, Flotillin 1 (Flot1), a nanodomain-organizing protein, associates with the kinase domains of NFR1, NFR5 and RinRK1. RinRK1 promotes the interactions between Flot1 and NF receptors and both RinRK1 and Flot1 are necessary for the accumulation of NF receptors at root hair tips upon NF stimulation. Our study shows that RinRK1 and Flot1 play a crucial role in NF receptor complex assembly within localized plasma membrane signaling centers to promote symbiotic infection.
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Affiliation(s)
- Ning Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Xiaolin Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Zhiqiong Zheng
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jing Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - J Allan Downie
- John Innes Centre, Norwich Research Park, NR4 7UH, Norwich, UK
| | - Fang Xie
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
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3
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Hlaváčková K, Šamaj J, Ovečka M. Cytoskeleton as a roadmap navigating rhizobia to establish symbiotic root nodulation in legumes. Biotechnol Adv 2023; 69:108263. [PMID: 37775072 DOI: 10.1016/j.biotechadv.2023.108263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/28/2023] [Accepted: 09/24/2023] [Indexed: 10/01/2023]
Abstract
Legumes enter into symbiotic associations with soil nitrogen-fixing rhizobia, culminating in the creation of new organs, root nodules. This complex process relies on chemical and physical interaction between legumes and rhizobia, including early signalling events informing the host legume plant of a potentially beneficial microbe and triggering the nodulation program. The great significance of this plant-microbe interaction rests upon conversion of atmospheric dinitrogen not accessible to plants into a biologically active form of ammonia available to plants. The plant cytoskeleton consists in a highly dynamic network and undergoes rapid remodelling upon sensing various developmental and environmental cues, including response to attachment, internalization, and accommodation of rhizobia in plant root and nodule cells. This dynamic nature is governed by cytoskeleton-associated proteins that modulate cytoskeletal behaviour depending on signal perception and transduction. Precisely localized cytoskeletal rearrangements are therefore essential for the uptake of rhizobia, their targeted delivery, and establishing beneficial root nodule symbiosis. This review summarizes current knowledge about rhizobia-dependent rearrangements and functions of the cytoskeleton in legume roots and nodules. General patterns and nodule type-, nodule stage-, and species-specific aspects of actin filaments and microtubules remodelling are discussed. Moreover, emerging evidence is provided about fine-tuning the root nodulation process through cytoskeleton-associated proteins. We also consider future perspectives on dynamic localization studies of the cytoskeleton during early symbiosis utilizing state of the art molecular and advanced microscopy approaches. Based on acquired detailed knowledge of the mutualistic interactions with microbes, these approaches could contribute to broader biotechnological crop improvement.
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Affiliation(s)
- Kateřina Hlaváčková
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic.
| | - Jozef Šamaj
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic.
| | - Miroslav Ovečka
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic.
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4
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Goetsch AG, Ufearo D, Keiser G, Heiss C, Azadi P, Hershey DM. A novel exopolysaccharide pathway from a freshwater Sphingomonas isolate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.03.565537. [PMID: 37961232 PMCID: PMC10635127 DOI: 10.1101/2023.11.03.565537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Bacteria embellish their cell envelopes with a variety of specialized polysaccharides. Biosynthesis pathways for these glycans are complex, and final products vary greatly in their chemical structures, physical properties and biological activities. This tremendous diversity comes from the ability to arrange complex pools of monosaccharide building blocks into polymers with many possible linkage configurations. Due to the complex chemistry of bacterial glycans, very few biosynthetic pathways have been defined in detail. To better understand the breadth of polysaccharide production in nature we isolated a bacterium from Lake Michigan called Sphingomonas sp. LM7 that is proficient in exopolysaccharide (EPS) production. We identified genes that contribute to EPS biosynthesis in LM7 by screening a transposon mutant library for colonies displaying altered colony morphology. A gene cluster was identified that appears to encode a complete wzy/wzx-dependent polysaccharide assembly pathway. Deleting individual genes in this cluster caused a non-mucoid phenotype and a corresponding loss of EPS secretion, confirming that LM7 assembles a novel wzy/wzx-dependent polysaccharide. We extracted EPS from LM7 cultures and showed that it contains a linear chain of 3- and 4- linked glucose, galactose, and glucuronic acid residues. Finally, we found that the EPS pathway we identified diverges from those of adhesive polysaccharides such as the holdfast that are conserved in higher Alphaproteobacteria. Our approach of characterizing complete biosynthetic pathways holds promise for engineering of polysaccharides with valuable properties.
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Affiliation(s)
- Alexandra G. Goetsch
- Department of Bacteriology, University of Wisconsin – Madison, Madison, WI 53706, USA
| | - Daniel Ufearo
- Department of Bacteriology, University of Wisconsin – Madison, Madison, WI 53706, USA
| | - Griffin Keiser
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Christian Heiss
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - David M. Hershey
- Department of Bacteriology, University of Wisconsin – Madison, Madison, WI 53706, USA
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5
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Bhattacharyya A, Mavrodi O, Bhowmik N, Weller D, Thomashow L, Mavrodi D. Bacterial biofilms as an essential component of rhizosphere plant-microbe interactions. METHODS IN MICROBIOLOGY 2023; 53:3-48. [PMID: 38415193 PMCID: PMC10898258 DOI: 10.1016/bs.mim.2023.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Affiliation(s)
- Ankita Bhattacharyya
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Olga Mavrodi
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Niladri Bhowmik
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - David Weller
- USDA-ARS Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Linda Thomashow
- USDA-ARS Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Dmitri Mavrodi
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
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Rubio-Ribeaux D, da Costa RAM, Montero-Rodríguez D, do Amaral Marques NSA, Puerta-Díaz M, de Souza Mendonça R, Franco PM, Dos Santos JC, da Silva SS. Sustainable production of bioemulsifiers, a critical overview from microorganisms to promising applications. World J Microbiol Biotechnol 2023; 39:195. [PMID: 37171665 DOI: 10.1007/s11274-023-03611-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/06/2023] [Indexed: 05/13/2023]
Abstract
Microbial bioemulsifiers are molecules of amphiphilic nature and high molecular weight that are efficient in emulsifying two immiscible phases such as water and oil. These molecules are less effective in reducing surface tension and are synthesized by bacteria, yeast and filamentous fungi. Unlike synthetic emulsifiers, microbial bioemulsifiers have unique advantages such as biocompatibility, non-toxicity, biodegradability, efficiency at low concentrations and high selectivity under different conditions of pH, temperature and salinity. The adoption of microbial bioemulsifiers as alternatives to their synthetic counterparts has been growing in ongoing research. This article analyzes the production of microbial-based emulsifiers, the raw materials and fermentation processes used, as well as the scale-up and commercial applications of some of these biomolecules. The current trend of incorporating natural compounds into industrial formulations indicates that the search for new bioemulsifiers will continue to increase, with emphasis on performance improvement and economically viable processes.
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Affiliation(s)
- Daylin Rubio-Ribeaux
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, São Paulo, 12.602-810, Brazil.
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil.
| | - Rogger Alessandro Mata da Costa
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, São Paulo, 12.602-810, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
| | - Dayana Montero-Rodríguez
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, Pernambuco, 50050-590, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
| | - Nathália Sá Alencar do Amaral Marques
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, Pernambuco, 50050-590, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
| | - Mirelys Puerta-Díaz
- Pernambuco Institute of Agronomy, Recife, Pernambuco, 50761-000, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
| | - Rafael de Souza Mendonça
- Nucleus of Research in Environmental Sciences and Biotechnology, Catholic University of Pernambuco, Recife, Pernambuco, 50050-590, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
| | - Paulo Marcelino Franco
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, São Paulo, 12.602-810, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
| | - Júlio César Dos Santos
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, São Paulo, 12.602-810, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
| | - Silvio Silvério da Silva
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, São Paulo, 12.602-810, Brazil
- Faculty of Philosophy and Sciences, Campus Marília, São Paulo State University, São Paulo, 17.525-900, Brazil
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7
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Hlaváčková K, Šamajová O, Hrbáčková M, Šamaj J, Ovečka M. Advanced microscopy resolves dynamic localization patterns of stress-induced mitogen-activated protein kinase SIMK during alfalfa root hair interactions with Ensifer meliloti. JOURNAL OF EXPERIMENTAL BOTANY 2023:erad111. [PMID: 36951479 DOI: 10.1093/jxb/erad111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Indexed: 06/18/2023]
Abstract
Leguminous plants have established a mutualistic endosymbiotic interaction with nitrogen-fixing rhizobia to secure nitrogen sources in new specialised organs called root nodules. Before nodule formation, the development of early symbiotic structures is essential for rhizobia docking, internalization, targeted delivery and intracellular accommodation. We have recently reported that overexpression of stress-induced mitogen-activated protein kinase (SIMK) in alfalfa affects root hair, nodule and shoot formation, which raised the questions how SIMK may modulate these processes. In particular, detailed subcellular spatial distribution, activation and developmental relocation of SIMK during the early stages of alfalfa nodulation remain unclear. Here, we qualitatively and quantitatively characterised SIMK distribution patterns in Ensifer meliloti-infected root hairs using live-cell imaging and immunolocalization, employing alfalfa stable transgenic lines with genetically manipulated SIMK abundance and kinase activity. In the SIMKK-RNAi line, showing downregulation of SIMKK and SIMK, we found considerably decreased accumulation of phosphorylated SIMK around infection pockets and infection threads. However, this was strongly increased in the GFP-SIMK line, constitutively overexpressing GFP-tagged SIMK. Thus, genetically manipulated SIMK modulates root hair capacity to form infection pockets and infection threads. Employment of advanced light-sheet fluorescence microscopy (LSFM) on intact plants allowed gentle and non-invasive imaging of spatiotemporal interactions between root hairs and symbiotic Ensifer meliloti, while immunofluorescence detection confirmed that SIMK was activated in these locations. Our results shed new light on SIMK spatiotemporal participation in early interactions between alfalfa and Ensifer meliloti, and its internalization into root hairs, showing that local accumulation of active SIMK indeed modulates early nodulation in alfalfa.
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Affiliation(s)
- Kateřina Hlaváčková
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Olga Šamajová
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Miroslava Hrbáčková
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Jozef Šamaj
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Miroslav Ovečka
- Department of Biotechnology, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
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8
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Affiliation(s)
- Cecile Berne
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
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9
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Illuminating the signalomics of microbial biofilm on plant surfaces. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Rajendran K, Kumar V, Raja I, Kumariah M, Tennyson J. Identification of sigma factor 54-regulated small non-coding RNAs by employing genome-wide and transcriptome-based methods in rhizobium strains. 3 Biotech 2022; 12:328. [PMID: 36276463 PMCID: PMC9584007 DOI: 10.1007/s13205-022-03394-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/12/2022] [Indexed: 11/01/2022] Open
Abstract
Rhizobium-legume symbiosis is considered as the major contributor of biological nitrogen fixation. Bacterial small non-coding RNAs are crucial regulators in several cellular adaptation processes that occur due to the changes in metabolism, physiology, or the external environment. Identifying and analysing the conditional specific/sigma factor-54 regulated sRNAs provides a better understanding of sRNA regulation/mechanism in symbiotic association. In the present study, we have identified sigma factor 54-regulated sRNAs from the genome of six rhizobium strains and from the RNA-seq data of free-living and symbiotic conditions of Bradyrhizobium diazoefficiens USDA 110 to identify the novel putative sRNAs that are over expressed during the regulation of nitrogen fixation. A total of 1351 sRNAs were predicted from the genome of six rhizobium strains and 1375 sRNAs were predicted from the transcriptome data of B. diazoefficiens USDA 110. Analysis of target mRNA for these novel sRNAs was inferred to target several nodulation and nitrogen fixation genes including nodC, nodJ, nodY, nodJ, nodM, nodW, nodZ, nifD, nifN, nifQ, fixK, fixL, fdx, nolB, and several cytochrome proteins. In addition, sRNAs of B. diazoefficiens USDA 110 which targeted the regulatory genes of nitrogen fixation were confirmed by wet-lab experiments with semi-quantitative reverse transcription polymerase chain reaction. Predicted target mRNAs were functionally classified based on the COG analysis and GO annotations. The genome-wide and transcriptome-based integrated methods have led to the identification of several sRNAs involved in the nodulation and symbiosis. Further validation of the functional role of these sRNAs can help in exploring the role of sRNAs in nitrogen metabolism during free-living and symbiotic association with legumes. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03394-x.
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Affiliation(s)
- Kasthuri Rajendran
- Department of Plant Morphology and Algology, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu 625 021 India
| | - Vikram Kumar
- Department of Plant Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu 625 021 India
| | - Ilamathi Raja
- Department of Plant Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu 625 021 India
| | - Manoharan Kumariah
- Department of Plant Morphology and Algology, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu 625 021 India
| | - Jebasingh Tennyson
- Department of Plant Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu 625 021 India
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11
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What Glues the Glue to the Cell Surface? J Bacteriol 2022; 204:e0038622. [PMID: 36286485 PMCID: PMC9664948 DOI: 10.1128/jb.00386-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the
Caulobacterales
, a highly adhesive polysaccharide called the holdfast mediates attachment to exogenous surfaces. The mechanism by which this polysaccharide is anchored to the cell envelope is not well defined.
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12
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Onyeziri MC, Hardy GG, Natarajan R, Xu J, Reynolds IP, Kim J, Merritt PM, Danhorn T, Hibbing ME, Weisberg AJ, Chang JH, Fuqua C. Dual adhesive unipolar polysaccharides synthesized by overlapping biosynthetic pathways in Agrobacterium tumefaciens. Mol Microbiol 2022; 117:1023-1047. [PMID: 35191101 PMCID: PMC9149101 DOI: 10.1111/mmi.14887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 11/29/2022]
Abstract
Agrobacterium tumefaciens is a member of the Alphaproteobacteria that pathogenises plants and associates with biotic and abiotic surfaces via a single cellular pole. A. tumefaciens produces the unipolar polysaccharide (UPP) at the site of surface contact. UPP production is normally surface-contact inducible, but elevated levels of the second messenger cyclic diguanylate monophosphate (cdGMP) bypass this requirement. Multiple lines of evidence suggest that the UPP has a central polysaccharide component. Using an A. tumefaciens derivative with elevated cdGMP and mutationally disabled for other dispensable polysaccharides, a series of related genetic screens have identified a large number of genes involved in UPP biosynthesis, most of which are Wzx-Wzy-type polysaccharide biosynthetic components. Extensive analyses of UPP production in these mutants have revealed that the UPP is composed of two genetically, chemically, and spatially discrete forms of polysaccharide, and that each requires a specific Wzy-type polymerase. Other important biosynthetic, processing, and regulatory functions for UPP production are also revealed, some of which are common to both polysaccharides, and a subset of which are specific to each type. Many of the UPP genes identified are conserved among diverse rhizobia, whereas others are more lineage specific.
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Affiliation(s)
| | - Gail G. Hardy
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Ramya Natarajan
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Jing Xu
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Ian P. Reynolds
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Jinwoo Kim
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Peter M. Merritt
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Thomas Danhorn
- Department of Biology, Indiana University, Bloomington, IN 47405
| | | | - Alexandra J. Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, IN 47405
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13
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Huang R, Feng H, Xu Z, Zhang N, Liu Y, Shao J, Shen Q, Zhang R. Identification of Adhesins in Plant Beneficial Rhizobacteria Bacillus velezensis SQR9 and Their Effect on Root Colonization. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:64-72. [PMID: 34698535 DOI: 10.1094/mpmi-09-21-0234-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Probiotic Bacillus colonization of plant root surfaces has been reported to improve its beneficial effect. Chemotaxis, adhesion, aggregation, and biofilm formation are the four steps of root colonization by plant growth-promoting rhizobacteria (PGPRs). Compared with the other three well-studied processes, adhesion of PGPRs is less known. In this study, using mutant strains deleted for potential adhesin genes in PGPR strain Bacillus velezensis SQR9, adherence to both cucumber root surface and abiotic surface by those strains was evaluated. Results showed that deletion mutations ΔlytB, ΔV529_10500, ΔfliD, ΔyhaN, and ΔsacB reduced the adhesion to root surfaces, while, among them, only ΔfliD had significant defects in adhesion to abiotic surfaces (glass and polystyrene). In addition, B. velevzensis SQR9 mutants defective in adhesion to root surfaces showed a deficiency in rhizosphere colonization. Among the encoded proteins, FliD and YhaN played vital roles in root adhesion. This research systematically explored the potential adhesins in a well-studied PGPR strain and also indicated that adhesion progress was required for root colonization, which will help to enhance rhizosphere colonization and beneficial function of PGPRs in agricultural production.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Rong Huang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Haichao Feng
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Zhihui Xu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Nan Zhang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Yunpeng Liu
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China
| | - Jiahui Shao
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Ruifu Zhang
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China
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Surface Properties and Adherence of Bradyrhizobium diazoefficiens to Glycine max Roots Are Altered When Grown in Soil Extracted Nutrients. NITROGEN 2021. [DOI: 10.3390/nitrogen2040031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Soybean roots are colonized and nodulated by multiple strains of compatible nitrogen-fixing rhizobia primarily belonging to the Genus Bradyrhizobium. Motility towards the root and attachment to root hairs are key determinants of competitive colonization and subsequent nodulation. Bacterial surface properties and motility are known to vary with chemical composition of the culture medium, and root adhesion and nodulation occur in a soil environment rather than laboratory medium. We asked whether the nodulation-promoting factors motility, surface hydrophobicity and surface adhesion of Bradyrhizobium are affected by growth in a soil nutrient environment. B. diazoefficiens USDA 110, 126, 3384, and B. elkanii USDA 26 were grown in mineral salt medium with peptone, yeast extract and arabinose (PSY), and in a soil extracted soluble organic matter (SESOM) medium. Surface hydrophobicity was determined by partitioning into hydrocarbon, motility by transition through soft agar, and surface-exposed saccharides by lectin profiling, followed by biofilm formation and soybean root adhesion capacity of populations. SESOM-grown populations were generally less motile and more hydrophobic. They bound fewer lectins than PSY-grown populations, indicating a simpler surface saccharide profile. SESOM populations of USDA 110 did not form detectable biofilm, but showed increased binding to soy roots. Our results indicate that growth in a soil environment impacts surface properties, motility, and subsequent soy root adhesion propensity. Hence, evaluation of Bradyrhizobium for nodulation efficiency should be performed using soil from the specific field where the soybeans are to be planted, rather than laboratory culture media.
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15
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Mendoza-Suárez M, Andersen SU, Poole PS, Sánchez-Cañizares C. Competition, Nodule Occupancy, and Persistence of Inoculant Strains: Key Factors in the Rhizobium-Legume Symbioses. FRONTIERS IN PLANT SCIENCE 2021; 12:690567. [PMID: 34489993 PMCID: PMC8416774 DOI: 10.3389/fpls.2021.690567] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 07/19/2021] [Indexed: 05/06/2023]
Abstract
Biological nitrogen fixation by Rhizobium-legume symbioses represents an environmentally friendly and inexpensive alternative to the use of chemical nitrogen fertilizers in legume crops. Rhizobial inoculants, applied frequently as biofertilizers, play an important role in sustainable agriculture. However, inoculants often fail to compete for nodule occupancy against native rhizobia with inferior nitrogen-fixing abilities, resulting in low yields. Strains with excellent performance under controlled conditions are typically selected as inoculants, but the rates of nodule occupancy compared to native strains are rarely investigated. Lack of persistence in the field after agricultural cycles, usually due to the transfer of symbiotic genes from the inoculant strain to naturalized populations, also limits the suitability of commercial inoculants. When rhizobial inoculants are based on native strains with a high nitrogen fixation ability, they often have superior performance in the field due to their genetic adaptations to the local environment. Therefore, knowledge from laboratory studies assessing competition and understanding how diverse strains of rhizobia behave, together with assays done under field conditions, may allow us to exploit the effectiveness of native populations selected as elite strains and to breed specific host cultivar-rhizobial strain combinations. Here, we review current knowledge at the molecular level on competition for nodulation and the advances in molecular tools for assessing competitiveness. We then describe ongoing approaches for inoculant development based on native strains and emphasize future perspectives and applications using a multidisciplinary approach to ensure optimal performance of both symbiotic partners.
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Affiliation(s)
| | - Stig U. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Philip S. Poole
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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16
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Knights HE, Jorrin B, Haskett TL, Poole PS. Deciphering bacterial mechanisms of root colonization. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:428-444. [PMID: 33538402 PMCID: PMC8651005 DOI: 10.1111/1758-2229.12934] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 05/07/2023]
Abstract
Bacterial colonization of the rhizosphere is critical for the establishment of plant-bacteria interactions that represent a key determinant of plant health and productivity. Plants influence bacterial colonization primarily through modulating the composition of their root exudates and mounting an innate immune response. The outcome is a horizontal filtering of bacteria from the surrounding soil, resulting in a gradient of reduced bacterial diversity coupled with a higher degree of bacterial specialization towards the root. Bacteria-bacteria interactions (BBIs) are also prevalent in the rhizosphere, influencing bacterial persistence and root colonization through metabolic exchanges, secretion of antimicrobial compounds and other processes. Traditionally, bacterial colonization has been examined under sterile laboratory conditions that mitigate the influence of BBIs. Using simplified synthetic bacterial communities combined with microfluidic imaging platforms and transposon mutagenesis screening approaches, we are now able to begin unravelling the molecular mechanisms at play during the early stages of root colonization. This review explores the current state of knowledge regarding bacterial root colonization and identifies key tools for future exploration.
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Affiliation(s)
| | - Beatriz Jorrin
- Department of Plant SciencesUniversity of OxfordOxfordOX1 3RBUK
| | | | - Philip S. Poole
- Department of Plant SciencesUniversity of OxfordOxfordOX1 3RBUK
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17
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Krol E, Schäper S, Becker A. Cyclic di-GMP signaling controlling the free-living lifestyle of alpha-proteobacterial rhizobia. Biol Chem 2021; 401:1335-1348. [PMID: 32990642 DOI: 10.1515/hsz-2020-0232] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022]
Abstract
Cyclic-di-GMP (c-di-GMP) is a ubiquitous bacterial second messenger which has been associated with a motile to sessile lifestyle switch in many bacteria. Here, we review recent insights into c-di-GMP regulated processes related to environmental adaptations in alphaproteobacterial rhizobia, which are diazotrophic bacteria capable of fixing nitrogen in symbiosis with their leguminous host plants. The review centers on Sinorhizobium meliloti, which in the recent years was intensively studied for its c-di-GMP regulatory network.
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Affiliation(s)
- Elizaveta Krol
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, D-35032 Marburg, Germany.,Department of Biology, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Simon Schäper
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Anke Becker
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, D-35032 Marburg, Germany.,Department of Biology, Philipps-Universität Marburg, D-35032 Marburg, Germany
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18
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Structure and Development of the Legume-Rhizobial Symbiotic Interface in Infection Threads. Cells 2021; 10:cells10051050. [PMID: 33946779 PMCID: PMC8146911 DOI: 10.3390/cells10051050] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/25/2021] [Accepted: 04/27/2021] [Indexed: 02/06/2023] Open
Abstract
The intracellular infection thread initiated in a root hair cell is a unique structure associated with Rhizobium-legume symbiosis. It is characterized by inverted tip growth of the plant cell wall, resulting in a tunnel that allows invasion of host cells by bacteria during the formation of the nitrogen-fixing root nodule. Regulation of the plant-microbial interface is essential for infection thread growth. This involves targeted deposition of the cell wall and extracellular matrix and tight control of cell wall remodeling. This review describes the potential role of different actors such as transcription factors, receptors, and enzymes in the rearrangement of the plant-microbial interface and control of polar infection thread growth. It also focuses on the composition of the main polymers of the infection thread wall and matrix and the participation of reactive oxygen species (ROS) in the development of the infection thread. Mutant analysis has helped to gain insight into the development of host defense reactions. The available data raise many new questions about the structure, function, and development of infection threads.
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19
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Oleńska E, Małek W, Kotowska U, Wydrych J, Polińska W, Swiecicka I, Thijs S, Vangronsveld J. Exopolysaccharide Carbohydrate Structure and Biofilm Formation by Rhizobium leguminosarum bv. trifolii Strains Inhabiting Nodules of Trifoliumrepens Growing on an Old Zn-Pb-Cd-Polluted Waste Heap Area. Int J Mol Sci 2021; 22:ijms22062808. [PMID: 33802057 PMCID: PMC7998805 DOI: 10.3390/ijms22062808] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/04/2021] [Accepted: 03/06/2021] [Indexed: 12/03/2022] Open
Abstract
Heavy metals polluting the 100-year-old waste heap in Bolesław (Poland) are acting as a natural selection factor and may contribute to adaptations of organisms living in this area, including Trifolium repens and its root nodule microsymbionts—rhizobia. Exopolysaccharides (EPS), exuded extracellularly and associated with bacterial cell walls, possess variable structures depending on environmental conditions; they can bind metals and are involved in biofilm formation. In order to examine the effects of long-term exposure to metal pollution on EPS structure and biofilm formation of rhizobia, Rhizobium leguminosarum bv. trifolii strains originating from the waste heap area and a non-polluted reference site were investigated for the characteristics of the sugar fraction of their EPS using gas chromatography mass-spectrometry and also for biofilm formation and structural characteristics using confocal laser scanning microscopy under control conditions as well as when exposed to toxic concentrations of zinc, lead, and cadmium. Significant differences in EPS structure, biofilm thickness, and ratio of living/dead bacteria in the biofilm were found between strains originating from the waste heap and from the reference site, both without exposure to metals and under metal exposure. Received results indicate that studied rhizobia can be assumed as potentially useful in remediation processes.
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Affiliation(s)
- Ewa Oleńska
- Department of Microbiology and Biotechnology, Faculty of Biology, University of Białystok, 1J Ciołkowski, 15-245 Białystok, Poland;
- Correspondence: ; Tel.: +48-8-5738-8366
| | - Wanda Małek
- Department of Genetics and Microbiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, 19 Akademicka, 20-033 Lublin, Poland;
| | - Urszula Kotowska
- Division of Environmental Chemistry, Department of Analytic and Inorganic Chemistry, Faculty of Chemistry, University of Białystok, 1K Ciołkowski, 15-245 Białystok, Poland;
| | - Jerzy Wydrych
- Department of Functional Anatomy and Cytobiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, 19 Akademicka, 20-033 Lublin, Poland;
| | - Weronika Polińska
- Doctoral School of Exact and Natural Sciences, University of Białystok, 1K Ciołkowski, 15-245 Białystok, Poland;
| | - Izabela Swiecicka
- Department of Microbiology and Biotechnology, Faculty of Biology, University of Białystok, 1J Ciołkowski, 15-245 Białystok, Poland;
- Laboratory of Applied Microbiology, Faculty of Biology, University of Białystok, 1J Ciołkowski, 15-245 Białystok, Poland
| | - Sofie Thijs
- Centre for Environmental Sciences, Faculty of Sciences, Hasselt University, Agoralaan D, B-3590 Diepenbeek, Belgium; (S.T.); (J.V.)
| | - Jaco Vangronsveld
- Centre for Environmental Sciences, Faculty of Sciences, Hasselt University, Agoralaan D, B-3590 Diepenbeek, Belgium; (S.T.); (J.V.)
- Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, 19 Akademicka, 20-033 Lublin, Poland
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20
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Exploring the Role of Bacterial Extracellular Polymeric Substances for Sustainable Development in Agriculture. Curr Microbiol 2020; 77:3224-3239. [PMID: 32876713 DOI: 10.1007/s00284-020-02169-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 08/18/2020] [Indexed: 01/02/2023]
Abstract
The incessant need to increase crop yields has led to the development of many chemical fertilizers containing NPK (nitrogen-phosphorous-potassium) which can degrade soil health in the long term. In addition, these fertilizers are often leached into nearby water bodies causing algal bloom and eutrophication. Bacterial secondary metabolites exuded into the extracellular space, termed extracellular polymeric substances (EPS) have gained commercial significance because of their biodegradability, non-toxicity, and renewability. In many habitats, bacterial communities faced with adversity will adhere together by production of EPS which also serves to bond them to surfaces. Typically, hygroscopic, EPS retain moisture in desiccating conditions and modulate nutrient exchange. Many plant growth-promoting bacteria (PGPR) combat harsh environmental conditions like salinity, drought, and attack of pathogens by producing EPS. The adhesive nature of EPS promotes soil aggregation and restores moisture thus combating soil erosion and promoting soil fertility. In addition, these molecules play vital roles in maintaining symbiosis and nitrogen fixation thus enhancing sustainability. Thus, along with other commercial applications, EPS show promising avenues for improving agricultural productivity thus helping to address land scarcity as well as minimizing environmental pollution.
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21
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Liu Y, Bellich B, Hug S, Eberl L, Cescutti P, Pessi G. The Exopolysaccharide Cepacian Plays a Role in the Establishment of the Paraburkholderia phymatum - Phaseolus vulgaris Symbiosis. Front Microbiol 2020; 11:1600. [PMID: 32765457 PMCID: PMC7378592 DOI: 10.3389/fmicb.2020.01600] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/18/2020] [Indexed: 12/19/2022] Open
Abstract
Paraburkholderia phymatum is a rhizobial strain that belongs to the beta-proteobacteria, a group known to form efficient nitrogen-fixing symbioses within root nodules of several legumes, including the agriculturally important common bean. The establishment of the symbiosis requires the exchange of rhizobial and plant signals such as lipochitooligosaccharides (Nod factors), polysaccharides, and flavonoids. Inspection of the genome of the competitive rhizobium P. phymatum revealed the presence of several polysaccharide biosynthetic gene clusters. In this study, we demonstrate that bceN, a gene encoding a GDP-D-mannose 4,6-dehydratase, which is involved in the production of the exopolysaccharide cepacian, an important component of biofilms produced by closely related opportunistic pathogens of the Burkholderia cepacia complex (Bcc), is required for efficient plant colonization. Wild-type P. phymatum was shown to produce cepacian while a bceN mutant did not. Additionally, the bceN mutant produced a significantly lower amount of biofilm and formed less root nodules compared to the wild-type strain with Phaseolus vulgaris as host plant. Finally, expression of the operon containing bceN was induced by the presence of germinated P. vulgaris seeds under nitrogen limiting conditions suggesting a role of this polysaccharide in the establishment of this ecologically important symbiosis.
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Affiliation(s)
- Yilei Liu
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Barbara Bellich
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Sebastian Hug
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Paola Cescutti
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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22
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Rhizobium-Legume Symbiosis: Molecular Determinants and Geospecificity. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2020. [DOI: 10.22207/jpam.14.2.04] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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23
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Kyrychenko ОV. SYMBIOTIC PRODUCTIVITY OF PHYTO-BACTERIAL SYSTEMS UNDER THE ACTION OF N-ACETYL-D-GLUCOSAMINE ON DIAZOTROPHIC MICROORGANISMS. BIOTECHNOLOGIA ACTA 2020. [DOI: 10.15407/biotech13.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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24
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Role of Caulobacter Cell Surface Structures in Colonization of the Air-Liquid Interface. J Bacteriol 2019; 201:JB.00064-19. [PMID: 31010900 DOI: 10.1128/jb.00064-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/15/2019] [Indexed: 01/17/2023] Open
Abstract
In aquatic environments, Caulobacter spp. can be found at the boundary between liquid and air known as the neuston. I report an approach to study temporal features of Caulobacter crescentus colonization and pellicle biofilm development at the air-liquid interface and have defined the role of cell surface structures in this process. At this interface, C. crescentus initially forms a monolayer of cells bearing a surface adhesin known as the holdfast. When excised from the liquid surface, this monolayer strongly adheres to glass. The monolayer subsequently develops into a three-dimensional structure that is highly enriched in clusters of stalked cells known as rosettes. As this pellicle film matures, it becomes more cohesive and less adherent to a glass surface. A mutant strain lacking a flagellum does not efficiently reach the surface, and strains lacking type IV pili exhibit defects in organization of the three-dimensional pellicle. Strains unable to synthesize the holdfast fail to accumulate at the boundary between air and liquid and do not form a pellicle. Phase-contrast images support a model whereby the holdfast functions to trap C. crescentus cells at the air-liquid boundary. Unlike the holdfast, neither the flagellum nor type IV pili are required for C. crescentus to partition to the air-liquid interface. While it is well established that the holdfast enables adherence to solid surfaces, this study provides evidence that the holdfast has physicochemical properties that allow partitioning of nonmotile mother cells to the air-liquid interface and facilitate colonization of this microenvironment.IMPORTANCE In aquatic environments, the boundary at the air interface is often highly enriched with nutrients and oxygen. Colonization of this niche likely confers a significant fitness advantage in many cases. This study provides evidence that the cell surface adhesin known as a holdfast enables Caulobacter crescentus to partition to and colonize the air-liquid interface. Additional surface structures, including the flagellum and type IV pili, are important determinants of colonization and biofilm formation at this boundary. Considering that holdfast-like adhesins are broadly conserved in Caulobacter spp. and other members of the diverse class Alphaproteobacteria, these surface structures may function broadly to facilitate colonization of air-liquid boundaries in a range of ecological contexts, including freshwater, marine, and soil ecosystems.
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25
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Abstract
Genetic analysis of Rickettsia has been difficult. We developed a transposon and selection scheme to facilitate the isolation of Rickettsia conorii mutants with insertional lesions. Here, we demonstrate that the R. conorii polysaccharide synthesisoperon (pso) encompasses genetic determinants for biosynthesis of the O antigen, which also affect the composition of outer-membrane proteins, invasion of host cells, and pathogenesis. The O antigen provides essential barrier functions and plays a major role in host–pathogen interactions. Our findings suggest that infected hosts develop protective immunity against R. conorii via the production of antibodies targeting the O antigen. Conservation of pso among rickettsial species suggests that it may play a universal role in O-antigen synthesis, disease pathogenesis, and the development of immunity. Rickettsial diseases have long been diagnosed with serum antibodies cross-reactive against Proteus vulgaris (Weil–Felix reaction). Although Weil–Felix antibodies are associated with the development of immunity, their rickettsial target and contribution to disease pathogenesis are not established. Here, we developed a transposon for insertional mutagenesis of Rickettsia conorii, isolating variants defective for replication in cultured cells and in spotted fever pathogenesis. Mutations in the polysaccharide synthesis operon (pso) abolish lipopolysaccharide O-antigen synthesis and Weil–Felix serology and alter outer-membrane protein assembly. Unlike wild-type R. conorii, pso mutants cannot elicit bactericidal antibodies that bind O antigen. The pso operon is conserved among rickettsial pathogens, suggesting that bactericidal antibodies targeting O antigen may generate universal immunity that could be exploited to develop vaccines against rickettsial diseases.
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26
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Lipa P, Vinardell JM, Janczarek M. Transcriptomic Studies Reveal that the Rhizobium leguminosarum Serine/Threonine Protein Phosphatase PssZ has a Role in the Synthesis of Cell-Surface Components, Nutrient Utilization, and Other Cellular Processes. Int J Mol Sci 2019; 20:ijms20122905. [PMID: 31197117 PMCID: PMC6628131 DOI: 10.3390/ijms20122905] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 02/07/2023] Open
Abstract
Rhizobium leguminosarum bv. trifolii is a soil bacterium capable of establishing symbiotic associations with clover plants (Trifolium spp.). Surface polysaccharides, transport systems, and extracellular components synthesized by this bacterium are required for both the adaptation to changing environmental conditions and successful infection of host plant roots. The pssZ gene located in the Pss-I region, which is involved in the synthesis of extracellular polysaccharide, encodes a protein belonging to the group of serine/threonine protein phosphatases. In this study, a comparative transcriptomic analysis of R. leguminosarum bv. trifolii wild-type strain Rt24.2 and its derivative Rt297 carrying a pssZ mutation was performed. RNA-Seq data identified a large number of genes differentially expressed in these two backgrounds. Transcriptome profiling of the pssZ mutant revealed a role of the PssZ protein in several cellular processes, including cell signalling, transcription regulation, synthesis of cell-surface polysaccharides and components, and bacterial metabolism. In addition, we show that inactivation of pssZ affects the rhizobial ability to grow in the presence of different sugars and at various temperatures, as well as the production of different surface polysaccharides. In conclusion, our results identified a set of genes whose expression was affected by PssZ and confirmed the important role of this protein in the rhizobial regulatory network.
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Affiliation(s)
- Paulina Lipa
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland.
| | - José-María Vinardell
- Department of Microbiology, Faculty of Biology, University of Sevilla, Avda. Reina Mercedes 6, 41012 Sevilla, Spain.
| | - Monika Janczarek
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland.
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27
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Thompson MA, Onyeziri MC, Fuqua C. Function and Regulation of Agrobacterium tumefaciens Cell Surface Structures that Promote Attachment. Curr Top Microbiol Immunol 2019; 418:143-184. [PMID: 29998422 PMCID: PMC6330146 DOI: 10.1007/82_2018_96] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Agrobacterium tumefaciens attaches stably to plant host tissues and abiotic surfaces. During pathogenesis, physical attachment to the site of infection is a prerequisite to infection and horizontal gene transfer to the plant. Virulent and avirulent strains may also attach to plant tissue in more benign plant associations, and as with other soil microbes, to soil surfaces in the terrestrial environment. Although most A. tumefaciens virulence functions are encoded on the tumor-inducing plasmid, genes that direct general surface attachment are chromosomally encoded, and thus this process is not obligatorily tied to virulence, but is a more fundamental capacity. Several different cellular structures are known or suspected to contribute to the attachment process. The flagella influence surface attachment primarily via their propulsive activity, but control of their rotation during the transition to the attached state may be quite complex. A. tumefaciens produces several pili, including the Tad-type Ctp pili, and several plasmid-borne conjugal pili encoded by the Ti and At plasmids, as well as the so-called T-pilus, involved in interkingdom horizontal gene transfer. The Ctp pili promote reversible interactions with surfaces, whereas the conjugal and T-pili drive horizontal gene transfer (HGT) interactions with other cells and tissues. The T-pilus is likely to contribute to physical association with plant tissues during DNA transfer to plants. A. tumefaciens can synthesize a variety of polysaccharides including cellulose, curdlan (β-1,3 glucan), β-1,2 glucan (cyclic and linear), succinoglycan, and a localized polysaccharide(s) that is confined to a single cellular pole and is called the unipolar polysaccharide (UPP). Lipopolysaccharides are also in the outer leaflet of the outer membrane. Cellulose and curdlan production can influence attachment under certain conditions. The UPP is required for stable attachment under a range of conditions and on abiotic and biotic surfaces. Other factors that have been reported to play a role in attachment include the elusive protein called rhicadhesin. The process of surface attachment is under extensive regulatory control and can be modulated by environmental conditions, as well as by direct responses to surface contact. Complex transcriptional and post-transcriptional control circuitry underlies much of the production and deployment of these attachment functions.
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Affiliation(s)
- Melene A Thompson
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | | | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.
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28
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Wheatley RM, Poole PS. Mechanisms of bacterial attachment to roots. FEMS Microbiol Rev 2018; 42:448-461. [PMID: 29672765 DOI: 10.1093/femsre/fuy014] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 04/14/2018] [Indexed: 11/13/2022] Open
Abstract
The attachment of bacteria to roots constitutes the first physical step in many plant-microbe interactions. These interactions exert both positive and negative influences on agricultural systems depending on whether a growth-promoting, symbiotic or pathogenic relationship transpires. A common biphasic mechanism of root attachment exists across agriculturally important microbial species, including Rhizobium, Agrobacterium, Pseudomonas, Azospirillum and Salmonella. Attachment studies have revealed how plant-microbe interactions develop, and how to manipulate these relationships for agricultural benefit. Here, we review our current understanding of the molecular mechanisms governing plant-microbe root attachment and draw together a common biphasic model.
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Affiliation(s)
- Rachel M Wheatley
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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29
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Naseem H, Ahsan M, Shahid MA, Khan N. Exopolysaccharides producing rhizobacteria and their role in plant growth and drought tolerance. J Basic Microbiol 2018; 58:1009-1022. [DOI: 10.1002/jobm.201800309] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/01/2018] [Accepted: 08/17/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Hafsa Naseem
- Department of Plant Sciences; Quaid-i-Azam University; Islamabad Pakistan
| | - Muhammad Ahsan
- Department of Chemistry; Allama Iqbal Open University; Islamabad Pakistan
| | - Muhammad A. Shahid
- Horticultural Science Department; Institute of Food and Agricultural Sciences; University of Florida; Gainesville Florida
| | - Naeem Khan
- Department of Plant Sciences; Quaid-i-Azam University; Islamabad Pakistan
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Osińska-Jaroszuk M, Jaszek M, Starosielec M, Sulej J, Matuszewska A, Janczarek M, Bancerz R, Wydrych J, Wiater A, Jarosz-Wilkołazka A. Bacterial exopolysaccharides as a modern biotechnological tool for modification of fungal laccase properties and metal ion binding. Bioprocess Biosyst Eng 2018; 41:973-989. [PMID: 29582151 PMCID: PMC6013525 DOI: 10.1007/s00449-018-1928-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/22/2018] [Indexed: 11/29/2022]
Abstract
Four bacterial EPSs extracted from Rhizobium leguminosarum bv. trifolii Rt24.2, Sinorhizobium meliloti Rm1021, Bradyrhizobium japonicum USDA110, and Bradyrhizobium elkanii USDA76 were determined towards their metal ion adsorption properties and possible modification of Cerrena unicolor laccase properties. The highest magnesium and iron ion-sorption capacity (~ 42 and ~ 14.5%, respectively) was observed for EPS isolated from B. japonicum USDA110. An evident influence of EPSs on the stability of laccase compared to the control values (without EPSs) was shown after 30-day incubation at 25 °C. The residual activity of laccases was obtained in the presence of Rh76EPS and Rh1021EPS, i.e., 49.5 and 41.5% of the initial catalytic activity, respectively. This result was confirmed by native PAGE electrophoresis. The EPS effect on laccase stability at different pH (from 3.8 to 7.0) was also estimated. The most significant changes at the optimum pH value (pH 5.8) was observed in samples of laccase stabilized by Rh76EPS and Rh1021EPS. Cyclic voltamperometry was used for analysis of electrochemical parameters of laccase stabilized by bacterial EPS and immobilized on single-walled carbon nanotubes (SWCNTs) with aryl residues. Laccases with Rh76EPS and Rh1021EPS had an evident shift of the value of the redox potential compared to the control without EPS addition. In conclusion, the results obtained in this work present a new potential use of bacterial EPSs as a metal-binding component and a modulator of laccase properties especially stability of enzyme activity, which can be a very effective tool in biotechnology and industrial applications.
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Affiliation(s)
- Monika Osińska-Jaroszuk
- Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland.
| | - Magdalena Jaszek
- Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Magdalena Starosielec
- Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Justyna Sulej
- Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Anna Matuszewska
- Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Monika Janczarek
- Department of Genetics and Microbiology, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Renata Bancerz
- Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Jerzy Wydrych
- Department of Comparative Anatomy and Anthropology, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Adrian Wiater
- Department of Industrial Microbiology, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Anna Jarosz-Wilkołazka
- Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka 19, 20-033, Lublin, Poland
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Kopycińska M, Lipa P, Cieśla J, Kozieł M, Janczarek M. Extracellular polysaccharide protects Rhizobium leguminosarum cells against zinc stress in vitro and during symbiosis with clover. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:355-368. [PMID: 29633524 DOI: 10.1111/1758-2229.12646] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 03/27/2018] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
Rhizobium leguminosarum bv. trifolii is a soil bacterium that establishes symbiosis with clover (Trifolium spp.) under nitrogen-limited conditions. This microorganism produces exopolysaccharide (EPS), which plays an important role in symbiotic interactions with the host plant. The aim of the current study was to establish the role of EPS in the response of R. leguminosarum bv. trifolii cells, free-living and during symbiosis, to zinc stress. We show that EPS-deficient mutants were more sensitive to Zn2+ exposure than EPS-producing strains, and that EPS overexpression conferred some protection onto the strains beyond that observed in the wild type. Exposure of the bacteria to Zn2+ ions stimulated EPS and biofilm production, and increased cell hydrophobicity. However, zinc stress negatively affected the motility and attachment of bacteria to clover roots, as well as the symbiosis with the host plant. In the presence of Zn2+ ions, cell viability, root attachment, biofilm formation and symbiotic efficiency of EPS-overproducing strains were significantly higher than those of the EPS-deficient mutants. We conclude that EPS plays an important role in the adaptation of rhizobia to zinc stress, in both the free-living stage and during symbiosis.
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Affiliation(s)
- Magdalena Kopycińska
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Paulina Lipa
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Jolanta Cieśla
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290, Lublin, Poland
| | - Marta Kozieł
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Monika Janczarek
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
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Lace B, Ott T. Commonalities and Differences in Controlling Multipartite Intracellular Infections of Legume Roots by Symbiotic Microbes. PLANT & CELL PHYSIOLOGY 2018; 59:661-672. [PMID: 29474692 DOI: 10.1093/pcp/pcy043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Indexed: 05/11/2023]
Abstract
Legumes have the almost unique ability to establish symbiotic associations with rhizobia and arbuscular mycorrhizal fungi. Forward and reverse genetics have identified a large number of genes that are required for either or both interactions. However, and in sharp contrast to natural soils, these interactions have been almost exclusively investigated under laboratory conditions by using separate inoculation systems, whereas both symbionts are simultaneously present in the field. Considering our recent understanding of the individual symbioses, the community is now promisingly positioned to co-inoculate plants with two or more microbes in order to understand mechanistically how legumes efficiently balance, regulate and potentially separate these symbioses and other endophytic microbes within the same root. Here, we discuss a number of key control layers that should be considered when assessing tri- or multipartite beneficial interactions and that may contribute to colonization patterns in legume roots.
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Affiliation(s)
- Beatrice Lace
- University of Freiburg, Faculty of Biology, Cell Biology, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Thomas Ott
- University of Freiburg, Faculty of Biology, Cell Biology, Schänzlestr. 1, D-79104 Freiburg, Germany
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Abstract
Agrobacterium exopolysaccharides play a major role in the life of the cell. Exopolysaccharides are required for bacterial growth as a biofilm and they protect the bacteria against environmental stresses. Five of the exopolysaccharides made by A. tumefaciens have been characterized extensively with respect to their structure, synthesis, regulation, and role in the life of the bacteria. These are cyclic-β-(1, 2)-glucan, cellulose, curdlan, succinoglycan, and the unipolar polysaccharide (UPP). This chapter describes the structure, synthesis, regulation, and function of these five exopolysaccharides.
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Role of Secondary Metabolites from Plant Growth-Promoting Rhizobacteria in Combating Salinity Stress. PLANT MICROBIOME: STRESS RESPONSE 2018. [DOI: 10.1007/978-981-10-5514-0_6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Marczak M, Mazur A, Koper P, Żebracki K, Skorupska A. Synthesis of Rhizobial Exopolysaccharides and Their Importance for Symbiosis with Legume Plants. Genes (Basel) 2017; 8:E360. [PMID: 29194398 PMCID: PMC5748678 DOI: 10.3390/genes8120360] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/26/2017] [Accepted: 11/29/2017] [Indexed: 12/25/2022] Open
Abstract
Rhizobia dwell and multiply in the soil and represent a unique group of bacteria able to enter into a symbiotic interaction with plants from the Fabaceae family and fix atmospheric nitrogen inside de novo created plant organs, called nodules. One of the key determinants of the successful interaction between these bacteria and plants are exopolysaccharides, which represent species-specific homo- and heteropolymers of different carbohydrate units frequently decorated by non-carbohydrate substituents. Exopolysaccharides are typically built from repeat units assembled by the Wzx/Wzy-dependent pathway, where individual subunits are synthesized in conjunction with the lipid anchor undecaprenylphosphate (und-PP), due to the activity of glycosyltransferases. Complete oligosaccharide repeat units are transferred to the periplasmic space by the activity of the Wzx flippase, and, while still being anchored in the membrane, they are joined by the polymerase Wzy. Here we have focused on the genetic control over the process of exopolysaccharides (EPS) biosynthesis in rhizobia, with emphasis put on the recent advancements in understanding the mode of action of the key proteins operating in the pathway. A role played by exopolysaccharide in Rhizobium-legume symbiosis, including recent data confirming the signaling function of EPS, is also discussed.
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Affiliation(s)
- Małgorzata Marczak
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
| | - Andrzej Mazur
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
| | - Piotr Koper
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
| | - Kamil Żebracki
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
| | - Anna Skorupska
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
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Curtis PD. Stalk formation of Brevundimonas and how it compares to Caulobacter crescentus. PLoS One 2017; 12:e0184063. [PMID: 28886080 PMCID: PMC5590869 DOI: 10.1371/journal.pone.0184063] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/17/2017] [Indexed: 11/18/2022] Open
Abstract
The Caulobacter crescentus cell extension known as a stalk represents an unusual bacterial morphology. C. crescentus produces stalks under multiple nutrient conditions, but the length of the stalk is increased in response to phosphate starvation. However, the exact function of the stalk is not known, nor is it known how much stalk biogenesis or function is conserved with other stalked bacteria. Work presented here shows that many organisms in the Caulobacter genus and the next closest genus (Brevundimonas) generally do not synthesize stalks in the relatively-rich PYE growth medium, suggesting that the synthesis of a stalk under nutrient-rich conditions by C. crescentus may be the exception instead of the norm among its phylogenetic group. Brevundimonas subvibrioides can be induced to synthesize stalks by genetically mimicking phosphate starvation conditions, indicating stalk synthesis in this organism may be performed on an as-need basis. This mutation, however, does not appear to increase the incidence of holdfast synthesis. While B. subvibrioides stalks appear to be synthesized with the same polarity with respect to holdfast as C. crescentus stalks, evidence is presented that suggests B. subvibrioides may disassemble stalks when they are no longer needed. Many homologs of C. crescentus genes encoding stalk-associated proteins are absent in the B. subvibrioides genome, and B. subvibrioides PstA-GFP as well as C. crescentus StpX-GFP are able to enter the B. subvibrioides stalk compartment, calling into question the level of compartmentalization of the B. subvibrioides stalk. In summary, this work begins to address how much the C. crescentus model for this unusual morphological adaptation can be extended to related organisms.
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Affiliation(s)
- Patrick D. Curtis
- Department of Biology, University of Mississippi, University, MS, United States of America
- * E-mail:
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Kutkowska J, Marek-Kozaczuk M, Wielbo J, Wójcik M, Urbanik-Sypniewska T. Electrophoretic profiles of lipopolysaccharides from Rhizobium strains nodulating Pisum sativum do not reflect phylogenetic relationships between these strains. Arch Microbiol 2017; 199:1011-1021. [PMID: 28386666 PMCID: PMC5548859 DOI: 10.1007/s00203-017-1374-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 03/24/2017] [Accepted: 03/30/2017] [Indexed: 11/03/2022]
Abstract
Rhizobia that nodulate peas comprise a heterogeneous group of bacteria. The aim of this study was to investigate the relationship between phylogeny and electrophoretic and hydroxy fatty acid lipopolysaccharide (LPS) profiles of pea microsymbionts. Based on amplified fragment length polymorphism (AFLP) fingerprinting data, the pea microsymbionts were grouped into two clusters distinguished at 58% similarity level. Based on the concatenated 16S rRNA, recA, and atpD housekeeping gene data, the microsymbionts appeared to be most closely related to Rhizobium leguminosarum biovars viciae and trifolii. Applying cluster analysis to their LPS electrophoretic profiles, the strains were assigned to two major groups with different banding patterns. All hydroxy fatty acids common to R. leguminosarum and R. etli were detected in each examined strain. Differences in the proportions of 3- to ω-1 hydroxy fatty acids allowed us to distinguish two groups of strains. This classification did not overlap with one based on LPS electrophoretic profiles. No clear correlation was apparent between the genetic traits and LPS profiles of the pea nodule isolates.
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Affiliation(s)
- Jolanta Kutkowska
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Lublin, Poland.
| | - Monika Marek-Kozaczuk
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Lublin, Poland
| | - Jerzy Wielbo
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Lublin, Poland
| | - Marek Wójcik
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Lublin, Poland
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A Rhizobiales-Specific Unipolar Polysaccharide Adhesin Contributes to Rhodopseudomonas palustris Biofilm Formation across Diverse Photoheterotrophic Conditions. Appl Environ Microbiol 2017; 83:AEM.03035-16. [PMID: 27986718 DOI: 10.1128/aem.03035-16] [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: 11/02/2016] [Accepted: 12/08/2016] [Indexed: 12/25/2022] Open
Abstract
Bacteria predominantly exist as members of surfaced-attached communities known as biofilms. Many bacterial species initiate biofilms and adhere to each other using cell surface adhesins. This is the case for numerous ecologically diverse Alphaprotebacteria, which use polar exopolysaccharide adhesins for cell-cell adhesion and surface attachment. Here, we show that Rhodopseudomonas palustris, a metabolically versatile member of the alphaproteobacterial order Rhizobiales, contains a functional unipolar polysaccharide (UPP) biosynthesis gene cluster. Deletion of genes predicted to be critical for UPP biosynthesis and export abolished UPP production. We also found that R. palustris uses UPP to mediate biofilm formation across diverse photoheterotrophic growth conditions, wherein light and organic substrates are used to support growth. However, UPP was less important for biofilm formation during photoautotrophy, where light and CO2 support growth, and during aerobic respiration with organic compounds. Expanding our analysis beyond R. palustris, we examined the phylogenetic distribution and genomic organization of UPP gene clusters among Rhizobiales species that inhabit diverse niches. Our analysis suggests that UPP is a conserved ancestral trait of the Rhizobiales but that it has been independently lost multiple times during the evolution of this clade, twice coinciding with adaptation to intracellular lifestyles within animal hosts. IMPORTANCE Bacteria are ubiquitously found as surface-attached communities and cellular aggregates in nature. Here, we address how bacterial adhesion is coordinated in response to diverse environments using two complementary approaches. First, we examined how Rhodopseudomonas palustris, one of the most metabolically versatile organisms ever described, varies its adhesion to surfaces in response to different environmental conditions. We identified critical genes for the production of a unipolar polysaccharide (UPP) and showed that UPP is important for adhesion when light and organic substrates are used for growth. Looking beyond R. palustris, we performed the most comprehensive survey to date on the conservation of UPP biosynthesis genes among a group of closely related bacteria that occupy diverse niches. Our findings suggest that UPP is important for free-living and plant-associated lifestyles but dispensable for animal pathogens. Additionally, we propose guidelines for classifying the adhesins produced by various Alphaprotebacteria, facilitating future functional and comparative studies.
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Surface Properties of Wild-Type Rhizobium leguminosarum bv. trifolii Strain 24.2 and Its Derivatives with Different Extracellular Polysaccharide Content. PLoS One 2016; 11:e0165080. [PMID: 27760230 PMCID: PMC5070845 DOI: 10.1371/journal.pone.0165080] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/05/2016] [Indexed: 11/19/2022] Open
Abstract
Rhizobium leguminosarum bv. trifolii is a soil bacterium able to establish symbiosis with agriculturally important legumes, i.e., clover plants (Trifolium spp.). Cell surface properties of rhizobia play an essential role in their interaction with both biotic and abiotic surfaces. Physicochemical properties of bacterial cells are underpinned by the chemical composition of their envelope surrounding the cells, and depend on various environmental conditions. In this study, we performed a comprehensive characterization of cell surface properties of a wild-type R. leguminosarum bv. trifolii strain 24.2 and its derivatives producing various levels of exopolysaccharide (EPS), namely, pssA mutant Rt5819 deficient in EPS synthesis, rosR mutant Rt2472 producing diminished amounts of this polysaccharide, and two EPS-overproducing strains, Rt24.2(pBA1) and Rt24.2(pBR1), under different growth conditions (medium type, bacterial culture age, cell viability, and pH). We established that EPS plays an essential role in the electrophoretic mobility of rhizobial cells, and that higher amounts of EPS produced resulted in greater negative electrophoretic mobility and higher acidity (lower pKapp,av) of the bacterial cell surface. From the tested strains, the electrophoretic mobility was lowest in EPS-deficient pssA mutant. Moreover, EPS produced by rhizobial strains resulted not only in an increase of negative surface charge but also in increased hydrophobicity of bacterial cell surface. This was determined by measurements of water contact angle, surface free energy, and free energy of bacterial surface-water-bacterial surface interaction. Electrophoretic mobility of the studied strains was also affected by the structure of the bacterial population (i.e., live/dead cell ratio), medium composition (ionic strength and mono- and divalent cation concentrations), and pH.
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Vozza NF, Abdian PL, Russo DM, Mongiardini EJ, Lodeiro AR, Molin S, Zorreguieta A. A Rhizobium leguminosarum CHDL- (Cadherin-Like-) Lectin Participates in Assembly and Remodeling of the Biofilm Matrix. Front Microbiol 2016; 7:1608. [PMID: 27790205 PMCID: PMC5061743 DOI: 10.3389/fmicb.2016.01608] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/26/2016] [Indexed: 11/13/2022] Open
Abstract
In natural environments most bacteria live in multicellular structures called biofilms. These cell aggregates are enclosed in a self-produced polymeric extracellular matrix, which protects the cells, provides mechanical stability and mediates cellular cohesion and adhesion to surfaces. Although important advances were made in the identification of the genetic and extracellular factors required for biofilm formation, the mechanisms leading to biofilm matrix assembly, and the roles of extracellular proteins in these processes are still poorly understood. The symbiont Rhizobium leguminosarum requires the synthesis of the acidic exopolysaccharide and the PrsDE secretion system to develop a mature biofilm. PrsDE is responsible for the secretion of the Rap family of proteins that share one or two Ra/CHDL (cadherin-like-) domains. RapA2 is a calcium-dependent lectin with a cadherin-like β sheet structure that specifically recognizes the exopolysaccharide, either as a capsular polysaccharide (CPS) or in its released form [extracellular polysaccharide (EPS)]. In this study, using gain and loss of function approaches combined with phenotypic and microscopic studies we demonstrated that RapA lectins are involved in biofilm matrix development and cellular cohesion. While the absence of any RapA protein increased the compactness of bacterial aggregates, high levels of RapA1 expanded distances between cells and favored the production of a dense matrix network. Whereas endogenous RapA(s) are predominantly located at one bacterial pole, we found that under overproduction conditions, RapA1 surrounded the cell in a way that was reminiscent of the capsule. Accordingly, polysaccharide analyses showed that the RapA lectins promote CPS formation at the expense of lower EPS production. Besides, polysaccharide analysis suggests that RapA modulates the EPS size profile. Collectively, these results show that the interaction of RapA lectins with the polysaccharide is involved in rhizobial biofilm matrix assembly and remodeling.
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Affiliation(s)
- Nicolás F. Vozza
- Fundación Instituto Leloir, IIBBA-CONICETBuenos Aires, Argentina
| | | | - Daniela M. Russo
- Fundación Instituto Leloir, IIBBA-CONICETBuenos Aires, Argentina
| | - Elías J. Mongiardini
- Instituto de Bioquímica y Biología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Centro Científico Technológico COINCET La PlataLa Plata, Argentina
| | - Aníbal R. Lodeiro
- Instituto de Bioquímica y Biología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Centro Científico Technológico COINCET La PlataLa Plata, Argentina
| | - Søren Molin
- Department of Systems Biology, Technical University of DenmarkLyngby, Denmark
| | - Angeles Zorreguieta
- Fundación Instituto Leloir, IIBBA-CONICETBuenos Aires, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
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Grillo MA, Stinchcombe JR, Heath KD. Nitrogen addition does not influence pre-infection partner choice in the legume-rhizobium symbiosis. AMERICAN JOURNAL OF BOTANY 2016; 103:1763-1770. [PMID: 27671532 DOI: 10.3732/ajb.1600090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 08/09/2016] [Indexed: 05/26/2023]
Abstract
PREMISE OF THE STUDY Resource mutualisms such as the symbiosis between legumes and nitrogen-fixing rhizobia are context dependent and are sensitive to various aspects of the environment, including nitrogen (N) addition. Mutualist hosts such as legumes are also thought to use mechanisms such as partner choice to discriminate among potential symbionts that vary in partner quality (fitness benefits conferred to hosts) and thus impose selection on rhizobium populations. Together, context dependency and partner choice might help explain why the legume-rhizobium mutualism responds evolutionarily to N addition, since plant-mediated selection that shifts in response to N might be expected to favor different rhizobium strains in different N environments. METHODS We test for the influence of context dependency on partner choice in the model legume, Medicago truncatula, using a factorial experiments with three plant families across three N levels with a mixed inoculation of three rhizobia strains. KEY RESULTS Neither the relative frequencies of rhizobium strains occupying host nodules, nor the size of those nodules, differed in response to N level. CONCLUSIONS Despite the lack of context dependence, plant genotypes respond very differently to mixed populations of rhizobia, suggesting that these traits are genetically variable and thus could evolve in response to longer-term increases in N.
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Affiliation(s)
- Michael A Grillo
- University of Illinois, Department of Plant Biology, Urbana, Illinois 61801, USA
| | - John R Stinchcombe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Katy D Heath
- University of Illinois, Department of Plant Biology, Urbana, Illinois 61801, USA
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42
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Rachwał K, Boguszewska A, Kopcińska J, Karaś M, Tchórzewski M, Janczarek M. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover. Front Microbiol 2016; 7:1302. [PMID: 27602024 PMCID: PMC4993760 DOI: 10.3389/fmicb.2016.01302] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/08/2016] [Indexed: 11/13/2022] Open
Abstract
Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca(2+)-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with the wild type, the rosR mutant infected host plant roots much less effectively and its nodule occupation was disturbed. At the ultrastructural level, the most striking differences between the mutant and the wild-type nodules concerned the structure of infection threads, release of bacteria, and bacteroid differentiation. This confirms an essential role of RosR in establishment of successful symbiotic interaction of R. leguminosarum bv. trifolii with clover plants.
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Affiliation(s)
- Kamila Rachwał
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Aleksandra Boguszewska
- Department of Molecular Biology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Joanna Kopcińska
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences Warsaw, Poland
| | - Magdalena Karaś
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Marek Tchórzewski
- Department of Molecular Biology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Monika Janczarek
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
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Abstract
During the first step of biofilm formation, initial attachment is dictated by physicochemical and electrostatic interactions between the surface and the bacterial envelope. Depending on the nature of these interactions, attachment can be transient or permanent. To achieve irreversible attachment, bacterial cells have developed a series of surface adhesins promoting specific or nonspecific adhesion under various environmental conditions. This article reviews the recent advances in our understanding of the secretion, assembly, and regulation of the bacterial adhesins during biofilm formation, with a particular emphasis on the fimbrial, nonfimbrial, and discrete polysaccharide adhesins in Gram-negative bacteria.
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Short-Stalked Prosthecomicrobium hirschii Cells Have a Caulobacter-Like Cell Cycle. J Bacteriol 2016; 198:1149-59. [PMID: 26833409 DOI: 10.1128/jb.00896-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/24/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The dimorphic alphaproteobacterium Prosthecomicrobium hirschii has both short-stalked and long-stalked morphotypes. Notably, these morphologies do not arise from transitions in a cell cycle. Instead, the maternal cell morphology is typically reproduced in daughter cells, which results in microcolonies of a single cell type. In this work, we further characterized the short-stalked cells and found that these cells have a Caulobacter-like life cycle in which cell division leads to the generation of two morphologically distinct daughter cells. Using a microfluidic device and total internal reflection fluorescence (TIRF) microscopy, we observed that motile short-stalked cells attach to a surface by means of a polar adhesin. Cells attached at their poles elongate and ultimately release motile daughter cells. Robust biofilm growth occurs in the microfluidic device, enabling the collection of synchronous motile cells and downstream analysis of cell growth and attachment. Analysis of a draft P. hirschii genome sequence indicates the presence of CtrA-dependent cell cycle regulation. This characterization of P. hirschii will enable future studies on the mechanisms underlying complex morphologies and polymorphic cell cycles. IMPORTANCE Bacterial cell shape plays a critical role in regulating important behaviors, such as attachment to surfaces, motility, predation, and cellular differentiation; however, most studies on these behaviors focus on bacteria with relatively simple morphologies, such as rods and spheres. Notably, complex morphologies abound throughout the bacteria, with striking examples, such as P. hirschii, found within the stalked Alphaproteobacteria. P. hirschii is an outstanding candidate for studies of complex morphology generation and polymorphic cell cycles. Here, the cell cycle and genome of P. hirschii are characterized. This work sets the stage for future studies of the impact of complex cell shapes on bacterial behaviors.
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Rachwał K, Matczyńska E, Janczarek M. Transcriptome profiling of a Rhizobium leguminosarum bv. trifolii rosR mutant reveals the role of the transcriptional regulator RosR in motility, synthesis of cell-surface components, and other cellular processes. BMC Genomics 2015; 16:1111. [PMID: 26715155 PMCID: PMC4696191 DOI: 10.1186/s12864-015-2332-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/17/2015] [Indexed: 11/10/2022] Open
Abstract
Background Rhizobium leguminosarum bv. trifolii is a soil bacterium capable of establishing a symbiotic relationship with red clover (Trifolium pratense). The presence of surface polysaccharides and other extracellular components as well as motility and competitiveness are essential traits for both adaptation of this bacterium to changing environmental conditions and successful infection of host plant roots. The R. leguminosarum bv. trifolii rosR gene encodes a protein belonging to the family of Ros/MucR transcriptional regulators, which contain a Cys2His2-type zinc-finger motif and are involved in the regulation of exopolysaccharide synthesis in several rhizobial species. Previously, it was established that a mutation in the rosR gene significantly decreased exopolysaccharide synthesis, increased bacterial sensitivity to some stress factors, and negatively affected infection of clover roots. Results RNA-Seq analysis performed for the R. leguminosarum bv. trifolii wild-type strain Rt24.2 and its derivative Rt2472 carrying a rosR mutation identified a large number of genes which were differentially expressed in these two backgrounds. A considerable majority of these genes were up-regulated in the mutant (63.22 %), indicating that RosR functions mainly as a repressor. Transcriptome profiling of the rosR mutant revealed a role of this regulator in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Moreover, it was established that the Rt2472 strain was characterized by a longer generation time and showed an increased aggregation ability, but was impaired in motility as a result of considerably reduced flagellation of its cells. Conclusions The comparative transcriptome analysis of R. leguminosarum bv. trifolii wild-type Rt24.2 and the Rt2472 mutant identified a set of genes belonging to the RosR regulon and confirmed the important role of RosR in the regulatory network. The data obtained in this study indicate that this protein affects several cellular processes and plays an important role in bacterial adaptation to environmental conditions. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2332-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kamila Rachwał
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Ewa Matczyńska
- Department of Mathematics and Computer Science, Institute of Computer Science, Jagiellonian University, Łojasiewicza 6, 30-348, Cracow, Poland.,Genomed SA, Ponczowa 12, 02-971, Warsaw, Poland
| | - Monika Janczarek
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland.
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Augimeri RV, Varley AJ, Strap JL. Establishing a Role for Bacterial Cellulose in Environmental Interactions: Lessons Learned from Diverse Biofilm-Producing Proteobacteria. Front Microbiol 2015; 6:1282. [PMID: 26635751 PMCID: PMC4646962 DOI: 10.3389/fmicb.2015.01282] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/31/2015] [Indexed: 01/21/2023] Open
Abstract
Bacterial cellulose (BC) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. Biosynthesis of BC-containing biofilms occurs in a variety of Proteobacteria that inhabit diverse ecological niches. The enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of BC are equally as diverse. Though the magnitude and environmental consequences of BC production are species-specific, the common role of BC-containing biofilms is to establish close contact with a preferred host to facilitate efficient host-bacteria interactions. Universally, BC aids in attachment, adherence, and subsequent colonization of a substrate. Bi-directional interactions influence host physiology, bacterial physiology, and regulation of BC biosynthesis, primarily through modulation of intracellular bis-(3'→5')-cyclic diguanylate (c-di-GMP) levels. Depending on the circumstance, BC producers exhibit a pathogenic or symbiotic relationship with plant, animal, or fungal hosts. Rhizobiaceae species colonize plant roots, Pseudomonadaceae inhabit the phyllosphere, Acetobacteriaceae associate with sugar-loving insects and inhabit the carposphere, Enterobacteriaceae use fresh produce as vehicles to infect animal hosts, and Vibrionaceae, particularly Aliivibrio fischeri, colonize the light organ of squid. This review will highlight the diversity of the biosynthesis and regulation of BC in nature by discussing various examples of Proteobacteria that use BC-containing biofilms to facilitate host-bacteria interactions. Through discussion of current data we will establish new directions for the elucidation of BC biosynthesis, its regulation and its ecophysiological roles.
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Affiliation(s)
| | | | - Janice L. Strap
- Molecular Microbial Biochemistry Laboratory, Faculty of Science, University of Ontario Institute of TechnologyOshawa, ON, Canada
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Cyclic Di-GMP Regulates Multiple Cellular Functions in the Symbiotic Alphaproteobacterium Sinorhizobium meliloti. J Bacteriol 2015; 198:521-35. [PMID: 26574513 DOI: 10.1128/jb.00795-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 11/09/2015] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Sinorhizobium meliloti undergoes major lifestyle changes between planktonic states, biofilm formation, and symbiosis with leguminous plant hosts. In many bacteria, the second messenger 3',5'-cyclic di-GMP (c-di-GMP, or cdG) promotes a sessile lifestyle by regulating a plethora of processes involved in biofilm formation, including motility and biosynthesis of exopolysaccharides (EPS). Here, we systematically investigated the role of cdG in S. meliloti Rm2011 encoding 22 proteins putatively associated with cdG synthesis, degradation, or binding. Single mutations in 21 of these genes did not cause evident changes in biofilm formation, motility, or EPS biosynthesis. In contrast, manipulation of cdG levels by overproducing endogenous or heterologous diguanylate cyclases (DGCs) or phosphodiesterases (PDEs) affected these processes and accumulation of N-Acyl-homoserine lactones in the culture supernatant. Specifically, individual overexpression of the S. meliloti genes pleD, SMb20523, SMb20447, SMc01464, and SMc03178 encoding putative DGCs and of SMb21517 encoding a single-domain PDE protein had an impact and resulted in increased levels of cdG. Compared to the wild type, an S. meliloti strain that did not produce detectable levels of cdG (cdG(0)) was more sensitive to acid stress. However, it was symbiotically potent, unaffected in motility, and only slightly reduced in biofilm formation. The SMc01790-SMc01796 locus, homologous to the Agrobacterium tumefaciens uppABCDEF cluster governing biosynthesis of a unipolarly localized polysaccharide, was found to be required for cdG-stimulated biofilm formation, while the single-domain PilZ protein McrA was identified as a cdG receptor protein involved in regulation of motility. IMPORTANCE We present the first systematic genome-wide investigation of the role of 3',5'-cyclic di-GMP (c-di-GMP, or cdG) in regulation of motility, biosynthesis of exopolysaccharides, biofilm formation, quorum sensing, and symbiosis in a symbiotic alpha-rhizobial species. Phenotypes of an S. meliloti strain unable to produce cdG (cdG(0)) demonstrated that this second messenger is not essential for root nodule symbiosis but may contribute to acid tolerance. Our data further suggest that enhanced levels of cdG promote sessility of S. meliloti and uncovered a single-domain PilZ protein as regulator of motility.
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Lira MA, Nascimento LRS, Fracetto GGM. Legume-rhizobia signal exchange: promiscuity and environmental effects. Front Microbiol 2015; 6:945. [PMID: 26441880 PMCID: PMC4561803 DOI: 10.3389/fmicb.2015.00945] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 08/27/2015] [Indexed: 12/29/2022] Open
Abstract
Although signal exchange between legumes and their rhizobia is among the best-known examples of this biological process, most of the more characterized data comes from just a few legume species and environmental stresses. Although a relative wealth of information is available for some model legumes and some of the major pulses such as soybean, little is known about tropical legumes. This relative disparity in current knowledge is also apparent in the research on the effects of environmental stress on signal exchange; cool-climate stresses, such as low-soil temperature, comprise a relatively large body of research, whereas high-temperature stresses and drought are not nearly as well understood. Both tropical legumes and their environmental stress-induced effects are increasingly important due to global population growth (the demand for protein), climate change (increasing temperatures and more extreme climate behavior), and urbanization (and thus heavy metals). This knowledge gap for both legumes and their environmental stresses is compounded because whereas most temperate legume-rhizobia symbioses are relatively specific and cultivated under relatively stable environments, the converse is true for tropical legumes, which tend to be promiscuous, and grow in highly variable conditions. This review will clarify some of this missing information and highlight fields in which further research would benefit our current knowledge.
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Affiliation(s)
- Mario A. Lira
- Agronomy Department, Federal Rural University of PernambucoRecife, Brazil
- National Council for Research and Scientific and Technological DevelopmentBrasília, Brazil
| | - Luciana R. S. Nascimento
- Agronomy Department, Federal Rural University of PernambucoRecife, Brazil
- National Council for Research and Scientific and Technological DevelopmentBrasília, Brazil
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Gardères J, Bourguet-Kondracki ML, Hamer B, Batel R, Schröder HC, Müller WEG. Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential. Mar Drugs 2015; 13:5059-101. [PMID: 26262628 PMCID: PMC4557014 DOI: 10.3390/md13085059] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/09/2015] [Accepted: 07/27/2015] [Indexed: 12/29/2022] Open
Abstract
An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest.
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Affiliation(s)
- Johan Gardères
- Unité Molécules de Communication et Adaptation des Microorganismes, UMR 7245 CNRS, Muséum National d’Histoire Naturelle, CP 54, 57 rue Cuvier, Paris 75005, France; E-Mails: (J.G.); (M.-L.B.-K.)
- Laboratory for Marine Molecular Biology, Center for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, 52210 Rovinj, Croatia; E-Mails: (B.H.); (R.B.)
- ERC Advanced Investigator Grant Research Group at Institute for Physiological Chemistry, University Medical Center of Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz D-55128, Germany; E-Mail:
| | - Marie-Lise Bourguet-Kondracki
- Unité Molécules de Communication et Adaptation des Microorganismes, UMR 7245 CNRS, Muséum National d’Histoire Naturelle, CP 54, 57 rue Cuvier, Paris 75005, France; E-Mails: (J.G.); (M.-L.B.-K.)
| | - Bojan Hamer
- Laboratory for Marine Molecular Biology, Center for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, 52210 Rovinj, Croatia; E-Mails: (B.H.); (R.B.)
| | - Renato Batel
- Laboratory for Marine Molecular Biology, Center for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, 52210 Rovinj, Croatia; E-Mails: (B.H.); (R.B.)
| | - Heinz C. Schröder
- ERC Advanced Investigator Grant Research Group at Institute for Physiological Chemistry, University Medical Center of Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz D-55128, Germany; E-Mail:
| | - Werner E. G. Müller
- ERC Advanced Investigator Grant Research Group at Institute for Physiological Chemistry, University Medical Center of Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz D-55128, Germany; E-Mail:
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