1
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He L, Zhu G. Regulation and application of quorum sensing on anaerobic digestion system. CHEMOSPHERE 2024:142983. [PMID: 39089336 DOI: 10.1016/j.chemosphere.2024.142983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 07/29/2024] [Accepted: 07/29/2024] [Indexed: 08/03/2024]
Abstract
Quorum sensing (QS) plays an important role in the social behavior of microbial communities. Anaerobic digestion (AD) is a biological process using anaerobic microorganisms to degrade organic macromolecules into small molecules for biogas and biofertilizer production. In AD, the QS signaling molecule N-acyl homoserine lactones (AHLs) induces bacterial metabolism, improving AD process efficiency. However, there are fewer systematic reports about QS regulation of microbial behavior in AD. In this report, the effects of signaling molecules on extracellular polymer secretion, biofilm formation, granulation of granular sludge and bacterial metabolism in AD were investigated in detail. At present, the regulation behavior of QS on AD is a group phenomenon, and there are few in-depth studies on the regulation pathway. Therefore, we conducted an in-depth analysis of the pure culture system, granular sludge and reactor in the AD. Then we pointed out that the future application potential of QS in the AD may be combined with quorum quenching (QQ) and omics technology, which is of great significance for the future application of AD.
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Affiliation(s)
- Liyan He
- School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, PR China
| | - Gefu Zhu
- School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, PR China.
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2
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Zhang J, Pan L, Xu W, Yang H, He F, Ma J, Bai L, Zhang Q, Zhou Q, Gao H. Extracellular vesicles in plant-microbe interactions: Recent advances and future directions. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 341:111999. [PMID: 38307350 DOI: 10.1016/j.plantsci.2024.111999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/18/2024] [Accepted: 01/24/2024] [Indexed: 02/04/2024]
Abstract
Extracellular vesicles (EVs) are membrane-enclosed nanoparticles that have a crucial role in mediating intercellular communication in mammals by facilitating the transport of proteins and small RNAs. However, the study of plant EVs has been limited for a long time due to insufficient isolation and detection methods. Recent research has shown that both plants and plant pathogens can release EVs, which contain various bioactive molecules like proteins, metabolites, lipids, and small RNAs. These EVs play essential roles in plant-microbe interactions by transferring these bioactive molecules across different kingdoms. Additionally, it has been discovered that EVs may contribute to symbiotic communication between plants and pathogens. This review provides a comprehensive summary of the pivotal roles played by EVs in mediating interactions between plants and microbes, including pathogenic fungi, bacteria, viruses, and symbiotic pathogens. We highlight the potential of EVs in transferring immune signals between plant cells and facilitating the exchange of active substances between different species.
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Affiliation(s)
- Junsong Zhang
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China; College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Liying Pan
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Wenjie Xu
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Hongchao Yang
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Fuge He
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Jianfeng Ma
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Linlin Bai
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Qingchen Zhang
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Qingfeng Zhou
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China
| | - Hang Gao
- College of Biology and Food, Shangqiu Normal University, Shangqiu 476000, China.
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3
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Surano A, del Grosso C, Musio B, Todisco S, Giampetruzzi A, Altamura G, Saponari M, Gallo V, Mastrorilli P, Boscia D, Saldarelli P. Exploring the xylem-sap to unravel biological features of Xylella fastidiosa subspecies pauca ST53 in immune, resistant and susceptible crop species through metabolomics and in vitro studies. FRONTIERS IN PLANT SCIENCE 2024; 14:1343876. [PMID: 38312355 PMCID: PMC10834688 DOI: 10.3389/fpls.2023.1343876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 12/28/2023] [Indexed: 02/06/2024]
Abstract
Xylella fastidiosa subsp. pauca ST53 (Xfp) is a pathogenic bacterium causing one of the most severe plant diseases currently threatening the olive-growing areas of the Mediterranean, the Olive Quick Decline Syndrome (OQDS). The majority of the olive cultivars upon infections more or less rapidly develop severe desiccation phenomena, while few are resistant (e.g. Leccino and FS17), being less impacted by the infections. The present study contributes to elucidating the basis of the resistance phenomenon by investigating the influence of the composition of the xylem sap of plant species on the rate of bacterial multiplication. Xylem saps from Xfp host and non-host species were used for growing the bacterium in vitro, monitoring bacterial growth, biofilm formation, and the expression of specific genes. Moreover, species-specific metabolites, such as mannitol, quinic acid, tartaric acid, and choline were identified by non-targeted NMR-based metabolomic analysis in olive, grapevine, and citrus. In general, the xylem saps of immune species, including grapevine and citrus, were richer in amino acids, organic acids, and glucose. The results showed greater bacterial growth in the olive cultivar notoriously susceptible to Xfp (Cellina di Nardò), compared to that recorded in the resistant cultivar Leccino. Conversely, higher biofilm formation occurred in Leccino compared to Cellina di Nardò. Using the xylem saps of two Xfp-immune species (citrus and grapevine), a divergent bacterial behavior was recorded: low planktonic growth and biofilm production were detected in citrus compared to the grapevine. A parallel evaluation of the expression of 15 genes showed that Xfp directs its molecular functions mainly to virulence. Overall, the results gained through this multidisciplinary study contribute to extending the knowledge on the host-pathogen interaction, while confirming that the host response and resistance mechanism have a multifactorial basis, most likely with a cumulative effect on the phenotype.
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Affiliation(s)
- Antony Surano
- Institute for Sustainable Plant Protection, National Research Council (CNR), Bari, Italy
| | - Carmine del Grosso
- Institute for Sustainable Plant Protection, National Research Council (CNR), Bari, Italy
| | - Biagia Musio
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Bari, Italy
| | - Stefano Todisco
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Bari, Italy
| | - Annalisa Giampetruzzi
- Institute for Sustainable Plant Protection, National Research Council (CNR), Bari, Italy
| | - Giuseppe Altamura
- CRSFA-Centro Ricerca, Sperimentazione e Formazione in Agricoltura Basile Caramia, Locorotondo, Italy
| | - Maria Saponari
- Institute for Sustainable Plant Protection, National Research Council (CNR), Bari, Italy
| | - Vito Gallo
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Bari, Italy
- Innovative Solutions S.r.l.—Spin-Off Company of Polytechnic University of Bari, Noci, Italy
| | - Piero Mastrorilli
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Bari, Italy
- Innovative Solutions S.r.l.—Spin-Off Company of Polytechnic University of Bari, Noci, Italy
| | - Donato Boscia
- Institute for Sustainable Plant Protection, National Research Council (CNR), Bari, Italy
| | - Pasquale Saldarelli
- Institute for Sustainable Plant Protection, National Research Council (CNR), Bari, Italy
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4
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Li K, Ma C, Zhou X, Xiong C, Wang B, Wang Y, Liu F. Regulatory Effects of Diverse DSF Family Quorum-Sensing Signals in Plant-Associated Bacteria. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:6-14. [PMID: 37880815 DOI: 10.1094/mpmi-05-23-0074-cr] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Numerous bacterial species employ diffusible signal factor (DSF)-based quorum sensing (QS) as a widely conserved cell-cell signaling communication system to collectively regulate various behaviors crucial for responding to environmental changes. cis-11-Methyl-dodecenoic acid, known as DSF, was first identified as a signaling molecule in Xanthomonas campestris pv. campestris. Subsequently, many structurally related molecules have been identified in different bacterial species. This review aims to provide an overview of current understanding regarding the biosynthesis and regulatory role of DSF signals in both pathogenic bacteria and a biocontrol bacterium. Recent studies have revealed that the DSF-based QS system regulates antimicrobial factor production in a cyclic dimeric GMP-independent manner in the biocontrol bacterium Lysobacter enzymogenes. Additionally, the DSF family signals have been found to be involved in suppressing plant innate immunity. The discovery of these diverse signaling mechanisms holds significant promise for developing novel strategies to combat stubborn plant pathogens. [Formula: see text] Copyright © 2024 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)
- Kaihuai Li
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Key Laboratory of Agricultural Microbiology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Institute of Vegetable Industry Technology Research, Guizhou University, Guiyang 550025, China
| | - Chaoyun Ma
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Key Laboratory of Agricultural Microbiology, College of Agriculture, Guizhou University, Guiyang 550025, China
| | - Xue Zhou
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Key Laboratory of Agricultural Microbiology, College of Agriculture, Guizhou University, Guiyang 550025, China
| | - Chunlan Xiong
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Key Laboratory of Agricultural Microbiology, College of Agriculture, Guizhou University, Guiyang 550025, China
| | - Bo Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Yong Wang
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Key Laboratory of Agricultural Microbiology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Institute of Vegetable Industry Technology Research, Guizhou University, Guiyang 550025, China
| | - Fengquan Liu
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Key Laboratory of Agricultural Microbiology, College of Agriculture, Guizhou University, Guiyang 550025, China
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
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5
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Beccaccioli M, Pucci N, Salustri M, Scortichini M, Zaccaria M, Momeni B, Loreti S, Reverberi M, Scala V. Fungal and bacterial oxylipins are signals for intra- and inter-cellular communication within plant disease. FRONTIERS IN PLANT SCIENCE 2022; 13:823233. [PMID: 36186042 PMCID: PMC9524268 DOI: 10.3389/fpls.2022.823233] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Lipids are central at various stages of host-pathogen interactions in determining virulence and modulating plant defense. Free fatty acids may act as substrates for oxidizing enzymes [e.g., lipoxygenases (LOXs) and dioxygenases (DOXs)] that synthesize oxylipins. Fatty acids and oxylipins function as modulators of several pathways in cell-to-cell communication; their structural similarity among plant, fungal, and bacterial taxa suggests potential in cross-kingdom communication. We provide a prospect of the known role of fatty acids and oxylipins in fungi and bacteria during plant-pathogen interactions. In the pathogens, oxylipin-mediated signaling pathways are crucial both in development and host infection. Here, we report on case studies suggesting that oxylipins derived from oleic, linoleic, and linolenic acids are crucial in modulating the pathogenic lifestyle in the host plant. Intriguingly, overlapping (fungi-plant/bacteria-plant) results suggest that different inter-kingdom pathosystems use similar lipid signals to reshape the lifestyle of the contenders and occasionally determine the outcome of the challenge.
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Affiliation(s)
- Marzia Beccaccioli
- Department of Environmental Biology, Sapienza University of Rome, Rome, Italy
| | - Nicoletta Pucci
- Research Centre for Plant Protection and Certification, Council for Agricultural Research and the Analysis of Agricultural Economics (CREA), Rome, Italy
| | - Manuel Salustri
- Department of Environmental Biology, Sapienza University of Rome, Rome, Italy
| | - Marco Scortichini
- Research Centre for Olive, Fruit and Citrus Crops, Council for Agricultural Research and the Analysis of Agricultural Economics (CREA), Rome, Italy
| | - Marco Zaccaria
- Department of Biology, Boston College, Newton, MA, United States
| | - Babak Momeni
- Department of Biology, Boston College, Newton, MA, United States
| | - Stefania Loreti
- Research Centre for Plant Protection and Certification, Council for Agricultural Research and the Analysis of Agricultural Economics (CREA), Rome, Italy
| | - Massimo Reverberi
- Department of Environmental Biology, Sapienza University of Rome, Rome, Italy
| | - Valeria Scala
- Research Centre for Plant Protection and Certification, Council for Agricultural Research and the Analysis of Agricultural Economics (CREA), Rome, Italy
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6
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Pandey SS, Chatterjee S. Insights into the Cell-to-Cell Signaling and Iron Homeostasis in Xanthomonas Virulence and Lifestyle. PHYTOPATHOLOGY 2022; 112:209-218. [PMID: 34289715 DOI: 10.1094/phyto-11-20-0513-rvw] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The Xanthomonas group of phytopathogens causes economically important diseases that lead to severe yield loss in major crops. Some Xanthomonas species are known to have an epiphytic and in planta lifestyle that is coordinated by several virulence-associated functions, cell-to-cell signaling (using diffusible signaling factor [DSF]), and environmental conditions, including iron availability. In this review, we described the role of cell-to-cell signaling by the DSF molecule and iron in the regulation of virulence-associated functions. Although DSF and iron are involved in the regulation of several virulence-associated functions, members of the Xanthomonas group of plant pathogens exhibit atypical patterns of regulation. Atypical patterns contribute to the adaptation to different lifestyles. Studies on DSF and iron biology indicate that virulence-associated functions can be regulated in completely contrasting fashions by the same signaling system in closely related xanthomonads.
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Affiliation(s)
- Sheo Shankar Pandey
- Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850, U.S.A
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7
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Wang Q, Guo J, An L, Bao Y. Integration of DSF and Temperature Signals for RpfC/RpfG Two-Component System Modulating Protease Production in Stenotrophomonas maltophilia FF11. Curr Microbiol 2022; 79:54. [PMID: 34982238 DOI: 10.1007/s00284-021-02731-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 11/29/2021] [Indexed: 11/26/2022]
Abstract
Two-component signal system (TCS) is the predominant bacterial sense-and-response machinery. RpfC/RpfG TCS involved in quorum sensing molecule Diffuse Signal Factor (DSF) signal perception and transduction was well studied in many bacteria. However, whether other environmental factors participating in the signal perception and transduction of RpfC/RpfG was still unclear. Here, we showed that RpfC/RpfG could integrate temperature and DSF signal partially controlling the production of the temperature-dependent protease (SmtP) in S. maltophilia FF11, a strain isolated from frozen Antarctic krill, exhibited spoilage potential due to secret more protease at low temperatures involving in protein degradation. qRT-PCR analysis revealed rpf system mediating approximately 60% transcription activity of Clp, a critical transcription factor linking with LotS/LotR, consisting a signal network controlling completely the SmtP production in previous study. Protease production was partially reduced in rpfF (coding DSF synthetase) mutant strains at 15 °C or 25 °C, not be increased through addition DSF or overexpression RpfF in WT at 37 °C, indicating that DSF was effective for protease production only at low temperatures in S. maltophilia. Additionally, biochemical analysis revealed the enzymatic activity of RpfG from strain FF11 cultured at 37 °C or DSF-deficient strains grown at 25 °C was significantly reduced compared to that of RpfG from strain FF11 cultured at 25 °C. These findings outline an interplay mechanism that allows S. maltophilia to integrate quorum sensing and temperature cues controlling protease production, and imply a potential relationship between two distinct systems of RpfC/RpfG and LotS/LotR.
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Affiliation(s)
- Qingling Wang
- Shaanxi Natural Carbohydrate Resource Engineering Research Center, College of Food Science and Technology, Northwest University, Xi'an, 710069, China.
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China.
| | - Jianli Guo
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Lijia An
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Yongming Bao
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China.
- School of Food and Environment Science and Technology, Dalian University of Technology, Panjin, 124221, China.
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8
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Controlled spatial organization of bacterial growth reveals key role of cell filamentation preceding Xylella fastidiosa biofilm formation. NPJ Biofilms Microbiomes 2021; 7:86. [PMID: 34876576 PMCID: PMC8651647 DOI: 10.1038/s41522-021-00258-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 11/11/2021] [Indexed: 12/21/2022] Open
Abstract
The morphological plasticity of bacteria to form filamentous cells commonly represents an adaptive strategy induced by stresses. In contrast, for diverse human and plant pathogens, filamentous cells have been recently observed during biofilm formation, but their functions and triggering mechanisms remain unclear. To experimentally identify the underlying function and hypothesized cell communication triggers of such cell morphogenesis, spatially controlled cell patterning is pivotal. Here, we demonstrate highly selective cell adhesion of the biofilm-forming phytopathogen Xylella fastidiosa to gold-patterned SiO2 substrates with well-defined geometries and dimensions. The consequent control of both cell density and distances between cell clusters demonstrated that filamentous cell formation depends on cell cluster density, and their ability to interconnect neighboring cell clusters is distance-dependent. This process allows the creation of large interconnected cell clusters that form the structural framework for macroscale biofilms. The addition of diffusible signaling molecules from supernatant extracts provides evidence that cell filamentation is induced by quorum sensing. These findings and our innovative platform could facilitate therapeutic developments targeting biofilm formation mechanisms of X. fastidiosa and other pathogens.
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9
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Chowdhury R, Pavinski Bitar PD, Adams MC, Chappie JS, Altier C. AraC-type regulators HilC and RtsA are directly controlled by an intestinal fatty acid to regulate Salmonella invasion. Mol Microbiol 2021; 116:1464-1475. [PMID: 34687258 DOI: 10.1111/mmi.14835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 01/30/2023]
Abstract
Invasion of the intestinal epithelium is an essential but energetically expensive survival strategy and is, therefore, tightly regulated by using specific cues from the environment. The enteric pathogen Salmonella controls its invasion machinery through the elegant coordination of three AraC-type transcription activators, HilD, HilC, and RtsA. Most environmental signals target HilD to control invasion, whereas HilC and RtsA are known only to augment these effects on HilD. Here we show that a fatty acid found in the murine colon, cis-2-hexadecenoic acid (c2-HDA), represses Salmonella invasion by directly targeting HilC and RtsA, in addition to HilD. c2-HDA directly binds each of these regulators and inhibits their attachment to DNA targets, repressing invasion even in the absence of HilD. Fatty acid binding, however, does not affect HilC and RtsA protein stability, unlike HilD. Importantly, we show that HilC and RtsA are highly effective in restoring HilD production and invasion gene expression after elimination of the repressive fatty acid c2-HDA. Together, these results illuminate a precise mechanism by which HilC and RtsA may modulate invasion as Salmonella navigates through different regions of the intestine, contributing to our understanding of how this enteric pathogen senses and adapts to a diverse intestinal environment while maintaining its virulence.
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Affiliation(s)
- Rimi Chowdhury
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Paulina D Pavinski Bitar
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Myfanwy C Adams
- Department of Molecular Medicine, Cornell University, Ithaca, New York, USA
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, New York, USA
| | - Craig Altier
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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10
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Xylella fastidiosa in Olive: A Review of Control Attempts and Current Management. Microorganisms 2021; 9:microorganisms9081771. [PMID: 34442850 PMCID: PMC8397937 DOI: 10.3390/microorganisms9081771] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/09/2021] [Accepted: 08/14/2021] [Indexed: 11/17/2022] Open
Abstract
Since 2013, Xylella fastidiosa Wells et al. has been reported to infect several hosts and to be present in different areas of Europe. The main damage has been inflicted on the olive orchards of southern Apulia (Italy), where a severe disease associated with X. fastidiosa subspecies pauca strain De Donno has led to the death of millions of trees. This dramatic and continuously evolving situation has led to European and national (Italian and Spanish) measures being implemented to reduce the spread of the pathogen and the associated olive quick decline syndrome (OQDS). Research has been also carried out to find solutions to better and directly fight the bacterium and its main insect vector, Philaenus spumarius L. In the course of this frantic effort, several treatments based on chemical or biological substances have been tested, in addition to plant breeding techniques and integrated pest management approaches. This review aims to summarize the attempts made so far and describe the prospects for better management of this serious threat, which poses alarming questions for the future of olive cultivation in the Mediterranean basin and beyond.
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11
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HPLC-MS/MS method applied to an untargeted metabolomics approach for the diagnosis of "olive quick decline syndrome". Anal Bioanal Chem 2021; 414:465-473. [PMID: 33765220 PMCID: PMC8748322 DOI: 10.1007/s00216-021-03279-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/09/2021] [Accepted: 03/05/2021] [Indexed: 11/04/2022]
Abstract
Olive quick decline syndrome (OQDS) is a disorder associated with bacterial infections caused by Xylella fastidiosa subsp. pauca ST53 in olive trees. Metabolic profile changes occurring in infected olive trees are still poorly investigated, but have the potential to unravel reliable biomarkers to be exploited for early diagnosis of infections. In this study, an untargeted metabolomic method using high-performance liquid chromatography coupled to quadrupole-time-of-flight high-resolution mass spectrometry (HPLC-ESI-Q-TOF-MS) was used to detect differences in samples (leaves) from healthy (Ctrl) and infected (Xf) olive trees. Both unsupervised and supervised data analysis clearly differentiated the groups. Different metabolites have been identified as potential specific biomarkers, and their characterization strongly suggests that metabolism of flavonoids and long-chain fatty acids is perturbed in Xf samples. In particular, a decrease in the defence capabilities of the host after Xf infection is proposed because of a significant dysregulation of some metabolites belonging to flavonoid family. Moreover, oleic acid is confirmed as a putative diffusible signal factor (DSF). This study provides new insights into the host-pathogen interactions and confirms LC-HRMS-based metabolomics as a powerful approach for disease-associated biomarkers discovery in plants.
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12
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Chowdhury R, Pavinski Bitar PD, Keresztes I, Condo AM, Altier C. A diffusible signal factor of the intestine dictates Salmonella invasion through its direct control of the virulence activator HilD. PLoS Pathog 2021; 17:e1009357. [PMID: 33617591 PMCID: PMC7932555 DOI: 10.1371/journal.ppat.1009357] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 03/04/2021] [Accepted: 02/02/2021] [Indexed: 12/16/2022] Open
Abstract
Successful intestinal infection by Salmonella requires optimized invasion of the gut epithelium, a function that is energetically costly. Salmonella have therefore evolved to intricately regulate the expression of their virulence determinants by utilizing specific environmental cues. Here we show that a powerful repressor of Salmonella invasion, a cis-2 unsaturated long chain fatty acid, is present in the murine large intestine. Originally identified in Xylella fastidiosa as a diffusible signal factor for quorum sensing, this fatty acid directly interacts with HilD, the master transcriptional regulator of Salmonella, and prevents hilA activation, thus inhibiting Salmonella invasion. We further identify the fatty acid binding region of HilD and show it to be selective and biased in favour of signal factors with a cis-2 unsaturation over other intestinal fatty acids. Single mutation of specific HilD amino acids to alanine prevented fatty acid binding, thereby alleviating their repressive effect on invasion. Together, these results highlight an exceedingly sensitive mechanism used by Salmonella to colonize its host by detecting and exploiting specific molecules present within the complex intestinal environment.
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Affiliation(s)
- Rimi Chowdhury
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail: (RC); (CA)
| | - Paulina D. Pavinski Bitar
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Ivan Keresztes
- Chemistry NMR Facility, Cornell University, Ithaca, New York, United States of America
| | - Anthony M. Condo
- Chemistry NMR Facility, Cornell University, Ithaca, New York, United States of America
| | - Craig Altier
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail: (RC); (CA)
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13
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Phenotypic Characterization and Transformation Attempts Reveal Peculiar Traits of Xylella fastidiosa Subspecies pauca Strain De Donno. Microorganisms 2020; 8:microorganisms8111832. [PMID: 33233703 PMCID: PMC7699976 DOI: 10.3390/microorganisms8111832] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/19/2022] Open
Abstract
Xylella fastidiosa subsp. pauca strain De Donno has been recently identified as the causal agent of a severe disease affecting olive trees in a wide area of the Apulia Region (Italy). While insights on the genetics and epidemiology of this virulent strain have been gained, its phenotypic and biological traits remained to be explored. We investigated in vitro behavior of the strain and compare its relevant biological features (growth rate, biofilm formation, cell-cell aggregation, and twitching motility) with those of the type strain Temecula1. The experiments clearly showed that the strain De Donno did not show fringe on the agar plates, produced larger amounts of biofilm and had a more aggregative behavior than the strain Temecula1. Repeated attempts to transform, by natural competence, the strain De Donno failed to produce a GFP-expressing and a knockout mutant for the rpfF gene. Computational prediction allowed us to identify potentially deleterious sequence variations most likely affecting the natural competence and the lack of fringe formation. GFP and rpfF- mutants were successfully obtained by co-electroporation in the presence of an inhibitor of the type I restriction-modification system. The availability of De Donno mutant strains will open for new explorations of its interactions with hosts and insect vectors.
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Kumar P, Lee JH, Beyenal H, Lee J. Fatty Acids as Antibiofilm and Antivirulence Agents. Trends Microbiol 2020; 28:753-768. [DOI: 10.1016/j.tim.2020.03.014] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 03/09/2020] [Accepted: 03/25/2020] [Indexed: 12/21/2022]
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15
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Scala V, Pucci N, Salustri M, Modesti V, L’Aurora A, Scortichini M, Zaccaria M, Momeni B, Reverberi M, Loreti S. Xylella fastidiosa subsp. pauca and olive produced lipids moderate the switch adhesive versus non-adhesive state and viceversa. PLoS One 2020; 15:e0233013. [PMID: 32413086 PMCID: PMC7228078 DOI: 10.1371/journal.pone.0233013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/26/2020] [Indexed: 12/14/2022] Open
Abstract
Global trade and climate change are re-shaping the distribution map of pandemic pathogens. One major emerging concern is Xylella fastidiosa, a tropical bacterium recently introduced into Europe from America. In last decades, X. fastidiosa was detected in several European countries. X. fastidiosa is an insect vector-transmitted bacterial plant pathogen associated with severe diseases in a wide range of hosts. X. fastidiosa through a tight coordination of the adherent biofilm and the planktonic states, invades the host systemically. The planktonic phase is correlated to low cell density and vessel colonization. Increase in cell density triggers a quorum sensing system based on mixture of cis 2-enoic fatty acids-diffusible signalling factors (DSF) that promote stickiness and biofilm. The lipidome profile of Olea europaea L. (cv. Ogliarola salentina) samples, collected in groves located in infected zones and uninfected zones was performed. The untargeted analysis of the lipid profiles of Olive Quick Decline Syndrome (OQDS) positive (+) and negative (-) plants showed a clustering of OQDS+ plants apart from OQDS-. The targeted lipids profile of plants OQDS+ and OQDS- identified a shortlist of 10 lipids that increase their amount in OQDS+ and X. fastidiosa positive olive trees. These lipid entities, provided to X. fastidiosa subsp. pauca pure culture, impact on the dual phase, e.g. planktonic ↔ biofilm. This study provides novel insights on OQDS lipid hallmarks and on molecules that might modulate biofilm phase in X. fastidiosa subsp. pauca.
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Affiliation(s)
- Valeria Scala
- Council for Agricultural research and Economics (CREA), Research Centre for Plant Protection and Certification, Roma, Italy
| | - Nicoletta Pucci
- Council for Agricultural research and Economics (CREA), Research Centre for Plant Protection and Certification, Roma, Italy
| | - Manuel Salustri
- Dept. of Environmental Biology, Sapienza University, Roma, Italy
| | - Vanessa Modesti
- Council for Agricultural research and Economics (CREA), Research Centre for Plant Protection and Certification, Roma, Italy
| | - Alessia L’Aurora
- Council for Agricultural research and Economics (CREA), Research Centre for Plant Protection and Certification, Roma, Italy
| | - Marco Scortichini
- Council for Agricultural research and Economics (CREA), Research Centre for Olive, Fruit Trees and Citrus, Roma, Italy
| | - Marco Zaccaria
- Department of Biology, Boston College, Chestnut Hill, MA, United States of America
| | - Babak Momeni
- Department of Biology, Boston College, Chestnut Hill, MA, United States of America
| | | | - Stefania Loreti
- Council for Agricultural research and Economics (CREA), Research Centre for Plant Protection and Certification, Roma, Italy
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16
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Feitosa-Junior OR, Stefanello E, Zaini PA, Nascimento R, Pierry PM, Dandekar AM, Lindow SE, da Silva AM. Proteomic and Metabolomic Analyses of Xylella fastidiosa OMV-Enriched Fractions Reveal Association with Virulence Factors and Signaling Molecules of the DSF Family. PHYTOPATHOLOGY 2019; 109:1344-1353. [PMID: 30973310 DOI: 10.1094/phyto-03-19-0083-r] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Xylella fastidiosa releases outer membrane vesicles (OMVs) known to play a role in the systemic dissemination of this pathogen. OMVs inhibit bacterial attachment to xylem wall and traffic lipases/esterases that act on the degradation of plant cell wall. Here, we extended the characterization of X. fastidiosa OMVs by identifying proteins and metabolites potentially associated with OMVs produced by Temecula1, a Pierce's disease strain, and by 9a5c and Fb7, two citrus variegated chlorosis strains. These results strengthen that one of the OMVs multiple functions is to carry determinants of virulence, such as lipases/esterases, adhesins, proteases, porins, and a pectin lyase-like protein. For the first time, we show that the two citrus variegated chlorosis strains produce X. fastidiosa diffusible signaling factor 2 (DSF2) and citrus variegated chlorosis-DSF (likewise, Temecula1) and most importantly, that these compounds of the DSF (X. fastidiosa DSF) family are associated with OMV-enriched fractions. Altogether, our findings widen the potential functions of X. fastidiosa OMVs in intercellular signaling and host-pathogen interactions.
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Affiliation(s)
- Oséias R Feitosa-Junior
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Eliezer Stefanello
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Paulo A Zaini
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
- 2Department of Plant Sciences, University of California, Davis, CA 95616, U.S.A
| | - Rafael Nascimento
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
- 3Instituto de Genética e Bioquímica, Universidade Federal de Uberlândia, Uberlândia, MG 38400-902, Brazil
| | - Paulo M Pierry
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Abhaya M Dandekar
- 2Department of Plant Sciences, University of California, Davis, CA 95616, U.S.A
| | - Steven E Lindow
- 4Department Plant and Microbial Biology, University of California, Berkeley, CA 94720, U.S.A
| | - Aline M da Silva
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
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17
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An SQ, Murtagh J, Twomey KB, Gupta MK, O'Sullivan TP, Ingram R, Valvano MA, Tang JL. Modulation of antibiotic sensitivity and biofilm formation in Pseudomonas aeruginosa by interspecies signal analogues. Nat Commun 2019; 10:2334. [PMID: 31133642 PMCID: PMC6536496 DOI: 10.1038/s41467-019-10271-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 04/24/2019] [Indexed: 11/15/2022] Open
Abstract
Pseudomonas aeruginosa, a significant opportunistic pathogen, can participate in inter-species communication through signaling by cis-2-unsaturated fatty acids of the diffusible signal factor (DSF) family. Sensing these signals leads to altered biofilm formation and increased tolerance to various antibiotics, and requires the histidine kinase PA1396. Here, we show that the membrane-associated sensory input domain of PA1396 has five transmembrane helices, two of which are required for DSF sensing. DSF binding is associated with enhanced auto-phosphorylation of PA1396 incorporated into liposomes. Further, we examined the ability of synthetic DSF analogues to modulate or inhibit PA1396 activity. Several of these analogues block the ability of DSF to trigger auto-phosphorylation and gene expression, whereas others act as inverse agonists reducing biofilm formation and antibiotic tolerance, both in vitro and in murine infection models. These analogues may thus represent lead compounds to develop novel adjuvants improving the efficacy of existing antibiotics.
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Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centers, Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
- The Wellcome-Wolfson Institute for Experimental Medicine, Queen's University of Belfast, Belfast, BT9 7BL, UK.
| | - Julie Murtagh
- School of Microbiology, Biosciences Institute, University College Cork, Cork, T12, Ireland
| | - Kate B Twomey
- School of Microbiology, Biosciences Institute, University College Cork, Cork, T12, Ireland
| | - Manoj K Gupta
- School of Chemistry, University College Cork, Cork, T12, Ireland
- Department of Chemistry, Central University of Haryana, Mahendergarh, 123029, Haryana, India
| | - Timothy P O'Sullivan
- School of Chemistry, University College Cork, Cork, T12, Ireland
- School of Pharmacy, University College Cork, Cork, T12, Ireland
| | - Rebecca Ingram
- The Wellcome-Wolfson Institute for Experimental Medicine, Queen's University of Belfast, Belfast, BT9 7BL, UK
| | - Miguel A Valvano
- The Wellcome-Wolfson Institute for Experimental Medicine, Queen's University of Belfast, Belfast, BT9 7BL, UK.
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, China.
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18
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Diab AA, Cao XQ, Chen H, Song K, Zhou L, Chen B, He YW. BDSF Is the Predominant In-Planta Quorum-Sensing Signal Used During Xanthomonas campestris Infection and Pathogenesis in Chinese Cabbage. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:240-254. [PMID: 30570452 DOI: 10.1094/mpmi-07-18-0197-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Xanthomonas campestris pv. campestris uses the diffusible signal factor (DSF) family of quorum-sensing (QS) signals to coordinate virulence and adaptation. DSF family signals have been well-characterized using laboratory-based cell cultures. The in-planta QS signal used during X. campestris pv. campestris infection remains unclear. To achieve this goal, we first mimic in-planta X. campestris pv. campestris growth conditions by supplementing the previously developed XYS medium with cabbage hydrolysate and found that the dominant signal produced in these conditions was BDSF. Secondly, by using XYS medium supplemented with diverse plant-derived compounds, we examined the effects of diverse plant-derived compounds on the biosynthesis of DSF family signals. Several compounds were found to promote biosynthesis of BDSF. Finally, using an X. campestris pv. campestris ΔrpfB-Chinese cabbage infection model and an ultra-performance liquid chromatographic-time of flight-mass spectrometry-based assay, BDSF was found to comprise >70% of the DSF family signals present in infected cabbage tissue. BDSF at a concentration of 2.0 μM induced both protease activity and engXCA expression. This is the first report to directly show that BDSF is the predominant in-planta QS signal used during X. campestris pv. campestris infection. It provides a better understanding of the molecular interactions between X. campestris pv. campestris and its cruciferous hosts and also provides the logical target for designing strategies to counteract BDSF signaling and, thus, infection. Further studies are needed to get an exact idea about the DSF production dynamics of the wild-type strain inside the plant.
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Affiliation(s)
- Abdelgader Abdeen Diab
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Xue-Qiang Cao
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Hui Chen
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Kai Song
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Lian Zhou
- 2 Zhiyuan Innovation Research Centre, Student Innovation Centre, Zhiyuan College, Shanghai Jiao Tong University
| | - Bo Chen
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Ya-Wen He
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
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Baccari C, Antonova E, Lindow S. Biological Control of Pierce's Disease of Grape by an Endophytic Bacterium. PHYTOPATHOLOGY 2019; 109:248-256. [PMID: 30540526 DOI: 10.1094/phyto-07-18-0245-fi] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Effective preventive measures and therapies are lacking for control of Pierce's disease of grape caused by the xylem-colonizing bacterium Xylella fastidiosa responsible for serious losses in grape production. In this study we explored the potential for endophytic bacteria to alter the disease process. While most endophytic bacteria found within grape did not grow or multiply when inoculated into mature grape vines, Paraburkholderia phytofirmans strain PsJN achieved population sizes as large as 106 cells/g and moved 1 m or more within 4 weeks after inoculation into vines. While X. fastidiosa achieved large population sizes and moved extensively in grape when inoculated alone, few viable cells were recovered from plants in which it was co-inoculated with strain PsJN and the incidence of leaves exhibiting scorching symptoms typical of Pierce's disease was consistently greatly reduced from that in control plants. Suppression of disease symptoms occurred not only when strain PsJN was co-inoculated with the pathogen by puncturing stems in the same site in plants, but also when inoculated at the same time but at different sites in the plant. Large population sizes of strain PsJN could be established in both leaf lamina and petioles by topical application of cell suspensions in 0.2% of an organo-silicon surfactant conferring low surface tension, and such treatments were as effective as direct puncture inoculations of this biocontrol strain in reducing disease severity. While inoculation of strain PsJN into plants by either method at the same time as or even 4 weeks after that of the pathogen resulted in large reductions in disease severity, much less disease control was conferred by inoculation of PsJN 4 weeks prior to that of the pathogen. The expression of grapevine PR1 and ETR1 within 3 weeks of inoculation was substantially higher in plants inoculated with both X. fastidiosa and strain PsJN compared with that in plants inoculated only with the pathogen or strain PsJN, suggesting that this biological control agent reduces disease by priming expression of innate disease resistance pathways in plants that otherwise would have exhibited minimal responses to the pathogen. Strain PsJN thus appears highly efficacious for the control of Pierce's disease when used as an eradicant treatment that can be easily made even by spray application.
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Affiliation(s)
- Clelia Baccari
- Department of Plant and Microbial Biology, University of California, Berkeley 94720
| | - Elena Antonova
- Department of Plant and Microbial Biology, University of California, Berkeley 94720
| | - Steven Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley 94720
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20
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Zeilinger AR, Turek D, Cornara D, Sicard A, Lindow SE, Almeida RPP. Bayesian vector transmission model detects conflicting interactions from transgenic disease‐resistant grapevines. Ecosphere 2018. [DOI: 10.1002/ecs2.2494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Adam R. Zeilinger
- Department of Environmental Science, Policy, and Management University of California 130 Mulford Hall Berkeley California 94720 USA
| | - Daniel Turek
- Department of Mathematics and Statistics Williams College Williamstown Massachusetts 01267 USA
| | - Daniele Cornara
- Instituto de Ciencias Agrarias Consejo Superior de Investigaciones Cientificas ICA‐CSIC Calle Serrano 115 dpdo Madrid 28006 Spain
| | - Anne Sicard
- Department of Environmental Science, Policy, and Management University of California 130 Mulford Hall Berkeley California 94720 USA
| | - Steven E. Lindow
- Department of Plant and Microbial Biology University of California Berkeley Berkeley California 94720 USA
| | - Rodrigo P. P. Almeida
- Department of Environmental Science, Policy, and Management University of California 130 Mulford Hall Berkeley California 94720 USA
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21
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Kyrkou I, Pusa T, Ellegaard-Jensen L, Sagot MF, Hansen LH. Pierce's Disease of Grapevines: A Review of Control Strategies and an Outline of an Epidemiological Model. Front Microbiol 2018; 9:2141. [PMID: 30258423 PMCID: PMC6143690 DOI: 10.3389/fmicb.2018.02141] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/21/2018] [Indexed: 11/13/2022] Open
Abstract
Xylella fastidiosa is a notorious plant pathogenic bacterium that represents a threat to crops worldwide. Its subspecies, Xylella fastidiosa subsp. fastidiosa is the causal agent of Pierce's disease of grapevines. Pierce's disease has presented a serious challenge for the grapevine industry in the United States and turned into an epidemic in Southern California due to the invasion of the insect vector Homalodisca vitripennis. In an attempt to minimize the effects of Xylella fastidiosa subsp. fastidiosa in vineyards, various studies have been developing and testing strategies to prevent the occurrence of Pierce's disease, i.e., prophylactic strategies. Research has also been undertaken to investigate therapeutic strategies to cure vines infected by Xylella fastidiosa subsp. fastidiosa. This report explicitly reviews all the strategies published to date and specifies their current status. Furthermore, an epidemiological model of Xylella fastidiosa subsp. fastidiosa is proposed and key parameters for the spread of Pierce's disease deciphered in a sensitivity analysis of all model parameters. Based on these results, it is concluded that future studies should prioritize therapeutic strategies, while investments should only be made in prophylactic strategies that have demonstrated promising results in vineyards.
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Affiliation(s)
- Ifigeneia Kyrkou
- Laboratory of Environmental Microbiology and Biotechnology, Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Taneli Pusa
- INRIA Grenoble Rhône-Alpes, Montbonnot-Saint-Martin, France
- Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université de Lyon, Université Lyon 1, Villeurbanne, France
- Department of Computer, Automatic and Management Engineering, Sapienza University of Rome, Rome, Italy
| | - Lea Ellegaard-Jensen
- Laboratory of Environmental Microbiology and Biotechnology, Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Marie-France Sagot
- INRIA Grenoble Rhône-Alpes, Montbonnot-Saint-Martin, France
- Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université de Lyon, Université Lyon 1, Villeurbanne, France
| | - Lars Hestbjerg Hansen
- Laboratory of Environmental Microbiology and Biotechnology, Department of Environmental Science, Aarhus University, Roskilde, Denmark
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Caserta R, Souza-Neto RR, Takita MA, Lindow SE, De Souza AA. Ectopic Expression of Xylella fastidiosa rpfF Conferring Production of Diffusible Signal Factor in Transgenic Tobacco and Citrus Alters Pathogen Behavior and Reduces Disease Severity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:866-875. [PMID: 28777044 DOI: 10.1094/mpmi-07-17-0167-r] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The pathogenicity of Xylella fastidiosa is associated with its ability to colonize the xylem of host plants. Expression of genes contributing to xylem colonization are suppressed, while those necessary for insect vector acquisition are increased with increasing concentrations of diffusible signal factor (DSF), whose production is dependent on RpfF. We previously demonstrated that transgenic citrus plants ectopically expressing rpfF from a citrus strain of X. fastidiosa subsp. pauca exhibited less susceptibility to Xanthomonas citri subsp. citri, another pathogen whose virulence is modulated by DSF accumulation. Here, we demonstrate that ectopic expression of rpfF in both transgenic tobacco and sweet orange also confers a reduction in disease severity incited by X. fastidiosa and reduces its colonization of those plants. Decreased disease severity in the transgenic plants was generally associated with increased expression of genes conferring adhesiveness to the pathogen and decreased expression of genes necessary for active motility, accounting for the reduced population sizes achieved in the plants, apparently by limiting pathogen dispersal through the plant. Plant-derived DSF signal molecules in a host plant can, therefore, be exploited to interfere with more than one pathogen whose virulence is controlled by DSF signaling.
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Affiliation(s)
- R Caserta
- 1 Centro de Citricultura Sylvio Moreira/IAC, Corderiópolis, SP, Brazil
| | - R R Souza-Neto
- 1 Centro de Citricultura Sylvio Moreira/IAC, Corderiópolis, SP, Brazil
- 2 Universidade Estadual de Campinas-UNICAMP, Campinas, SP, Brazil; and
| | - M A Takita
- 1 Centro de Citricultura Sylvio Moreira/IAC, Corderiópolis, SP, Brazil
| | - S E Lindow
- 3 University of California, Berkeley, CA, U.S.A
| | - A A De Souza
- 1 Centro de Citricultura Sylvio Moreira/IAC, Corderiópolis, SP, Brazil
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Silva MMD, Andrade MDS, Bauermeister A, Merfa MV, Forim MR, Fernandes JB, Vieira PC, Silva MFDGFD, Lopes NP, Machado MA, Souza AAD. A Simple Defined Medium for the Production of True Diketopiperazines in Xylella fastidiosa and Their Identification by Ultra-Fast Liquid Chromatography-Electrospray Ionization Ion Trap Mass Spectrometry. Molecules 2017; 22:E985. [PMID: 28608830 PMCID: PMC6152636 DOI: 10.3390/molecules22060985] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/24/2017] [Accepted: 06/08/2017] [Indexed: 11/28/2022] Open
Abstract
Diketopiperazines can be generated by non-enzymatic cyclization of linear dipeptides at extreme temperature or pH, and the complex medium used to culture bacteria and fungi including phytone peptone and trypticase peptone, can also produce cyclic peptides by heat sterilization. As a result, it is not always clear if many diketopiperazines reported in the literature are artifacts formed by the different complex media used in microorganism growth. An ideal method for analysis of these compounds should identify whether they are either synthesized de novo from the products of primary metabolism and deliver true diketopiperazines. A simple defined medium (X. fastidiosa medium or XFM) containing a single carbon source and no preformed amino acids has emerged as a method with a particularly high potential for the grown of X. fastidiosa and to produce genuine natural products. In this work, we identified a range of diketopiperazines from X. fastidiosa 9a5c growth in XFM, using Ultra-Fast Liquid Chromatography coupled with mass spectrometry. Diketopiperazines are reported for the first time from X. fastidiosa, which is responsible for citrus variegated chlorosis. We also report here fatty acids from X. fastidiosa, which were not biologically active as diffusible signals, and the role of diketopiperazines in signal transduction still remains unknown.
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Affiliation(s)
| | - Moacir Dos Santos Andrade
- Departamento de Química, Universidade Federal de São Carlos, CP 676, 13565-905 São Carlos-SP, Brazil.
| | - Anelize Bauermeister
- Núcleo Pesquisas em Produtos Naturais e Sintéticos, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto-SP, Brazil.
| | - Marcus Vinícius Merfa
- Centro APTA Citros Sylvio Moreira, Instituto Agronômico, CP 04, 13490-970 Cordeirópolis-SP, Brazil.
| | - Moacir Rossi Forim
- Departamento de Química, Universidade Federal de São Carlos, CP 676, 13565-905 São Carlos-SP, Brazil.
| | - João Batista Fernandes
- Departamento de Química, Universidade Federal de São Carlos, CP 676, 13565-905 São Carlos-SP, Brazil.
| | - Paulo Cezar Vieira
- Departamento de Química, Universidade Federal de São Carlos, CP 676, 13565-905 São Carlos-SP, Brazil.
| | | | - Norberto Peporine Lopes
- Núcleo Pesquisas em Produtos Naturais e Sintéticos, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto-SP, Brazil.
| | - Marcos Antônio Machado
- Centro APTA Citros Sylvio Moreira, Instituto Agronômico, CP 04, 13490-970 Cordeirópolis-SP, Brazil.
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Zhou L, Zhang LH, Cámara M, He YW. The DSF Family of Quorum Sensing Signals: Diversity, Biosynthesis, and Turnover. Trends Microbiol 2017; 25:293-303. [DOI: 10.1016/j.tim.2016.11.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 11/09/2016] [Accepted: 11/22/2016] [Indexed: 01/18/2023]
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25
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Mendes JS, Santiago AS, Toledo MAS, Horta MAC, de Souza AA, Tasic L, de Souza AP. In vitro Determination of Extracellular Proteins from Xylella fastidiosa. Front Microbiol 2016; 7:2090. [PMID: 28082960 PMCID: PMC5183587 DOI: 10.3389/fmicb.2016.02090] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 12/09/2016] [Indexed: 12/20/2022] Open
Abstract
The phytopathogen Xylella fastidiosa causes economic losses in important agricultural crops. Xylem vessel occlusion caused by biofilm formation is the major mechanism underlying the pathogenicity of distinct strains of X. fastidiosa. Here, we provide a detailed in vitro characterization of the extracellular proteins of X. fastidiosa. Based on the results, we performed a comparison with a strain J1a12, which cannot induce citrus variegated chlorosis symptoms when inoculated into citrus plants. We then extend this approach to analyze the extracellular proteins of X. fastidiosa in media supplemented with calcium. We verified increases in extracellular proteins concomitant with the days of growth and, consequently, biofilm development (3-30 days). Outer membrane vesicles carrying toxins were identified beginning at 10 days of growth in the 9a5c strain. In addition, a decrease in extracellular proteins in media supplemented with calcium was observed in both strains. Using mass spectrometry, 71 different proteins were identified during 30 days of X. fastidiosa biofilm development, including proteases, quorum-sensing proteins, biofilm formation proteins, hypothetical proteins, phage-related proteins, chaperones, toxins, antitoxins, and extracellular vesicle membrane components.
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Affiliation(s)
- Juliano S. Mendes
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de CampinasCampinas, Brazil
| | - André S. Santiago
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de CampinasCampinas, Brazil
| | - Marcelo A. S. Toledo
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de CampinasCampinas, Brazil
| | - Maria A. C. Horta
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de CampinasCampinas, Brazil
| | | | - Ljubica Tasic
- Departamento de Química Orgânica, Instituto de Química, Universidade Estadual de CampinasCampinas, Brazil
| | - Anete P. de Souza
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de CampinasCampinas, Brazil
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de CampinasCampinas, Brazil
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Dow J. Diffusible signal factor-dependent quorum sensing in pathogenic bacteria and its exploitation for disease control. J Appl Microbiol 2016; 122:2-11. [DOI: 10.1111/jam.13307] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/16/2016] [Accepted: 09/23/2016] [Indexed: 12/25/2022]
Affiliation(s)
- J.M. Dow
- School of Microbiology; University College Cork; Cork Ireland
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Pfeilmeier S, Caly DL, Malone JG. Bacterial pathogenesis of plants: future challenges from a microbial perspective: Challenges in Bacterial Molecular Plant Pathology. MOLECULAR PLANT PATHOLOGY 2016; 17:1298-313. [PMID: 27170435 PMCID: PMC6638335 DOI: 10.1111/mpp.12427] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/08/2016] [Accepted: 05/10/2016] [Indexed: 05/03/2023]
Abstract
Plant infection is a complicated process. On encountering a plant, pathogenic microorganisms must first adapt to life on the epiphytic surface, and survive long enough to initiate an infection. Responsiveness to the environment is critical throughout infection, with intracellular and community-level signal transduction pathways integrating environmental signals and triggering appropriate responses in the bacterial population. Ultimately, phytopathogens must migrate from the epiphytic surface into the plant tissue using motility and chemotaxis pathways. This migration is coupled with overcoming the physical and chemical barriers to entry into the plant apoplast. Once inside the plant, bacteria use an array of secretion systems to release phytotoxins and protein effectors that fulfil diverse pathogenic functions (Fig. ) (Melotto and Kunkel, ; Phan Tran et al., ). As our understanding of the pathways and mechanisms underpinning plant pathogenicity increases, a number of central research challenges are emerging that will profoundly shape the direction of research in the future. We need to understand the bacterial phenotypes that promote epiphytic survival and surface adaptation in pathogenic bacteria. How do these pathways function in the context of the plant-associated microbiome, and what impact does this complex microbial community have on the onset and severity of plant infections? The huge importance of bacterial signal transduction to every stage of plant infection is becoming increasingly clear. However, there is a great deal to learn about how these signalling pathways function in phytopathogenic bacteria, and the contribution they make to various aspects of plant pathogenicity. We are increasingly able to explore the structural and functional diversity of small-molecule natural products from plant pathogens. We need to acquire a much better understanding of the production, deployment, functional redundancy and physiological roles of these molecules. Type III secretion systems (T3SSs) are important and well-studied contributors to bacterial disease. Several key unanswered questions will shape future investigations of these systems. We need to define the mechanism of hierarchical and temporal control of effector secretion. For successful infection, effectors need to interact with host components to exert their function. Advanced biochemical, proteomic and cell biological techniques will enable us to study the function of effectors inside the host cell in more detail and on a broader scale. Population genomics analyses provide insight into evolutionary adaptation processes of phytopathogens. The determination of the diversity and distribution of type III effectors (T3Es) and other virulence genes within and across pathogenic species, pathovars and strains will allow us to understand how pathogens adapt to specific hosts, the evolutionary pathways available to them, and the possible future directions of the evolutionary arms race between effectors and molecular plant targets. Although pathogenic bacteria employ a host of different virulence and proliferation strategies, as a result of the space constraints, this review focuses mainly on the hemibiotrophic pathogens. We discuss the process of plant infection from the perspective of these important phytopathogens, and highlight new approaches to address the outstanding challenges in this important and fast-moving field.
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Affiliation(s)
- Sebastian Pfeilmeier
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Delphine L Caly
- Université de Lille, EA 7394, ICV - Institut Charles Viollette, Lille, F-59000, France
| | - Jacob G Malone
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
- University of East Anglia, Norwich, NR4 7TJ, UK.
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Gouran H, Gillespie H, Nascimento R, Chakraborty S, Zaini PA, Jacobson A, Phinney BS, Dolan D, Durbin-Johnson BP, Antonova ES, Lindow SE, Mellema MS, Goulart LR, Dandekar AM. The Secreted Protease PrtA Controls Cell Growth, Biofilm Formation and Pathogenicity in Xylella fastidiosa. Sci Rep 2016; 6:31098. [PMID: 27492542 PMCID: PMC4974619 DOI: 10.1038/srep31098] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/13/2016] [Indexed: 11/09/2022] Open
Abstract
Pierce's disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the pathogenicity factors of X. fastidiosa in grapevines that leads to leaf scorching and chlorosis. Herein, we characterize another such factor encoded by PD0956, designated as an antivirulence secreted protease "PrtA" that displays a central role in controlling in vitro cell proliferation, length, motility, biofilm formation, and in planta virulence. The mutant in X. fastidiosa exhibited reduced cell length, hypermotility (and subsequent lack of biofilm formation) and hypervirulence in grapevines. These findings are supported by transcriptomic and proteomic analyses with corresponding plant infection data. Of particular interest, is the hypervirulent response in grapevines observed when X. fastidiosa is disrupted for production of PrtA, and that PD-model tobacco plants transformed to express PrtA exhibited decreased symptoms after infection by X. fastidiosa.
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Affiliation(s)
- Hossein Gouran
- Plant Sciences Department, University of California, Davis, CA, USA
| | - Hyrum Gillespie
- Plant Sciences Department, University of California, Davis, CA, USA
| | - Rafael Nascimento
- Plant Sciences Department, University of California, Davis, CA, USA
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Brazil
| | | | - Paulo A. Zaini
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Brazil
| | - Aaron Jacobson
- Plant Sciences Department, University of California, Davis, CA, USA
| | - Brett S. Phinney
- Proteomics Core, Genome Center, University of California, Davis, USA
| | - David Dolan
- Plant Sciences Department, University of California, Davis, CA, USA
| | | | - Elena S. Antonova
- Plant and Microbial Biology Department, University of Berkeley, Berkeley, CA, USA
| | - Steven E. Lindow
- Plant and Microbial Biology Department, University of Berkeley, Berkeley, CA, USA
| | - Matthew S. Mellema
- Surgical and Radiological Sciences, Vet Med, University of California, Davis, CA, USA
| | - Luiz R. Goulart
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Brazil
- Department of Medical Microbiology and Immunology, University of California, Davis, CA, USA
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Ionescu M, Yokota K, Antonova E, Garcia A, Beaulieu E, Hayes T, Iavarone AT, Lindow SE. Promiscuous Diffusible Signal Factor Production and Responsiveness of the Xylella fastidiosa Rpf System. mBio 2016; 7:e01054-16. [PMID: 27435463 PMCID: PMC4958263 DOI: 10.1128/mbio.01054-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 06/16/2016] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED Cell density-dependent regulation of gene expression in Xylella fastidiosa that is crucial to its switching between plant hosts and insect vectors is dependent on RpfF and its production of 2-enoic acids known as diffusible signal factor (DSF). We show that X. fastidiosa produces a particularly large variety of similar, relatively long-chain-length 2-enoic acids that are active in modulating gene expression. Both X. fastidiosa itself and a Pantoea agglomerans surrogate host harboring X. fastidiosa RpfF (XfRpfF) is capable of producing a variety of both saturated and unsaturated free fatty acids. However, only 2-cis unsaturated acids were found to be biologically active in X. fastidiosa X. fastidiosa produces, and is particularly responsive to, a novel DSF species, 2-cis-hexadecanoic acid that we term XfDSF2. It is also responsive to other, even longer 2-enoic acids to which other taxa such as Xanthomonas campestris are unresponsive. The 2-enoic acids that are produced by X. fastidiosa are strongly affected by the cellular growth environment, with XfDSF2 not detected in culture media in which 2-tetradecenoic acid (XfDSF1) had previously been found. X. fastidiosa is responsive to much lower concentrations of XfDSF2 than XfDSF1. Apparently competitive interactions can occur between various saturated and unsaturated fatty acids that block the function of those agonistic 2-enoic fatty acids. By altering the particular 2-enoic acids produced and the relative balance of free enoic and saturated fatty acids, X. fastidiosa might modulate the extent of DSF-mediated quorum sensing. IMPORTANCE X. fastidiosa, having a complicated lifestyle in which it moves and multiplies within plants but also must be vectored by insects, utilizes DSF-based quorum sensing to partition the expression of traits needed for these two processes within different cells in this population based on local cellular density. The finding that it can produce a variety of DSF species in a strongly environmentally context-dependent manner provides insight into how it coordinates the many genes under the control of DSF signaling to successfully associate with its two hosts. Since the new DSF variant XfDSF2 described here is much more active than the previously recognized DSF species, it should contribute to plant disease control, given that the susceptibility of plants can be greatly reduced by artificially elevating the levels of DSF in plants, creating "pathogen confusion," resulting in lower virulence.
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Affiliation(s)
- Michael Ionescu
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Kenji Yokota
- Department of Applied Biology and Chemistry, Tokyo University of Agriculture, Tokyo, Japan
| | - Elena Antonova
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Angelica Garcia
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Ellen Beaulieu
- Biosciences Division, SRI International, Menlo Park, California, USA
| | - Terry Hayes
- Biosciences Division, SRI International, Menlo Park, California, USA
| | - Anthony T Iavarone
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California, USA
| | - Steven E Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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Dow JM, Naughton LM, Hollmann B, An SQ, Ryan RP. The Diffusible Signal Factor Family of Bacterial CellCell Signals. Isr J Chem 2016. [DOI: 10.1002/ijch.201500075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Suppiger A, Aguilar C, Eberl L. Evidence for the widespread production of DSF family signal molecules by members of the genus Burkholderia by the aid of novel biosensors. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:38-44. [PMID: 26487448 DOI: 10.1111/1758-2229.12348] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/08/2015] [Accepted: 10/17/2015] [Indexed: 06/05/2023]
Abstract
Many bacteria employ cis-2-unsaturated fatty acids, referred to as DSF (diffusible signal factor) family signals, to communicate with each other. Such systems have been shown to control biofilm formation, motility, production of hydrolytic enzymes and expression of virulence factors. We report the construction of novel biosensors on the basis of components of the Burkholderia-DSF (BDSF) dependent circuitry of Burkholderia cenocepacia H111 and evaluated their utility for detecting the production of DSF family signal molecules. We show that a luxAB-based biosensor responds to nM levels of synthetic BDSF and is suitable to detect a wide range of cis-2 fatty acid molecules. Using this biosensor we show that the production of DSF family molecules is widespread among members of the B. cepacia complex and demonstrate for the first time that DSF-based molecules are also produced by plant-associated Burkholderia species.
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Affiliation(s)
- Angela Suppiger
- Department of Microbiology, Institute of Plant Biology, University of Zurich, Zurich, Switzerland
| | - Claudio Aguilar
- Department of Microbiology, Institute of Plant Biology, University of Zurich, Zurich, Switzerland
| | - Leo Eberl
- Department of Microbiology, Institute of Plant Biology, University of Zurich, Zurich, Switzerland
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Control of Biofilms with the Fatty Acid Signaling Molecule cis-2-Decenoic Acid. Pharmaceuticals (Basel) 2015; 8:816-35. [PMID: 26610524 PMCID: PMC4695811 DOI: 10.3390/ph8040816] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/11/2015] [Accepted: 11/18/2015] [Indexed: 12/26/2022] Open
Abstract
Biofilms are complex communities of microorganisms in organized structures attached to surfaces. Importantly, biofilms are a major cause of bacterial infections in humans, and remain one of the most significant challenges to modern medical practice. Unfortunately, conventional therapies have shown to be inadequate in the treatment of most chronic biofilm infections based on the extraordinary innate tolerance of biofilms to antibiotics. Antagonists of quorum sensing signaling molecules have been used as means to control biofilms. QS and other cell-cell communication molecules are able to revert biofilm tolerance, prevent biofilm formation and disrupt fully developed biofilms, albeit with restricted effectiveness. Recently however, it has been demonstrated that Pseudomonas aeruginosa produces a small messenger molecule cis-2-decenoic acid (cis-DA) that shows significant promise as an effective adjunctive to antimicrobial treatment of biofilms. This molecule is responsible for induction of the native biofilm dispersion response in a range of Gram-negative and Gram-positive bacteria and in yeast, and has been shown to reverse persistence, increase microbial metabolic activity and significantly enhance the cidal effects of conventional antimicrobial agents. In this manuscript, the use of cis-2-decenoic acid as a novel agent for biofilm control is discussed. Stimulating the biofilm dispersion response as a novel antimicrobial strategy holds significant promise for enhanced treatment of infections and in the prevention of biofilm formation.
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Kakkar A, Nizampatnam NR, Kondreddy A, Pradhan BB, Chatterjee S. Xanthomonas campestris cell-cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6697-714. [PMID: 26248667 PMCID: PMC4623683 DOI: 10.1093/jxb/erv377] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell-cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell-cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery.
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Affiliation(s)
- Akanksha Kakkar
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India Graduate studies, Manipal University, Manipal, India
| | | | - Anil Kondreddy
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
| | - Binod Bihari Pradhan
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
| | - Subhadeep Chatterjee
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
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Zhou L, Yu Y, Chen X, Diab AA, Ruan L, He J, Wang H, He YW. The Multiple DSF-family QS Signals are Synthesized from Carbohydrate and Branched-chain Amino Acids via the FAS Elongation Cycle. Sci Rep 2015; 5:13294. [PMID: 26289160 PMCID: PMC4542539 DOI: 10.1038/srep13294] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/21/2015] [Indexed: 12/29/2022] Open
Abstract
Members of the diffusible signal factor (DSF) family are a novel class of quorum sensing (QS) signals in diverse Gram-negative bacteria. Although previous studies have identified RpfF as a key enzyme for the biosynthesis of DSF family signals, many questions in their biosynthesis remain to be addressed. In this study with the phytopathogen Xanthomonas campestris pv. campestris (Xcc), we show that Xcc produces four DSF-family signals (DSF, BDSF, CDSF and IDSF) during cell culture, and that IDSF is a new functional signal characterized as cis-10-methyl-2-dodecenoic acid. Using a range of defined media, we further demonstrate that Xcc mainly produces BDSF in the presence of carbohydrates; leucine and valine are the primary precursor for DSF biosynthesis; isoleucine is the primary precursor for IDSF biosynthesis. Furthermore, our biochemical analyses show that the key DSF synthase RpfF has both thioesterase and dehydratase activities, and uses 3-hydroxydedecanoyl-ACP as a substrate to produce BDSF. Finally, our results show that the classic fatty acid synthesis elongation cycle is required for the biosynthesis of DSF-family signals. Taken all together, these findings establish a general biosynthetic pathway for the DSF-family quorum sensing signals.
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Affiliation(s)
- Lian Zhou
- State Key Laboratory of Microbial Metabolism, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yonghong Yu
- College of Life Sciences, South China Agricultural University, Guangzhou 510650, China
| | - Xiping Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Abdelgader Abdeen Diab
- State Key Laboratory of Microbial Metabolism, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Haihong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou 510650, China
| | - Ya-Wen He
- State Key Laboratory of Microbial Metabolism, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Huedo P, Yero D, Martinez-Servat S, Ruyra À, Roher N, Daura X, Gibert I. Decoding the genetic and functional diversity of the DSF quorum-sensing system in Stenotrophomonas maltophilia. Front Microbiol 2015; 6:761. [PMID: 26284046 PMCID: PMC4517397 DOI: 10.3389/fmicb.2015.00761] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 07/13/2015] [Indexed: 11/13/2022] Open
Abstract
Stenotrophomonas maltophilia uses the Diffusible Signal Factor (DSF) quorum sensing (QS) system to mediate intra- and inter-specific signaling and regulate virulence-related processes. The components of this system are encoded by the rpf cluster, with genes rpfF and rpfC encoding for the DSF synthase RpfF and sensor RpfC, respectively. Recently, we have shown that there exist two variants of the rpf cluster (rpf-1 and rpf-2), distinguishing two groups of S. maltophilia strains. Surprisingly, only rpf-1 strains produce detectable DSF, correlating with their ability to control biofilm formation, swarming motility and virulence. The evolutive advantage of acquiring two different rpf clusters, the phylogenetic time point and mechanism of this acquisition and the conditions that activate DSF production in rpf-2 strains, are however not known. Examination of this cluster in various species suggests that its variability originated most probably by genetic exchange between rhizosphere bacteria. We propose that rpf-2 variant strains make use of a strategy recently termed as "social cheating." Analysis of cellular and extracellular fatty acids (FAs) of strains E77 (rpf-1) and M30 (rpf-2) suggests that their RpfFs have also a thioesterase activity that facilitates the release of unspecific FAs to the medium in addition to DSF. Production of DSF in rpf-1 strains appears in fact to be modulated by some of these extracellular FAs in addition to other factors such as temperature and nutrients, while in rpf-2 strains DSF biosynthesis is derepressed only upon detection of DSF itself, suggesting that they require cohabitation with DSF-producer bacteria to activate their DSF regulatory machinery. Finally, we show that the mixed rpf-1/rpf-2 population presents synergism in DSF production and virulence capacity in an in vivo infection model. Recovery and quantification of DSF from co-infected animals correlates with the observed mortality rate.
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Affiliation(s)
- Pol Huedo
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Daniel Yero
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Sònia Martinez-Servat
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Àngels Ruyra
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain
| | - Nerea Roher
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain
| | - Xavier Daura
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Catalan Institution for Research and Advanced Studies Barcelona, Spain
| | - Isidre Gibert
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB) Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
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Ryan RP, An SQ, Allan JH, McCarthy Y, Dow JM. The DSF Family of Cell-Cell Signals: An Expanding Class of Bacterial Virulence Regulators. PLoS Pathog 2015; 11:e1004986. [PMID: 26181439 PMCID: PMC4504480 DOI: 10.1371/journal.ppat.1004986] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many pathogenic bacteria use cell–cell signaling systems involving the synthesis and perception of diffusible signal molecules to control virulence as a response to cell density or confinement to niches. Bacteria produce signals of diverse structural classes. Signal molecules of the diffusible signal factor (DSF) family are cis-2-unsaturated fatty acids. The paradigm is cis-11-methyl-2-dodecenoic acid from Xanthomonas campestris pv. campestris (Xcc), which controls virulence in this plant pathogen. Although DSF synthesis was thought to be restricted to the xanthomonads, it is now known that structurally related molecules are produced by the unrelated bacteria Burkholderia cenocepacia and Pseudomonas aeruginosa. Furthermore, signaling involving these DSF family members contributes to bacterial virulence, formation of biofilms and antibiotic tolerance in these important human pathogens. Here we review the recent advances in understanding DSF signaling and its regulatory role in different bacteria. These advances include the description of the pathway/mechanism of DSF biosynthesis, identification of novel DSF synthases and new members of the DSF family, the demonstration of a diversity of DSF sensors to include proteins with a Per-Arnt-Sim (PAS) domain and the description of some of the signal transduction mechanisms that impinge on virulence factor expression. In addition, we address the role of DSF family signals in interspecies signaling that modulates the behavior of other microorganisms. Finally, we consider a number of recently reported approaches for the control of bacterial virulence through the modulation of DSF signaling.
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Affiliation(s)
- Robert P. Ryan
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail: (RPR); (JMD)
| | - Shi-qi An
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - John H. Allan
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Yvonne McCarthy
- School of Microbiology, Biosciences Institute, University College Cork, Cork, Ireland
| | - J. Maxwell Dow
- School of Microbiology, Biosciences Institute, University College Cork, Cork, Ireland
- * E-mail: (RPR); (JMD)
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Yamashita S, Igarashi M, Hayashi C, Shitara T, Nomoto A, Mizote T, Shibasaki M. Identification of self-growth-inhibiting compounds lauric acid and 7-(Z)-tetradecenoic acid from Helicobacter pylori. MICROBIOLOGY-SGM 2015; 161:1231-9. [PMID: 25767109 DOI: 10.1099/mic.0.000077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Helicobacter pylori growth medium is usually supplemented with horse serum (HS) or FCS. However, cyclodextrin derivatives or activated charcoal can replace serum. In this study, we purified self-growth-inhibiting (SGI) compounds from H. pylori growth medium. The compounds were recovered from porous resin, Diaion HP-20, which was added to the H. pylori growth medium instead of known supplements. These SGI compounds were also identified from 2,6-di-O-methyl-β-cyclodextrin, which was supplemented in a pleuropneumonia-like organisms broth. The growth-inhibiting compounds were identified as lauric acid (LA) and 7-(Z)-tetradecenoic acid [7-(Z)-TDA]. Although several fatty acids had been identified in H. pylori, these specific compounds were not previously found in this species. However, we confirmed that these fatty acids were universally present in the cultivation medium of the H. pylori strains examined in this study. A live/dead assay carried out without HS indicated that these compounds were bacteriostatic; however, no significant growth-inhibiting effect was observed against other tested bacterial species that constituted the indigenous bacterial flora. These findings suggested that LA and 7-(Z)-TDA might play important roles in the survival of H. pylori in human stomach epithelial cells.
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Affiliation(s)
- Shinpei Yamashita
- 1Department of Human Nutrition, Yamaguchi Prefectural University, Yamaguchi, Japan
| | | | | | - Tetsuo Shitara
- 2Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan
| | - Akio Nomoto
- 2Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan
| | - Tomoko Mizote
- 1Department of Human Nutrition, Yamaguchi Prefectural University, Yamaguchi, Japan
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Rai R, Javvadi S, Chatterjee S. Cell-cell signalling promotes ferric iron uptake inXanthomonas oryzaepv.oryzicolathat contribute to its virulence and growth inside rice. Mol Microbiol 2015; 96:708-27. [DOI: 10.1111/mmi.12965] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2015] [Indexed: 01/25/2023]
Affiliation(s)
- Rikky Rai
- Centre for DNA Fingerprinting and Diagnostics; Nampally Hyderabad 500001 India
- Graduate studies; Manipal University; India
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Scientific Opinion on the risks to plant health posed byXylella fastidiosain the EU territory, with the identification and evaluation of risk reduction options. EFSA J 2015. [DOI: 10.2903/j.efsa.2015.3989] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Caserta R, Picchi SC, Takita MA, Tomaz JP, Pereira WEL, Machado MA, Ionescu M, Lindow S, De Souza AA. Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:1241-52. [PMID: 25099341 DOI: 10.1094/mpmi-03-14-0090-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants.
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Xylella fastidiosa outer membrane vesicles modulate plant colonization by blocking attachment to surfaces. Proc Natl Acad Sci U S A 2014; 111:E3910-8. [PMID: 25197068 DOI: 10.1073/pnas.1414944111] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Outer membrane vesicles (OMVs) of Gram-negative bacteria have been studied intensively in recent years, primarily in their role in delivering virulence factors and antigens during pathogenesis. However, the near ubiquity of their production suggests that they may play other roles, such as responding to envelope stress or trafficking various cargoes to prevent dilution or degradation by other bacterial species. Here we show that OMVs produced by Xylella fastidiosa, a xylem-colonizing plant pathogenic bacterium, block its interaction with various surfaces such as the walls of xylem vessels in host plants. The release of OMVs was suppressed by the diffusible signal factor-dependent quorum-sensing system, and a X. fastidiosa ΔrpfF mutant in which quorum signaling was disrupted was both much more virulent to plants and less adhesive to glass and plant surfaces than the WT strain. The higher virulence of the ΔrpfF mutant was associated with fivefold higher numbers of OMVs recovered from xylem sap of infected plants. The frequency of attachment of X. fastidiosa to xylem vessels was 20-fold lower in the presence of OMVs than in their absence. OMV production thus is a strategy used by X. fastidiosa cells to adjust attachment to surfaces in its transition from adhesive cells capable of insect transmission to an "exploratory" lifestyle for systemic spread within the plant host which would be hindered by attachment. OMV production may contribute to the movement of other bacteria in porous environments by similarly reducing their contact with environmental constituents.
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Two different rpf clusters distributed among a population of Stenotrophomonas maltophilia clinical strains display differential diffusible signal factor production and virulence regulation. J Bacteriol 2014; 196:2431-42. [PMID: 24769700 DOI: 10.1128/jb.01540-14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The quorum-sensing (QS) system present in the emerging nosocomial pathogen Stenotrophomonas maltophilia is based on the signaling molecule diffusible signal factor (DSF). Production and detection of DSF are governed by the rpf cluster, which encodes the synthase RpfF and the sensor RpfC, among other components. Despite a well-studied system, little is known about its implication in virulence regulation in S. maltophilia. Here, we have analyzed the rpfF gene from 82 S. maltophilia clinical isolates. Although rpfF was found to be present in all of the strains, it showed substantial variation, with two populations (rpfF-1 and rpfF-2) clearly distinguishable by the N-terminal region of the protein. Analysis of rpfC in seven complete genome sequences revealed a corresponding variability in the N-terminal transmembrane domain of its product, suggesting that each RpfF variant has an associated RpfC variant. We show that only RpfC-RpfF-1 variant strains display detectable DSF production. Heterologous rpfF complementation of ΔrpfF mutants of a representative strain of each variant suggests that RpfF-2 is, however, functional and that the observed DSF-deficient phenotype of RpfC-RpfF-2 variant strains is due to permanent repression of RpfF-2 by RpfC-2. This is corroborated by the ΔrpfC mutant of the RpfC-RpfF-2 representative strain. In line with this observations, deletion of rpfF from the RpfC-RpfF-1 strain leads to an increase in biofilm formation, a decrease in swarming motility, and relative attenuation in the Caenorhabditis elegans and zebrafish infection models, whereas deletion of the same gene from the representative RpfC-RpfF-2 strain has no significant effect on these virulence-related phenotypes.
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Lindow S, Newman K, Chatterjee S, Baccari C, Lavarone AT, Ionescu M. Production of Xylella fastidiosa diffusible signal factor in transgenic grape causes pathogen confusion and reduction in severity of Pierce's disease. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:244-54. [PMID: 24499029 DOI: 10.1094/mpmi-07-13-0197-fi] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The rpfF gene from Xylella fastidiosa, encoding the synthase for diffusible signal factor (DSF), was expressed in 'Freedom' grape to reduce the pathogen's growth and mobility within the plant. Symptoms in such plants were restricted to near the point of inoculation and incidence of disease was two- to fivefold lower than in the parental line. Both the longitudinal and lateral movement of X. fastidiosa in the xylem was also much lower. DSF was detected in both leaves and xylem sap of RpfF-expressing plants using biological sensors, and both 2-Z-tetradecenoic acid, previously identified as a component of X. fastidiosa DSF, and cis-11-methyl-2-dodecenoic acid were detected in xylem sap using electrospray ionization mass spectrometry. A higher proportion of X. fastidiosa cells adhered to xylem vessels of the RpfF-expressing line than parental 'Freedom' plants, reflecting a higher adhesiveness of the pathogen in the presence of DSF. Disease incidence in RpfF-expressing plants in field trials in which plants were either mechanically inoculated with X. fastidiosa or subjected to natural inoculation by sharpshooter vectors was two- to fourfold lower in than that of the parental line. The number of symptomatic leaves on infected shoots was reduced proportionally more than the incidence of infection, reflecting a decreased ability of X. fastidiosa to move within DSF-producing plants.
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Qian G, Xu F, Venturi V, Du L, Liu F. Roles of a solo LuxR in the biological control agent Lysobacter enzymogenes strain OH11. PHYTOPATHOLOGY 2014; 104:224-31. [PMID: 24111575 PMCID: PMC4161204 DOI: 10.1094/phyto-07-13-0188-r] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Lysobacter enzymogenes is a ubiquitous plant-associated and environmentally friendly bacterium emerging as a novel biological control agent of plant disease. This bacterium produces diverse antifungal factors, such as lytic enzymes and a secondary metabolite (heat-stable antifungal factor [HSAF]) having antifungal activity with a novel structure and mode of action. The regulatory mechanisms for biosynthesis of antifungal factors is largely unknown in L. enzymogenes. The solo LuxR proteins have been shown to be widespread, playing important roles in plant-associated bacteria. Here, we cloned and studied a solo LuxR protein, LesR, from L. enzymogenes strain OH11. Overexpression but not deletion of lesR significantly impaired HSAF biosynthesis levels and antimicrobial activities but did not show visible effect on production of major lytic enzymes. Overexpression of lesR also led to remarkably accelerated cell aggregation and induced production of a melanin-like pigment in L. enzymogenes; these two phenotypes are mediated by the diffusible factor cell-to-cell signaling system of L. enzymogenes. The C-terminus helix-turn-helix domain was shown to be critical for several lesR-controlled functions. Overall, our study provides the first example of the roles and mechanisms of a solo LuxR protein in a plant-associated L. enzymogenes.
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Affiliation(s)
- Guoliang Qian
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education
| | - Feifei Xu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy
| | - Liangcheng Du
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Fengquan Liu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education
- To whom correspondence should be addressed. Tel: +86-25-84396726. Fax: +86-25-84395325.
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Baccari C, Killiny N, Ionescu M, Almeida RPP, Lindow SE. Diffusible signal factor-repressed extracellular traits enable attachment of Xylella fastidiosa to insect vectors and transmission. PHYTOPATHOLOGY 2014; 104:27-33. [PMID: 24571393 DOI: 10.1094/phyto-06-13-0151-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The hypothesis that a wild-type strain of Xylella fastidiosa would restore the ability of rpfF mutants blocked in diffusible signal factor production to be transmitted to new grape plants by the sharpshooter vector Graphocephala atropunctata was tested. While the rpfF mutant was very poorly transmitted by vectors irrespective of whether they had also fed on plants infected with the wild-type strain, wild-type strains were not efficiently transmitted if vectors had fed on plants infected with the rpfF mutant. About 100-fewer cells of a wild-type strain attached to wings of a vector when suspended in xylem sap from plants infected with an rpfF mutant than in sap from uninfected grapes. The frequency of transmission of cells suspended in sap from plants that were infected by the rpfF mutant was also reduced over threefold. Wild-type cells suspended in a culture supernatant of an rpfF mutant also exhibited 10-fold less adherence to wings than when suspended in uninoculated culture media. A factor released into the xylem by rpfF mutants, and to a lesser extent by the wild-type strain, thus inhibits their attachment to, and thus transmission by, sharpshooter vectors and may also enable them to move more readily through host plants.
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Ionescu M, Baccari C, Da Silva AM, Garcia A, Yokota K, Lindow SE. Diffusible signal factor (DSF) synthase RpfF of Xylella fastidiosa is a multifunction protein also required for response to DSF. J Bacteriol 2013; 195:5273-84. [PMID: 24056101 PMCID: PMC3837960 DOI: 10.1128/jb.00713-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 09/13/2013] [Indexed: 11/20/2022] Open
Abstract
Xylella fastidiosa, like related Xanthomonas species, employs an Rpf cell-cell communication system consisting of a diffusible signal factor (DSF) synthase, RpfF, and a DSF sensor, RpfC, to coordinate expression of virulence genes. While phenotypes of a ΔrpfF strain in Xanthomonas campestris could be complemented by its own DSF, the DSF produced by X. fastidiosa (XfDSF) did not restore expression of the XfDSF-dependent genes hxfA and hxfB to a ΔrpfF strain of X. fastidiosa, suggesting that RpfF is involved in XfDSF sensing or XfDSF-dependent signaling. To test this conjecture, rpfC and rpfF of X. campestris were replaced by those of X. fastidiosa, and the contribution of each gene to the induction of a X. campestris DSF-dependent gene was assessed. As in X. fastidiosa, XfDSF-dependent signaling required both X. fastidiosa proteins RpfF and RpfC. RpfF repressed RpfC signaling activity, which in turn was derepressed by XfDSF. A mutated X. fastidiosa RpfF protein with two substitutions of glutamate to alanine in its active site was incapable of XfDSF production yet enabled a response to XfDSF, indicating that XfDSF production and the response to XfDSF are two separate functions in which RpfF is involved. This mutant was also hypervirulent to grape, demonstrating the antivirulence effects of XfDSF itself in X. fastidiosa. The Rpf system of X. fastidiosa is thus a novel example of a quorum-sensing signal synthase that is also involved in the response to the signal molecule that it synthesizes.
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Affiliation(s)
- Michael Ionescu
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Clelia Baccari
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Aline Maria Da Silva
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Angelica Garcia
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Kenji Yokota
- Department of Applied Biology and Chemistry, Tokyo University of Agriculture, Tokyo, Japan
| | - Steven E. Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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The putative enoyl-coenzyme A hydratase DspI is required for production of the Pseudomonas aeruginosa biofilm dispersion autoinducer cis-2-decenoic acid. J Bacteriol 2013; 195:4600-10. [PMID: 23935049 DOI: 10.1128/jb.00707-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the present study, we report the identification of a putative enoyl-coenzyme A (CoA) hydratase/isomerase that is required for synthesis of the biofilm dispersion autoinducer cis-2-decenoic acid in the human pathogen Pseudomonas aeruginosa. The protein is encoded by PA14_54640 (PA0745), named dspI for dispersion inducer. The gene sequence for this protein shows significant homology to RpfF in Xanthomonas campestris. Inactivation of dspI was shown to abolish biofilm dispersion autoinduction in continuous cultures of P. aeruginosa and resulted in biofilms that were significantly greater in thickness and biomass than those of the parental wild-type strain. Dispersion was shown to be inducible in dspI mutants by the exogenous addition of synthetic cis-2-decenoic acid or by complementation of ΔdspI in trans under the control of an arabinose-inducible promoter. Mutation of dspI was also shown to abolish cis-2-decenoic acid production, as revealed by gas chromatography-mass spectrometry (GC-MS) analysis of cell-free spent culture medium. The transcript abundance of dspI correlated with cell density, as determined by quantitative reverse transcriptase (RT) PCR. This regulation is consistent with the characterization of cis-2-decenoic acid as a cell-to-cell communication molecule that regulates biofilm dispersion in a cell density-dependent manner.
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