51
|
Chagas FO, Pessotti RDC, Caraballo-Rodríguez AM, Pupo MT. Chemical signaling involved in plant-microbe interactions. Chem Soc Rev 2018; 47:1652-1704. [PMID: 29218336 DOI: 10.1039/c7cs00343a] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microorganisms are found everywhere, and they are closely associated with plants. Because the establishment of any plant-microbe association involves chemical communication, understanding crosstalk processes is fundamental to defining the type of relationship. Although several metabolites from plants and microbes have been fully characterized, their roles in the chemical interplay between these partners are not well understood in most cases, and they require further investigation. In this review, we describe different plant-microbe associations from colonization to microbial establishment processes in plants along with future prospects, including agricultural benefits.
Collapse
Affiliation(s)
- Fernanda Oliveira Chagas
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (FCFRP-USP), Avenida do Café, s/n, 14040-903, Ribeirão Preto-SP, Brazil.
| | | | | | | |
Collapse
|
52
|
Passera A, Marcolungo L, Casati P, Brasca M, Quaglino F, Cantaloni C, Delledonne M. Hybrid genome assembly and annotation of Paenibacillus pasadenensis strain R16 reveals insights on endophytic life style and antifungal activity. PLoS One 2018; 13:e0189993. [PMID: 29351296 PMCID: PMC5774705 DOI: 10.1371/journal.pone.0189993] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/06/2017] [Indexed: 01/27/2023] Open
Abstract
Bacteria of the Paenibacillus genus are becoming important in many fields of science, including agriculture, for their positive effects on the health of plants. However, there are little information available on this genus compared to other bacteria (such as Bacillus or Pseudomonas), especially when considering genomic information. Sequencing the genomes of plant-beneficial bacteria is a crucial step to identify the genetic elements underlying the adaptation to life inside a plant host and, in particular, which of these features determine the differences between a helpful microorganism and a pathogenic one. In this study, we have characterized the genome of Paenibacillus pasadenensis, strain R16, recently investigated for its antifungal activities and plant-associated features. An hybrid assembly approach was used integrating the very precise reads obtained by Illumina technology and long fragments acquired with Oxford Nanopore Technology (ONT) sequencing. De novo genome assembly based solely on Illumina reads generated a relatively fragmented assembly of 5.72 Mbp in 99 ungapped sequences with an N50 length of 544 Kbp; hybrid assembly, integrating Illumina and ONT reads, improved the assembly quality, generating a genome of 5.75 Mbp, organized in 6 contigs with an N50 length of 3.4 Mbp. Annotation of the latter genome identified 4987 coding sequences, of which 1610 are hypothetical proteins. Enrichment analysis identified pathways of particular interest for the endophyte biology, including the chitin-utilization pathway and the incomplete siderophore pathway which hints at siderophore parasitism. In addition the analysis led to the identification of genes for the production of terpenes, as for example farnesol, that was hypothesized as the main antifungal molecule produced by the strain. The functional analysis on the genome confirmed several plant-associated, plant-growth promotion, and biocontrol traits of strain R16, thus adding insights in the genetic bases of these complex features, and of the Paenibacillus genus in general.
Collapse
Affiliation(s)
- Alessandro Passera
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Università degli Studi di Milano, Milan, Italy
| | - Luca Marcolungo
- Department of Biotechnologies, Università degli Studi di Verona, Verona, Italy
| | - Paola Casati
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Università degli Studi di Milano, Milan, Italy
- * E-mail:
| | - Milena Brasca
- Institute of Sciences of Food Production, Italian National Research Council, Milan, Italy
| | - Fabio Quaglino
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Università degli Studi di Milano, Milan, Italy
| | - Chiara Cantaloni
- Department of Biotechnologies, Università degli Studi di Verona, Verona, Italy
| | - Massimo Delledonne
- Department of Biotechnologies, Università degli Studi di Verona, Verona, Italy
| |
Collapse
|
53
|
Barton IS, Fuqua C, Platt TG. Ecological and evolutionary dynamics of a model facultative pathogen: Agrobacterium and crown gall disease of plants. Environ Microbiol 2018; 20:16-29. [PMID: 29105274 PMCID: PMC5764771 DOI: 10.1111/1462-2920.13976] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 10/20/2017] [Accepted: 10/25/2017] [Indexed: 01/09/2023]
Abstract
Many important pathogens maintain significant populations in highly disparate disease and non-disease environments. The consequences of this environmental heterogeneity in shaping the ecological and evolutionary dynamics of these facultative pathogens are incompletely understood. Agrobacterium tumefaciens, the causative agent for crown gall disease of plants has proven a productive model for many aspects of interactions between pathogens and their hosts and with other microbes. In this review, we highlight how this past work provides valuable context for the use of this system to examine how heterogeneity and transitions between disease and non-disease environments influence the ecology and evolution of facultative pathogens. We focus on several features common among facultative pathogens, such as the physiological remodelling required to colonize hosts from environmental reservoirs and the consequences of competition with host and non-host associated microbiota. In addition, we discuss how the life history of facultative pathogens likely often results in ecological tradeoffs associated with performance in disease and non-disease environments. These pathogens may therefore have different competitive dynamics in disease and non-disease environments and are subject to shifting selective pressures that can result in pathoadaptation or the within-host spread of avirulent phenotypes.
Collapse
Affiliation(s)
- Ian S. Barton
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Thomas G. Platt
- Division of Biology, Kansas State University, Manhattan, KS, USA
| |
Collapse
|
54
|
Jacoby R, Peukert M, Succurro A, Koprivova A, Kopriva S. The Role of Soil Microorganisms in Plant Mineral Nutrition-Current Knowledge and Future Directions. FRONTIERS IN PLANT SCIENCE 2017; 8:1617. [PMID: 28974956 PMCID: PMC5610682 DOI: 10.3389/fpls.2017.01617] [Citation(s) in RCA: 351] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 09/04/2017] [Indexed: 05/18/2023]
Abstract
In their natural environment, plants are part of a rich ecosystem including numerous and diverse microorganisms in the soil. It has been long recognized that some of these microbes, such as mycorrhizal fungi or nitrogen fixing symbiotic bacteria, play important roles in plant performance by improving mineral nutrition. However, the full range of microbes associated with plants and their potential to replace synthetic agricultural inputs has only recently started to be uncovered. In the last few years, a great progress has been made in the knowledge on composition of rhizospheric microbiomes and their dynamics. There is clear evidence that plants shape microbiome structures, most probably by root exudates, and also that bacteria have developed various adaptations to thrive in the rhizospheric niche. The mechanisms of these interactions and the processes driving the alterations in microbiomes are, however, largely unknown. In this review, we focus on the interaction of plants and root associated bacteria enhancing plant mineral nutrition, summarizing the current knowledge in several research fields that can converge to improve our understanding of the molecular mechanisms underpinning this phenomenon.
Collapse
Affiliation(s)
| | | | | | | | - Stanislav Kopriva
- Botanical Institute, Cluster of Excellence on Plant Sciences (CEPLAS), University of CologneCologne, Germany
| |
Collapse
|
55
|
Quorum sensing activity of the plant growth-promoting rhizobacterium Serratia glossinae GS2 isolated from the sesame (Sesamum indicum L.) rhizosphere. ANN MICROBIOL 2017. [DOI: 10.1007/s13213-017-1291-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
56
|
Interkingdom signaling in plant-microbe interactions. SCIENCE CHINA-LIFE SCIENCES 2017; 60:785-796. [PMID: 28755299 DOI: 10.1007/s11427-017-9092-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/04/2017] [Indexed: 12/18/2022]
Abstract
The widespread communications between prokaryotes and eukaryotes via signaling molecules are believed to affect gene expression in both partners. During the communication process, the contacted organisms produce and release small molecules that establish communication channels between two kingdoms-this procedure is known as interkingdom signaling. Interkingdom communications are widespread between pathogenic or beneficial bacteria and their host plants, with diversified outcomes depending on the specific chemical-triggered signaling pathways. Deciphering the signals or language of this interkingdom communication and uncovering the underlying mechanisms are major current challenges in this field. It is evident that diverse signaling molecules can be produced or derived from bacteria and plants, and researchers have sought to identify these signals and explore the mechanisms of the signaling pathways. The results of such studies will lead to the development of strategies to improve plant disease resistance through controlling interkingdom signals, rather than directly killing the pathogenic bacteria. Also, the identification of signals produced by beneficial bacteria will be useful for agricultural applications. In this review, we summarize the recent progress of cross-kingdom interactions between plant and bacteria, and how LuxR-family transcription factors in plant associated bacterial quorum sensing system are involved in the interkingdom signaling.
Collapse
|
57
|
Uzelac G, Patel HK, Devescovi G, Licastro D, Venturi V. Quorum sensing and RsaM regulons of the rice pathogen Pseudomonas fuscovaginae. MICROBIOLOGY-SGM 2017; 163:765-777. [PMID: 28530166 DOI: 10.1099/mic.0.000454] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pseudomonas fuscovaginae (Pfv) is an emerging plant pathogen causing sheath brown rot in rice, as well as diseases in other gramineae food crops including maize, sorghum and wheat. Pfv possesses two conserved N-acyl homoserine lactone (AHL) quorum sensing (QS) systems called PfvI/R and PfsI/R, which are repressed by RsaL and RsaM, respectively. The two systems are not hierarchically organized and are involved in plant virulence. In this study the AHL QS PfsI/R, PfvI/R and RsaM regulons were determined by transcriptomic analysis. The PfsI/R system regulates 98 genes, whereas 26 genes are regulated by the PfvI/R AHL QS system; only two genes are regulated by both systems. RsaM, on the other hand, regulates over 400 genes: 206 are negatively regulated and 260 are positively regulated. More than half of the genes controlled by the PfsI/R system and 65 % by the PfvI/R system are also part of the RsaM regulon; this is due to RsaM being involved in the regulation of both systems. It is concluded that the two QS systems regulate a unique set of genes and that RsaM is a global regulator mediating the expression of different genes through the two QS systems as well as genes independently of QS.
Collapse
Affiliation(s)
- Gordana Uzelac
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Hitendra Kumar Patel
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.,Present address: CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, India
| | - Giulia Devescovi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| |
Collapse
|
58
|
Shiva KJ, Sharanaiah U. Enhancement of the expression of defense genes in tomato against Ralstonia solanacearum by N-octanoyl-L-homoserine lactone. ACTA ACUST UNITED AC 2017. [DOI: 10.5897/ajmr2016.8370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
59
|
Nunes-Costa D, Maranha A, Costa M, Alarico S, Empadinhas N. Glucosylglycerate metabolism, bioversatility and mycobacterial survival. Glycobiology 2016; 27:213-227. [DOI: 10.1093/glycob/cww132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/14/2016] [Indexed: 12/17/2022] Open
|
60
|
Padje AV, Whiteside MD, Kiers ET. Signals and cues in the evolution of plant-microbe communication. CURRENT OPINION IN PLANT BIOLOGY 2016; 32:47-52. [PMID: 27348594 DOI: 10.1016/j.pbi.2016.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 05/23/2023]
Abstract
Communication has played a key role in organismal evolution. If sender and receiver have a shared interest in propagating reliable information, such as when they are kin relatives, then effective communication can bring large fitness benefits. However, interspecific communication (among different species) is more prone to dishonesty. Over the last decade, plants and their microbial root symbionts have become a model system for studying interspecific molecular crosstalk. However, less is known about the evolutionary stability of plant-microbe communication. What prevents partners from hijacking or manipulating information to their own benefit? Here, we focus on communication between arbuscular mycorrhizal fungi and their host plants. We ask how partners use directed signals to convey specific information, and highlight research on the problem of dishonest signaling.
Collapse
Affiliation(s)
- Anouk Van't Padje
- Institute of Ecological Science, Vrije Universiteit, 1081 HV Amsterdam, Netherlands
| | - Matthew D Whiteside
- Institute of Ecological Science, Vrije Universiteit, 1081 HV Amsterdam, Netherlands
| | - E Toby Kiers
- Institute of Ecological Science, Vrije Universiteit, 1081 HV Amsterdam, Netherlands.
| |
Collapse
|
61
|
Welsh MA, Blackwell HE. Chemical probes of quorum sensing: from compound development to biological discovery. FEMS Microbiol Rev 2016; 40:774-94. [PMID: 27268906 DOI: 10.1093/femsre/fuw009] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2016] [Indexed: 01/20/2023] Open
Abstract
Bacteria can utilize chemical signals to coordinate the expression of group-beneficial behaviors in a method of cell-cell communication called quorum sensing (QS). The discovery that QS controls the production of virulence factors and biofilm formation in many common pathogens has driven an explosion of research aimed at both deepening our fundamental understanding of these regulatory networks and developing chemical agents that can attenuate QS signaling. The inherently chemical nature of QS makes studying these pathways with small molecule tools a complementary approach to traditional microbiology techniques. Indeed, chemical tools are beginning to yield new insights into QS regulation and provide novel strategies to inhibit QS. Here, we review the most recent advances in the development of chemical probes of QS systems in Gram-negative bacteria, with an emphasis on the opportunistic pathogen Pseudomonas aeruginosa We first describe reports of novel small molecule modulators of QS receptors and QS signal synthases. Next, in several case studies, we showcase how chemical tools have been deployed to reveal new knowledge of QS biology and outline lessons for how researchers might best target QS to combat bacterial virulence. To close, we detail the outstanding challenges in the field and suggest strategies to overcome these issues.
Collapse
Affiliation(s)
- Michael A Welsh
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| |
Collapse
|
62
|
Corral-Lugo A, Daddaoua A, Ortega A, Espinosa-Urgel M, Krell T. So different and still so similar: The plant compound rosmarinic acid mimics bacterial homoserine lactone quorum sensing signals. Commun Integr Biol 2016; 9:e1156832. [PMID: 27195067 PMCID: PMC4857781 DOI: 10.1080/19420889.2016.1156832] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 02/17/2016] [Indexed: 01/30/2023] Open
Abstract
Apart from inter-bacteria communication quorum sensing (QS) mechanisms also enable inter-domain interactions. To interfere with bacterial QS, plants were found to secrete compounds; most of which of unknown identity. We have identified the plant compound rosmarinic acid (RA) to modulate Pseudomonas aeruginosa QS by binding to the RhlR QS regulator. RA was found to be a homoserine-lactone (HSL) mimic that caused agonistic effects on transcription, resulting ultimately in a stimulation of several RhlR controlled phenotypes like virulence factor synthesis or biofilm formation. Our study was initiated by in silico screening of an RhlR model with compound libraries, demonstrating that this approach is suitable to tackle a major bottleneck in signal transduction research, which is the identification of sensor protein ligands. Previous work has shown that plant compounds interfere with the function of orphan QS regulators. Our study demonstrates that this has not necessarily to be the case since RhlR forms a functional pair with the RhlI synthase. A wide range of structurally dissimilar compounds have been found to mimic HSLs suggesting that this class of QS regulators is characterized by a significant plasticity in the recognition of effector molecules. Further research will show to what extent RA impacts on QS mechanisms of other bacteria.
Collapse
Affiliation(s)
- Andrés Corral-Lugo
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas , C/ Prof. Albareda , Granada, Spain
| | - Abdelali Daddaoua
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas , C/ Prof. Albareda , Granada, Spain
| | - Alvaro Ortega
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas , C/ Prof. Albareda , Granada, Spain
| | - Manuel Espinosa-Urgel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas , C/ Prof. Albareda , Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas , C/ Prof. Albareda , Granada, Spain
| |
Collapse
|
63
|
Rosier A, Bishnoi U, Lakshmanan V, Sherrier DJ, Bais HP. A perspective on inter-kingdom signaling in plant-beneficial microbe interactions. PLANT MOLECULAR BIOLOGY 2016; 90:537-48. [PMID: 26792782 DOI: 10.1007/s11103-016-0433-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 01/06/2016] [Indexed: 05/14/2023]
Abstract
Recent work has shown that the rhizospheric and phyllospheric microbiomes of plants are composed of highly diverse microbial species. Though the information pertaining to the diversity of the aboveground and belowground microbes associated with plants is known, an understanding of the mechanisms by which these diverse microbes function is still in its infancy. Plants are sessile organisms, that depend upon chemical signals to interact with the microbiota. Of late, the studies related to the impact of microbes on plants have gained much traction in the research literature, supporting diverse functional roles of microbes on plant health. However, how these microbes interact as a community to confer beneficial traits to plants is still poorly understood. Recent advances in the use of "biologicals" as bio-fertilizers and biocontrol agents for sustainable agricultural practices is promising, and a fundamental understanding of how microbes in community work on plants could help this approach be more successful. This review attempts to highlight the importance of different signaling events that mediate a beneficial plant microbe interaction. Fundamental research is needed to understand how plants react to different benign microbes and how these microbes are interacting with each other. This review highlights the importance of chemical signaling, and biochemical and genetic events which determine the efficacy of benign microbes to promote the development of beneficial traits in plants.
Collapse
Affiliation(s)
- Amanda Rosier
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA
- Delaware Biotechnology Institute, Newark, DE, 19711, USA
| | - Usha Bishnoi
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA
- Delaware Biotechnology Institute, Newark, DE, 19711, USA
| | - Venkatachalam Lakshmanan
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA
- Delaware Biotechnology Institute, Newark, DE, 19711, USA
| | - D Janine Sherrier
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA
- Delaware Biotechnology Institute, Newark, DE, 19711, USA
| | - Harsh P Bais
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19716, USA.
- Delaware Biotechnology Institute, Newark, DE, 19711, USA.
| |
Collapse
|
64
|
Ismail AS, Valastyan JS, Bassler BL. A Host-Produced Autoinducer-2 Mimic Activates Bacterial Quorum Sensing. Cell Host Microbe 2016; 19:470-80. [PMID: 26996306 DOI: 10.1016/j.chom.2016.02.020] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/26/2016] [Accepted: 02/29/2016] [Indexed: 12/31/2022]
Abstract
Host-microbial symbioses are vital to health; nonetheless, little is known about the role crosskingdom signaling plays in these relationships. In a process called quorum sensing, bacteria communicate with one another using extracellular signal molecules called autoinducers. One autoinducer, AI-2, is proposed to promote interspecies bacterial communication, including in the mammalian gut. We show that mammalian epithelia produce an AI-2 mimic activity in response to bacteria or tight-junction disruption. This AI-2 mimic is detected by the bacterial AI-2 receptor, LuxP/LsrB, and can activate quorum-sensing-controlled gene expression, including in the enteric pathogen Salmonella typhimurium. AI-2 mimic activity is induced when epithelia are directly or indirectly exposed to bacteria, suggesting that a secreted bacterial component(s) stimulates its production. Mutagenesis revealed genes required for bacteria to both detect and stimulate production of the AI-2 mimic. These findings uncover a potential role for the mammalian AI-2 mimic in fostering crosskingdom signaling and host-bacterial symbioses.
Collapse
Affiliation(s)
- Anisa S Ismail
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544 USA
| | - Julie S Valastyan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544 USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815 USA
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544 USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815 USA.
| |
Collapse
|
65
|
Venturi V, Keel C. Signaling in the Rhizosphere. TRENDS IN PLANT SCIENCE 2016; 21:187-198. [PMID: 26832945 DOI: 10.1016/j.tplants.2016.01.005] [Citation(s) in RCA: 258] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 05/20/2023]
Abstract
Signaling studies in the rhizosphere have focused on close interactions between plants and symbiotic microorganisms. However, this focus is likely to expand to other microorganisms because the rhizomicrobiome is important for plant health and is able to influence the structure of the microbial community. We discuss here the shaping of the rhizomicrobiome and define which aspects can be considered signaling. We divide signaling in the rhizosphere into three categories: (i) between microbes, (ii) from plants to microorganisms, and (iii) from microorganisms to plants. Signals act on diverse organisms including the plant. Mycorrhizal and rhizobial interkingdom signaling has revealed its pivotal role in establishing associations, and the recent discovery of signaling with non-symbiotic microorganisms indicates the important role of communication in shaping the rhizomicrobiome.
Collapse
Affiliation(s)
- Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy.
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| |
Collapse
|
66
|
Abstract
Agrobacterium tumefaciens is a plant pathogen with the capacity to deliver a segment of oncogenic DNA carried on a large plasmid called the tumor-inducing or Ti plasmid to susceptible plant cells. A. tumefaciens belongs to the class Alphaproteobacteria, whose members include other plant pathogens (Agrobacterium rhizogenes), plant and insect symbionts (Rhizobium spp. and Wolbachia spp., respectively), human pathogens (Brucella spp., Bartonella spp., Rickettsia spp.), and nonpathogens (Caulobacter crescentus, Rhodobacter sphaeroides). Many species of Alphaproteobacteria carry large plasmids ranging in size from ∼100 kb to nearly 2 Mb. These large replicons typically code for functions essential for cell physiology, pathogenesis, or symbiosis. Most of these elements rely on a conserved gene cassette termed repABC for replication and partitioning, and maintenance at only one or a few copies per cell. The subject of this review is the ∼200-kb Ti plasmids carried by infectious strains of A. tumefaciens. We will summarize the features of this plasmid as a representative of the repABC family of megaplasmids. We will also describe novel features of this plasmid that enable A. tumefaciens cells to incite tumor formation in plants, sense and respond to an array of plant host and bacterial signal molecules, and maintain and disseminate the plasmid among populations of agrobacteria. At the end of this review, we will describe how this natural genetic engineer has been adapted to spawn an entire industry of plant biotechnology and review its potential for use in future therapeutic applications of plant and nonplant species.
Collapse
|
67
|
Corral-Lugo A, Daddaoua A, Ortega A, Espinosa-Urgel M, Krell T. Rosmarinic acid is a homoserine lactone mimic produced by plants that activates a bacterial quorum-sensing regulator. Sci Signal 2016; 9:ra1. [PMID: 26732761 DOI: 10.1126/scisignal.aaa8271] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Quorum sensing is a bacterial communication mechanism that controls genes, enabling bacteria to live as communities, such as biofilms. Homoserine lactone (HSL) molecules function as quorum-sensing signals for Gram-negative bacteria. Plants also produce previously unidentified compounds that affect quorum sensing. We identified rosmarinic acid as a plant-derived compound that functioned as an HSL mimic. In vitro assays showed that rosmarinic acid bound to the quorum-sensing regulator RhlR of Pseudomonas aeruginosa PAO1 and competed with the bacterial ligand N-butanoyl-homoserine lactone (C4-HSL). Furthermore, rosmarinic acid stimulated a greater increase in RhlR-mediated transcription in vitro than that of C4-HSL. In P. aeruginosa, rosmarinic acid induced quorum sensing-dependent gene expression and increased biofilm formation and the production of the virulence factors pyocyanin and elastase. Because P. aeruginosa PAO1 infection induces rosmarinic acid secretion from plant roots, our results indicate that rosmarinic acid secretion is a plant defense mechanism to stimulate a premature quorum-sensing response. P. aeruginosa is a ubiquitous pathogen that infects plants and animals; therefore, identification of rosmarinic acid as an inducer of premature quorum-sensing responses may be useful in agriculture and inform human therapeutic strategies.
Collapse
Affiliation(s)
- Andrés Corral-Lugo
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Abdelali Daddaoua
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Alvaro Ortega
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Manuel Espinosa-Urgel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain.
| |
Collapse
|
68
|
Singh RP, Reddy CRK. Unraveling the Functions of the Macroalgal Microbiome. Front Microbiol 2016; 6:1488. [PMID: 26779144 PMCID: PMC4700259 DOI: 10.3389/fmicb.2015.01488] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/10/2015] [Indexed: 01/11/2023] Open
Abstract
Macroalgae are a diverse group of photosynthetic eukaryotic lower organisms and offer indispensable ecosystem services toward sustainable productivity of rocky coastal areas. The earlier studies have mainly focused on elucidation of the roles of the epiphytic bacterial communities in the ecophysiology of the host macroalga. However, mutualistic interactions have become topic of current interest. It is evident from recent studies that a fraction of epiphytic bacterial communities can be categorized as “core microbial species”, suggesting an obligate association. Epiphytic bacterial communities have also been reported to protect macroalgal surfaces from biofouling microorganisms through production of biologically active metabolites. Because of their intrinsic roles in the host life cycle, the host in turn may provide necessary organic nutrients in order to woo pelagic microbial communities to settle on the host surfaces. However, the precise composition of microbiomes and their functional partnership with hosts are hardly understood. In contrast, the microbial studies associated with human skin and gut and plants have significantly advanced our knowledge on microbiome and their functional interactions with the host. This has led to manipulation of the microbial flora of the human gut and of agricultural plants for improving health and performance. Therefore, it is highly imperative to investigate the functional microbiome that is closely involved in the life cycles of the host macroalgae using high-throughput techniques (metagenomics and metatranscriptomics). The findings from such investigations would help in promoting health and productivity in macroalgal species through regulation of functionally active microbiome.
Collapse
Affiliation(s)
- Ravindra Pal Singh
- Laboratory of Microbial Technology, Department of Bioscience and Biotechnology, Graduate School, Faculty of Agriculture, Kyushu UniversityFukuoka, Japan; Seaweed Biology and Cultivation, Division of Marine Biotechnology and Ecology, Council of Scientific and Industrial Research-Central Salt and Marine Chemicals Research InstituteBhavnagar, India
| | - C R K Reddy
- Seaweed Biology and Cultivation, Division of Marine Biotechnology and Ecology, Council of Scientific and Industrial Research-Central Salt and Marine Chemicals Research InstituteBhavnagar, India; Academy of Scientific and Innovative ResearchNew Delhi, India
| |
Collapse
|
69
|
Endophytic Streptomyces in the traditional medicinal plant Arnica montana L.: secondary metabolites and biological activity. Antonie van Leeuwenhoek 2015; 108:391-402. [PMID: 26036671 DOI: 10.1007/s10482-015-0492-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/24/2015] [Indexed: 10/23/2022]
Abstract
Arnica montana L. is a medical plant of the Asteraceae family and grows preferably on nutrient poor soils in mountainous environments. Such surroundings are known to make plants dependent on symbiosis with other organisms. Up to now only arbuscular mycorrhizal fungi were found to act as endophytic symbiosis partners for A. montana. Here we identified five Streptomyces strains, microorganisms also known to occur as endophytes in plants and to produce a huge variety of active secondary metabolites, as inhabitants of A. montana. The secondary metabolite spectrum of these strains does not contain sesquiterpene lactones, but consists of the glutarimide antibiotics cycloheximide and actiphenol as well as the diketopiperazines cyclo-prolyl-valyl, cyclo-prolyl-isoleucyl, cyclo-prolyl-leucyl and cyclo-prolyl-phenylalanyl. Notably, genome analysis of one strain was performed and indicated a huge genome size with a high number of natural products gene clusters among which genes for cycloheximide production were detected. Only weak activity against the Gram-positive bacterium Staphylococcus aureus was revealed, but the extracts showed a marked cytotoxic activity as well as an antifungal activity against Candida parapsilosis and Fusarium verticillioides. Altogether, our results provide evidence that A. montana and its endophytic Streptomyces benefit from each other by completing their protection against competitors and pathogens and by exchanging plant growth promoting signals with nutrients.
Collapse
|
70
|
Subramoni S, Florez Salcedo DV, Suarez-Moreno ZR. A bioinformatic survey of distribution, conservation, and probable functions of LuxR solo regulators in bacteria. Front Cell Infect Microbiol 2015; 5:16. [PMID: 25759807 PMCID: PMC4338825 DOI: 10.3389/fcimb.2015.00016] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 02/02/2015] [Indexed: 12/25/2022] Open
Abstract
LuxR solo transcriptional regulators contain both an autoinducer binding domain (ABD; N-terminal) and a DNA binding Helix-Turn-Helix domain (HTH; C-terminal), but are not associated with a cognate N-acyl homoserine lactone (AHL) synthase coding gene in the same genome. Although a few LuxR solos have been characterized, their distributions as well as their role in bacterial signal perception and other processes are poorly understood. In this study we have carried out a systematic survey of distribution of all ABD containing LuxR transcriptional regulators (QS domain LuxRs) available in the InterPro database (IPR005143), and identified those lacking a cognate AHL synthase. These LuxR solos were then analyzed regarding their taxonomical distribution, predicted functions of neighboring genes and the presence of complete AHL-QS systems in the genomes that carry them. Our analyses reveal the presence of one or multiple predicted LuxR solos in many proteobacterial genomes carrying QS domain LuxRs, some of them harboring genes for one or more AHL-QS circuits. The presence of LuxR solos in bacteria occupying diverse environments suggests potential ecological functions for these proteins beyond AHL and interkingdom signaling. Based on gene context and the conservation levels of invariant amino acids of ABD, we have classified LuxR solos into functionally meaningful groups or putative orthologs. Surprisingly, putative LuxR solos were also found in a few non-proteobacterial genomes which are not known to carry AHL-QS systems. Multiple predicted LuxR solos in the same genome appeared to have different levels of conservation of invariant amino acid residues of ABD questioning their binding to AHLs. In summary, this study provides a detailed overview of distribution of LuxR solos and their probable roles in bacteria with genome sequence information.
Collapse
Affiliation(s)
- Sujatha Subramoni
- Grupo de Bioprospección, Facultad de Ingeniería, Universidad de La Sabana, Campus del Puente del Común Chía, Colombia
| | | | - Zulma R Suarez-Moreno
- Grupo de Bioprospección, Facultad de Ingeniería, Universidad de La Sabana, Campus del Puente del Común Chía, Colombia
| |
Collapse
|
71
|
Buonaurio R, Moretti C, da Silva DP, Cortese C, Ramos C, Venturi V. The olive knot disease as a model to study the role of interspecies bacterial communities in plant disease. FRONTIERS IN PLANT SCIENCE 2015; 6:434. [PMID: 26113855 PMCID: PMC4461811 DOI: 10.3389/fpls.2015.00434] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 05/27/2015] [Indexed: 05/03/2023]
Abstract
There is an increasing interest in studying interspecies bacterial interactions in diseases of animals and plants as it is believed that the great majority of bacteria found in nature live in complex communities. Plant pathologists have thus far mainly focused on studies involving single species or on their interactions with antagonistic competitors. A bacterial disease used as model to study multispecies interactions is the olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi (Psv). Knots caused by Psv in branches and other aerial parts of the olive trees are an ideal niche not only for the pathogen but also for many other plant-associated bacterial species, mainly belonging to the genera Pantoea, Pectobacterium, Erwinia, and Curtobacterium. The non-pathogenic bacterial species Erwinia toletana, Pantoea agglomerans, and Erwinia oleae, which are frequently isolated inside the olive knots, cooperate with Psv in modulating the disease severity. Co-inoculations of these species with Psv result in bigger knots and better bacterial colonization when compared to single inoculations. Moreover, harmless bacteria co-localize with the pathogen inside the knots, indicating the formation of stable bacterial consortia that may facilitate the exchange of quorum sensing signals and metabolites. Here we discuss the possible role of bacterial communities in the establishment and development of olive knot disease, which we believe could be taking place in many other bacterial plant diseases.
Collapse
Affiliation(s)
- Roberto Buonaurio
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
- *Correspondence: Roberto Buonaurio, Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Via Borgo XX Giugno, 74 06121 Perugia, Italy,
| | - Chiaraluce Moretti
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
| | | | - Chiara Cortese
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
| | - Cayo Ramos
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Vittorio Venturi
- Bacteriology Group, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| |
Collapse
|
72
|
Rouleau N, Dotta BT. Electromagnetic fields as structure-function zeitgebers in biological systems: environmental orchestrations of morphogenesis and consciousness. Front Integr Neurosci 2014; 8:84. [PMID: 25426035 PMCID: PMC4224074 DOI: 10.3389/fnint.2014.00084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 10/09/2014] [Indexed: 11/13/2022] Open
Abstract
Within a cell system structure dictates function. Any interaction between cells, or a cell and its environment, has the potential to have long term implications on the function of a given cell and emerging cell aggregates. The structure and function of cells are continuously subjected to modification by electrical and chemical stimuli. However, biological systems are also subjected to an ever-present influence: the electromagnetic (EM) environment. Biological systems have the potential to be influenced by subtle energies which are exchanged at atomic and subatomic scales as EM phenomena. These energy exchanges have the potential to manifest at higher orders of discourse and affect the output (behavior) of a biological system. Here we describe theoretical and experimental evidence of EM influence on cells and the integration of whole systems. Even weak interactions between EM energies and biological systems display the potential to affect a developing system. We suggest the growing literature of EM effects on biological systems has significant implications to the cell and its functional aggregates.
Collapse
Affiliation(s)
- Nicolas Rouleau
- Behavioural Neuroscience Program, Laurentian UniversitySudbury, ON, Canada
- Department of Psychology, Laurentian UniversitySudbury, ON, Canada
| | - Blake T. Dotta
- Behavioural Neuroscience Program, Laurentian UniversitySudbury, ON, Canada
- Department of Psychology, Laurentian UniversitySudbury, ON, Canada
- Department of Biomolecular Sciences, Laurentian UniversitySudbury, ON, Canada
| |
Collapse
|
73
|
Jahid IK, Ha SD. The Paradox of Mixed-Species Biofilms in the Context of Food Safety. Compr Rev Food Sci Food Saf 2014. [DOI: 10.1111/1541-4337.12087] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Iqbal Kabir Jahid
- School of Food Science and Technology; Chung-Ang Univ; 72-1 Nae-Ri, Daedeok-Myun Anseong-Si Gyeonggi-do 456-756 South Korea
- Dept. of Microbiology; Jessore Univ. of Science and Technology; Jessore-7408 Bangladesh
| | - Sang-Do Ha
- School of Food Science and Technology; Chung-Ang Univ; 72-1 Nae-Ri, Daedeok-Myun Anseong-Si Gyeonggi-do 456-756 South Korea
| |
Collapse
|
74
|
Palmer AG, Senechal AC, Mukherjee A, Ané JM, Blackwell HE. Plant responses to bacterial N-acyl L-homoserine lactones are dependent on enzymatic degradation to L-homoserine. ACS Chem Biol 2014; 9:1834-45. [PMID: 24918118 PMCID: PMC4136694 DOI: 10.1021/cb500191a] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
![]()
Many
bacteria use quorum sensing (QS) to regulate phenotypes that
ultimately benefit the bacterial population at high cell densities.
These QS-dependent phenotypes are diverse and can have significant
impacts on the bacterial host, including virulence factor production,
motility, biofilm formation, bioluminescence, and root nodulation.
As bacteria and their eukaryotic hosts have coevolved over millions
of years, it is not surprising that certain hosts appear to be able
to sense QS signals, potentially allowing them to alter QS outcomes.
Recent experiments have established that eukaryotes have marked responses
to the N-acyl l-homoserine lactone (AHL)
signals used by Gram-negative bacteria for QS, and the responses of
plants to AHLs have received considerable scrutiny to date. However,
the molecular mechanisms by which plants, and eukaryotes in general,
sense bacterial AHLs remain unclear. Herein, we report a systematic
analysis of the responses of the model plants Arabidopsis
thaliana and Medicago truncatula to a series
of native AHLs and byproducts thereof. Our results establish that
AHLs can significantly alter seedling growth in an acyl-chain length
dependent manner. Based upon A. thaliana knockout
studies and in vitro biochemical assays, we conclude
that the observed growth effects are dependent upon AHL amidolysis
by a plant-derived fatty acid amide hydrolase (FAAH) to yield l-homoserine. The accumulation of l-homoserine appears
to encourage plant growth at low concentrations by stimulating transpiration,
while higher concentrations inhibit growth by stimulating ethylene
production. These results offer new insights into the mechanisms by
which plant hosts can respond to QS signals and the potential role
of QS in interkingdom associations.
Collapse
Affiliation(s)
- Andrew G. Palmer
- Department
of Chemistry, 1101 University
Avenue, University of Wisconsin−Madison, Madison Wisconsin 53706, United States
| | - Amanda C. Senechal
- Department
of Chemistry, 1101 University
Avenue, University of Wisconsin−Madison, Madison Wisconsin 53706, United States
| | - Arijit Mukherjee
- Department
of Agronomy, 1575 Linden
Drive, University of Wisconsin−Madison, Madison Wisconsin 53706, United States
| | - Jean-Michel Ané
- Department
of Agronomy, 1575 Linden
Drive, University of Wisconsin−Madison, Madison Wisconsin 53706, United States
| | - Helen E. Blackwell
- Department
of Chemistry, 1101 University
Avenue, University of Wisconsin−Madison, Madison Wisconsin 53706, United States
| |
Collapse
|
75
|
Patel HK, Ferrante P, Covaceuszach S, Lamba D, Scortichini M, Venturi V. The kiwifruit emerging pathogen Pseudomonas syringae pv. actinidiae does not produce AHLs but possesses three luxR solos. PLoS One 2014; 9:e87862. [PMID: 24498215 PMCID: PMC3909224 DOI: 10.1371/journal.pone.0087862] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/30/2013] [Indexed: 12/30/2022] Open
Abstract
Pseudomonas syringae pv. actinidiae (Psa) is an emerging phytopathogen causing bacterial canker disease in kiwifruit plants worldwide. Quorum sensing (QS) gene regulation plays important roles in many different bacterial plant pathogens. In this study we analyzed the presence and possible role of N-acyl homoserine lactone (AHL) quorum sensing in Psa. It was established that Psa does not produce AHLs and that a typical complete LuxI/R QS system is absent in Psa strains. Psa however possesses three putative luxR solos designated here as PsaR1, PsaR2 and PsaR3. PsaR2 belongs to the sub-family of LuxR solos present in many plant associated bacteria (PAB) that binds and responds to yet unknown plant signal molecules. PsaR1 and PsaR3 are highly similar to LuxRs which bind AHLs and are part of the canonical LuxI/R AHL QS systems. Mutation in all the three luxR solos of Psa showed reduction of in planta survival and also showed additive effect if more than one solo was inactivated in double mutants. Gene promoter analysis revealed that the three solos are not auto-regulated and investigated their possible role in several bacterial phenotypes.
Collapse
Affiliation(s)
| | - Patrizia Ferrante
- Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy
| | - Sonia Covaceuszach
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, U.O.S di Trieste, Trieste, Italy
| | - Doriano Lamba
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, U.O.S di Trieste, Trieste, Italy
| | - Marco Scortichini
- Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy
- Research Unit for Fruit Trees, Agricultural Research Council, Caserta, Italy
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| |
Collapse
|
76
|
Dudnik A, Dudler R. Genomics-Based Exploration of Virulence Determinants and Host-Specific Adaptations of Pseudomonas syringae Strains Isolated from Grasses. Pathogens 2014; 3:121-48. [PMID: 25437611 PMCID: PMC4235733 DOI: 10.3390/pathogens3010121] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 12/14/2022] Open
Abstract
The Pseudomonas syringae species complex has recently been named the number one plant pathogen, due to its economic and environmental impacts, as well as for its role in scientific research. The bacterium has been repeatedly reported to cause outbreaks on bean, cucumber, stone fruit, kiwi and olive tree, as well as on other crop and non-crop plants. It also serves as a model organism for research on the Type III secretion system (T3SS) and plant-pathogen interactions. While most of the current work on this pathogen is either carried out on one of three model strains found on dicot plants with completely sequenced genomes or on isolates obtained from recent outbreaks, not much is known about strains isolated from grasses (Poaceae). Here, we use comparative genomics in order to identify putative virulence-associated genes and other Poaceae-specific adaptations in several newly available genome sequences of strains isolated from grass species. All strains possess only a small number of known Type III effectors, therefore pointing to the importance of non-Type III secreted virulence factors. The implications of this finding are discussed.
Collapse
Affiliation(s)
- Alexey Dudnik
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
| | - Robert Dudler
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
| |
Collapse
|
77
|
Patel HK, Suárez-Moreno ZR, Degrassi G, Subramoni S, González JF, Venturi V. Bacterial LuxR solos have evolved to respond to different molecules including signals from plants. FRONTIERS IN PLANT SCIENCE 2013; 4:447. [PMID: 24273546 DOI: 10.3389/fpls.2013.00447.03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/19/2013] [Indexed: 05/26/2023]
Abstract
A future challenge will be understanding the extensive communication that most likely takes place in bacterial interspecies and interkingdom signaling between plants and bacteria. A major bacterial inter-cellular signaling system in Gram-negative bacteria is LuxI/R quorum sensing (QS) based on the production (via the LuxI-family proteins) and detection (via the LuxR-family proteins) of N-acyl homoserine lactones (AHLs) signaling molecules. LuxR proteins which have the same modular structure of QS LuxRs but are devoid of a cognate LuxI AHL synthase are called solos. LuxR solos have been shown to be responsible to respond to exogenous AHLs produced by neighboring cells as well endogenously produced AHLs. It is now also evident that some LuxR proteins have evolved from the ability to binding AHLs and respond to other molecules/signals. For example, recent research has shown that a sub-family of LuxR solos responds to small molecules produced by plants. This indicates the presence of a uni-directional interkingdom signaling system occurring from plants to bacteria. In addition LuxR solos have now been also implicated to respond to endogenously produced signals which are not AHLs. In this Mini Review article we will discuss current trends and implications of the role of LuxR solos in bacterial responses to other signals using proteins related to AHL QS systems.
Collapse
Affiliation(s)
- Hitendra K Patel
- International Centre for Genetic Engineering and Biotechnology Trieste, Italy
| | | | | | | | | | | |
Collapse
|
78
|
Covaceuszach S, Degrassi G, Venturi V, Lamba D. Structural insights into a novel interkingdom signaling circuit by cartography of the ligand-binding sites of the homologous quorum sensing LuxR-family. Int J Mol Sci 2013; 14:20578-96. [PMID: 24132148 PMCID: PMC3821632 DOI: 10.3390/ijms141020578] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/13/2013] [Accepted: 10/01/2013] [Indexed: 01/06/2023] Open
Abstract
Recent studies have identified a novel interkingdom signaling circuit, via plant signaling molecules, and a bacterial sub-family of LuxR proteins, bridging eukaryotes and prokaryotes. Indeed pivotal plant-bacteria interactions are regulated by the so called Plant Associated Bacteria (PAB) LuxR solo regulators that, although closely related to the quorum sensing (QS) LuxR family, do not bind or respond to canonical quorum sensing N-acyl homoserine lactones (AHLs), but only to specific host plant signal molecules. The large body of structural data available for several members of the QS LuxR family complexed with different classes of ligands (AHLs and other compounds), has been exploited to dissect the cartography of their regulatory domains through structure-based multiple sequence alignments, structural superimposition and a comparative analysis of the contact residues involved in ligand binding. In the absence of experimentally determined structures of members of the PAB LuxR solos subfamily, an homology model of its prototype OryR is presented, aiming to elucidate the architecture of its ligand-binding site. The obtained model, in combination with the cartography of the regulatory domains of the homologous QS LuxRs, provides novel insights into the 3D structure of its ligand-binding site and unveils the probable molecular determinants responsible for differences in selectivity towards specific host plant signal molecules, rather than to canonical QS compounds.
Collapse
Affiliation(s)
- Sonia Covaceuszach
- Institute of Crystallography, National Research Council, Trieste Outstation, Area Science Park-Basovizza, S.S. n° 14 Km 163.5, I-34149 Trieste, Italy; E-Mail:
| | - Giuliano Degrassi
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34149 Trieste, Italy; E-Mail:
- IBIOBA-CONICET-ICGEB, International Centre for Genetic Engineering and Biotechnology, Scientific and Technological Center, Godoy Cruz 2390, C1425FQD, Buenos Aires, Argentina
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34149 Trieste, Italy; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (V.V.); (D.L.); Tel.: +39-40-3757319 (V.V.); +39-40-3758514 (D.L.); Fax: +39-40-226555 (V.V.); +39-40-9221126 (D.L.)
| | - Doriano Lamba
- Institute of Crystallography, National Research Council, Trieste Outstation, Area Science Park-Basovizza, S.S. n° 14 Km 163.5, I-34149 Trieste, Italy; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (V.V.); (D.L.); Tel.: +39-40-3757319 (V.V.); +39-40-3758514 (D.L.); Fax: +39-40-226555 (V.V.); +39-40-9221126 (D.L.)
| |
Collapse
|
79
|
Patel HK, Suárez-Moreno ZR, Degrassi G, Subramoni S, González JF, Venturi V. Bacterial LuxR solos have evolved to respond to different molecules including signals from plants. FRONTIERS IN PLANT SCIENCE 2013; 4:447. [PMID: 24273546 PMCID: PMC3824090 DOI: 10.3389/fpls.2013.00447] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/19/2013] [Indexed: 05/08/2023]
Abstract
A future challenge will be understanding the extensive communication that most likely takes place in bacterial interspecies and interkingdom signaling between plants and bacteria. A major bacterial inter-cellular signaling system in Gram-negative bacteria is LuxI/R quorum sensing (QS) based on the production (via the LuxI-family proteins) and detection (via the LuxR-family proteins) of N-acyl homoserine lactones (AHLs) signaling molecules. LuxR proteins which have the same modular structure of QS LuxRs but are devoid of a cognate LuxI AHL synthase are called solos. LuxR solos have been shown to be responsible to respond to exogenous AHLs produced by neighboring cells as well endogenously produced AHLs. It is now also evident that some LuxR proteins have evolved from the ability to binding AHLs and respond to other molecules/signals. For example, recent research has shown that a sub-family of LuxR solos responds to small molecules produced by plants. This indicates the presence of a uni-directional interkingdom signaling system occurring from plants to bacteria. In addition LuxR solos have now been also implicated to respond to endogenously produced signals which are not AHLs. In this Mini Review article we will discuss current trends and implications of the role of LuxR solos in bacterial responses to other signals using proteins related to AHL QS systems.
Collapse
Affiliation(s)
| | | | | | | | | | - Vittorio Venturi
- *Correspondence: Vittorio Venturi, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy e-mail:
| |
Collapse
|