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Chen J, Jiang J, Zhang N, Song Y. Effects of habitats in typical karst areas of Guizhou on ultrastructural morphology of Typhlocybinae. Ecol Evol 2023; 13:e10680. [PMID: 37933325 PMCID: PMC10625857 DOI: 10.1002/ece3.10680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 09/24/2023] [Accepted: 10/16/2023] [Indexed: 11/08/2023] Open
Abstract
Biology and the environment are inextricably linked. Insects are intricately linked to their habitats as part of the ecosystem. In this study, scanning electron microscopy (SEM) observations showed two sensilla chaetica, several sensilla trichodea, and at least one sensilla basiconicum on the antennae of typhlocybine insects. There were no sensilla on the labrum; however, the surface morphology was different. There were more sensilla trichodea on the surface, mostly symmetrically distributed along the labial groove, and there was little difference in the structure of the stylet fascicle. The correlation between the sensilla number on the body surface of typhlocybine insects and environmental factors in the 3 study areas was as follows: Huajiang > Bijie > Shibing, which is consistent with the classification of rocky desertification grade; that is, the higher the rocky desertification grade, the greater the sensilla number on leafhoppers affected by the environment. The correlation between the number of leafhoppers and environmental factors in the 3 months was as follows: end of September > end of May > end of July, which was consistent with the changing temperature trends. The results of this study enrich our knowledge of the morphological characteristics of leafhoppers and explore the potential value of insect surface ultra-morphology for use by humans.
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Affiliation(s)
- Jiajia Chen
- School of Karst ScienceGuizhou Normal UniversityGuiyangChina
- Engineering Technology Institute for Karst Desertification ControlGuiyangChina
| | - Jia Jiang
- School of Karst ScienceGuizhou Normal UniversityGuiyangChina
- Engineering Technology Institute for Karst Desertification ControlGuiyangChina
| | - Ni Zhang
- School of Karst ScienceGuizhou Normal UniversityGuiyangChina
- Engineering Technology Institute for Karst Desertification ControlGuiyangChina
| | - Yuehua Song
- School of Karst ScienceGuizhou Normal UniversityGuiyangChina
- Engineering Technology Institute for Karst Desertification ControlGuiyangChina
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2
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Guiraud J, Le Roy C, Rideau F, Sirand-Pugnet P, Lartigue C, Bébéar C, Arfi Y, Pereyre S. Improved transformation efficiency in Mycoplasma hominis enables disruption of the MIB-MIP system targeting human immunoglobulins. Microbiol Spectr 2023; 11:e0187323. [PMID: 37737635 PMCID: PMC10581049 DOI: 10.1128/spectrum.01873-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/18/2023] [Indexed: 09/23/2023] Open
Abstract
The pathogenicity of Mycoplasma hominis is poorly understood, mainly due to the absence of efficient genetic tools. A polyethylene glycol-mediated transformation protocol was recently developed for the M. hominis reference strain M132 using the pMT85-Tet plasmid. The transformation efficiency remained low, hampering generation of a large mutant library. In this study, we improved transformation efficiency by designing M. hominis-specific pMT85 derivatives. Using the Gibson Assembly, the Enterococcus-derived tet(M) gene of the pMT85-Tet plasmid was replaced by that of a M. hominis clinical isolate. Next, the Spiroplasma-derived spiralin gene promoter driving tet(M) expression was substituted by one of three putative regulatory regions (RRs): the M. hominis arginine deiminase RR, the M. hominis elongation factor Tu RR, or the 68 bp SynMyco synthetic RR. SynMyco-based construction led to a 100-fold increase in transformation efficiency in M. hominis M132. This construct was also transformed into the M. hominis PG21 reference strain and three other clinical isolates. The transposon insertion locus was determined for 128 M132-transformants. The majority of the impacted coding sequences encoded lipoproteins and proteins involved in DNA repair or in gene transfer. One transposon integration site was in the mycoplasma immunoglobulin protease gene. Phenotypic characterization of the mutant showed complete disruption of the human antibody cleavage ability of the transformant. These results demonstrate that our M. hominis-optimized plasmid can be used to generate large random transposon insertion libraries, enabling future studies of the pathogenicity of M. hominis. IMPORTANCE Mycoplasma hominis is an opportunistic human pathogen, whose physiopathology is poorly understood and for which genetic tools for transposition mutagenesis have been unavailable for years. A PEG-mediated transformation protocol was developed using the pMT85-Tet plasmid, but the transformation efficiency remained low. We designed a modified pMT85-Tet plasmid suitable for M. hominis. The use of a synthetic regulatory region upstream of the antibiotic resistance marker led to a 100-fold increase in the transformation efficiency. The generation and characterization of large transposon mutagenesis mutant libraries will provide insight into M. hominis pathogenesis. We selected a transformant in which the transposon was integrated in the locus encoding the immunoglobulin cleavage system MIB-MIP. Phenotypic characterization showed that the wild-type strain has a functional MIB-MIP system, whereas the mutant strain had lost the ability to cleave human immunoglobulins.
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Affiliation(s)
- Jennifer Guiraud
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
- Bacteriology Department, National Reference Centre for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital, Bordeaux, France
| | - Chloé Le Roy
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
| | - Fabien Rideau
- INRAE, BFP, UMR 1332, Univ. Bordeaux, Villenave d Ornon, France
| | | | - Carole Lartigue
- INRAE, BFP, UMR 1332, Univ. Bordeaux, Villenave d Ornon, France
| | - Cécile Bébéar
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
- Bacteriology Department, National Reference Centre for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital, Bordeaux, France
| | - Yonathan Arfi
- INRAE, BFP, UMR 1332, Univ. Bordeaux, Villenave d Ornon, France
| | - Sabine Pereyre
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
- Bacteriology Department, National Reference Centre for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital, Bordeaux, France
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3
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Zhao G, Lu D, Li M, Wang Y. Gene editing tools for mycoplasmas: references and future directions for efficient genome manipulation. Front Microbiol 2023; 14:1191812. [PMID: 37275127 PMCID: PMC10232828 DOI: 10.3389/fmicb.2023.1191812] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023] Open
Abstract
Mycoplasmas are successful pathogens that cause debilitating diseases in humans and various animal hosts. Despite the exceptionally streamlined genomes, mycoplasmas have evolved specific mechanisms to access essential nutrients from host cells. The paucity of genetic tools to manipulate mycoplasma genomes has impeded studies of the virulence factors of pathogenic species and mechanisms to access nutrients. This review summarizes several strategies for editing of mycoplasma genomes, including homologous recombination, transposons, clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system, and synthetic biology. In addition, the mechanisms and features of different tools are discussed to provide references and future directions for efficient manipulation of mycoplasma genomes.
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Affiliation(s)
- Gang Zhao
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources in the Western China, Yinchuan, China
- School of Life Sciences, Ningxia University, Yinchuan, China
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Doukun Lu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Min Li
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources in the Western China, Yinchuan, China
- School of Life Sciences, Ningxia University, Yinchuan, China
| | - Yujiong Wang
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources in the Western China, Yinchuan, China
- School of Life Sciences, Ningxia University, Yinchuan, China
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4
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González-García M, Pérez-López E. Looking for a Cultured Surrogate for Effectome Studies of the Clubroot Pathogen. Front Microbiol 2021; 12:650307. [PMID: 34122364 PMCID: PMC8193517 DOI: 10.3389/fmicb.2021.650307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/05/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Melaine González-García
- Department of Plant Sciences, Faculté des Sciences de l'agriculture et de l'alimentation (FSAA), Université Laval, Québec, QC, Canada
| | - Edel Pérez-López
- Department of Plant Sciences, Faculté des Sciences de l'agriculture et de l'alimentation (FSAA), Université Laval, Québec, QC, Canada
- Centre de recherche et d'innovation sur les végétaux (CRIV), Université Laval, Québec, QC, Canada
- Institut de biologie intégrative et des systèmes (IBIS), Université Laval, Québec, QC, Canada
- Centre de recherche en sciences du végétal (Centre SÈVE), Fonds de recherche du Québec - Nature et technologies (FRQNT), Québec, QC, Canada
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5
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Garcion C, Béven L, Foissac X. Comparison of Current Methods for Signal Peptide Prediction in Phytoplasmas. Front Microbiol 2021; 12:661524. [PMID: 33841387 PMCID: PMC8026896 DOI: 10.3389/fmicb.2021.661524] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/02/2021] [Indexed: 11/13/2022] Open
Abstract
Although phytoplasma studies are still hampered by the lack of axenic cultivation methods, the availability of genome sequences allowed dramatic advances in the characterization of the virulence mechanisms deployed by phytoplasmas, and highlighted the detection of signal peptides as a crucial step to identify effectors secreted by phytoplasmas. However, various signal peptide prediction methods have been used to mine phytoplasma genomes, and no general evaluation of these methods is available so far for phytoplasma sequences. In this work, we compared the prediction performance of SignalP versions 3.0, 4.0, 4.1, 5.0 and Phobius on several sequence datasets originating from all deposited phytoplasma sequences. SignalP 4.1 with specific parameters showed the most exhaustive and consistent prediction ability. However, the configuration of SignalP 4.1 for increased sensitivity induced a much higher rate of false positives on transmembrane domains located at N-terminus. Moreover, sensitive signal peptide predictions could similarly be achieved by the transmembrane domain prediction ability of TMHMM and Phobius, due to the relatedness between signal peptides and transmembrane regions. Beyond the results presented herein, the datasets assembled in this study form a valuable benchmark to compare and evaluate signal peptide predictors in a field where experimental evidence of secretion is scarce. Additionally, this study illustrates the utility of comparative genomics to strengthen confidence in bioinformatic predictions.
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Affiliation(s)
- Christophe Garcion
- INRAE, Univ. Bordeaux, Biologie du Fruit et Pathologie, UMR 1332, Villenave d'Ornon, France
| | - Laure Béven
- INRAE, Univ. Bordeaux, Biologie du Fruit et Pathologie, UMR 1332, Villenave d'Ornon, France
| | - Xavier Foissac
- INRAE, Univ. Bordeaux, Biologie du Fruit et Pathologie, UMR 1332, Villenave d'Ornon, France
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6
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Harne S, Duret S, Pande V, Bapat M, Béven L, Gayathri P. MreB5 Is a Determinant of Rod-to-Helical Transition in the Cell-Wall-less Bacterium Spiroplasma. Curr Biol 2020; 30:4753-4762.e7. [PMID: 32976813 DOI: 10.1016/j.cub.2020.08.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/05/2020] [Accepted: 08/26/2020] [Indexed: 12/22/2022]
Abstract
In most rod-shaped bacteria, the spatial coordination of cell wall synthesis machinery by MreBs is the main theme for shape determination and maintenance in cell-walled bacteria [1-9]. However, how rod or spiral shapes are achieved and maintained in cell-wall-less bacteria is currently unknown. Spiroplasma, a helical Mollicute that lacks cell wall synthesis genes, encodes five MreB paralogs and a unique cytoskeletal protein fibril [10, 11]. Here, we show that MreB5, one of the five MreB paralogs, contributes to cell elongation and is essential for the transition from rod-to-helical shape in Spiroplasma. Comparative genomic and proteomic characterization of a helical and motile wild-type Spiroplasma strain and a non-helical, non-motile natural variant helped delineate the specific roles of MreB5. Moreover, complementation of the non-helical strain with MreB5 restored its helical shape and motility by a kink-based mechanism described for Spiroplasma [12]. Earlier studies had proposed that length changes in fibril filaments are responsible for the change in handedness of the helical cell and kink propagation during motility [13]. Through structural and biochemical characterization, we identify that MreB5 exists as antiparallel double protofilaments that interact with fibril and the membrane, and thus potentially assists in kink propagation. In summary, our study provides direct experimental evidence for MreB in maintaining cell length, helical shape, and motility-revealing the role of MreB in sculpting the cell in the absence of a cell wall.
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Affiliation(s)
- Shrikant Harne
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Sybille Duret
- INRAE, University of Bordeaux, UMR 1332 BFP, Villenave d'Ornon, Bordeaux, France
| | - Vani Pande
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Mrinmayee Bapat
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Laure Béven
- INRAE, University of Bordeaux, UMR 1332 BFP, Villenave d'Ornon, Bordeaux, France.
| | - Pananghat Gayathri
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
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7
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Huang W, Reyes-Caldas P, Mann M, Seifbarghi S, Kahn A, Almeida RPP, Béven L, Heck M, Hogenhout SA, Coaker G. Bacterial Vector-Borne Plant Diseases: Unanswered Questions and Future Directions. MOLECULAR PLANT 2020; 13:1379-1393. [PMID: 32835885 PMCID: PMC7769051 DOI: 10.1016/j.molp.2020.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 06/01/2023]
Abstract
Vector-borne plant diseases have significant ecological and economic impacts, affecting farm profitability and forest composition throughout the world. Bacterial vector-borne pathogens have evolved sophisticated strategies to interact with their hemipteran insect vectors and plant hosts. These pathogens reside in plant vascular tissue, and their study represents an excellent opportunity to uncover novel biological mechanisms regulating intracellular pathogenesis and to contribute to the control of some of the world's most invasive emerging diseases. In this perspective, we highlight recent advances and major unanswered questions in the realm of bacterial vector-borne disease, focusing on liberibacters, phytoplasmas, spiroplasmas, and Xylella fastidiosa.
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Affiliation(s)
- Weijie Huang
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Paola Reyes-Caldas
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA
| | - Marina Mann
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Shirin Seifbarghi
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA
| | - Alexandra Kahn
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Rodrigo P P Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Laure Béven
- UMR 1332 Biologie du Fruit et Pathologie, Univ. Bordeaux, INRAE, Villenave d'Ornon 33882 France
| | - Michelle Heck
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; Boyce Thompson Institute, Ithaca, NY 14853, USA; Emerging Pests and Pathogens Research Unit, Robert W. Holley Center, USDA ARS, Ithaca, NY 14853, USA
| | - Saskia A Hogenhout
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK; School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA.
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8
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Malembic-Maher S, Desqué D, Khalil D, Salar P, Bergey B, Danet JL, Duret S, Dubrana-Ourabah MP, Beven L, Ember I, Acs Z, Della Bartola M, Materazzi A, Filippin L, Krnjajic S, Krstić O, Toševski I, Lang F, Jarausch B, Kölber M, Jović J, Angelini E, Arricau-Bouvery N, Maixner M, Foissac X. When a Palearctic bacterium meets a Nearctic insect vector: Genetic and ecological insights into the emergence of the grapevine Flavescence dorée epidemics in Europe. PLoS Pathog 2020; 16:e1007967. [PMID: 32210479 PMCID: PMC7135369 DOI: 10.1371/journal.ppat.1007967] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 04/06/2020] [Accepted: 02/18/2020] [Indexed: 11/28/2022] Open
Abstract
Flavescence dorée (FD) is a European quarantine grapevine disease transmitted by the Deltocephalinae leafhopper Scaphoideus titanus. Whereas this vector had been introduced from North America, the possible European origin of FD phytoplasma needed to be challenged and correlated with ecological and genetic drivers of FD emergence. For that purpose, a survey of genetic diversity of these phytoplasmas in grapevines, S. titanus, black alders, alder leafhoppers and clematis were conducted in five European countries. Out of 132 map genotypes, only 11 were associated to FD outbreaks, three were detected in clematis, whereas 127 were detected in alder trees, alder leafhoppers or in grapevines out of FD outbreaks. Most of the alder trees were found infected, including 8% with FD genotypes M6, M38 and M50, also present in alders neighboring FD-free vineyards and vineyard-free areas. The Macropsinae Oncopsis alni could transmit genotypes unable to achieve transmission by S. titanus, while the Deltocephalinae Allygus spp. and Orientus ishidae transmitted M38 and M50 that proved to be compatible with S. titanus. Variability of vmpA and vmpB adhesin-like genes clearly discriminated 3 genetic clusters. Cluster Vmp-I grouped genotypes only transmitted by O. alni, while clusters Vmp-II and -III grouped genotypes transmitted by Deltocephalinae leafhoppers. Interestingly, adhesin repeated domains evolved independently in cluster Vmp-I, whereas in clusters Vmp-II and-III showed recent duplications. Latex beads coated with various ratio of VmpA of clusters II and I, showed that cluster II VmpA promoted enhanced adhesion to the Deltocephalinae Euscelidius variegatus epithelial cells and were better retained in both E. variegatus and S. titanus midguts. Our data demonstrate that most FD phytoplasmas are endemic to European alders. Their emergence as grapevine epidemic pathogens appeared restricted to some genetic variants pre-existing in alders, whose compatibility to S. titanus correlates with different vmp gene sequences and VmpA binding properties.
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Affiliation(s)
| | | | - Dima Khalil
- INRAE, Univ. Bordeaux, UMR BFP, Villenave d’Ornon, France
| | - Pascal Salar
- INRAE, Univ. Bordeaux, UMR BFP, Villenave d’Ornon, France
| | - Bernard Bergey
- INRAE, Univ. Bordeaux, UMR BFP, Villenave d’Ornon, France
| | - Jean-Luc Danet
- INRAE, Univ. Bordeaux, UMR BFP, Villenave d’Ornon, France
| | - Sybille Duret
- INRAE, Univ. Bordeaux, UMR BFP, Villenave d’Ornon, France
| | | | - Laure Beven
- INRAE, Univ. Bordeaux, UMR BFP, Villenave d’Ornon, France
| | | | - Zoltan Acs
- Genlogs Biodiagnosztika Ltd, Budapest, Hungary
| | | | - Alberto Materazzi
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy
| | | | - Slobodan Krnjajic
- Department of Plant Pests, Institute of Plant Protection and Environment, Zemun, Serbia
| | - Oliver Krstić
- Department of Plant Pests, Institute of Plant Protection and Environment, Zemun, Serbia
| | - Ivo Toševski
- Department of Plant Pests, Institute of Plant Protection and Environment, Zemun, Serbia
- CABI, Delémont, Switzerland
| | - Friederike Lang
- JKI, Institute for Plant Protection in Fruit Crops and Viticulture, Siebeldingen, Germany
| | - Barbara Jarausch
- JKI, Institute for Plant Protection in Fruit Crops and Viticulture, Siebeldingen, Germany
| | | | - Jelena Jović
- Department of Plant Pests, Institute of Plant Protection and Environment, Zemun, Serbia
| | | | | | - Michael Maixner
- JKI, Institute for Plant Protection in Fruit Crops and Viticulture, Siebeldingen, Germany
| | - Xavier Foissac
- INRAE, Univ. Bordeaux, UMR BFP, Villenave d’Ornon, France
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9
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Genetic Diversity of Flavescence Dorée Phytoplasmas at the Vineyard Scale. Appl Environ Microbiol 2019; 85:AEM.03123-18. [PMID: 30877117 DOI: 10.1128/aem.03123-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 02/24/2019] [Indexed: 11/20/2022] Open
Abstract
To study the role of wild areas around the vineyards in the epidemiology of flavescence dorée (FD) and track the origin of new foci, two phytoplasma genetic markers, dnaK and malG, were developed for FD phytoplasma (FDp) characterization. The two genes and the vmpA locus were used to genetically characterize FDp populations at seven agroecosystems of a wine-growing Italian region. Vitis vinifera, "gone-wild" V. vinifera and rootstocks, Clematis spp., and Scaphoideus titanus adults were sampled within and outside the vineyards. A range of genotypes infecting the different hosts of the FDp epidemiological cycle was found. Type FD-C isolates were fairly homogeneous compared to type FD-D ones. Most of the FD-D variability was correlated with the malG sequence, and a duplication of this locus was demonstrated for this strain. Coinfection with FD-C and FD-D strains was rare, suggesting possible competition between the two. Similar levels of FDp genetic variation recorded for grapevines or leafhoppers of cultivated and wild areas and co-occurrence of many FDp genotypes inside and outside the vineyards supported the idea of the importance of wild or abandoned Vitis plants and associated S. titanus insects in the epidemiology of the disease. Genetic profiles of FDp found in Clematis were never found in the other hosts, indicating that this species does not take part in the disease cycle in the area. Due to the robustness of analyses using dnaK for discriminating between FD-C and FD-D strains and the high variability of malG sequences, these are efficient markers to study FDp populations and epidemiology at a small geographical scale.IMPORTANCE Flavescence dorée, a threatening disease of grapevine caused by FD phytoplasma (FDp), is distributed within the most important wine-producing areas of Europe and has severe effects on both vineyard productivity and landscape management. FDp is a quarantine pest in Europe, and despite the efforts to contain the pathogen, the disease is still spreading. In this work, new genetic markers for the fine genetic characterization of FDp at local scale are presented. Our findings improve the knowledge of FDp epidemiological cycle and offer the possibility of tracking the route of the FDp infection. In particular, due to its high genetic variability, one of the newly developed markers could be sufficient to track the origin of new infection foci, either from the wild areas or from nurseries.
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10
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Variable Membrane Protein A of Flavescence Dorée Phytoplasma Binds the Midgut Perimicrovillar Membrane of Euscelidius variegatus and Promotes Adhesion to Its Epithelial Cells. Appl Environ Microbiol 2018; 84:AEM.02487-17. [PMID: 29439985 DOI: 10.1128/aem.02487-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/30/2018] [Indexed: 01/27/2023] Open
Abstract
Phytoplasmas are uncultivated plant pathogens and cell wall-less bacteria and are transmitted from plant to plant by hemipteran insects. The phytoplasma's circulative propagative cycle in insects requires the crossing of the midgut and salivary glands, and primary adhesion to cells is an initial step toward the invasion process. The flavescence dorée (FD) phytoplasma possesses a set of variable membrane proteins (Vmps) exposed on its surface, and this pathogen is suspected to interact with insect cells. The results showed that VmpA is expressed by the flavescence dorée phytoplasma present in the midgut and salivary glands. Phytoplasmas cannot be cultivated at present, and no mutant can be produced to investigate the putative role of Vmps in the adhesion of phytoplasma to insect cells. To overcome this difficulty, we engineered the Spiroplasma citri mutant G/6, which lacks the ScARP adhesins, for VmpA expression and used VmpA-coated fluorescent beads to determine if VmpA acts as an adhesin in ex vivo adhesion assays and in vivo ingestion assays. VmpA specifically interacted with Euscelidius variegatus insect cells in culture and promoted the retention of VmpA-coated beads to the midgut of E. variegatus In this latest case, VmpA-coated fluorescent beads were localized and embedded in the perimicrovillar membrane of the insect midgut. Thus, VmpA functions as an adhesin that could be essential in the colonization of the insect by the FD phytoplasmas.IMPORTANCE Phytoplasmas infect a wide variety of plants, ranging from wild plants to cultivated species, and are transmitted by different leafhoppers, planthoppers, and psyllids. The specificity of the phytoplasma-insect vector interaction has a major impact on the phytoplasma plant host range. As entry into insect cells is an obligate process for phytoplasma transmission, the bacterial adhesion to insect cells is a key step. Thus, studying surface-exposed proteins of phytoplasma will help to identify the adhesins implicated in the specific recognition of insect vectors. In this study, it is shown that the membrane protein VmpA of the flavescence dorée (FD) phytoplasma acts as an adhesin that is able to interact with cells of Euscelidius variegatus, the experimental vector of the FD phytoplasma.
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11
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Dubrana MP, Guéguéniat J, Bertin C, Duret S, Arricau-Bouvery N, Claverol S, Lartigue C, Blanchard A, Renaudin J, Béven L. Proteolytic Post-Translational Processing of Adhesins in a Pathogenic Bacterium. J Mol Biol 2017; 429:1889-1902. [PMID: 28501585 DOI: 10.1016/j.jmb.2017.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 04/25/2017] [Accepted: 05/04/2017] [Indexed: 11/29/2022]
Abstract
Mollicutes, including mycoplasmas and spiroplasmas, have been considered as good representatives of the « minimal cell » concept: these wall-less bacteria are small in size and possess a minimal genome and restricted metabolic capacities. However, the recent discovery of the presence of post-translational modifications unknown so far, such as the targeted processing of membrane proteins of mycoplasma pathogens for human and swine, revealed a part of the hidden complexity of these microorganisms. In this study, we show that in the phytopathogen, insect-vectored Spiroplasma citri GII-3 adhesion-related protein (ScARP) adhesins are post-translationally processed through an ATP-dependent targeted cleavage. The cleavage efficiency could be enhanced in vitro when decreasing the extracellular pH or upon the addition of polyclonal antibodies directed against ScARP repeated units, suggesting that modification of the surface charge and/or ScARP conformational changes could initiate the cleavage. The two major sites for primary cleavage are localized within predicted disordered regions and do not fit any previously reported cleavage motif; in addition, the inhibition profile and the metal ion requirements indicate that this post-translational modification involves at least one non-conventional protease. Such a proteolytic process may play a role in S. citri colonization of cells of the host insect. Furthermore, our work indicates that post-translational cleavage of adhesins represents a common feature to mollicutes colonizing distinct hosts and that processing of surface antigens could represent a way to make the most out of a minimal genome.
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Affiliation(s)
| | - Julia Guéguéniat
- UMR BFP 1332, Univ. Bordeaux, INRA, Villenave d'Ornon, 33882 France
| | - Clothilde Bertin
- UMR BFP 1332, Univ. Bordeaux, INRA, Villenave d'Ornon, 33882 France
| | - Sybille Duret
- UMR BFP 1332, Univ. Bordeaux, INRA, Villenave d'Ornon, 33882 France
| | | | | | - Carole Lartigue
- UMR BFP 1332, Univ. Bordeaux, INRA, Villenave d'Ornon, 33882 France
| | - Alain Blanchard
- UMR BFP 1332, Univ. Bordeaux, INRA, Villenave d'Ornon, 33882 France
| | - Joël Renaudin
- UMR BFP 1332, Univ. Bordeaux, INRA, Villenave d'Ornon, 33882 France
| | - Laure Béven
- UMR BFP 1332, Univ. Bordeaux, INRA, Villenave d'Ornon, 33882 France.
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Perilla-Henao LM, Casteel CL. Vector-Borne Bacterial Plant Pathogens: Interactions with Hemipteran Insects and Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:1163. [PMID: 27555855 PMCID: PMC4977473 DOI: 10.3389/fpls.2016.01163] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 07/20/2016] [Indexed: 05/22/2023]
Abstract
Hemipteran insects are devastating pests of crops due to their wide host range, rapid reproduction, and ability to transmit numerous plant-infecting pathogens as vectors. While the field of plant-virus-vector interactions has flourished in recent years, plant-bacteria-vector interactions remain poorly understood. Leafhoppers and psyllids are by far the most important vectors of bacterial pathogens, yet there are still significant gaps in our understanding of their feeding behavior, salivary secretions, and plant responses as compared to important viral vectors, such as whiteflies and aphids. Even with an incomplete understanding of plant-bacteria-vector interactions, some common themes have emerged: (1) all known vector-borne bacteria share the ability to propagate in the plant and insect host; (2) particular hemipteran families appear to be incapable of transmitting vector-borne bacteria; (3) all known vector-borne bacteria have highly reduced genomes and coding capacity, resulting in host-dependence; and (4) vector-borne bacteria encode proteins that are essential for colonization of specific hosts, though only a few types of proteins have been investigated. Here, we review the current knowledge on important vector-borne bacterial pathogens, including Xylella fastidiosa, Spiroplasma spp., Liberibacter spp., and 'Candidatus Phytoplasma spp.'. We then highlight recent approaches used in the study of vector-borne bacteria. Finally, we discuss the application of this knowledge for control and future directions that will need to be addressed in the field of vector-plant-bacteria interactions.
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Affiliation(s)
| | - Clare L. Casteel
- Department of Plant Pathology, University of California at Davis, Davis, CAUSA
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Bonnefois T, Vernerey MS, Rodrigues V, Totté P, Puech C, Ripoll C, Thiaucourt F, Manso-Silván L. Development of fluorescence expression tools to study host-mycoplasma interactions and validation in two distant mycoplasma clades. J Biotechnol 2016; 236:35-44. [PMID: 27497759 DOI: 10.1016/j.jbiotec.2016.08.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 07/27/2016] [Accepted: 08/04/2016] [Indexed: 11/30/2022]
Abstract
Fluorescence expression tools for stable and innocuous whole mycoplasma cell labelling have been developed. A Tn4001-derivative mini-transposon affording unmarked, stable mutagenesis in mycoplasmas was modified to allow the constitutive, high-level expression of mCherry, mKO2 and mNeonGreen. These tools were used to introduce the respective fluorescent proteins as chromosomal tags in the phylogenetically distant species Mycoplasma mycoides subsp. mycoides and Mycoplasma bovis. The production, selection and characterisation of fluorescent clones were straightforward and resulted in the unprecedented observation of red and green fluorescent mycoplasma colonies in the two species, with no apparent cytotoxicity. Equivalent fluorescence expression levels were quantified by flow cytometry in both species, suggesting that these tools can be broadly applied in mycoplasmas. A macrophage infection assay was performed to assess the usefulness of mNeonGreen-expressing strains for monitoring mycoplasma infections, and notably cell invasion. The presence of fluorescent mycoplasmas inside live phagocytic cells was detected and quantified by flow cytometry and corroborated by confocal microscopy, which allowed the identification of individual mycoplasmas in the cytoplasm of infected cells. The fluorescence expression tools developed in this study are suitable for host-pathogen interaction studies and offer innumerable perspectives for the functional analysis of mycoplasmas both in vitro and in vivo.
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Affiliation(s)
- Tiffany Bonnefois
- CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
| | - Marie-Stéphanie Vernerey
- INRA, Joint Research Unit 385 UMR BGPI, Campus International de Baillarguet, Montpellier, France.
| | - Valérie Rodrigues
- CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
| | - Philippe Totté
- CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
| | - Carinne Puech
- CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
| | - Chantal Ripoll
- INSERM U1051-Hôpital Saint Eloi INM. 80, rue Augustin Fliche, 34091 Montpellier cedex 5, France.
| | - François Thiaucourt
- CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
| | - Lucía Manso-Silván
- CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
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Role of the major antigenic membrane protein in phytoplasma transmission by two insect vector species. BMC Microbiol 2015; 15:193. [PMID: 26424332 PMCID: PMC4589916 DOI: 10.1186/s12866-015-0522-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/18/2015] [Indexed: 11/17/2022] Open
Abstract
Background Phytoplasmas are bacterial plant pathogens (class Mollicutes), transmitted by phloem feeding leafhoppers, planthoppers and psyllids in a persistent/propagative manner. Transmission of phytoplasmas is under the control of behavioral, environmental and geographical factors, but molecular interactions between membrane proteins of phytoplasma and vectors may also be involved. The aim of the work was to provide experimental evidence that in vivo interaction between phytoplasma antigenic membrane protein (Amp) and vector proteins has a role in the transmission process. In doing so, we also investigated the topology of the interaction at the gut epithelium and at the salivary glands, the two barriers encountered by the phytoplasma during vector colonization. Methods Experiments were performed on the ‘Candidatus Phytoplasma asteris’ chrysanthemum yellows strain (CYP), and the two leafhopper vectors Macrosteles quadripunctulatus Kirschbaum and Euscelidius variegatus Kirschbaum. To specifically address the interaction of CYP Amp at the gut epithelium barrier, insects were artificially fed with media containing either the recombinant phytoplasma protein Amp, or the antibody (A416) or both, and transmission, acquisition and inoculation efficiencies were measured. An abdominal microinjection protocol was employed to specifically address the interaction of CYP Amp at the salivary gland barrier. Phytoplasma suspension was added with Amp or A416 or both, injected into healthy E. variegatus adults and then infection and inoculation efficiencies were measured. An internalization assay was developed, consisting of dissected salivary glands from healthy E. variegatus exposed to phytoplasma suspension alone or together with A416 antibody. The organs were then either observed in confocal microscopy or subjected to DNA extraction and phytoplasma quantification by qPCR, to visualize and quantify possible differences among treatments in localization/presence/number of CYP cells. Results Artificial feeding and abdominal microinjection protocols were developed to address the two barriers separately. The in vivo interactions between Amp of ‘Candidatus Phytoplasma asteris’ Chrysanthemum yellows strain (CYP) and vector proteins were studied by evaluating their effects on phytoplasma transmission by Euscelidius variegatus and Macrosteles quadripunctulatus leafhoppers. An internalization assay was developed, consisting of dissected salivary glands from healthy E. variegatus exposed to phytoplasma suspension alone or together with anti-Amp antibody. To visualize possible differences among treatments in localization/presence of CYP cells, the organs were observed in confocal microscopy. Pre-feeding of E. variegatus and M. quadripunctulatus on anti-Amp antibody resulted in a significant decrease of acquisition efficiencies in both species. Inoculation efficiency of microinjected E. variegatus with CYP suspension and anti-Amp antibody was significantly reduced compared to that of the control with phytoplasma suspension only. The possibility that this was due to reduced infection efficiency or antibody-mediated inhibition of phytoplasma multiplication was ruled out. These results provided the first indirect proof of the role of Amp in the transmission process. Conclusion Protocols were developed to assess the in vivo role of the phytoplasma native major antigenic membrane protein in two phases of the vector transmission process: movement through the midgut epithelium and colonization of the salivary glands. These methods will be useful also to characterize other phytoplasma-vector combinations. Results indicated for the first time that native CYP Amp is involved in vivo in specific crossing of the gut epithelium and salivary gland colonization during early phases of vector infection. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0522-5) contains supplementary material, which is available to authorized users.
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