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Wang R, Bai B, Li D, Wang J, Huang W, Wu Y, Zhao L. Phytoplasma: A plant pathogen that cannot be ignored in agricultural production-Research progress and outlook. MOLECULAR PLANT PATHOLOGY 2024; 25:e13437. [PMID: 38393681 PMCID: PMC10887288 DOI: 10.1111/mpp.13437] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/01/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024]
Abstract
Phytoplasmas are phloem-restricted plant-pathogenic bacteria transmitted by insects. They cause diseases in a wide range of host plants, resulting in significant economic and ecological losses worldwide. Research on phytoplasmas has a long history, with significant progress being made in the past 30 years. Notably, with the rapid development of phytoplasma research, scientists have identified the primary agents involved in phytoplasma transmission, established classification and detection systems for phytoplasmas, and 243 genomes have been sequenced and assembled completely or to draft quality. Multiple possible phytoplasma effectors have been investigated, elucidating the molecular mechanisms by which phytoplasmas manipulate their hosts. This review summarizes recent advances in phytoplasma research, including identification techniques, host range studies, whole- or draft-genome sequencing, effector pathogenesis and disease control methods. Additionally, future research directions in the field of phytoplasma research are discussed.
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Affiliation(s)
- Ruotong Wang
- State Key Laboratory for Crop Stress Resistance and High‐Efficiency ProductionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
| | - Bixin Bai
- State Key Laboratory for Crop Stress Resistance and High‐Efficiency ProductionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
| | - Danyang Li
- State Key Laboratory for Crop Stress Resistance and High‐Efficiency ProductionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
| | - Jingke Wang
- State Key Laboratory for Crop Stress Resistance and High‐Efficiency ProductionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
| | - Weijie Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghaiChina
| | - Yunfeng Wu
- State Key Laboratory for Crop Stress Resistance and High‐Efficiency ProductionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
| | - Lei Zhao
- State Key Laboratory for Crop Stress Resistance and High‐Efficiency ProductionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture and Rural Affairs, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxiChina
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Kirdat K, Tiwarekar B, Sathe S, Yadav A. From sequences to species: Charting the phytoplasma classification and taxonomy in the era of taxogenomics. Front Microbiol 2023; 14:1123783. [PMID: 36970684 PMCID: PMC10033645 DOI: 10.3389/fmicb.2023.1123783] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/13/2023] [Indexed: 03/11/2023] Open
Abstract
Phytoplasma taxonomy has been a topic of discussion for the last two and half decades. Since the Japanese scientists discovered the phytoplasma bodies in 1967, the phytoplasma taxonomy was limited to disease symptomology for a long time. The advances in DNA-based markers and sequencing improved phytoplasma classification. In 2004, the International Research Programme on Comparative Mycoplasmology (IRPCM)- Phytoplasma/Spiroplasma Working Team – Phytoplasma taxonomy group provided the description of the provisional genus ‘Candidatus Phytoplasma’ with guidelines to describe the new provisional phytoplasma species. The unintentional consequences of these guidelines led to the description of many phytoplasma species where species characterization was restricted to a partial sequence of the 16S rRNA gene alone. Additionally, the lack of a complete set of housekeeping gene sequences or genome sequences, as well as the heterogeneity among closely related phytoplasmas limited the development of a comprehensive Multi-Locus Sequence Typing (MLST) system. To address these issues, researchers tried deducing the definition of phytoplasma species using phytoplasmas genome sequences and the average nucleotide identity (ANI). In another attempts, a new phytoplasma species were described based on the Overall Genome relatedness Values (OGRI) values fetched from the genome sequences. These studies align with the attempts to standardize the classification and nomenclature of ‘Candidatus’ bacteria. With a brief historical account of phytoplasma taxonomy and recent developments, this review highlights the current issues and provides recommendations for a comprehensive system for phytoplasma taxonomy until phytoplasma retains ‘Candidatus’ status.
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Affiliation(s)
- Kiran Kirdat
- National Centre for Cell Science, NCCS Complex, Savitribai Phule Pune University, Pune, India
- Department of Microbiology, Tuljaram Chaturchand College, Baramati, India
| | - Bhavesh Tiwarekar
- National Centre for Cell Science, NCCS Complex, Savitribai Phule Pune University, Pune, India
| | - Shivaji Sathe
- Department of Microbiology, Tuljaram Chaturchand College, Baramati, India
| | - Amit Yadav
- National Centre for Cell Science, NCCS Complex, Savitribai Phule Pune University, Pune, India
- *Correspondence: Amit Yadav, ,
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Wei W, Zhao Y. Phytoplasma Taxonomy: Nomenclature, Classification, and Identification. BIOLOGY 2022; 11:1119. [PMID: 35892975 PMCID: PMC9394401 DOI: 10.3390/biology11081119] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/22/2022] [Accepted: 07/25/2022] [Indexed: 11/30/2022]
Abstract
Phytoplasmas are pleomorphic, wall-less intracellular bacteria that can cause devastating diseases in a wide variety of plant species. Rapid diagnosis and precise identification of phytoplasmas responsible for emerging plant diseases are crucial to preventing further spread of the diseases and reducing economic losses. Phytoplasma taxonomy (identification, nomenclature, and classification) has lagged in comparison to culturable bacteria, largely due to lack of axenic phytoplasma culture and consequent inaccessibility of phenotypic characteristics. However, the rapid expansion of molecular techniques and the advent of high throughput genome sequencing have tremendously enhanced the nucleotide sequence-based phytoplasma taxonomy. In this article, the key events and milestones that shaped the current phytoplasma taxonomy are highlighted. In addition, the distinctions and relatedness of two parallel systems of 'Candidatus phytoplasma' species/nomenclature system and group/subgroup classification system are clarified. Both systems are indispensable as they serve different purposes. Furthermore, some hot button issues in phytoplasma nomenclature are also discussed, especially those pertinent to the implementation of newly revised guidelines for 'Candidatus Phytoplasma' species description. To conclude, the challenges and future perspectives of phytoplasma taxonomy are briefly outlined.
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Affiliation(s)
- Wei Wei
- Molecular Plant Pathology Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA;
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Bertaccini A. Plants and Phytoplasmas: When Bacteria Modify Plants. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11111425. [PMID: 35684198 PMCID: PMC9182842 DOI: 10.3390/plants11111425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/18/2022] [Accepted: 05/24/2022] [Indexed: 05/14/2023]
Abstract
Plant pathogen presence is very dangerous for agricultural ecosystems and causes huge economic losses. Phytoplasmas are insect-transmitted wall-less bacteria living in plants, only in the phloem tissues and in the emolymph of their insect vectors. They are able to manipulate several metabolic pathways of their hosts, very often without impairing their life. The molecular diversity described (49 'Candidatus Phytoplasma' species and about 300 ribosomal subgroups) is only in some cases related to their associated symptomatology. As for the other plant pathogens, it is necessary to verify their identity and recognize the symptoms associated with their presence to appropriately manage the diseases. However, the never-ending mechanism of patho-adaptation and the copresence of other pathogens makes this management difficult. Reducing the huge impact of phytoplasma-associated diseases in all the main crops and wild species is, however, relevant, in order to reduce their effects that are jeopardizing plant biodiversity.
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Affiliation(s)
- Assunta Bertaccini
- Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, 40127 Bologna, Italy
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Bertaccini A, Arocha-Rosete Y, Contaldo N, Duduk B, Fiore N, Montano HG, Kube M, Kuo CH, Martini M, Oshima K, Quaglino F, Schneider B, Wei W, Zamorano A. Revision of the ' Candidatus Phytoplasma' species description guidelines. Int J Syst Evol Microbiol 2022; 72. [PMID: 35471141 DOI: 10.1099/ijsem.0.005353] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The genus 'Candidatus Phytoplasma' was proposed to accommodate cell wall-less bacteria that are molecularly and biochemically incompletely characterized, and colonize plant phloem and insect vector tissues. This provisional classification is highly relevant due to its application in epidemiological and ecological studies, mainly aimed at keeping the severe phytoplasma plant diseases under control worldwide. Given the increasing discovery of molecular diversity within the genus 'Ca. Phytoplasma', the proposed guidelines were revised and clarified to accommodate those 'Ca. Phytoplasma' species strains sharing >98.65 % sequence identity of their full or nearly full 16S rRNA gene sequences, obtained with at least twofold coverage of the sequence, compared with those of the reference strain of such species. Strains sharing <98.65 % sequence identity with the reference strain but >98.65 % with other strain(s) within the same 'Ca. Phytoplasma' species should be considered related strains to that 'Ca. Phytoplasma' species. The guidelines herein, keep the original published reference strains. However, to improve 'Ca. Phytoplasma' species assignment, complementary strains are suggested as an alternative to the reference strains. This will be implemented when only a partial 16S rRNA gene and/or a few other genes have been sequenced, or the strain is no longer available for further molecular characterization. Lists of 'Ca. Phytoplasma' species and alternative reference strains described are reported. For new 'Ca. Phytoplasma' species that will be assigned with identity ≥98.65 % of their 16S rRNA gene sequences, a threshold of 95 % genome-wide average nucleotide identity is suggested. When the whole genome sequences are unavailable, two among conserved housekeeping genes could be used. There are 49 officially published 'Candidatus Phytoplasma' species, including 'Ca. P. cocostanzaniae' and 'Ca. P. palmae' described in this manuscript.
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Affiliation(s)
- Assunta Bertaccini
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | | | - Nicoletta Contaldo
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Bojan Duduk
- Institute of Pesticides and Environmental Protection, Belgrade, Serbia
| | - Nicola Fiore
- Faculty of Agricultural Sciences, Department of Plant Protection, University of Chile, Santiago, Chile
| | - Helena Guglielmi Montano
- Department of Entomology and Plant Pathology, Federal Rural University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Michael Kube
- Department of Integrative Infection Biology Crops-Livestock, University of Hohenheim, Stuttgart, Germany
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, ROC
| | - Marta Martini
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
| | - Kenro Oshima
- Faculty of Bioscience and Applied Chemistry, Department of Clinical Plant Science, Hosei University, Japan
| | - Fabio Quaglino
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, University of Milan, Milan, Italy
| | - Bernd Schneider
- Julius Kuehn-Institute, Federal Research Centre for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture, Dossenheim, Germany
| | - Wei Wei
- Molecular Plant Pathology Laboratory, USDA/ARS, Beltsville, MD, USA
| | - Alan Zamorano
- Faculty of Agricultural Sciences, Department of Plant Protection, University of Chile, Santiago, Chile
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Zhao Y, Wei W, Davis RE, Lee IM, Bottner-Parker KD. The agent associated with blue dwarf disease in wheat represents a new phytoplasma taxon, ' Candidatus Phytoplasma tritici'. Int J Syst Evol Microbiol 2021; 71. [PMID: 33464199 DOI: 10.1099/ijsem.0.004604] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wheat blue dwarf (WBD) is one of the most economically damaging cereal crop diseases in northwestern PR China. The agent associated with the WBD disease is a phytoplasma affiliated with the aster yellows (AY) group, subgroup C (16SrI-C). Since phytoplasma strains within the AY group are ecologically and genetically diverse, it has been conceived that the AY phytoplasma group may consist of more than one species. This communication presents evidence to demonstrate that, while each of the two 16 rRNA genes of the WBD phytoplasma shares >97.5 % sequence similarity with that of the 'Candidatus Phytoplasma asteris' reference strain, the WBD phytoplasma clearly represents an ecologically separated lineage: the WBD phytoplasma not only has its unique transmitting vector (Psammotettix striatus) but also elicits a distinctive symptom in its predominant plant host (wheat). In addition, the WBD phytoplasma possesses molecular characteristics that further manifest its significant divergence from 'Ca. P. asteris'. Such molecular characteristics include lineage-specific antigenic membrane proteins and a lower than 95 % genome-wide average nucleotide identity score with 'Ca. P. asteris'. These ecological, molecular and genomic evidences justify the recognition of the WBD phytoplasma as a novel taxon, 'Candidatus Phytoplasma tritici'.
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Affiliation(s)
- Yan Zhao
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Wei Wei
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Robert E Davis
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Ing-Ming Lee
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Kristi D Bottner-Parker
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
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7
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Ramos Hernández E, Lesher Gordillo JM, Oropeza Salín C, Ortiz García CF, Magaña Alejandro MA, Sánchez Soto S, García Estrada Y. Detection and Identification of Phytoplasmas in the 16SrIV-A, -B, and -D Subgroups in Palms in Tabasco, Mexico. PLANT DISEASE 2020; 104:2606-2612. [PMID: 32813613 DOI: 10.1094/pdis-09-18-1488-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The 16SrIV-A phytoplasmas are associated with the devastating disease lethal yellowing (LY) of palms. In Tabasco (Mexico), the death of Cocos nucifera, Adonidia merrillii, and Attalea butyracea palms have been suspected to be associated with LY based on symptomatology. Samples from the trunk of both symptomatic and nonsymptomatic palms were collected in three different environments: two species of palms within a rural zone and the other within an urban zone. DNA was extracted to perform a nested PCR with phytoplasma primers P1/P7-LY16SF/R16R2. A 1,345-bp fragment was amplified from the DNA extracted from each of the 29 LY-symptomatic palms sampled. Phytoplasma identification was achieved by amplicon sequencing and virtual restriction fragment length polymorphism analyses. Three 16SrIV phytoplasma subgroups were detected: 16SrIV-A in C. nucifera, 16SrIV-B in A. merrillii, and 16SrIV-D in C. nucifera, A. merrillii, and A. butyracea. Phylogenetic analysis showed also that the three phytoplasma strains found in the palm species clustered with phytoplasmas reported in the literature in the three subgroups identified. This is the first report of phytoplasmas associated with these palm species in Tabasco.
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Affiliation(s)
- Eder Ramos Hernández
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Campo Experimental Huimanguillo, 86400, Huimanguillo, Tabasco, México
| | - Julia M Lesher Gordillo
- Universidad Juárez Autónoma de Tabasco, División Académica de Ciencias Biológicas, 86150, Villahermosa, Tabasco, México
| | - Carlos Oropeza Salín
- Centro de Investigación Científica de Yucatán A.C., 97205, Chuburná de Hidalgo, Mérida, Yucatán, México
| | | | - Miguel A Magaña Alejandro
- Universidad Juárez Autónoma de Tabasco, División Académica de Ciencias Biológicas, 86150, Villahermosa, Tabasco, México
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8
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Oren A, Garrity GM, Parker CT, Chuvochina M, Trujillo ME. Lists of names of prokaryotic Candidatus taxa. Int J Syst Evol Microbiol 2020; 70:3956-4042. [DOI: 10.1099/ijsem.0.003789] [Citation(s) in RCA: 782] [Impact Index Per Article: 195.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We here present annotated lists of names of Candidatus taxa of prokaryotes with ranks between subspecies and class, proposed between the mid-1990s, when the provisional status of Candidatus taxa was first established, and the end of 2018. Where necessary, corrected names are proposed that comply with the current provisions of the International Code of Nomenclature of Prokaryotes and its Orthography appendix. These lists, as well as updated lists of newly published names of Candidatus taxa with additions and corrections to the current lists to be published periodically in the International Journal of Systematic and Evolutionary Microbiology, may serve as the basis for the valid publication of the Candidatus names if and when the current proposals to expand the type material for naming of prokaryotes to also include gene sequences of yet-uncultivated taxa is accepted by the International Committee on Systematics of Prokaryotes.
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Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus, 9190401 Jerusalem, Israel
| | - George M. Garrity
- NamesforLife, LLC, PO Box 769, Okemos MI 48805-0769, USA
- Department of Microbiology & Molecular Genetics, Biomedical Physical Sciences, Michigan State University, East Lansing, MI 48824-4320, USA
| | | | - Maria Chuvochina
- Australian Centre for Ecogenomics, University of Queensland, St. Lucia QLD 4072, Brisbane, Australia
| | - Martha E. Trujillo
- Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca, 37007, Salamanca, Spain
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Trivellone V, Ripamonti M, Angelini E, Filippin L, Rossi M, Marzachí C, Galetto L. Evidence suggesting interactions between immunodominant membrane protein Imp of Flavescence dorée phytoplasma and protein extracts from distantly related insect species. J Appl Microbiol 2019; 127:1801-1813. [PMID: 31509633 DOI: 10.1111/jam.14445] [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: 05/05/2019] [Revised: 09/03/2019] [Accepted: 09/06/2019] [Indexed: 12/14/2022]
Abstract
AIMS In this study, binding between the immunodominant membrane protein Imp of the 16SrV-D phytoplasma associated with Flavescence dorée disease (FD-Dp) and insect proteins of vectors and non-vectors of FD-Dp was tested. METHODS AND RESULTS Six Auchenorrhyncha species, from distantly related groups were selected: Scaphoideus titanus, Euscelidius variegatus, Macrosteles quadripunctulatus, Zyginidia pullula (Cicadomorpha), Ricania speculum and Metcalfa pruinosa (Fulgoromorpha). The vector status of each species was retrieved from the literature or determined by transmission trials in this study. A His-tagged partial Imp protein and a rabbit polyclonal antibody were synthesized and used for Western and Far-Western dot Blot (FWdB) experiments. Total native and membrane proteins (MP) were extracted from entire bodies and organs (gut and salivary glands) of each insect species. FWdB showed decreasing interaction intensities of Imp fusion protein with total proteins from entire bodies of S. titanus, E. variegatus (competent vectors) and M. quadripunctulatus (non-vector), while no interaction signal was detected with the other three species (non-vectors). A strong signal detected upon interaction of FD-D Imp and MP from guts of closely related insects supports the role of this organ as the first barrier to ensure successful transmission. CONCLUSIONS Our results showed that specific Imp binding, correlated with vector status, is involved in interactions between FD-Dp and insect proteins. SIGNIFICANCE AND IMPACT OF THE STUDY Integrating knowledge on host-pathogen protein-protein interactions and on insect phylogeny would help to identify the actual range of vectors of phytoplasma strains of economic importance.
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Affiliation(s)
- V Trivellone
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, IL, USA.,Council for Agricultural Research and Economics (CREA), Research Centre for Viticulture and Enology, Conegliano, TV, Italy
| | - M Ripamonti
- Institute for Sustainable Plant Protection, National Research Council, Turin, Italy.,Dipartimento di Scienze Agrarie, Forestali ed Alimentari DISAFA, Università degli Studi di Torino, Grugliasco, TO, Italy
| | - E Angelini
- Council for Agricultural Research and Economics (CREA), Research Centre for Viticulture and Enology, Conegliano, TV, Italy
| | - L Filippin
- Council for Agricultural Research and Economics (CREA), Research Centre for Viticulture and Enology, Conegliano, TV, Italy
| | - M Rossi
- Institute for Sustainable Plant Protection, National Research Council, Turin, Italy
| | - C Marzachí
- Institute for Sustainable Plant Protection, National Research Council, Turin, Italy
| | - L Galetto
- Institute for Sustainable Plant Protection, National Research Council, Turin, Italy
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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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11
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Multilocus Sequence Analysis Reveals Three Distinct Populations of " Candidatus Phytoplasma palmicola" with a Specific Geographical Distribution on the African Continent. Appl Environ Microbiol 2019; 85:AEM.02716-18. [PMID: 30770404 PMCID: PMC6450020 DOI: 10.1128/aem.02716-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/05/2019] [Indexed: 12/15/2022] Open
Abstract
Coconut is an important crop for both industry and small stakeholders in many intertropical countries. Phytoplasma-associated lethal yellowing-like diseases have become one of the major pests that limit coconut cultivation as they have emerged in different parts of the world. We developed a multilocus sequence typing scheme (MLST) for tracking epidemics of “Ca. Phytoplasma palmicola,” which is responsible for coconut lethal yellowing disease (CLYD) on the African continent. MLST analysis applied to diseased coconut samples collected in western and eastern African countries also showed the existence of three distinct populations of “Ca. Phytoplasma palmicola” with low intrapopulation diversity. The reasons for the observed strong geographic patterns remain to be established but could result from the lethality of CLYD and the dominance of short-distance insect-mediated transmission. To sustain epidemiological studies on coconut lethal yellowing disease (CLYD), a devastating disease in Africa caused by a phytoplasma, we developed a multilocus sequence typing (MLST) scheme for “Candidatus Phytoplasma palmicola” based on eight housekeeping genes. At the continental level, eight different sequence types were identified among 132 “Candidatus Phytoplasma palmicola”-infected coconuts collected in Ghana, Nigeria, and Mozambique, where CLYD epidemics are still very active. “Candidatus Phytoplasma palmicola” appeared to be a bacterium that is subject to strong bottlenecks, reducing the fixation of positively selected beneficial mutations into the bacterial population. This phenomenon, as well as a limited plant host range, might explain the observed country-specific distribution of the eight haplotypes. As an alternative means to increase fitness, bacteria can also undergo genetic exchange; however, no evidence for such recombination events was found for “Candidatus Phytoplasma palmicola.” The implications for CLYD epidemiology and prophylactic control are discussed. The usefulness of seven housekeeping genes to investigate the genetic diversity in the genus “Candidatus Phytoplasma” is underlined. IMPORTANCE Coconut is an important crop for both industry and small stakeholders in many intertropical countries. Phytoplasma-associated lethal yellowing-like diseases have become one of the major pests that limit coconut cultivation as they have emerged in different parts of the world. We developed a multilocus sequence typing scheme (MLST) for tracking epidemics of “Ca. Phytoplasma palmicola,” which is responsible for coconut lethal yellowing disease (CLYD) on the African continent. MLST analysis applied to diseased coconut samples collected in western and eastern African countries also showed the existence of three distinct populations of “Ca. Phytoplasma palmicola” with low intrapopulation diversity. The reasons for the observed strong geographic patterns remain to be established but could result from the lethality of CLYD and the dominance of short-distance insect-mediated transmission.
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Silva FG, Passos EM, Diniz LEC, Farias AP, Teodoro AV, Fernandes MF, Dollet M. Rainfall and Coconut Accession Explain the Composition and Abundance of the Community of Potential Auchenorrhyncha Phytoplasma Vectors in Brazil. ENVIRONMENTAL ENTOMOLOGY 2018; 47:318-324. [PMID: 29490037 DOI: 10.1093/ee/nvy010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Coconut plantations are attacked by the lethal yellowing (LY), which is spreading rapidly with extremely destructive effects in several countries. The disease is caused by phytoplasmas that occur in the plant phloem and are transmitted by Haplaxius crudus (Van Duzee) (Auchenorrhyncha: Cixiidae). Owing to their phloem-sap feeding habit, other planthopper species possibly act as vectors. Here, we aimed at assessing the seasonal variation in the Auchenorrhyncha community in six dwarf coconut accessions. Also, we assessed the relative contribution of biotic (coconut accession) and abiotic (rainfall, temperature) in explaining Auchenorrhyncha composition and abundance. The Auchenorrhyncha community was monthly evaluated for 1 yr using yellow sticky traps. Among the most abundant species, Oecleus sp., Balclutha sp., Deltocephalinae sp.2, Deltocephalinae sp.3, Cenchreini sp., Omolicna nigripennis Caldwell (Derbidae), and Cedusa sp. are potential phytoplasma vectors. The composition of the Auchenorrhyncha community differed between dwarf coconut accessions and periods, namely, in March and April (transition from dry to rainy season) and August (transition from rainy to dry season). In these months, Oecleus sp. was predominantly found in the accessions Cameroon Red Dwarf, Malayan Red Dwarf, and Brazilian Red Dwarf Gramame, while Cenchreini sp. and Bolbonota sp. were dominant in the accessions Brazilian Yellow Dwarf Gramame, Malayan Yellow Dwarf, and Brazilian Green Dwarf Jequi. We conclude that dwarf coconut host several Auchenorrhyncha species potential phytoplasma vectors. Furthermore, coconut accessions could be exploited in breeding programs aiming at prevention of LY. However, rainfall followed by accessions mostly explained the composition and abundance of the Auchenorrhyncha community.
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Affiliation(s)
- Flaviana G Silva
- Programa de Pós-graduação em Agricultura e Biodiversidade, Universidade Federal de Sergipe, Avenida Marechal Rodon, Jardim Rosa Elze, São Cristovão, Sergipe, Brazil
| | - Eliana M Passos
- Embrapa Tabuleiros Costeiros, Avenida Beira Mar, Aracaju, Sergipe, Brazil
| | - Leandro E C Diniz
- Embrapa Tabuleiros Costeiros, Avenida Beira Mar, Aracaju, Sergipe, Brazil
| | - Adriano P Farias
- Programa de Pós-graduação em Agricultura e Biodiversidade, Universidade Federal de Sergipe, Avenida Marechal Rodon, Jardim Rosa Elze, São Cristovão, Sergipe, Brazil
| | - Adenir V Teodoro
- Programa de Pós-graduação em Agricultura e Biodiversidade, Universidade Federal de Sergipe, Avenida Marechal Rodon, Jardim Rosa Elze, São Cristovão, Sergipe, Brazil
- Embrapa Tabuleiros Costeiros, Avenida Beira Mar, Aracaju, Sergipe, Brazil
| | - Marcelo F Fernandes
- Programa de Pós-graduação em Agricultura e Biodiversidade, Universidade Federal de Sergipe, Avenida Marechal Rodon, Jardim Rosa Elze, São Cristovão, Sergipe, Brazil
- Embrapa Tabuleiros Costeiros, Avenida Beira Mar, Aracaju, Sergipe, Brazil
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Miyazaki A, Shigaki T, Koinuma H, Iwabuchi N, Rauka GB, Kembu A, Saul J, Watanabe K, Nijo T, Maejima K, Yamaji Y, Namba S. ‘Candidatus Phytoplasma noviguineense’, a novel taxon associated with Bogia coconut syndrome and banana wilt disease on the island of New Guinea. Int J Syst Evol Microbiol 2018; 68:170-175. [DOI: 10.1099/ijsem.0.002480] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Akio Miyazaki
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Toshiro Shigaki
- National Agricultural Research Institute, PO Box 1639, Lae, Morobe Province 411, Papua New Guinea
| | - Hiroaki Koinuma
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Nozomu Iwabuchi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Gou Bue Rauka
- National Agricultural Research Institute, PO Box 1639, Lae, Morobe Province 411, Papua New Guinea
| | - Alfred Kembu
- Cocoa Coconut Institute Stewart Research Station, PO Box 642, Madang, Madang Province, Papua New Guinea
| | - Josephine Saul
- Cocoa Coconut Institute Stewart Research Station, PO Box 642, Madang, Madang Province, Papua New Guinea
| | - Kiyoto Watanabe
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takamichi Nijo
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kensaku Maejima
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yasuyuki Yamaji
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Shigetou Namba
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Jeger M, Bragard C, Candresse T, Chatzivassiliou E, Dehnen-Schmutz K, Gilioli G, Gregoire JC, Jaques Miret JA, MacLeod A, Navajas Navarro M, Niere B, Parnell S, Potting R, Rafoss T, Rossi V, Urek G, Van Bruggen A, Van der Werf W, West J, Winter S, Dickinson M, Marzachi C, Hollo G, Caffier D. Pest categorisation of Palm lethal yellowing phytoplasmas. EFSA J 2017; 15:e05028. [PMID: 32625317 PMCID: PMC7009989 DOI: 10.2903/j.efsa.2017.5028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The EFSA Panel on Plant Health performed a pest categorisation of Palm lethal yellowing phytoplasmas for the EU territory. This name is used to describe diseases that share the same succession of symptoms in palms that are caused by a number of strains of phytoplasma, for which efficient molecular detection assays are available. The pest is not known to occur in the EU and therefore does not meet one of the criteria for being a Union regulated non-quarantine pest. For 'Candidatus Phytoplasma palmae', the planthopper Haplaxius crudus, which is not known to be present in the EU, is the confirmed vector, but for the other strains, the vectors are unknown. The host range of the pest is restricted to Arecaceae species, in particular coconut. The pest is regulated on all known hosts in Annex IIAI of Directive 2000/29/EC. It could potentially enter the EU via plants for planting or through infected vectors. The phytoplasmas could become established in the EU as host plants are present. It is unknown whether arthropods present in the EU could be vectors. The potential impact of the pest if introduced into the EU is difficult to assess given this uncertainty but is estimated to be limited. The main knowledge gaps concern the status of potential vector insects in the EU; the possibility for seed transmission of the phytoplasmas; the origin and volume of the trade in palm seeds and plants for planting; the host status and susceptibility of many palm species grown in the EU and the potential new assignments of phytoplasmas to this categorisation that might have associated alternate hosts. Palm lethal yellowing phytoplasmas meet the criteria assessed by EFSA for consideration as Union quarantine pest.
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15
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Naderali N, Nejat N, Vadamalai G, Davis RE, Wei W, Harrison NA, Kong L, Kadir J, Tan YH, Zhao Y. 'Candidatus Phytoplasma wodyetiae', a new taxon associated with yellow decline disease of foxtail palm (Wodyetia bifurcata) in Malaysia. Int J Syst Evol Microbiol 2017; 67:3765-3772. [PMID: 28905707 DOI: 10.1099/ijsem.0.002187] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Landscape-grown foxtail palm (Wodyetia bifurcata A. K. Irvine) trees displaying symptoms of severe foliar chlorosis, stunting, general decline and mortality reminiscent of coconut yellow decline disease were observed in Bangi, Malaysia, during 2012. DNA samples from foliage tissues of 15 symptomatic palms were analysed by employing a nested PCR assay primed by phytoplasma universal ribosomal RNA operon primer pairs, P1/P7 followed by R16F2n/R2. The assay yielded amplicons of a single band of 1.25 kb from DNA samples of 11 symptomatic palms. Results from cloning and sequence analysis of the PCR-amplified 16S rRNA gene segments revealed that, in three palms, three mutually distinct phytoplasmas comprising strains related to 'Candidatus Phytoplasma asteris' and 'Candidatus Phytoplasma cynodontis', as well as a novel phytoplasma, were present as triple infections. The 16S rRNA gene sequence derived from the novel phytoplasma shared less than 96 % nucleotide sequence identity with that of each previously describedspecies of the provisional genus 'Ca. Phytoplasma', justifying its recognition as the reference strain of a new taxon, 'Candidatus Phytoplasma wodyetiae'. Virtual RFLP profiles of the R16F2n/R2 portion of the 16S rRNA gene and the pattern similarity coefficient value (0.74) supported the delineation of 'Ca. Phytoplasma wodyetiae' as the sole representative subgroup A member of a new phytoplasma ribosomal group, 16SrXXXVI.
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Affiliation(s)
- Neda Naderali
- Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400, Malaysia
| | - Naghmeh Nejat
- Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400, Malaysia.,School of Science, Health Innovations Research Institute, RMIT University, Melbourne, Victoria, Australia
| | - Ganesan Vadamalai
- Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400, Malaysia.,Plant Protection Department, Universiti Putra Malaysia, 43400, Malaysia
| | - Robert E Davis
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Wei Wei
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Nigel A Harrison
- Department of Plant Pathology, Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, FL 33314, USA
| | - LihLing Kong
- Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400, Malaysia
| | - Jugah Kadir
- Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400, Malaysia
| | - Yee-How Tan
- Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400, Malaysia
| | - Yan Zhao
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
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Fernández FD, Galdeano E, Kornowski MV, Arneodo JD, Conci LR. Description of ‘Candidatus Phytoplasma meliae’, a phytoplasma associated with Chinaberry (Melia azedarach L.) yellowing in South America. Int J Syst Evol Microbiol 2016; 66:5244-5251. [DOI: 10.1099/ijsem.0.001503] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Franco Daniel Fernández
- Instituto de Patología Vegetal (IPAVE), CIAP-INTA, Camino 60 cuadras km 5 ½ (X5020ICA), Córdoba, Argentina
| | - Ernestina Galdeano
- Instituto de Botánica del Nordeste, (CONICET-UNNE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Sargento Cabral 2131 (3400), Corrientes, Argentina
| | - Marcela Victoria Kornowski
- Estación Experimental Agropecuaria Montecarlo-INTA, Av. El Libertador 2472 (3384), Montecarlo, Argentina
| | - Joel Demián Arneodo
- Instituto de Microbiología y Zoología Agrícola (IMyZA), INTA, Nicolas Repetto y de los Reseros s/n (1686), Hurlingham, Argentina
| | - Luis Rogelio Conci
- Instituto de Patología Vegetal (IPAVE), CIAP-INTA, Camino 60 cuadras km 5 ½ (X5020ICA), Córdoba, Argentina
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17
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Gopurenko D, Fletcher MJ, Liu J, Gurr GM. Expanding and exploring the diversity of phytoplasmas from lucerne (Medicago sativa). Sci Rep 2016; 6:37746. [PMID: 27886229 PMCID: PMC5123570 DOI: 10.1038/srep37746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/01/2016] [Indexed: 11/09/2022] Open
Abstract
Phytoplasmas are a group of insect-vectored bacteria responsible for disease in many plant species worldwide. Among the crop species affected is the economically valuable forage species lucerne. Here we provide comprehensive molecular evidence for infection in multiple lucerne plants by a phytoplasma not previously known from this plant species. This phytoplasma had a >99% genetic similarity to an unclassified 16S rRNA subgroup previously reported as Stylosanthes little leaf from Stylosanthes spp. and was genetically and symptomatically distinct from a co-occurring but less common 16SrIIA group phytoplasma. Neighbour-joining analyses with publicly available sequence data confirmed the presence of two distinct phytoplasma lineages in the plant population. No PCR detections were made among 38 individuals of 12 co-occurring weed species. Sequence analysis revealed that all nine PCR detections from among 106 individuals of five Hemiptera insect species from the site, three of which had previously been reported as likely vectors, were false positives. This study demonstrates the importance of sequencing to complement PCR detection and avoid potentially inaccurate conclusions regarding vectors, highlights that sampling over a wide spatio-temporal scale is important for vector and alternative host studies, and extends to eight the number of phytoplasma 16 Sr groups known from lucerne.
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Affiliation(s)
- David Gopurenko
- Graham Centre for Agricultural Innovation (Charles Sturt University & NSW Department of Primary Industries), NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Pine Gully Rd, Wagga Wagga, NSW 2650, Australia
| | - Murray J. Fletcher
- Graham Centre for Agricultural Innovation (Charles Sturt University & NSW Department of Primary Industries), PO Box 883, Orange, NSW 2800, Australia
| | - Jian Liu
- Graham Centre for Agricultural Innovation (Charles Sturt University & NSW Department of Primary Industries), PO Box 883, Orange, NSW 2800, Australia
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Applied Ecology, Fujian Agriculture & Forestry University, Fuzhou 350002, China
| | - Geoff M. Gurr
- Graham Centre for Agricultural Innovation (Charles Sturt University & NSW Department of Primary Industries), PO Box 883, Orange, NSW 2800, Australia
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Applied Ecology, Fujian Agriculture & Forestry University, Fuzhou 350002, China
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Gurr GM, Johnson AC, Ash GJ, Wilson BAL, Ero MM, Pilotti CA, Dewhurst CF, You MS. Coconut Lethal Yellowing Diseases: A Phytoplasma Threat to Palms of Global Economic and Social Significance. FRONTIERS IN PLANT SCIENCE 2016; 7:1521. [PMID: 27833616 PMCID: PMC5080360 DOI: 10.3389/fpls.2016.01521] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 09/26/2016] [Indexed: 05/25/2023]
Abstract
The recent discovery of Bogia coconut syndrome in Papua New Guinea (PNG) is the first report of a lethal yellowing disease (LYD) in Oceania. Numerous outbreaks of LYDs of coconut have been recorded in the Caribbean and Africa since the late Nineteenth century and have caused the death of millions of palms across several continents during the Twentieth century. Despite the severity of economic losses, it was only in the 1970s that the causes of LYDs were identified as phytoplasmas, a group of insect-transmitted bacteria associated with diseases in many other economically important crop species. Since the development of polymerase chain reaction (PCR) technology, knowledge of LYDs epidemiology, ecology and vectors has grown rapidly. There is no economically viable treatment for LYDs and vector-based management is hampered by the fact that vectors have been positively identified in very few cases despite many attempted transmission trials. Some varieties and hybrids of coconut palm are known to be less susceptible to LYD but none are completely resistant. Optimal and current management of LYD is through strict quarantine, prompt detection and destruction of symptomatic palms, and replanting with less susceptible varieties or crop species. Advances in technology such as loop mediated isothermal amplification (LAMP) for detection and tracking of phytoplasma DNA in plants and insects, remote sensing for identifying symptomatic palms, and the advent of clustered regularly interspaced short palindromic repeats (CRISPR)-based tools for gene editing and plant breeding are likely to allow rapid progress in taxonomy as well as understanding and managing LYD phytoplasma pathosystems.
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Affiliation(s)
- Geoff M. Gurr
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujain Agriculture and Forestry UniversityFuzhou, China
- Institute of Applied Ecology, College of Plant Protection, Fujian Agriculture and Forestry UniversityFuzhou, China
- Graham Centre of Agricultural Innovation, Charles Sturt UniversityOrange, NSW, Australia
| | - Anne C. Johnson
- Graham Centre of Agricultural Innovation, Charles Sturt UniversityOrange, NSW, Australia
| | - Gavin J. Ash
- Research and Innovation Division, Centre for Crop Health, Institute for Agriculture and the Environment, University of Southern QueenslandToowoomba, QLD, Australia
| | - Bree A. L. Wilson
- Research and Innovation Division, Centre for Crop Health, Institute for Agriculture and the Environment, University of Southern QueenslandToowoomba, QLD, Australia
| | - Mark M. Ero
- PNG Oil Palm Research AssociationKimbe, Papua New Guinea
| | | | - Charles F. Dewhurst
- Formerly affiliated with the PNG Oil Palm Research AssociationKimbe, Papua New Guinea
| | - Minsheng S. You
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujain Agriculture and Forestry UniversityFuzhou, China
- Institute of Applied Ecology, College of Plant Protection, Fujian Agriculture and Forestry UniversityFuzhou, China
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Abeysinghe S, Abeysinghe PD, Kanatiwela-de Silva C, Udagama P, Warawichanee K, Aljafar N, Kawicha P, Dickinson M. Refinement of the Taxonomic Structure of 16SrXI and 16SrXIV Phytoplasmas of Gramineous Plants using Multilocus Sequence Typing. PLANT DISEASE 2016; 100:2001-2010. [PMID: 30683016 DOI: 10.1094/pdis-02-16-0244-re] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phytoplasmas that infect gramineous plants, including Napier grass stunt, sugarcane whiteleaf, sugarcane grassy shoot, and Bermuda grass whiteleaf, have been classified into two closely related groups, 16SrXI and 16SrXIV, based on the 16S ribosomal RNA (rRNA) gene. Subsequently, phytoplasmas associated with coconut and Areca palm in southern India and Sri Lanka have been added into the 16SrXI group. However, the 16S rRNA gene gives relatively poor resolution between these phytoplasmas. In this study, a new set of universal phytoplasma primers that amplify approximately 1 kb of the leucyl transfer RNA synthetase (leuS) gene have been validated on a broad range of phytoplasma taxonomic groups. These have been used along with partial sequences of the secA gene to clarify the taxonomic classification of 16SrXI and 16SrXIV phytoplasmas. Based on this data, the sugarcane whiteleaf and grassy shoot phytoplasmas appear to be the same phytoplasma. The Napier grass stunt phytoplasma forms a distinct group from the Bermuda grass whiteleaf and sugarcane phytoplasmas, suggesting that Napier grass stunt should be in its own 'Candidatus Phytoplasma sp.'. The phytoplasmas associated with coconut and arecanut in southern India and Sri Lanka, which are in the same 16SrXI group, appear in different groups based on secA analysis.
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Affiliation(s)
- Saman Abeysinghe
- Department of Botany, Faculty of Science, University of Ruhuna, Matara, Sri Lanka
| | | | | | - Preethi Udagama
- Department of Zoology, Faculty of Science, University of Colombo, Colombo 03, Sri Lanka
| | - Kanjana Warawichanee
- Plant Virology Section, Department of Agriculture, Chatuchak, Bangkok, 10900, Thailand
| | - Naofel Aljafar
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, LE12 5RD, UK
| | - Praphat Kawicha
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, LE12 5RD, UK
| | - Matt Dickinson
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, LE12 5RD, UK
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Pérez-López E, Olivier CY, Luna-Rodríguez M, Dumonceaux TJ. Phytoplasma classification and phylogeny based on in silico and in vitro RFLP analysis of cpn60 universal target sequences. Int J Syst Evol Microbiol 2016; 66:5600-5613. [PMID: 27667728 PMCID: PMC5244502 DOI: 10.1099/ijsem.0.001501] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phytoplasmas are unculturable, phytopathogenic bacteria that cause economic losses worldwide. As unculturable micro-organisms, phytoplasma taxonomy has been based on the use of the 16S rRNA-encoding gene to establish 16Sr groups and subgroups based on the restriction fragment length polymorphism (RFLP) pattern resulting from the digestion of amplicon (in vitro) or sequence (in silico) with seventeen restriction enzymes. Problems such as heterogeneity of the ribosomal operon and the inability to differentiate closely related phytoplasma strains has motivated the search for additional markers capable of providing finer differentiation of phytoplasma strains. In this study we developed and validated a scheme to classify phytoplasmas based on the use of cpn60 universal target (cpn60 UT) sequences. Ninety-six cpn60 UT sequences from strains belonging to 19 16Sr subgroups were subjected to in silico RFLP using pDRAW32 software, resulting in 25 distinctive RFLP profiles. Based on these results we delineated cpn60 UT groups and subgroups, and established a threshold similarity coefficient for groups and subgroups classifying all the strains analysed in this study. The nucleotide identity among the reference strains, the correspondence between in vitro and in silico RFLP, and the phylogenetic relationships of phytoplasma strains based on cpn60 UT sequences are also discussed.
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Affiliation(s)
- Edel Pérez-López
- Instituto de Biotecnología y Ecología Aplicada (INBIOTECA), Universidad Veracruzana, Avenida de Las Culturas Veracruzanas Xalapa, Veracruz, México
| | - Chrystel Y. Olivier
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, Ontario, Canada
| | - Mauricio Luna-Rodríguez
- Laboratorio de Alta Tecnología de Xalapa - DGI, Universidad Veracruzana, Médicos 5, Unidad del Bosque Xalapa, Veracruz, México
| | - Tim J. Dumonceaux
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Saskatchewan, Canada
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Correspondence Tim J. Dumonceaux
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Davis RE, Harrison NA, Zhao Y, Wei W, Dally EL. ‘Candidatus Phytoplasma hispanicum’, a novel taxon associated with Mexican periwinkle virescence disease of Catharanthus roseus. Int J Syst Evol Microbiol 2016; 66:3463-3467. [DOI: 10.1099/ijsem.0.001218] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Robert E. Davis
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Nigel A. Harrison
- Plant Pathology Department, Research and Education Center, University of Florida, Fort Lauderdale, FL 33314, USA
| | - Yan Zhao
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Wei Wei
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Ellen L. Dally
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
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22
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Yang Y, Jiang L, Che H, Cao X, Luo D. Identification of a novel subgroup 16SrII-U phytoplasma associated with papaya little leaf disease. Int J Syst Evol Microbiol 2016; 66:3485-3491. [PMID: 27266888 DOI: 10.1099/ijsem.0.001221] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Papaya is an important fruit crop cultivated in tropical and subtropical regions. Papaya little leaf (PLL) disease was observed in China. The phytoplasma 16S rRNA gene was detected from symptomatic papaya trees via PCR using phytoplasma universal primers P1/P7 followed by R16F2n/R16R2. No amplification products were obtained from templates of asymptomatic papaya trees. These results indicated a direct association between phytoplasma infection and PLL disease. Comparative and phylogenetic analyses of 16S rRNA gene sequences indicated that the papaya-infecting phytoplasmas under study belonged to the peanut witches' broom phytoplasma group (16SrII). Genotyping through use of computer-simulated RFLP analysis of 16S rRNA genes and coefficients of RFLP pattern similarities (0.97) reveal that the PLL phytoplasma was placed in a new subgroup. In this article, we describe the molecular characterization of a new phytoplasma associated with PLL disease and propose that the PLL phytoplasma be considered as a novel subgroup, 16SrII-U.
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Affiliation(s)
- Yi Yang
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture; Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou 571101, PR China
| | - Lei Jiang
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture; Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou 571101, PR China
| | - Haiyan Che
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture; Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou 571101, PR China
| | - Xueren Cao
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture; Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou 571101, PR China
| | - Daquan Luo
- Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture; Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou 571101, PR China
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23
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Zhao Y, Davis RE. Criteria for phytoplasma 16Sr group/subgroup delineation and the need of a platform for proper registration of new groups and subgroups. Int J Syst Evol Microbiol 2016; 66:2121-2123. [DOI: 10.1099/ijsem.0.000999] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Yan Zhao
- Molecular Plant Pathology Laboratory, Beltsville Agricultural Research Center,ARS-USDA, Beltsville, MD 20705,USA
| | - Robert E. Davis
- Molecular Plant Pathology Laboratory, Beltsville Agricultural Research Center,ARS-USDA, Beltsville, MD 20705,USA
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24
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Šafárˇová D, Zemánek T, Válová P, Navrátil M. 'Candidatus Phytoplasma cirsii', a novel taxon from creeping thistle [Cirsium arvense (L.) Scop]. Int J Syst Evol Microbiol 2016; 66:1745-1753. [PMID: 26849880 DOI: 10.1099/ijsem.0.000937] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Creeping thistle [Cirsium arvense (L.) Scop.] and dahlia (Dahlia sp.) plants showing typical symptoms of phytoplasma infection including yellowing, stunting, inflorescence and proliferation, were sampled; the presence of phytoplasma was confirmed by standard PCR using universal primers. RFLP analysis allowed classification of the detected phytoplasma strains CirYS, CirYS1 and DahlP within the 16SrXI group, the unique restriction profile F2nR2 fragment obtained in silico by iPhyClassifier indicated that they belong to the new 16SrXI-E subgroup. Genetic analysis of the 16S rRNA gene revealed that the studied strains shared less than 97.5% similarity with all of the previously described 'Candidatus Phytoplasma' species. The closest relatives are 'Candidatus Phytoplasma cynodontis' and 'Candidatus Phytoplasma oryzae' with 96.8% and 96.6% similarity. All strains studied bear three specific regions in the 16S rRNA gene, discriminating them from the other phytoplasma species. Phylogenetic analysis of the 16S rRNA and secA genes confirmed this specificity, as the creeping thistle and dahlia phytoplasma strains clustered in a distinguishable lineage group. The uniqueness of the genetic analysis agrees with the biological characterization of the studied phytoplasma strains, their host range, and geographical distribution. The strains only infect dicotyledonous plants in Europe, contrary to their closest relatives. Based on their unique properties, it could be concluded that the studied phytoplasma strains represent a discrete group that is proposed as a novel taxon 'Candidatus Phytoplasma cirsii', with strain CirYS as a reference strain.
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Affiliation(s)
- Dana Šafárˇová
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Šlechtitelu˚ 27, 783 71, Olomouc, Czech Republic
| | - Tomáš Zemánek
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Šlechtitelu˚ 27, 783 71, Olomouc, Czech Republic
| | - Pavla Válová
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Šlechtitelu˚ 27, 783 71, Olomouc, Czech Republic
| | - Milan Navrátil
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Šlechtitelu˚ 27, 783 71, Olomouc, Czech Republic
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25
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Pérez-López E, Luna-Rodríguez M, Olivier CY, Dumonceaux TJ. The underestimated diversity of phytoplasmas in Latin America. Int J Syst Evol Microbiol 2016; 66:492-513. [DOI: 10.1099/ijsem.0.000726] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Edel Pérez-López
- Instituto de Biotecnología y Ecología Aplicada (INBIOTECA), Universidad Veracruzana, Avenida de Las Culturas Veracruzanas, Xalapa, Veracruz, Mexico
| | - Mauricio Luna-Rodríguez
- DGI-LATEX, Universidad Veracruzana, Avenida de Las Culturas Veracruzanas, Xalapa, Veracruz, Mexico
| | - Chrystel Y. Olivier
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
| | - Tim J. Dumonceaux
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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26
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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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27
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Wei W, Davis RE, Suo X, Zhao Y. Occurrence, distribution and possible functional roles of simple sequence repeats in phytoplasma genomes. Int J Syst Evol Microbiol 2015; 65:2748-2760. [DOI: 10.1099/ijs.0.000273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Phytoplasmas are unculturable, cell-wall-less bacteria that parasitize plants and insects. This transkingdom life cycle requires rapid responses to vastly different environments, including transitions from plant phloem sieve elements to various insect tissues and alternations among diverse plant hosts. Features that enable such flexibility in other microbes include simple sequence repeats (SSRs) — mutation-prone, phase-variable short DNA tracts that function as ‘evolutionary rheostats’ and enhance rapid adaptations. To gain insights into the occurrence, distribution and potentially functional roles of SSRs in phytoplasmas, we performed computational analysis on the genomes of five completely sequenced phytoplasma strains, ‘Candidatus Phytoplasma asteris’-related strains OYM and AYWB, ‘Candidatus Phytoplasma australiense’-related strains CBWB and SLY and ‘Candidatus Phytoplasma mali’-related strain AP-AT. The overall density of SSRs in phytoplasma genomes was higher than in representative strains of other prokaryotes. While mono- and trinucleotide SSRs were significantly overrepresented in the phytoplasma genomes, dinucleotide SSRs and other higher-order SSRs were underrepresented. The occurrence and distribution of long SSRs in the prophage islands and phytoplasma-unique genetic loci indicated that SSRs played a role in compounding the complexity of sequence mosaics in individual genomes and in increasing allelic diversity among genomes. Findings from computational analyses were further complemented by an examination of SSRs in varied additional phytoplasma strains, with a focus on potential contingency genes. Some SSRs were located in regions that could profoundly alter the regulation of transcription and translation of affected genes and/or the composition of protein products.
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Affiliation(s)
- Wei Wei
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD, 20705, USA
| | - Robert E. Davis
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD, 20705, USA
| | - Xiaobing Suo
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD, 20705, USA
| | - Yan Zhao
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD, 20705, USA
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28
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Zhao Y, Davis RE, Wei W, Lee IM. Should 'Candidatus Phytoplasma' be retained within the order Acholeplasmatales? Int J Syst Evol Microbiol 2015; 65:1075-1082. [PMID: 25574038 DOI: 10.1099/ijs.0.000050] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phytoplasmas are a diverse but phylogenetically coherent group of cell-wall-less bacteria affiliated with the class Mollicutes. Due to difficulties in establishing axenic culture, phytoplasmas were assigned to a provisional genus, 'Candidatus Phytoplasma', and the genus was embraced within the order Acholeplasmatales. However, phytoplasmas differ significantly from species of the genus Acholeplasma in their habitat specificities, modes of life, metabolic capabilities, genomic architectures, and phylogenetic positions. This communication describes the unique ecological, nutritional, biochemical, genomic and phylogenetic properties that distinguish phytoplasmas from species of the genus Acholeplasma and all other taxa in the class Mollicutes. Since such distinguishing properties of the phytoplasmas are not referable to the descriptions of the order Acholeplasmatales and of all other existing orders, namely Mycoplasmatales, Entomoplasmatales and Anaeroplasmatales, this communication raises the question of whether 'Candidatus Phytoplasma' should be retained in the order Acholeplasmatales or whether a novel provisional order and family should be created to accommodate the genus 'Ca. Phytoplasma'.
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Affiliation(s)
- Yan Zhao
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Robert E Davis
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Wei Wei
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
| | - Ing-Ming Lee
- Molecular Plant Pathology Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705, USA
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29
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Bertaccini A, Duduk B, Paltrinieri S, Contaldo N. Phytoplasmas and Phytoplasma Diseases: A Severe Threat to Agriculture. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/ajps.2014.512191] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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