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Gallinger J, Zikeli K, Zimmermann MR, Görg LM, Mithöfer A, Reichelt M, Seemüller E, Gross J, Furch ACU. Specialized 16SrX phytoplasmas induce diverse morphological and physiological changes in their respective fruit crops. PLoS Pathog 2021; 17:e1009459. [PMID: 33765095 PMCID: PMC8023467 DOI: 10.1371/journal.ppat.1009459] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/06/2021] [Accepted: 03/07/2021] [Indexed: 11/19/2022] Open
Abstract
The host-pathogen combinations-Malus domestica (apple)/`Candidatus Phytoplasma mali´, Prunus persica (peach)/`Ca. P. prunorum´ and Pyrus communis (pear)/`Ca. P. pyri´ show different courses of diseases although the phytoplasma strains belong to the same 16SrX group. While infected apple trees can survive for decades, peach and pear trees die within weeks to few years. To this date, neither morphological nor physiological differences caused by phytoplasmas have been studied in these host plants. In this study, phytoplasma-induced morphological changes of the vascular system as well as physiological changes of the phloem sap and leaf phytohormones were analysed and compared with non-infected plants. Unlike peach and pear, infected apple trees showed substantial reductions in leaf and vascular area, affecting phloem mass flow. In contrast, in infected pear mass flow and physicochemical characteristics of phloem sap increased. Additionally, an increased callose deposition was detected in pear and peach leaves but not in apple trees in response to phytoplasma infection. The phytohormone levels in pear were not affected by an infection, while in apple and peach trees concentrations of defence- and stress-related phytohormones were increased. Compared with peach and pear trees, data from apple suggest that the long-lasting morphological adaptations in the vascular system, which likely cause reduced sap flow, triggers the ability of apple trees to survive phytoplasma infection. Some phytohormone-mediated defences might support the tolerance.
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Affiliation(s)
- Jannicke Gallinger
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Kerstin Zikeli
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Matthias R. Zimmermann
- Plant Physiology, Matthias-Schleiden-Institute for Genetics, Bioinformatics and Molecular Botany, Faculty of Biological Science, Friedrich-Schiller-University Jena, Jena, Germany
| | - Louisa M. Görg
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Axel Mithöfer
- Research Group Plant Defense Physiology, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Michael Reichelt
- Department of Biochemistry, Max-Planck Institute for Chemical Ecology, Jena, Germany
| | - Erich Seemüller
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Jürgen Gross
- Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Dossenheim, Germany
| | - Alexandra C. U. Furch
- Plant Physiology, Matthias-Schleiden-Institute for Genetics, Bioinformatics and Molecular Botany, Faculty of Biological Science, Friedrich-Schiller-University Jena, Jena, Germany
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2
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Sargolzaei M, Rustioni L, Cola G, Ricciardi V, Bianco PA, Maghradze D, Failla O, Quaglino F, Toffolatti SL, De Lorenzis G. Georgian Grapevine Cultivars: Ancient Biodiversity for Future Viticulture. FRONTIERS IN PLANT SCIENCE 2021; 12:630122. [PMID: 33613611 PMCID: PMC7892605 DOI: 10.3389/fpls.2021.630122] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/13/2021] [Indexed: 05/14/2023]
Abstract
Grapevine (Vitis vinifera) is one of the most widely cultivated plant species of agricultural interest, and is extensively appreciated for its fruits and the wines made from its fruits. Considering the high socio-economic impact of the wine sector all over the world, in recent years, there has been an increase in work aiming to investigate the biodiversity of grapevine germplasm available for breeding programs. Various studies have shed light on the genetic diversity characterizing the germplasm from the cradle of V. vinifera domestication in Georgia (South Caucasus). Georgian germplasm is placed in a distinct cluster from the European one and possesses a rich diversity for many different traits, including eno-carpological and phenological traits; resistance to pathogens, such as oomycetes and phytoplasmas; resistance to abiotic stresses, such as sunburn. The aim of this review is to assess the potential of Georgian cultivars as a source of useful traits for breeding programs. The unique genetic and phenotypic aspects of Georgian germplasm were unraveled, to better understand the diversity and quality of the genetic resources available to viticulturists, as valuable resources for the coming climate change scenario.
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Affiliation(s)
- Maryam Sargolzaei
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
| | - Laura Rustioni
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento – Centro Ecotekne, Lecce, Italy
| | - Gabriele Cola
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
| | - Valentina Ricciardi
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
| | - Piero A. Bianco
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
| | - David Maghradze
- Faculty of Viticulture and Winemaking, Caucasus International University, Tbilisi, Georgia
- National Wine Agency of Georgia, Tbilisi, Georgia
| | - Osvaldo Failla
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
| | - Fabio Quaglino
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
| | - Silvia L. Toffolatti
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
- *Correspondence: Silvia L. Toffolatti,
| | - Gabriella De Lorenzis
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milan, Italy
- Gabriella De Lorenzis,
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3
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Jollard C, Foissac X, Desqué D, Razan F, Garcion C, Beven L, Eveillard S. Flavescence Dorée Phytoplasma Has Multiple ftsH Genes that Are Differentially Expressed in Plants and Insects. Int J Mol Sci 2019; 21:E150. [PMID: 31878312 PMCID: PMC6981957 DOI: 10.3390/ijms21010150] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 12/24/2022] Open
Abstract
Flavescence dorée (FD) is a severe epidemic disease of grapevines caused by FD phytoplasma (FDP) transmitted by the leafhopper vector Scaphoideus titanus. The recent sequencing of the 647-kbp FDP genome highlighted an unusual number of genes encoding ATP-dependent zinc proteases FtsH, which have been linked to variations in the virulence of "Candidatus Phytoplasma mali" strains. The aims of the present study were to predict the FtsH repertoire of FDP, to predict the functional domains and topologies of the encoded proteins in the phytoplasma membrane and to measure the expression profiles in different hosts. Eight complete ftsH genes have been identified in the FDP genome. In addition to ftsH6, which appeared to be the original bacterial ortholog, the other seven gene copies were clustered on a common distinct phylogenetic branch, suggesting intra-genome duplication of ftsH. The expression of these proteins, quantified in plants and insect vectors in natural and experimental pathosystems, appeared to be modulated in a host-dependent manner. Two of the eight FtsH C-tails were predicted by Phobius software to be extracellular and, therefore, in direct contact with the host cellular content. As phytoplasmas cannot synthesize amino acids, our data raised questions regarding the involvement of FtsH in the adaptation to hosts via potentially enhanced recycling of phytoplasma cellular proteins and host protein degradation.
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Affiliation(s)
| | | | | | | | | | | | - Sandrine Eveillard
- UMR 1332, INRAE, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (C.J.); (X.F.); (D.D.); (F.R.); (C.G.); (L.B.)
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4
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Mittelberger C, Stellmach H, Hause B, Kerschbamer C, Schlink K, Letschka T, Janik K. A Novel Effector Protein of Apple Proliferation Phytoplasma Disrupts Cell Integrity of Nicotiana spp. Protoplasts. Int J Mol Sci 2019; 20:E4613. [PMID: 31540359 PMCID: PMC6770106 DOI: 10.3390/ijms20184613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 09/13/2019] [Accepted: 09/14/2019] [Indexed: 01/19/2023] Open
Abstract
Effector proteins play an important role in the virulence of plant pathogens such as phytoplasma, which are the causative agents of hundreds of different plant diseases. The plant hosts comprise economically relevant crops such as apples (Malus × domestica), which can be infected by 'Candidatus Phytoplasma mali' (P. mali), a highly genetically dynamic plant pathogen. As the result of the genetic and functional analyses in this study, a new putative P. mali effector protein was revealed. The so-called "Protein in Malus Expressed 2" (PME2), which is expressed in apples during P. mali infection but not in the insect vector, shows regional genetic differences. In a heterologous expression assay using Nicotiana benthamiana and Nicotiana occidentalis mesophyll protoplasts, translocation of both PME2 variants in the cell nucleus was observed. Overexpression of the effector protein affected cell integrity in Nicotiana spp. protoplasts, indicating a potential role of this protein in pathogenic virulence. Interestingly, the two genetic variants of PME2 differ regarding their potential to manipulate cell integrity. However, the exact function of PME2 during disease manifestation and symptom development remains to be further elucidated. Aside from the first description of the function of a novel effector of P. mali, the results of this study underline the necessity for a more comprehensive description and understanding of the genetic diversity of P. mali as an indispensable basis for a functional understanding of apple proliferation disease.
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Affiliation(s)
- Cecilia Mittelberger
- Applied Genomics and Molecular Biology, Laimburg Research Centre, 39040 Auer/Ora (BZ), Italy.
| | - Hagen Stellmach
- Jasmonate Function & Mycorrhiza, Leibniz Institute of Plant Biochemistry, 06120 Halle, Germany.
| | - Bettina Hause
- Jasmonate Function & Mycorrhiza, Leibniz Institute of Plant Biochemistry, 06120 Halle, Germany.
| | - Christine Kerschbamer
- Applied Genomics and Molecular Biology, Laimburg Research Centre, 39040 Auer/Ora (BZ), Italy.
| | - Katja Schlink
- Applied Genomics and Molecular Biology, Laimburg Research Centre, 39040 Auer/Ora (BZ), Italy.
| | - Thomas Letschka
- Applied Genomics and Molecular Biology, Laimburg Research Centre, 39040 Auer/Ora (BZ), Italy.
| | - Katrin Janik
- Applied Genomics and Molecular Biology, Laimburg Research Centre, 39040 Auer/Ora (BZ), Italy.
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5
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Contaldo N, D'Amico G, Paltrinieri S, Diallo HA, Bertaccini A, Arocha Rosete Y. Molecular and biological characterization of phytoplasmas from coconut palms affected by the lethal yellowing disease in Africa. Microbiol Res 2019; 223-225:51-57. [PMID: 31178051 DOI: 10.1016/j.micres.2019.03.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/26/2019] [Accepted: 03/29/2019] [Indexed: 01/06/2023]
Abstract
Côte d'Ivoire lethal yellowing (CILY) is a devastating disease associated with phytoplasmas and has recently rapidly spread to several coconut-growing areas in the Country. Phytoplasmas are phloem-restricted bacteria that affect plant species worldwide. These bacteria are transmitted by plant sap-feeding insects, and their cultivation was recently achieved in complex artificial media. In this study, phytoplasmas were isolated for the first time from coconut palm trunk borings in both solid and liquid media from CILY symptom-bearing and symptomless coconut palms. The colony morphology, PCR and sequencing analyses indicated the presence of phytoplasmas from different ribosomal groups. This study reports the first biochemical characterization of two of these phytoplasma isolates. Moreover, a disc-diffusion antibiotic susceptibility assay revealed that these bacteria exhibit tobramycin susceptibility and cephalexin hydrate and rifampicin resistance. Urea and arginine hydrolysis, and glucose fermentation tests that were performed on colonies of phytoplasmas and Acholeplasma laidlawii indicated that both phytoplasmas tested were negative for urea and positive for glucose and arginine, whereas A. laidlawii was positive for glucose and negative for urea and arginine. The growth of coconut phytoplasmas in both solid and liquid artificial media and the biological characterization of these isolates are novel and important advancements in the field of disease management and containment measures for the CILY disease. The characterization of isolated phytoplasmas will allow for more efficient management strategies in both the prevention of a coconut phytoplasma epidemics and the reduction of the economic impact of the disease in the affected areas.
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Affiliation(s)
- Nicoletta Contaldo
- Department of Agricultural and Food Sciences, Plant Pathology, Alma Mater Studiorum, University of Bologna, viale G. Fanin, 40, 40127 Bologna, Italy.
| | - Gianfranco D'Amico
- Department of Agricultural and Food Sciences, Plant Pathology, Alma Mater Studiorum, University of Bologna, viale G. Fanin, 40, 40127 Bologna, Italy
| | - Samanta Paltrinieri
- Department of Agricultural and Food Sciences, Plant Pathology, Alma Mater Studiorum, University of Bologna, viale G. Fanin, 40, 40127 Bologna, Italy
| | | | - Assunta Bertaccini
- Department of Agricultural and Food Sciences, Plant Pathology, Alma Mater Studiorum, University of Bologna, viale G. Fanin, 40, 40127 Bologna, Italy
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6
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Abstract
Phytoplasmas are associated with diseases in several hundreds of cultivated herbaceous and woody plants. Their impact in agriculture and the periodical outbreak of worrying epidemics make very important, besides precise laboratory-based diagnosis, the direct in-field recognition of phytoplasma disease symptoms. Even if some symptoms are typical of this kind of pathogens, in-field diagnosis requires the knowledge of the host plant, strong field experience, and awareness of the symptom variability of the various organs of the plant during different seasons and under various environmental conditions. It is therefore very important to be familiar with factors like environmental conditions, agronomical features, and disease progression that influence symptom expression. Therefore, a satisfactory diagnosis should be based on repeated and complete observations scored over the entire plant and across different times of the year. A more suitable diagnosis is possible if the observer is able to recognize and distinguish the symptoms of other biotic or abiotic diseases. A general rule is to observe three different symptoms, at least, and to seek input from the grower about the initial development, frequency, diffusion, and particular characteristics of the disease.After a short introduction the following symptoms are presented: the most common and representative symptoms caused by phytoplasmas; the most common symptoms of phytoplasma diseases occurring in particular plant organs, with some references to specific diseases; phytoplasma symptoms on the model plant periwinkle (Vinca rosea or Catharanthus roseus); the main factors influencing phytoplasma symptoms expression; and several practical procedures that should be followed for suitable diagnosis. A series of original photos have been included to illustrate typical symptoms.
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Affiliation(s)
- Paolo Ermacora
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy.
| | - Ruggero Osler
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
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7
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Pierro R, Passera A, Panattoni A, Casati P, Luvisi A, Rizzo D, Bianco PA, Quaglino F, Materazzi A. Molecular Typing of Bois Noir Phytoplasma Strains in the Chianti Classico Area (Tuscany, Central Italy) and Their Association with Symptom Severity in Vitis vinifera 'Sangiovese'. PHYTOPATHOLOGY 2018; 108:362-373. [PMID: 29027886 DOI: 10.1094/phyto-06-17-0215-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Bois noir (BN) is the most widespread disease of the grapevine yellows complex in the Euro-Mediterranean area. BN is caused by 'Candidatus Phytoplasma solani' (BNp), transmitted from herbaceous plants to grapevine by polyphagous insect vectors. In this study, genetic diversity among BNp strains and their prevalence and possible association with grapevine symptom severity were investigated in a Sangiovese clone organic vineyard in the Chianti Classico area (Tuscany). Field surveys over 2 years revealed a range of symptom severity on grapevine and an increase of BN incidence. A TaqMan allelic discrimination assay detected only tufB type b among BNp strains, suggesting the prevalence of the bindweed-related ecology. Nucleotide sequence analyses of vmp1 and stamp genes identified 12 vmp1 and 16 stamp sequence variants, showing an overall positive selection for such genes. The prevalent genotype was Vm43/St10, reported for the first time in this study and closely related to strains identified only in the French Eastern Pyrenees. BNp strains identified in the examined vineyard and mostly grouped in separate bindweed-related phylogenetic clusters showed statistically significant differences in their distribution in grapevines exhibiting distinct symptom severity. These results suggest the possible occurrence of a range of virulence within BNp strain populations in the Chianti Classico area.
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Affiliation(s)
- R Pierro
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - A Passera
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - A Panattoni
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - P Casati
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - A Luvisi
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - D Rizzo
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - P A Bianco
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - F Quaglino
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
| | - A Materazzi
- First, third, fifth, and ninth authors: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy; second, fourth, seventh, and eighth authors: Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, via Celoria 2, 20133 Milano, Italy; fifth author: Department of Biological and Environmental Sciences and Technologies-University of Salento, via Provinciale Monteroni, 73100 Lecce, Italy; and sixth author: Regional Phytosanitary Service, Laboratory of Phytopathological Diagnostics and Molecular Biology, via Ciliegiole 99, 51100 Pistoia, Italy
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8
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Janik K, Mithöfer A, Raffeiner M, Stellmach H, Hause B, Schlink K. An effector of apple proliferation phytoplasma targets TCP transcription factors-a generalized virulence strategy of phytoplasma? MOLECULAR PLANT PATHOLOGY 2017; 18:435-442. [PMID: 27037957 PMCID: PMC6638208 DOI: 10.1111/mpp.12409] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 03/14/2016] [Accepted: 03/25/2016] [Indexed: 05/04/2023]
Abstract
The plant pathogen Candidatus Phytoplasma mali (P. mali) is the causative agent of apple proliferation, a disease of increasing importance in apple-growing areas within Europe. Despite its economic importance, little is known about the molecular mechanisms of disease manifestation within apple trees. In this study, we identified two TCP (TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR) transcription factors of Malus x domestica as binding partners of the P. mali SAP11-like effector ATP_00189. Phytohormone analyses revealed an effect of P. mali infection on jasmonates, salicylic acid and abscisic acid levels, showing that P. mali affects phytohormonal levels in apple trees, which is in line with the functions of the effector assumed from its binding to TCP transcription factors. To our knowledge, this is the first characterization of the molecular targets of a P. mali effector and thus provides the basis to better understand symptom development and disease progress during apple proliferation. As SAP11 homologues are found in several Phytoplasma species infecting a broad range of different plants, SAP11-like proteins seem to be key players in phytoplasmal infection.
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Affiliation(s)
- Katrin Janik
- Research Centre for Agriculture and Forestry LaimburgLaimburg 6Auer/OraBZ39040Italy
| | - Axel Mithöfer
- Department of Bioorganic ChemistryMax Planck Institute for Chemical EcologyBeutenberg Campus, Hans‐Knöll‐Str. 8Jena07745Germany
| | - Margot Raffeiner
- Research Centre for Agriculture and Forestry LaimburgLaimburg 6Auer/OraBZ39040Italy
| | - Hagen Stellmach
- Department for Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryWeinberg 3Halle06120Germany
| | - Bettina Hause
- Department for Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryWeinberg 3Halle06120Germany
| | - Katja Schlink
- Research Centre for Agriculture and Forestry LaimburgLaimburg 6Auer/OraBZ39040Italy
- Present address:
Present address: Dr. Knoell Consult GmbHMarie‐Curie‐Str. 851377LeverkusenGermany
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9
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Quaglino F, Maghradze D, Casati P, Chkhaidze N, Lobjanidze M, Ravasio A, Passera A, Venturini G, Failla O, Bianco PA. Identification and Characterization of New 'Candidatus Phytoplasma solani' Strains Associated with Bois Noir Disease in Vitis vinifera L. Cultivars Showing a Range of Symptom Severity in Georgia, the Caucasus Region. PLANT DISEASE 2016; 100:904-915. [PMID: 30686148 DOI: 10.1094/pdis-09-15-0978-re] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Evidence from a preliminary survey highlighted that 'Candidatus Phytoplasma solani', the etiological agent of bois noir (BN) disease of grapevine, infects grapevine varieties in Georgia, a country of the South Caucasus. In this study, field surveys were carried out to investigate the BN symptom severity in international and Georgian native varieties. 'Ca. P. solani' was detected and identified by polymerase chain reaction-based amplification and restriction fragment length polymorphism analysis of 16S ribosomal DNA, and further characterized by multiple gene typing analysis (vmp1 and stamp genes). Obtained data highlighted that the majority of Georgian grapevine varieties showed moderate and mild symptoms, whereas international cultivars exhibited severe symptoms. Molecular characterization of 'Ca. P. solani' from grapevine revealed the presence of 11 distinct phytoplasma types. Only one type (VmGe12/StGe7) was identical to a strain previously reported in periwinkle from Lebanon; the other 'Ca. P. solani' types are described here for the first time. Phylogenetic analyses of vmp1 and stamp gene concatenated nucleotide sequences showed that 'Ca. P. solani' strains in Georgia are associated mainly with the bindweed-related BN host system. Moreover, the fact that 'Ca. P. solani' strains are distributed in grapevine cultivars showing a range of symptom intensity suggests a different susceptibility of such local cultivars to BN.
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Affiliation(s)
- Fabio Quaglino
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy (DISAA), University of Milan, Milano, Italy
| | - David Maghradze
- Institute of Horticulture, Viticulture and Oenology, Agricultural University of Georgia, Tbilisi, Georgia
| | | | - Nona Chkhaidze
- Laboratory of Plant Anatomy and Physiology, Agricultural University of Georgia, Tbilisi
| | - Mzagho Lobjanidze
- Institute of Entomology, Agricultural University of Georgia, Tbilisi
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10
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Rid M, Mesca C, Ayasse M, Gross J. Apple Proliferation Phytoplasma Influences the Pattern of Plant Volatiles Emitted Depending on Pathogen Virulence. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2015.00152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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11
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Asudi GO, Van den Berg J, Midega CAO, Schneider B, Seemüller E, Pickett JA, Khan ZR. Detection, Identification, and Significance of Phytoplasmas in Wild Grasses in East Africa. PLANT DISEASE 2016; 100:108-115. [PMID: 30688571 DOI: 10.1094/pdis-11-14-1173-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Plant-pathogenic phytoplasmas found in wild grasses in East Africa could pose a serious threat to the cultivation of Napier grass, Pennisetum purpureum, the most important livestock fodder in the region. To asses this threat, leaves from plants of 33 grass species were sampled from Mbita, Bungoma, and Busia districts in western Kenya; Tarime district in northern Tanzania; and Busia and Bugiri districts in the eastern Uganda to determine which species host phytoplasmas, the identity of the phytoplasmas, and their relationship with disease symptoms. Phytoplasmas were detected using universal primers based on conserved phytoplasma-specific 16S rDNA sequences from 11 grass species collected. Sequence and phylogenetic analysis revealed the presence of Napier grass stunt-related phytoplasmas in 11 grass species, 'Candidatus Phytoplasma cynodontis' in three, and goosegrass white leaf phytoplasma in 2 wild grass species. This study showed that the geographical distribution, diversity of phytoplasmas, and their grass host species in East Africa is greater than antecedently thought and that typical disease symptoms, including white leaf or stunting alone, are not reliable indicators of the presence of phytoplasma. It also shows the need to identify insect vectors responsible for phytoplasma transmission from native grasses to Napier grass or other cereals present in the region.
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Affiliation(s)
- George O Asudi
- Unit for Environmental Sciences and Development, North-West University, Potchefstroom 2520, South Africa; International Centre of Insect Physiology and Ecology, P.O. Box 30772-0010 Nairobi, Kenya; Biochemistry and Biotechnology Department, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
| | - Johnnie Van den Berg
- Unit for Environmental Sciences and Development, North-West University, Potchefstroom 2520, South Africa; International Centre of Insect Physiology and Ecology, P.O. Box 30772-0010 Nairobi, Kenya; Biochemistry and Biotechnology Department, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
| | - Charles A O Midega
- Unit for Environmental Sciences and Development, North-West University, Potchefstroom 2520, South Africa
| | - Bernd Schneider
- Julius Kuhn Institute, Federal Research Centre for Cultivated Plants Institute for Plant Protection in Fruit Crops and Viticulture, 69221 Dossenheim, Germany
| | - Erich Seemüller
- International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya
| | - John A Pickett
- Biological Chemistry and Crop Protection Department Rothamsted Research, Harpenden, Herts, AL5 2JQ, UK
| | - Zeyaur R Khan
- Unit for Environmental Sciences and Development, North-West University, South Africa and ICIPE, Kenya
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Schneider B, Sule S, Jelkmann W, Seemüller E. Suppression of aggressive strains of 'Candidatus phytoplasma mali' by mild strains in Catharanthus roseus and Nicotiana occidentalis and indication of similar action in apple trees. PHYTOPATHOLOGY 2014; 104:453-61. [PMID: 24724815 DOI: 10.1094/phyto-08-13-0230-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To study antagonistic interactions of 'Candidatus Phytoplasma mali' strains, graft inoculation of Catharanthus roseus and Nicotiana occidentalis was performed with mild strains 1/93Vin and 1/93Tab as suppressors and three aggressive strains as challengers. Inoculation of the suppressors was carried out in either the cross-protection modus prior to grafting of the challengers or by co-inoculating suppressors and challengers. Monitoring using multiplex real-time polymerase chain reaction assays revealed that, in long-term cross-protection trials with C. roseus, suppressor 1/93Vin was present in all root and randomly collected stem samples over the entire observation period. In contrast, the challengers were never detected in such stem samples and rarely in the roots. Following simultaneous inoculation, the suppressor successively colonized all stem and root regions whereas detection of challenger AT steadily decreased. However, this strain remained detectable in up to 13 and 27% of stem and root samples, respectively. The cross-protection trials with N. occidentalis yielded results similar to that of the cross-protection experiments with C. roseus. Comparison of the symptomatology of infected apple trees with the presence of putatively suppressive strains indicated that suppression of severe strains also occurs in apple. Phylogenetic analysis using a variable fragment of AAA+ ATPase gene AP460 of 'Ca. P. mali' revealed that suppressors 1/93Vin and 1/93Tab, together with several other mild strains maintained in apple, cluster distantly from obviously nonsuppressive strains that were predominantly highly virulent.
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Seemüller E, Sule S, Kube M, Jelkmann W, Schneider B. The AAA+ ATPases and HflB/FtsH proteases of 'Candidatus Phytoplasma mali': phylogenetic diversity, membrane topology, and relationship to strain virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:367-376. [PMID: 23387471 DOI: 10.1094/mpmi-09-12-0221-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Previous examination revealed a correlation of phytopathogenic data of 'Candidatus Phytoplasma mali' strains and the DNA sequence variability of a type ATP00464 hflB gene fragment. To further investigate such a relationship, all distinct genes previously annotated as hflB in the genome of 'Ca. P. mali' strain AT were fully sequenced and analyzed from a number of representative mild, moderate, and severe strains. The re-annotation indicated that the sequences encode six AAA+ ATPases and six HflB proteases. Each of the nine distinct deduced AAA+ proteins that were examined formed a coherent phylogenetic cluster. However, within these groups, sequences of three ATPases and three proteases from mild and severe strains clustered distantly, according to their virulence. This grouping was supported by an association with virulence-related amino acid substitutions. Another finding was that full-length genes from ATPase AP11 could only be identified in mild and moderate strains. Prediction of the membrane topology indicated that the long ATPase- and protease-carrying C-terminal tails of approximately half of the AAA+ proteins are extracellular, putatively facing the environment of the sieve tubes. Thus, they may be involved in pathogen-host interactions and may compromise phloem function, a major effect of phytoplasma infection. All full-length genes examined appear transcriptionally active and all deduced peptides show the key positions indicative for protein function.
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Marcone C. Pulsed-field gel electrophoresis for isolation of full-length phytoplasma chromosomes from plants. Methods Mol Biol 2013; 938:395-403. [PMID: 22987433 DOI: 10.1007/978-1-62703-089-2_33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Pulsed-field gel electrophoresis (PFGE) is a powerful technique for genomic studies of unculturable plant-pathogenic phytoplasmas, which enables separation of full-length phytoplasma chromosomes from contaminating host plant nucleic acids. The PFGE method described here involves isolation of phytoplasmal DNA from high-titer phytoplasma-infected herbaceous plants using a phytoplasma enrichment procedure, embedding of phytoplasma chromosomes in agarose blocks, and separation of entire phytoplasma chromosomes from contaminating host plant nucleic acids by electrophoresis. Full-length phytoplasma chromosomes are resolved as single, discrete bands in the gel. The identity of these bands can be confirmed by Southern blot hybridization using a ribosomal DNA fragment as a probe. The method does not utilize gamma-irradiation to linearize phytoplasma chromosomes prior to electrophoresis.
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Affiliation(s)
- Carmine Marcone
- Department of Pharmaceutical and Biomedical Sciences, University of Salerno, Salerno, Italy.
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Abstract
Tuf and secY genotyping techniques have been developed to distinguish phytoplasma strains. Tuf polymerase chain reaction sequence analyses are available for phytoplasma taxonomic groups 16SrI, 16SrV, 16SrXII-A, and XII-B. In addition to their use to confirm the taxonomic status of phytoplasma strains, they allow the spread of phytoplasma strains in host plants and insect vectors to be traced. SecY is more variable than tuf and is therefore more discriminatory than tuf, but secY and tuf phylogenies show congruence.
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Su YT, Chen JC, Lin CP. Phytoplasma-induced floral abnormalities in Catharanthus roseus are associated with phytoplasma accumulation and transcript repression of floral organ identity genes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:1502-1512. [PMID: 21864044 DOI: 10.1094/mpmi-06-11-0176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Floral symptoms caused by phytoplasma largely resemble floral reversion in other plants. Periwinkle leaf yellowing (PLY) phytoplasma and peanut witches'-broom (PnWB) phytoplasma caused different degrees of floral abnormalities on infected periwinkle plants. The PLY phytoplasma-infected plants exhibited floral discoloration, virescence, small flowers, and only occasionally full floral reversion. In contrast, PnWB phytoplasma frequently induced complete floral reversion and resulted in a witches'-broom symptom from the floral reversion. Although different degrees of floral symptoms were induced by these two phytoplasmas, the morphological disorders were similar to those of other plants carrying SEPALLATA mutations or gene silencing. Here, we compared expression levels of organ-identity-related genes and pigmentation genes during floral symptom development. Accumulation of phytoplasmas in malformed flowers and their closely surrounding leaves was also compared. In infected plants, transcript abundance of all examined organ identity genes and pigmentation genes was suppressed. Indeed, CrSEP3, a SEPALLALA3 ortholog, showed the greatest suppression among genes examined. Of the pigmentation genes, transcript reduction of chalcone synthase was most highly correlated with the loss in floral pigmentation. Floral symptom severities were associated with the accumulation of either phytoplasmas. Interestingly, both phytoplasmas accumulated to higher levels in malformed flowers than in their surrounding leaves. Many plant pathogens manipulate host plant development to their advantage. It is intriguing to see whether phytoplasmas alter floral development to increase their population.
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Affiliation(s)
- Yi-Ting Su
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
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Seemüller E, Kampmann M, Kiss E, Schneider B. HflB gene-based phytopathogenic classification of 'Candidatus phytoplasma mali' strains and evidence that strain composition determines virulence in multiply infected apple trees. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:1258-1266. [PMID: 21899439 DOI: 10.1094/mpmi-05-11-0126] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Analysis of pathological and molecular data of 'Candidatus Phytoplasma mali' accessions from 27 apple trees differing considerably in symptomatology was used to molecularly characterize and classify strains of the infecting apple proliferation phytoplasma. Single-strand conformation polymorphism and sequence analysis of a variable fragment of ATP00464-type hflB gene revealed that these sources consisted of single-strain and multiple-strain accessions that occurred in similar numbers. The latter group was composed of two to five distinct strains. Analysis of cloned sequences of mild and severe single-strain accessions resulted in two groups of reads that clustered, according to their virulence, distantly in the phylogram. Based on this data, the clustering patterns of multiple-strain accession sequences indicated that nearly all of them were composed of mild and severe strains. The distinct clustering of sequences representing mild and severe strains was associated with a range of molecular markers at the nucleotide and amino acid level. Data indicate that the virulence of multiple-strain accessions is determined by the ratio of the occurring mild and severe strains in that mild accessions were characterized by the predominance of sequences representing mild strains and vice versa. There is evidence that shifts in the population and other events may occur that drastically alter virulence of multiple-strain accessions.
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Affiliation(s)
- Erich Seemüller
- Julius Kuehn Institute, Federal Research Center for Cultivated Palnts, Institute for Plant Protection in Fruuit Crops, Germany.
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Danet JL, Balakishiyeva G, Cimerman A, Sauvion N, Marie-Jeanne V, Labonne G, Laviňa A, Batlle A, Križanac I, Škorić D, Ermacora P, Serçe ÇU, Çağlayan K, Jarausch W, Foissac X. Multilocus sequence analysis reveals the genetic diversity of European fruit tree phytoplasmas and supports the existence of inter-species recombination. MICROBIOLOGY-SGM 2010; 157:438-450. [PMID: 20847008 DOI: 10.1099/mic.0.043547-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The genetic diversity of three temperate fruit tree phytoplasmas 'Candidatus Phytoplasma prunorum', 'Ca. P. mali' and 'Ca. P. pyri' has been established by multilocus sequence analysis. Among the four genetic loci used, the genes imp and aceF distinguished 30 and 24 genotypes, respectively, and showed the highest variability. Percentage of substitution for imp ranged from 50 to 68 % according to species. Percentage of substitution varied between 9 and 12 % for aceF, whereas it was between 5 and 6 % for pnp and secY. In the case of 'Ca P. prunorum' the three most prevalent aceF genotypes were detected in both plants and insect vectors, confirming that the prevalent isolates are propagated by insects. The four isolates known to be hypo-virulent had the same aceF sequence, indicating a possible monophyletic origin. Haplotype network reconstructed by eBURST revealed that among the 34 haplotypes of 'Ca. P. prunorum', the four hypo-virulent isolates also grouped together in the same clade. Genotyping of some Spanish and Azerbaijanese 'Ca. P. pyri' isolates showed that they shared some alleles with 'Ca. P. prunorum', supporting for the first time to our knowledge, the existence of inter-species recombination between these two species.
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Affiliation(s)
- Jean Luc Danet
- UMR Génomique Diversité Pouvoir Pathogène, INRA, Université Victor Ségalen Bordeaux 2, 71 Avenue Edouard Bourlaux, BP81, F-33883 Villenave d'Ornon Cedex, France
| | - Gulnara Balakishiyeva
- Institute of Botany, National Academy of Sciences of Azerbaijan, Patamdar shosse 40, AZ-1073, Baku, Azerbaijan
| | - Agnès Cimerman
- UMR Génomique Diversité Pouvoir Pathogène, INRA, Université Victor Ségalen Bordeaux 2, 71 Avenue Edouard Bourlaux, BP81, F-33883 Villenave d'Ornon Cedex, France
| | - Nicolas Sauvion
- UMR Biologie et Génétique des Interactions Plante-Parasite, CIRAD, INRA, SUPAGRO, Campus International de Baillarguet, TA A-54/K, F-34398 Montpellier Cedex 5, France
| | - Véronique Marie-Jeanne
- UMR Biologie et Génétique des Interactions Plante-Parasite, CIRAD, INRA, SUPAGRO, Campus International de Baillarguet, TA A-54/K, F-34398 Montpellier Cedex 5, France
| | - Gérard Labonne
- UMR Biologie et Génétique des Interactions Plante-Parasite, CIRAD, INRA, SUPAGRO, Campus International de Baillarguet, TA A-54/K, F-34398 Montpellier Cedex 5, France
| | - Amparo Laviňa
- Institut de Recerca i Tecnologia Agroalimentaries (IRTA), Ctra Cabrils Km 2, E-08348 Cabrils, Barcelona, Spain
| | - Assumpcio Batlle
- Institut de Recerca i Tecnologia Agroalimentaries (IRTA), Ctra Cabrils Km 2, E-08348 Cabrils, Barcelona, Spain
| | - Ivana Križanac
- Institute for Plant Protection, Croatian Centre for Agriculture, Food and Rural Affairs, Svetošimunska 25, HR-10000 Zagreb, Croatia
| | - Dijana Škorić
- Department of Biology, University of Zagreb, Marulicev trg 9a, HR-10000 Zagreb, Croatia
| | - Paolo Ermacora
- Dipartimento di Biologia e Protezione delle Piante, Università degli Studi di Udine, via Delle Scienze 208, I-33100 Udine, Italy
| | - Çigdem Ulubaş Serçe
- Department of Plant Protection, Mustafa Kemal University, TK-31034 Antakya-Hatay, Turkey
| | - Kadriye Çağlayan
- Department of Plant Protection, Mustafa Kemal University, TK-31034 Antakya-Hatay, Turkey
| | - Wolfgang Jarausch
- AlPlanta - Institute for Plant Research, RLP AgroScience GmbH, Breitenweg 71, D-67435 Neustadt an der Weinstrasse, Germany
| | - Xavier Foissac
- UMR Génomique Diversité Pouvoir Pathogène, INRA, Université Victor Ségalen Bordeaux 2, 71 Avenue Edouard Bourlaux, BP81, F-33883 Villenave d'Ornon Cedex, France
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Seemüller E, Kiss E, Sule S, Schneider B. Multiple infection of apple trees by distinct strains of 'Candidatus Phytoplasma mali' and its pathological relevance. PHYTOPATHOLOGY 2010; 100:863-870. [PMID: 20701483 DOI: 10.1094/phyto-100-9-0863] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Forty-eight apple trees infected by 'Candidatus Phytoplasma mali' were examined using single-strand conformation polymorphism (SSCP) and sequence analysis of a variable hflB gene fragment and the immunodominant membrane protein-encoding imp gene. SSCP analysis of polymerase chain reaction-amplified hflB gene fragments revealed diverse profiles, differing in number and position of the bands. The 'Ca. P. mali' content of a single infected apple tree was termed an accession. Cloning of fragments from accessions that yielded fewer bands resulted in clone populations showing uniform or moderately polymorphic SSCP patterns and largely homogenous nucleotide sequences. In contrast, inserts from accessions yielding more bands were heterogeneous and formed two to four distinct groups of profiles. DNA fragments from such accessions were diverse and clustered distantly when subjected to phylogenetic analysis, mostly as two homogenous groups plus one or a few other sequences. Similar results were obtained upon imp gene examination. The collective data indicate that accessions exhibiting more complex patterns were composed of two or three distinct 'Ca. P. mali' strains. There is evidence that multiple infections are of pathological relevance due to strain interactions leading to shifts in the populations. In triply infected trees of one accession, no specific symptoms were induced by the presence of two of the strains. The rare appearance of pronounced symptoms was associated with a separate strain that possessed a unique SSCP profile and a unique hflB sequence. The two mild strains from this apple accession also induced only mild symptoms on periwinkle and tobacco and occurred specifically in one of these plants.
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Affiliation(s)
- Erich Seemüller
- Federal Research Centre for Cultivated Plants, Institute for plant protection in Fruit Crops and Viticulture, Dossenheim, German.
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Bisognin C, Schneider B, Salm H, Grando MS, Jarausch W, Moll E, Seemüller E. Apple proliferation resistance in apomictic rootstocks and its relationship to phytoplasma concentration and simple sequence repeat genotypes. PHYTOPATHOLOGY 2008; 98:153-158. [PMID: 18943191 DOI: 10.1094/phyto-98-2-0153] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In an effort to select and characterize apple rootstock resistant to apple proliferation (AP), progenies from seven apomictic rootstock selections and their parental apomictic species, Malus sieboldii and M. sargentii, were compared to standard stocks M 9 and M 11. Seedlings derived from open pollinated mother plants were grafted with cv. Golden Delicious and grown under natural infection conditions. The progenies differed greatly in resistance to the AP agent 'Candidatus Phytoplasma mali'. Progenies of M. sieboldii and its descendent rootstock selections D2212, 4608, 4551, and D1131 showed a high level of resistance, whereas progenies of M. sargentii and its descendent selections D1111 and C1828 proved susceptible. M 9 and M 11 showed an intermediate level of resistance. Phytoplasma titer in roots of the M. sieboldii and M. sargentii progeny groups was similarly low, whereas the concentration in the standard stocks was 100 to 5,000 times higher. In trees on most of the resistant stocks, only a minority was colonized in the scion, while in trees on susceptible and standard stocks, infection rate was often higher. Also, the titer in the top of trees on resistant stocks was usually lower than in trees on susceptible and standard stocks. Four progenies derived from open pollinated M. sieboldii and M. sieboldii descendents were subjected to DNA typing using simple sequence repeat (SSR) markers. This study revealed that the selected groups consisted mainly of mother-like plants (apomicts) and type I hybrids (unreduced mother genotype plus one male allele at each locus). Type II hybrids (full recombinants) and autopollinated offspring were rare. In the 4608 progeny, trees grown on type I hybrid rootstocks were significantly less affected than trees on mother-like stocks. In other progenies with fewer or no type I hybrids, trees on type II hybrids and autopollinated offspring suffered considerably more from disease than trees on mother-like stocks.
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Affiliation(s)
- C Bisognin
- IASMA Research Center, San Michele all'Adige TN, Italy
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