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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. Mol Plant Pathol 2024; 25:e13437. [PMID: 38393681 PMCID: PMC10887288 DOI: 10.1111/mpp.13437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Pardo JM, Chittarath K, Vongphachanh P, Hang LT, Oeurn S, Arinaitwe W, Rodriguez R, Sophearith S, Malik AI, Cuellar WJ. Cassava Witches' Broom Disease in Southeast Asia: A Review of Its Distribution and Associated Symptoms. Plants (Basel) 2023; 12:plants12112217. [PMID: 37299196 DOI: 10.3390/plants12112217] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023]
Abstract
Cassava witches' broom disease (CWBD) is one of the main diseases of cassava in Southeast Asia (SEA). Affected cassava plants show reduced internodal length and proliferation of leaves (phyllody) in the middle and top part of the plant, which results in reduced root yields of 50% or more. It is thought to be caused by phytoplasma; however, despite its widespread distribution in SEA still little is known about CWBD pathology. The overarching goal of this study was to review and corroborate published information on CWBD biology and epidemiology considering recent field observations. We report the following: (1) CWBD symptoms are conserved and persistent in SEA and are distinct from what has been reported as witches' broom in Argentina and Brazil. (2) In comparison with cassava mosaic disease, another major disease of cassava in SEA, symptoms of CWBD develop later. (3) Phytoplasma detected in CWBD-affected plants belong to different ribosomal groups and there is no association study available indicating phytoplasma as the causing agent of CWBD. These findings are essential clues for designing surveillance and management strategies and for future studies to better understand the biology, tissue localization and spatial spread of CWBD in SEA and other potential risk areas.
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Affiliation(s)
- Juan M Pardo
- Cassava Program, International Center for Tropical Agriculture (CIAT), The Americas Hub, Km 17 Recta Cali-Palmira, Cali 763537, Colombia
| | - Khonesavanh Chittarath
- Plant Protection Center (PPC), Department of Agriculture, Ministry of Agriculture and Forestry, Vientiane P.O. Box 811, Laos
| | - Pinkham Vongphachanh
- Plant Protection Center (PPC), Department of Agriculture, Ministry of Agriculture and Forestry, Vientiane P.O. Box 811, Laos
| | - Le Thi Hang
- Plant Protection Research Institute (PPRI), Duc Thang, Bac Tu Liem, Ha Noi 100000, Vietnam
| | - Samoul Oeurn
- Plant Protection Sanitary and Phytosanitary Department, General Directorate of Agriculture (GDA), Phnom Penh 120406, Cambodia
| | - Warren Arinaitwe
- Cassava Program Asia Office, International Center for Tropical Agriculture (CIAT), Vientiane P.O. Box 783, Laos
| | - Rafael Rodriguez
- Cassava Program, International Center for Tropical Agriculture (CIAT), The Americas Hub, Km 17 Recta Cali-Palmira, Cali 763537, Colombia
| | - Sok Sophearith
- Cassava Program Cambodia Office, International Center for Tropical Agriculture (CIAT), Phnom Penh 120904, Cambodia
| | - Al Imran Malik
- Cassava Program Asia Office, International Center for Tropical Agriculture (CIAT), Vientiane P.O. Box 783, Laos
| | - Wilmer J Cuellar
- Cassava Program, International Center for Tropical Agriculture (CIAT), The Americas Hub, Km 17 Recta Cali-Palmira, Cali 763537, Colombia
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Xue C, Zhang Y, Li H, Liu Z, Gao W, Liu M, Wang H, Liu P, Zhao J. The genome of Candidatus phytoplasma ziziphi provides insights into their biological characteristics. BMC Plant Biol 2023; 23:251. [PMID: 37173622 PMCID: PMC10176825 DOI: 10.1186/s12870-023-04243-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/22/2023] [Indexed: 05/15/2023]
Abstract
Phytoplasmas are obligate cell wall-less prokaryotic bacteria that primarily multiply in plant phloem tissue. Jujube witches' broom (JWB) associated with phytoplasma is a destructive disease of jujube (Ziziphus jujuba Mill.). Here we report the complete 'Candidatus Phytoplasma ziziphi' chromosome of strain Hebei-2018, which is a circular genome of 764,108-base pairs with 735 predicted CDS. Notably, extra 19,825 bp (from 621,995 to 641,819 bp) compared to the previously reported one complements the genes involved in glycolysis, such as pdhA, pdhB, pdhC, pdhD, ackA, pduL and LDH. The synonymous codon usage bias (CUB) patterns by using comparative genomics analysis among the 9 phytoplasmas were similar for most codons. The ENc-GC3s analysis among the 9 phytoplasmas showed a greater effect under the selection on the CUBs of phytoplasmas genes than mutation and other factors. The genome exhibited a strongly reduced ability in metabolic synthesis, while the genes encoding transporter systems were well developed. The genes involved in sec-dependent protein translocation system were also identified.The expressions of nine FtsHs encoding membrane associated ATP-dependent Zn proteases and Mn-SodA with redox capacity in the Ca. P. ziziphi was positively correlated with the phytoplasma concentration. Taken together, the genome will not only expand the number of phytoplasma species and provide some new information about Ca. P. ziziphi, but also contribute to exploring its pathogenic mechanism.
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Affiliation(s)
- Chaoling Xue
- College of Life Science, Hebei Agricultural University, Baoding, 071000, China
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, Hebei Agricultural University, Baoding, 071000, China
| | - Yao Zhang
- College of Life Science, Hebei Agricultural University, Baoding, 071000, China
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, Hebei Agricultural University, Baoding, 071000, China
| | - Hongtai Li
- College of Life Science, Hebei Agricultural University, Baoding, 071000, China
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, Hebei Agricultural University, Baoding, 071000, China
| | - Zhiguo Liu
- Research Center of Chinese Jujube, Hebei Agricultural University, Baoding, 071000, China
| | - Weilin Gao
- College of Life Science, Hebei Agricultural University, Baoding, 071000, China
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, Hebei Agricultural University, Baoding, 071000, China
| | - Mengjun Liu
- Research Center of Chinese Jujube, Hebei Agricultural University, Baoding, 071000, China
| | - Huibin Wang
- College of Life Science, Hebei Agricultural University, Baoding, 071000, China
| | - Ping Liu
- Research Center of Chinese Jujube, Hebei Agricultural University, Baoding, 071000, China.
| | - Jin Zhao
- College of Life Science, Hebei Agricultural University, Baoding, 071000, China.
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, Hebei Agricultural University, Baoding, 071000, China.
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Bai B, Zhang G, Pei B, Song Q, Hao X, Zhao L, Wu Y. The function of the phytoplasma effector SWP12 depends on the properties of two key amino acids. J Biol Chem 2023; 299:103052. [PMID: 36813236 PMCID: PMC10040895 DOI: 10.1016/j.jbc.2023.103052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/23/2023] Open
Abstract
Phytoplasmas are insect-borne bacterial pathogens capable of secreting effectors into host cells and interfering with host plant defense response processes. Previous studies have found that the Candidatus Phytoplasma tritici effector SWP12 binds to and destabilizes the wheat transcription factor TaWRKY74, increasing wheat susceptibility to phytoplasmas. Here, we used a Nicotiana benthamiana transient expression system to identify two key functional sites of SWP12 and screened a series of truncated mutants and amino acid substitution mutants to determine whether they inhibit Bax-induced cell death. Using a subcellular localization assay and online structure analysis websites, we found that structure rather than intracellular localization probably affects the function of SWP12. D33A and P85H are two inactive substitution mutants, neither of which interacts with TaWRKY74, and P85H does not inhibit Bax-induced cell death, suppress flg22-triggered reactive oxygen species (ROS) bursts, degrade TaWRKY74, or promote phytoplasma accumulation. D33A can weakly suppress Bax-induced cell death and flg22-triggered ROS bursts and degrade a portion of TaWRKY74 and weakly promote phytoplasma accumulation. S53L, CPP, and EPWB are three SWP12 homolog proteins from other phytoplasmas. Sequence analysis revealed that D33 was conserved in these proteins, and they exhibited the same polarity at P85. Transient expression in N. benthamiana showed that these proteins could inhibit Bax-induced cell death and suppress ROS bursts. Our findings clarified that P85 and D33 of SWP12 play critical and minor roles, respectively, in suppressing the plant defense response and that they play a preliminary role in determining the functions of homologous proteins.
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Affiliation(s)
- Bixin Bai
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Guoding Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Baoyan Pei
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Qingting Song
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Xing'an Hao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Lei Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
| | - Yunfeng Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
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Pusz-Bochenska K, Perez-Lopez E, Wist TJ, Bennypaul H, Sanderson D, Green M, Dumonceaux TJ. Multilocus sequence typing of diverse phytoplasmas using hybridization probe-based sequence capture provides high resolution strain differentiation. Front Microbiol 2022; 13:959562. [PMID: 36246242 PMCID: PMC9556853 DOI: 10.3389/fmicb.2022.959562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/05/2022] [Indexed: 11/26/2022] Open
Abstract
Phytoplasmas are insect-vectored, difficult-to-culture bacterial pathogens that infect a wide variety of crop and non-crop plants, and are associated with diseases that can lead to significant yield losses in agricultural production worldwide. Phytoplasmas are currently grouped in the provisional genus ‘Candidatus Phytoplasma’, which includes 49 ‘Candidatus’ species. Further differentiation of phytoplasmas into ribosomal groups is based on the restriction fragment length polymorphism (RFLP) pattern of the 16S rRNA-encoding operon, with more than 36 ribosomal groups (16Sr) and over 100 subgroups reported. Since disease symptoms on plants are not associated with phytoplasma identity, accurate diagnostics is of critical importance to manage disease associated with these microorganisms. Phytoplasmas are typically detected from plant and insect tissue using PCR-based methods targeting universal taxonomic markers. Although these methods are relatively sensitive, specific and are widely used, they have limitations, since they provide limited resolution of phytoplasma strains, thus necessitating further assessment of biological properties and delaying implementation of mitigation measures. Moreover, the design of PCR primers that can target multiple loci from phytoplasmas that differ at the sequence level can be a significant challenge. To overcome these limitations, a PCR-independent, multilocus sequence typing (MLST) assay to characterize an array of phytoplasmas was developed. Hybridization probe s targeting cpn60, tuf, secA, secY, and nusA genes, as well as 16S and rp operons, were designed and used to enrich DNA extracts from phytoplasma-infected samples for DNA fragments corresponding to these markers prior to Illumina sequencing. This method was tested using different phytoplasmas including ‘Ca. P. asteris’ (16SrI-B), ‘Ca. P. pruni’ (16SrIII-A),‘Ca. P. prunorum’ (16SrX-B), ‘Ca. P. pyri’ (16SrX-C), ‘Ca. P. mali’ (16SrX-A), and ‘Ca. P. solani’ (16SrXII-A). Thousands of reads were obtained for each gene with multiple overlapping fragments, which were assembled to generate full-length (typically >2 kb), high-quality sequences. Phytoplasma groups and subgroups were accurately determined based on 16S ribosomal RNA and cpn60 gene sequences. Hybridization-based MLST facilitates the enrichment of target genes of phytoplasmas and allows the simultaneous determination of sequences corresponding to seven different markers. In this proof-of-concept study, hybridization-based MLST was demonstrated to be an efficient way to generate data regarding ‘Ca. Phytoplasma’ species/strain differentiation.
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Affiliation(s)
- Karolina Pusz-Bochenska
- Agriculture and Agri-Food Canada Saskatoon Research and Development Centre, Saskatoon, SK, Canada
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Edel Perez-Lopez
- Centre de Recherche et D'innovation sur les Végétaux (CRIV), Faculté des Sciences de L'agriculture et de L'alimentation, Département de Phytologie, Université Laval, Québec, QC, Canada
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
| | - Tyler J. Wist
- Agriculture and Agri-Food Canada Saskatoon Research and Development Centre, Saskatoon, SK, Canada
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Harvinder Bennypaul
- Canadian Food Inspection Agency (CFIA), Sidney Laboratory, Centre for Plant Health, North Saanich, BC, Canada
| | - Daniel Sanderson
- Canadian Food Inspection Agency (CFIA), Sidney Laboratory, Centre for Plant Health, North Saanich, BC, Canada
| | - Margaret Green
- Canadian Food Inspection Agency (CFIA), Sidney Laboratory, Centre for Plant Health, North Saanich, BC, Canada
| | - Tim J. Dumonceaux
- Agriculture and Agri-Food Canada Saskatoon Research and Development Centre, Saskatoon, SK, Canada
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK, Canada
- *Correspondence: Tim J. Dumonceaux,
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Wei W, Zhao Y. Phytoplasma Taxonomy: Nomenclature, Classification, and Identification. Biology (Basel) 2022; 11:biology11081119. [PMID: 35892975 PMCID: PMC9394401 DOI: 10.3390/biology11081119] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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
Simple Summary Phytoplasmas are vector-borne and graft-transmissible bacteria that cause various plant diseases, leading to severe economic losses. Since phytoplasmas cannot be cultured in cell-free media, their identification and taxonomy rely on molecular techniques and gene sequences. In this article, we summarize the recent advances in phytoplasma taxonomy from three different aspects, including (i) nomenclature (naming Candidatus Phytoplasma species); (ii) classification (group and subgroup assignment based on 16S rRNA gene sequences); and (iii) identification (fine differentiation of phytoplasma strains). In addition, some important issues, especially those related to recognizing new ‘Candidatus Phytoplasma’ species, are discussed. This information will be helpful for rapid diagnosis of phytoplasma diseases and accurate taxonomic identification of both emerging and known phytoplasma strains. 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
- Correspondence: ; Tel.: +1-301-504-0786
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Wang XY, Zhang RY, Li J, Li YH, Shan HL, Li WF, Huang YK. The Diversity, Distribution and Status of Phytoplasma Diseases in China. Front Sustain Food Syst 2022. [DOI: 10.3389/fsufs.2022.943080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Phytoplasmas are important prokaryotic pathogenic bacteria without cell walls, which were formerly known as mycoplasma-like organisms, and belong to the Mollicutes class, Candidatus Phytoplasma genus. They are widely distributed in plants and insects, and can cause serious diseases in important food crops, vegetables, fruit trees, ornamental plants and trees, resulting in huge economic losses. To date, more than 100 phytoplasma diseases have been reported in China, which are distributed throughout the country. Jujube witches'-broom, paulownia witches'-broom, wheat blue dwarf, banana bunchy top, sugarcane white leaf, rice orange leaf and mulberry dwarf represent the phytoplasma diseases causing the most serious damage in China. New phytoplasma diseases and their strains are being reported continuously, indicating that phytoplasmas are more diverse than previously thought. Phytoplasmas are mainly transmitted by insect vectors, such as leafhopper and planthopper, and can also be spread by grafting or Cuscuta australis (known as dodder). Mixed infections of phytoplasmas and viruses, bacteria, and spiroplasmas have also become a serious problem in several crops and are responsible for more synergistic losses. With the continuous development and improvement of technology, molecular biological detection has become the main technique for phytoplasma detection and identification. Currently, research on phytoplasma diseases in China mainly focuses on pathogen identification and classification, and insect vector and host diversity; however, there is less focus on pathogenicity, comparative genomics, and effect factors. More research attention has been paid to wheat blue dwarf phytoplasma, paulownia witches'-broom phytoplasma, jujube witches'-broom phytoplasma, and sugarcane white leaf phytoplasma. Other phytoplasma diseases have been reported; however, there have been no in-depth studies. In this paper, the history and present situation of phytoplasma research, and the status, distribution, and diversity of phytoplasma diseases are summarized, and some possible research directions of phytoplasma in the future in China are proposed.
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Huang CT, Cho ST, Lin YC, Tan CM, Chiu YC, Yang JY, Kuo CH. Comparative Genome Analysis of ‘Candidatus Phytoplasma luffae’ Reveals the Influential Roles of Potential Mobile Units in Phytoplasma Evolution. Front Microbiol 2022; 13:773608. [PMID: 35300489 PMCID: PMC8923039 DOI: 10.3389/fmicb.2022.773608] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 02/07/2022] [Indexed: 12/23/2022] Open
Abstract
Phytoplasmas are insect-transmitted plant pathogens that cause substantial losses in agriculture. In addition to economic impact, phytoplasmas induce distinct disease symptoms in infected plants, thus attracting attention for research on molecular plant-microbe interactions and plant developmental processes. Due to the difficulty of establishing an axenic culture of these bacteria, culture-independent genome characterization is a crucial tool for phytoplasma research. However, phytoplasma genomes have strong nucleotide composition biases and are repetitive, which make it challenging to produce complete assemblies. In this study, we utilized Illumina and Oxford Nanopore sequencing technologies to obtain the complete genome sequence of ‘Candidatus Phytoplasma luffae’ strain NCHU2019 that is associated with witches’ broom disease of loofah (Luffa aegyptiaca) in Taiwan. The fully assembled circular chromosome is 769 kb in size and is the first representative genome sequence of group 16SrVIII phytoplasmas. Comparative analysis with other phytoplasmas revealed that NCHU2019 has a remarkably repetitive genome, possessing a pair of 75 kb repeats and at least 13 potential mobile units (PMUs) that account for ∼25% of its chromosome. This level of genome repetitiveness is exceptional for bacteria, particularly among obligate pathogens with reduced genomes. Our genus-level analysis of PMUs demonstrated that these phytoplasma-specific mobile genetic elements can be classified into three major types that differ in gene organization and phylogenetic distribution. Notably, PMU abundance explains nearly 80% of the variance in phytoplasma genome sizes, a finding that provides a quantitative estimate for the importance of PMUs in phytoplasma genome variability. Finally, our investigation found that in addition to horizontal gene transfer, PMUs also contribute to intra-genomic duplications of effector genes, which may provide redundancy for subfunctionalization or neofunctionalization. Taken together, this work improves the taxon sampling for phytoplasma genome research and provides novel information regarding the roles of mobile genetic elements in phytoplasma evolution.
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Affiliation(s)
- Ching-Ting Huang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Shu-Ting Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Chen Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Choon-Meng Tan
- Institute of Biochemistry, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Ching Chiu
- Institute of Biochemistry, National Chung Hsing University, Taichung, Taiwan
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung, Taiwan
| | - Jun-Yi Yang
- Institute of Biochemistry, National Chung Hsing University, Taichung, Taiwan
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung, Taiwan
- Advanced Plant Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- *Correspondence: Jun-Yi Yang,
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung-Hsing University and Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- Chih-Horng Kuo,
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Carminati G, Brusa V, Loschi A, Ermacora P, Martini M. Spatiotemporal and Quantitative Monitoring of the Fate of " Candidatus Phytoplasma Solani" in Tomato Plants Infected by Grafting. Pathogens 2021; 10:pathogens10070811. [PMID: 34206841 PMCID: PMC8308695 DOI: 10.3390/pathogens10070811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 11/16/2022] Open
Abstract
Understanding how phytoplasmas move and multiply within the host plant is fundamental for plant-pathogen interaction studies. In recent years, the tomato has been used as a model plant to study this type of interaction. In the present work, we investigated the distribution and multiplication dynamics of one strain of "Candidatus Phytoplasma (Ca. P.) solani", (16SrXII-A) in tomato (Solanum lycopersicum L., cv. Micro-Tom) plants. We obtained infected plants by grafting, a fast and effective method to maintain phytoplasma infection. In planta spread and multiplication of "Ca. P. solani" was monitored over time using qualitative and quantitative qPCR. Root, apical shoot, lower leaves, and upper leaves were sampled at each sampling time. We hypothesized that "Ca. P. solani" from the grafting site reached firstly the highest leaf, the apex and the roots; subsequently, the phytoplasmas spread to the rest of the upper leaves and then progressively to the lower leaves. Significant differences were found in "Ca. P. solani" titer among different plant tissues. In particular, the concentration of phytoplasma in the roots was significantly higher than that in the other plant compartments in almost all the sampling dates. Since the roots show rapid colonization and the highest concentration of phytoplasmas, they represent the ideal tissue to sample for an early, sensitive and robust diagnosis.
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Garcion C, Béven L, Foissac X. Comparison of Current Methods for Signal Peptide Prediction in Phytoplasmas. Front Microbiol 2021; 12:661524. [PMID: 33841387 PMCID: PMC8026896 DOI: 10.3389/fmicb.2021.661524] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/02/2021] [Indexed: 11/13/2022] Open
Abstract
Although phytoplasma studies are still hampered by the lack of axenic cultivation methods, the availability of genome sequences allowed dramatic advances in the characterization of the virulence mechanisms deployed by phytoplasmas, and highlighted the detection of signal peptides as a crucial step to identify effectors secreted by phytoplasmas. However, various signal peptide prediction methods have been used to mine phytoplasma genomes, and no general evaluation of these methods is available so far for phytoplasma sequences. In this work, we compared the prediction performance of SignalP versions 3.0, 4.0, 4.1, 5.0 and Phobius on several sequence datasets originating from all deposited phytoplasma sequences. SignalP 4.1 with specific parameters showed the most exhaustive and consistent prediction ability. However, the configuration of SignalP 4.1 for increased sensitivity induced a much higher rate of false positives on transmembrane domains located at N-terminus. Moreover, sensitive signal peptide predictions could similarly be achieved by the transmembrane domain prediction ability of TMHMM and Phobius, due to the relatedness between signal peptides and transmembrane regions. Beyond the results presented herein, the datasets assembled in this study form a valuable benchmark to compare and evaluate signal peptide predictors in a field where experimental evidence of secretion is scarce. Additionally, this study illustrates the utility of comparative genomics to strengthen confidence in bioinformatic predictions.
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Affiliation(s)
- Christophe Garcion
- INRAE, Univ. Bordeaux, Biologie du Fruit et Pathologie, UMR 1332, Villenave d'Ornon, France
| | - Laure Béven
- INRAE, Univ. Bordeaux, Biologie du Fruit et Pathologie, UMR 1332, Villenave d'Ornon, France
| | - Xavier Foissac
- INRAE, Univ. Bordeaux, Biologie du Fruit et Pathologie, UMR 1332, Villenave d'Ornon, France
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Fernández FD, Zübert C, Huettel B, Kube M, Conci LR. Draft Genome Sequence of " Candidatus Phytoplasma pruni" (X-Disease Group, Subgroup 16SrIII-B) Strain ChTDIII from Argentina. Microbiol Resour Announc 2020; 9:e00792-20. [PMID: 32943565 DOI: 10.1128/MRA.00792-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Herein, we report the draft genome sequence of "Candidatus Phytoplasma pruni" strain ChTDIII (subgroup 16SrIII-B). The final assembly consists of 790,517 nucleotides organized in 67 contigs (minimal size, 1 kb), with a G+C content of 29.4% and encoding 672 proteins.
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12
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Mori N, Cargnus E, Martini M, Pavan F. Relationships between Hyalesthes obsoletus, Its Herbaceous Hosts and Bois Noir Epidemiology in Northern Italian Vineyards. Insects 2020; 11:E606. [PMID: 32906774 DOI: 10.3390/insects11090606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/25/2020] [Accepted: 09/03/2020] [Indexed: 11/17/2022]
Abstract
Hyalesthes obsoletus is the vector of "Candidatus Phytoplasma (Ca. P.) solani," the causal agent of grapevine yellows Bois noir (BN). The relationships among the planthopper, its main herbaceous hosts as phytoplasma reservoirs (Convolvolus arvensis and Urtica dioica) and BN spreading were studied in northern Italy. In two areas the relationship between host plants and the phenology and survival of planthopper adults was investigated in potted plants and in field conditions. Moreover, H. obsoletus ecology, newly symptomatic grapevine occurrence and "Ca. P. solani" tuf-types' presence were studied in two vineyards (2014-2019). An earlier occurrence of H. obsoletus adults on C. arvensis than U. dioica and better adult survival of the originating host were observed. When U. dioica was prevalent, the vector occurred almost exclusively along the ditch outside the vineyard. Hyalesthes obsoletus amount varied widely from year to year and nymphal mortality due to late frosts was supposed. In one vineyard, the amount of newly symptomatic grapevines was significantly correlated with vector abundance in the previous year. The "Ca. P. solani" tuf-type was influenced by vector population levels on the two hosts. Since the abundance of H. obsoletus populations on the two hosts influences BN epidemiology and dynamics and the "Ca. P. solani" tuf-type, this must be considered in BN control strategies.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Polano C, Firrao G. Assembly of Phytoplasma Genome Drafts from Illumina Reads Using Phytoassembly. Methods Mol Biol 2019; 1875:203-211. [PMID: 30362006 DOI: 10.1007/978-1-4939-8837-2_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Genome drafts for the phytoplasmas may be rapidly and efficiently assembled from NGS sequence data alone exploiting the proper bioinformatic tools and starting from properly collected samples. Here, we describe the use of the Phytoassembly pipeline ( https://github.com/cpolano/phytoassembly ), a fully automated tool that accepts as input row Illumina data from two samples (a phytoplasma infected sample and a healthy reference sample) to produce a phytoplasma genome draft, using the healthy plant host genome as a filter and profiting from the difference in reads coverage between the genome of the pathogen and that of the host. For phytoplasma infected samples containing >2% of pathogen DNA and an isogenic healthy reference sequence the resulting assemblies span the almost entire genomes.
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Affiliation(s)
- Cesare Polano
- Department of Agricultural, Food, Environmental and Animal Sciences (DI4A), University of Udine, Udine, Italy
| | - Giuseppe Firrao
- Department of Agricultural, Food, Environmental and Animal Sciences (DI4A), University of Udine, Udine, Italy.
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Wang J, Song L, Jiao Q, Yang S, Gao R, Lu X, Zhou G. Comparative genome analysis of jujube witches'-broom Phytoplasma, an obligate pathogen that causes jujube witches'-broom disease. BMC Genomics 2018; 19:689. [PMID: 30231900 DOI: 10.1186/s12864-018-5075-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 09/13/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND JWB phytoplasma is a kind of insect-transmitted and uncultivable bacterial plant pathogen causeing a destructive Jujube disease. To date, no genome information about JWB phytoplasma has been published, which hindered its characterization at genomic level. To understand its pathogenicity and ecology, the genome of a JWB phytoplasma isolate jwb-nky was sequenced and compared with other phytoplasmas enabled us to explore the mechanisms of genomic rearrangement. RESULTS The complete genome sequence of JWB phytoplasma (jwb-nky) was determined, which consisting of one circular chromosome of 750,803 bp with a GC content of 23.3%. 694 protein-encoding genes, 2 operons for rRNA genes and 31 tRNA genes as well as 4 potential mobile units (PMUs) containing clusters of DNA repeats were identified. Based on PHIbaes analysis, a large number of genes were genome-specific and approximately 13% of JWB phytoplasma genes were predicted to be associated with virulence. Although transporters for maltose, dipeptides/oligopeptides, spermidine/putrescine, cobalt, Mn/Zn and methionine were identified, KEGG pathway analysis revealed the reduced metabolic capabilities of JWB phytoplasma. Comparative genome analyses between JWB phytoplasma and other phytoplasmas shows the occurrence of large-scale gene rearrangements. The low synteny with other phytoplasmas indicated that the expansion of multiple gene families/duplication probably occurred separately after differentiation. CONCLUSIONS In this study, the complete genome sequence of a JWB phytoplasma isolate jwb-nky that causing JWB disease was reported for the first time and a number of species-specific genes were identified in the genome. The study enhanced our understandings about genomic basis and the pathogenicity mechanism of this pathogen, which will aid in the development of improved strategies for efficient management of JWB diseases.
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Polano C, Firrao G. An Effective Pipeline Based on Relative Coverage for the Genome Assembly of Phytoplasmas and Other Fastidious Prokaryotes. Curr Genomics 2018; 19:491-498. [PMID: 30258279 PMCID: PMC6128390 DOI: 10.2174/1389202919666180314114628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/01/2018] [Accepted: 03/05/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND For the plant pathogenic phytoplasmas, as well as for several fastidious prokaryotes, axenic cultivation is extremely difficult or not possible yet; therefore, even with second generation sequencing methods, obtaining the sequence of their genomes is challenging due to host sequence contamination. OBJECTIVE With the Phytoassembly pipeline here presented, we aim to provide a method to obtain high quality genome drafts for the phytoplasmas and other uncultivable plant pathogens, by exploiting the coverage differential in the ILLUMINA sequences from the pathogen and the host, and using the sequencing of a healthy, isogenic plant as a filter. VALIDATION The pipeline has been benchmarked using simulated and real ILLUMINA runs from phytoplasmas whose genome is known, and it was then used to obtain high quality drafts for three new phytoplasma genomes. CONCLUSION For phytoplasma infected samples containing >2-4% of pathogen DNA and an isogenic reference healthy sample, the resulting assemblies can be next to complete. The Phytoassembly source code is available on GitHub at https://github.com/cpolano/phytoassembly.
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Affiliation(s)
- Cesare Polano
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
| | - Giuseppe Firrao
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
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Sparks ME, Bottner-Parker KD, Gundersen-Rindal DE, Lee IM. Draft genome sequence of the New Jersey aster yellows strain of 'Candidatus Phytoplasma asteris'. PLoS One 2018; 13:e0192379. [PMID: 29408883 PMCID: PMC5800598 DOI: 10.1371/journal.pone.0192379] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/20/2018] [Indexed: 01/21/2023] Open
Abstract
The NJAY (New Jersey aster yellows) strain of ‘Candidatus Phytoplasma asteris’ is a significant plant pathogen responsible for causing severe lettuce yellows in the U.S. state of New Jersey. A draft genome sequence was prepared for this organism. A total of 177,847 reads were assembled into 75 contigs > 518 bp with a total base value of 652,092 and an overall [G+C] content of 27.1%. A total of 733 protein coding genes were identified. This Whole Genome Shotgun project has been deposited at DDBJ/ENA/GenBank under the accession MAPF00000000. This draft genome was used for genome- and gene-based comparative phylogenetic analyses with other phytoplasmas, including the closely related ‘Ca. Phytoplasma asteris’ strain, aster yellows witches’- broom (AY-WB). NJAY and AY-WB exhibit approximately 0.5% dissimilarity at the nucleotide level among their shared genomic segments. Evidence indicated that NJAY harbors four plasmids homologous to those known to encode pathogenicity determinants in AY-WB, as well as a chromosome-encoded mobile unit. Apparent NJAY orthologs to the important AY-WB virulence factors, SAP11 and SAP54, were identified. A number of secreted proteins, both membrane-bound and soluble, were encoded, with many bearing similarity to known AY-WB effector molecules and others representing possible secreted proteins that may be novel to the NJAY lineage.
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Affiliation(s)
- Michael E. Sparks
- USDA-ARS Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, Maryland, United States of America
| | | | - Dawn E. Gundersen-Rindal
- USDA-ARS Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, Maryland, United States of America
| | - Ing-Ming Lee
- USDA-ARS Molecular Plant Pathology Laboratory, Beltsville, Maryland, United States of America
- * E-mail:
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Orlovskis Z, Canale MC, Haryono M, Lopes JRS, Kuo CH, Hogenhout SA. A few sequence polymorphisms among isolates of Maize bushy stunt phytoplasma associate with organ proliferation symptoms of infected maize plants. Ann Bot 2017; 119:869-884. [PMID: 28069632 PMCID: PMC5379588 DOI: 10.1093/aob/mcw213] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/16/2016] [Indexed: 05/18/2023]
Abstract
Background and Aims Maize bushy stunt phytoplasma (MBSP) is a bacterial pathogen of maize ( Zea mays L.) across Latin America. MBSP belongs to the 16SrI-B sub-group within the genus ' Candidatus Phytoplasma'. MBSP and its insect vector Dalbulus maidis (Hemiptera: Cicadellidae) are restricted to maize; both are thought to have coevolved with maize during its domestication from a teosinte-like ancestor. MBSP-infected maize plants show a diversity of symptoms. and it is likely that MBSP is under strong selection for increased virulence and insect transmission on maize hybrids that are widely grown in Brazil. In this study it was investigated whether the differences in genome sequences of MBSP isolates from two maize-growing regions in South-east Brazil explain variations in symptom severity of the MBSP isolates on various maize genotypes. Methods MBSP isolates were collected from maize production fields in Guaíra and Piracicaba in South-east Brazil for infection assays. One representative isolate was chosen for de novo whole-genome assembly and for the alignment of sequence reads from the genomes of other phytoplasma isolates to detect polymorphisms. Statistical methods were applied to investigate the correlation between variations in disease symptoms of infected maize plants and MBSP sequence polymorphisms. Key Results MBSP isolates contributed consistently to organ proliferation symptoms and maize genotype to leaf necrosis, reddening and yellowing of infected maize plants. The symptom differences are associated with polymorphisms in a phase-variable lipoprotein, which is a candidate effector, and an ATP-dependent lipoprotein ABC export protein, whereas no polymorphisms were observed in other candidate effector genes. Lipoproteins and ABC export proteins activate host defence responses, regulate pathogen attachment to host cells and activate effector secretion systems in other pathogens. Conclusions Polymorphisms in two putative virulence genes among MBSP isolates from maize-growing regions in South-east Brazil are associated with variations in organ proliferation symptoms of MBSP-infected maize plants.
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Affiliation(s)
- Zigmunds Orlovskis
- John Innes Centre, Department of Cell and Developmental Biology, Norwich Research Park, Norwich NR4 7UH, UK
| | - Maria Cristina Canale
- John Innes Centre, Department of Cell and Developmental Biology, Norwich Research Park, Norwich NR4 7UH, UK
- Luiz de Queiroz College of Agriculture, University of São Paulo, Department of Entomology and Acarology, Piracicaba 13·418-900, Brazil
| | - Mindia Haryono
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - João Roberto Spotti Lopes
- Luiz de Queiroz College of Agriculture, University of São Paulo, Department of Entomology and Acarology, Piracicaba 13·418-900, Brazil
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Saskia A. Hogenhout
- John Innes Centre, Department of Cell and Developmental Biology, Norwich Research Park, Norwich NR4 7UH, 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Zamorano A, Fiore N. Draft Genome Sequence of 16SrIII-J Phytoplasma, a Plant Pathogenic Bacterium with a Broad Spectrum of Hosts. Genome Announc 2016; 4:e00602-16. [PMID: 27365349 PMCID: PMC4929512 DOI: 10.1128/genomea.00602-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 05/10/2016] [Indexed: 11/30/2022]
Abstract
Phytoplasmas are bacterial plant pathogens that can affect different vegetal hosts. In South America, a phytoplasma belonging to ribosomal subgroup 16SrIII-J has been reported in many crops. Here we report its genomic draft sequence, showing a total length of 687,253 bp and a G+C content of 27.72%.
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Affiliation(s)
- Alan Zamorano
- Universidad de Chile, Facultad de Ciencias Agronómicas, Departamento de Sanidad Vegetal, Santiago, Chile
| | - Nicola Fiore
- Universidad de Chile, Facultad de Ciencias Agronómicas, Departamento de Sanidad Vegetal, Santiago, Chile
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21
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Lee IM, Shao J, Bottner-Parker KD, Gundersen-Rindal DE, Zhao Y, Davis RE. Draft Genome Sequence of "Candidatus Phytoplasma pruni" Strain CX, a Plant-Pathogenic Bacterium. Genome Announc 2015; 3:e01117-15. [PMID: 26472824 DOI: 10.1128/genomeA.01117-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
"Candidatus Phytoplasma pruni" strain CX, belonging to subgroup 16SrIII-A, is a plant-pathogenic bacterium causing economically important diseases in many fruit crops. Here, we report the draft genome sequence, which consists of 598,508 bases, with a G+C content of 27.21 mol%.
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Siampour M, Izadpanah K, Marzachi C, Salehi Abarkoohi M. Identification and characterization of conserved and variable regions of lime witches' broom phytoplasma genome. Microbiology (Reading) 2015; 161:1741-1751. [PMID: 26296664 DOI: 10.1099/mic.0.000133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several segments (∼20 kbp) of the lime witches' broom (LWB) phytoplasma genome (16SrII group) were sequenced and analysed. A 5.7 kbp segment (LWB-C) included conserved genes whose phylogenetic tree was consistent with that generated using 16S rRNA genes. Another 6.4 kbp LWB phytoplasma genome segment (LWB-NC) was structurally similar to the putative mobile unit or sequence variable mosaic genomic region of phytoplasmas, although it represented a new arrangement of genes or pseudogenes such as phage-related protein genes and tra5 insertion sequences. Sequence- and phylogenetic-based evidence suggested that LWB-NC is a genomic region which includes horizontally transferred genes and could be regarded as a hot region to incorporate more foreign genes into the genome of LWB phytoplasma. The presence of phylogenetically related fragments of retroelements was also verified in the LWB phytoplasma genome. Putative intragenomic retrotransposition or retrohoming of these elements might have been determinant in shaping and manipulating the LWB phytoplasma genome. Altogether, the results of this study suggested that the genome of LWB phytoplasma is colonized by a variety of genes that have been acquired through horizontal gene transfer events, which may have further affected the genome through intragenomic mobility and insertion at cognate or incognate sites. Some of these genes are expected to have been involved in the development of features specific to LWB phytoplasma.
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Affiliation(s)
- Majid Siampour
- Department of Plant Protection, College of Agriculture, Shahrekord University, Shahrekord, Iran
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Quaglino F, Kube M, Jawhari M, Abou-Jawdah Y, Siewert C, Choueiri E, Sobh H, Casati P, Tedeschi R, Lova MM, Alma A, Bianco PA. 'Candidatus Phytoplasma phoenicium' associated with almond witches'-broom disease: from draft genome to genetic diversity among strain populations. BMC Microbiol 2015; 15:148. [PMID: 26223451 PMCID: PMC4518686 DOI: 10.1186/s12866-015-0487-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/16/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Almond witches'-broom (AlmWB), a devastating disease of almond, peach and nectarine in Lebanon, is associated with 'Candidatus Phytoplasma phoenicium'. In the present study, we generated a draft genome sequence of 'Ca. P. phoenicium' strain SA213, representative of phytoplasma strain populations from different host plants, and determined the genetic diversity among phytoplasma strain populations by phylogenetic analyses of 16S rRNA, groEL, tufB and inmp gene sequences. RESULTS Sequence-based typing and phylogenetic analysis of the gene inmp, coding an integral membrane protein, distinguished AlmWB-associated phytoplasma strains originating from diverse host plants, whereas their 16S rRNA, tufB and groEL genes shared 100 % sequence identity. Moreover, dN/dS analysis indicated positive selection acting on inmp gene. Additionally, the analysis of 'Ca. P. phoenicium' draft genome revealed the presence of integral membrane proteins and effector-like proteins and potential candidates for interaction with hosts. One of the integral membrane proteins was predicted as BI-1, an inhibitor of apoptosis-promoting Bax factor. Bioinformatics analyses revealed the presence of putative BI-1 in draft and complete genomes of other 'Ca. Phytoplasma' species. CONCLUSION The genetic diversity within 'Ca. P. phoenicium' strain populations in Lebanon suggested that AlmWB disease could be associated with phytoplasma strains derived from the adaptation of an original strain to diverse hosts. Moreover, the identification of a putative inhibitor of apoptosis-promoting Bax factor (BI-1) in 'Ca. P. phoenicium' draft genome and within genomes of other 'Ca. Phytoplasma' species suggested its potential role as a phytoplasma fitness-increasing factor by modification of the host-defense response.
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Affiliation(s)
- Fabio Quaglino
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Università degli Studi di Milano, via Celoria 2, 20133, Milan, Italy.
| | - Michael Kube
- Division Phytomedicine, Thaer-Institute, Humboldt-Universität zu Berlin, Berlin, Germany.
| | - Maan Jawhari
- Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon.
| | - Yusuf Abou-Jawdah
- Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon.
| | - Christin Siewert
- Division Phytomedicine, Thaer-Institute, Humboldt-Universität zu Berlin, Berlin, Germany.
| | - Elia Choueiri
- Department of Plant Protection, Lebanese Agricultural Research Institute, Tal Amara, Lebanon.
| | - Hana Sobh
- Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon.
| | - Paola Casati
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Università degli Studi di Milano, via Celoria 2, 20133, Milan, Italy.
| | - Rosemarie Tedeschi
- Department of Agricultural, Forest and Food Sciences, Università degli Studi di Torino, Grugliasco (TO), Italy.
| | | | - Alberto Alma
- Department of Agricultural, Forest and Food Sciences, Università degli Studi di Torino, Grugliasco (TO), Italy.
| | - Piero Attilio Bianco
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, Università degli Studi di Milano, via Celoria 2, 20133, Milan, Italy.
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Pacifico D, Galetto L, Rashidi M, Abbà S, Palmano S, Firrao G, Bosco D, Marzachì C. Decreasing global transcript levels over time suggest that phytoplasma cells enter stationary phase during plant and insect colonization. Appl Environ Microbiol 2015; 81:2591-602. [PMID: 25636844 DOI: 10.1128/AEM.03096-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To highlight different transcriptional behaviors of the phytoplasma in the plant and animal host, expression of 14 genes of "Candidatus Phytoplasma asteris," chrysanthemum yellows strain, was investigated at different times following the infection of a plant host (Arabidopsis thaliana) and two insect vector species (Macrosteles quadripunctulatus and Euscelidius variegatus). Target genes were selected among those encoding antigenic membrane proteins, membrane transporters, secreted proteins, and general enzymes. Transcripts were detected for all analyzed genes in the three hosts; in particular, those encoding the antigenic membrane protein Amp, elements of the mechanosensitive channel, and two of the four secreted proteins (SAP54 and TENGU) were highly accumulated, suggesting that they play important roles in phytoplasma physiology during the infection cycle. Most transcripts were present at higher abundance in the plant host than in the insect hosts. Generally, transcript levels of the selected genes decreased significantly during infection of A. thaliana and M. quadripunctulatus but were more constant in E. variegatus. Such decreases may be explained by the fact that only a fraction of the phytoplasma population was transcribing, while the remaining part was aging to a stationary phase. This strategy might improve long-term survival, thereby increasing the likelihood that the pathogen may be acquired by a vector and/or inoculated to a healthy plant.
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Dumonceaux TJ, Green M, Hammond C, Perez E, Olivier C. Molecular diagnostic tools for detection and differentiation of phytoplasmas based on chaperonin-60 reveal differences in host plant infection patterns. PLoS One 2014; 9:e116039. [PMID: 25551224 PMCID: PMC4281212 DOI: 10.1371/journal.pone.0116039] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/01/2014] [Indexed: 12/28/2022] Open
Abstract
Phytoplasmas (‘Candidatus Phytoplasma’ spp.) are insect-vectored bacteria that infect a wide variety of plants, including many agriculturally important species. The infections can cause devastating yield losses by inducing morphological changes that dramatically alter inflorescence development. Detection of phytoplasma infection typically utilizes sequences located within the 16S–23S rRNA-encoding locus, and these sequences are necessary for strain identification by currently accepted standards for phytoplasma classification. However, these methods can generate PCR products >1400 bp that are less divergent in sequence than protein-encoding genes, limiting strain resolution in certain cases. We describe a method for accessing the chaperonin-60 (cpn60) gene sequence from a diverse array of ‘Ca.Phytoplasma’ spp. Two degenerate primer sets were designed based on the known sequence diversity of cpn60 from ‘Ca.Phytoplasma’ spp. and used to amplify cpn60 gene fragments from various reference samples and infected plant tissues. Forty three cpn60 sequences were thereby determined. The cpn60 PCR-gel electrophoresis method was highly sensitive compared to 16S-23S-targeted PCR-gel electrophoresis. The topology of a phylogenetic tree generated using cpn60 sequences was congruent with that reported for 16S rRNA-encoding genes. The cpn60 sequences were used to design a hybridization array using oligonucleotide-coupled fluorescent microspheres, providing rapid diagnosis and typing of phytoplasma infections. The oligonucleotide-coupled fluorescent microsphere assay revealed samples that were infected simultaneously with two subtypes of phytoplasma. These tools were applied to show that two host plants, Brassica napus and Camelina sativa, displayed different phytoplasma infection patterns.
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Affiliation(s)
- Tim J. Dumonceaux
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- * E-mail:
| | - Margaret Green
- Canadian Food Inspection Agency, Centre for Plant Health, Sidney, British Columbia, Canada
| | - Christine Hammond
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
| | - Edel Perez
- Instituto de Biotecnologia y Ecologia Aplicada (INBIOTECA), Universidad Veracruzana, Avenida de Las Culturas Veracruzanas, Xalapa, Veracruz, Mexico
| | - Chrystel Olivier
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
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Siewert C, Hess WR, Duduk B, Huettel B, Reinhardt R, Büttner C, Kube M. Complete genome determination and analysis of Acholeplasma oculi strain 19L, highlighting the loss of basic genetic features in the Acholeplasmataceae. BMC Genomics 2014; 15:931. [PMID: 25344468 PMCID: PMC4221730 DOI: 10.1186/1471-2164-15-931] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/25/2014] [Indexed: 11/17/2022] Open
Abstract
Background Acholeplasma oculi belongs to the Acholeplasmataceae family, comprising the genera Acholeplasma and ‘Candidatus Phytoplasma’. Acholeplasmas are ubiquitous saprophytic bacteria. Several isolates are derived from plants or animals, whereas phytoplasmas are characterised as intracellular parasitic pathogens of plant phloem and depend on insect vectors for their spread. The complete genome sequences for eight strains of this family have been resolved so far, all of which were determined depending on clone-based sequencing. Results The A. oculi strain 19L chromosome was sequenced using two independent approaches. The first approach comprised sequencing by synthesis (Illumina) in combination with Sanger sequencing, while single molecule real time sequencing (PacBio) was used in the second. The genome was determined to be 1,587,120 bp in size. Sequencing by synthesis resulted in six large genome fragments, while the single molecule real time sequencing approach yielded one circular chromosome sequence. High-quality sequences were obtained by both strategies differing in six positions, which are interpreted as reliable variations present in the culture population. Our genome analysis revealed 1,471 protein-coding genes and highlighted the absence of the F1FO-type Na+ ATPase system and GroEL/ES chaperone. Comparison of the four available Acholeplasma sequences revealed a core-genome encoding 703 proteins and a pan-genome of 2,867 proteins. Conclusions The application of two state-of-the-art sequencing technologies highlights the potential of single molecule real time sequencing for complete genome determination. Comparative genome analyses revealed that the process of losing particular basic genetic features during genome reduction occurs in both genera, as indicated for several phytoplasma strains and at least A. oculi. The loss of the F1FO-type Na+ ATPase system may separate Acholeplasmataceae from other Mollicutes, while the loss of those genes encoding the chaperone GroEL/ES is not a rare exception in this bacterial class. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-931) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Michael Kube
- Humboldt-Universität zu Berlin, Faculty of Life Science, Thaer-Institute, Division Phytomedicine, Lentzeallee 55/57, 14195 Berlin, Germany.
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Chen W, Li Y, Wang Q, Wang N, Wu Y. Comparative genome analysis of wheat blue dwarf phytoplasma, an obligate pathogen that causes wheat blue dwarf disease in China. PLoS One 2014; 9:e96436. [PMID: 24798075 PMCID: PMC4010473 DOI: 10.1371/journal.pone.0096436] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 04/07/2014] [Indexed: 11/18/2022] Open
Abstract
Wheat blue dwarf (WBD) disease is an important disease that has caused heavy losses in wheat production in northwestern China. This disease is caused by WBD phytoplasma, which is transmitted by Psammotettix striatus. Until now, no genome information about WBD phytoplasma has been published, seriously restricting research on this obligate pathogen. In this paper, we report a new sequencing and assembling strategy for phytoplasma genome projects. This strategy involves differential centrifugation, pulsed-field gel electrophoresis, whole genome amplification, shotgun sequencing, de novo assembly, screening of contigs from phytoplasma and the connection of phytoplasma contigs. Using this scheme, the WBD phytoplasma draft genome was obtained. It was comprised of six contigs with a total size of 611,462 bp, covering ∼94% of the chromosome. Five-hundred-twenty-five protein-coding genes, two operons for rRNA genes and 32 tRNA genes were identified. Comparative genome analyses between WBD phytoplasma and other phytoplasmas were subsequently carried out. The results showed that extensive arrangements and inversions existed among the WBD, OY-M and AY-WB phytoplasma genomes. Most protein-coding genes in WBD phytoplasma were found to be homologous to genes from other phytoplasmas; only 22 WBD-specific genes were identified. KEGG pathway analysis indicated that WBD phytoplasma had strongly reduced metabolic capabilities. However, 46 transporters were identified, which were involved with dipeptides/oligopeptides, spermidine/putrescine, cobalt and Mn/Zn transport, and so on. A total of 37 secreted proteins were encoded in the WBD phytoplasma chromosome and plasmids. Of these, three secreted proteins were similar to the reported phytoplasma virulence factors TENGU, SAP11 and SAP54. In addition, WBD phytoplasma possessed several proteins that were predicted to play a role in its adaptation to diverse environments. These results will provide clues for research on the pathogenic mechanisms of WBD phytoplasma and will also provide a perspective about the genome sequencing of other phytoplasmas and obligate organisms.
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Affiliation(s)
- Wang Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Crop Pest Integrated Pest Management on Crop in Northwestern Loess Plateau, Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Yan Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Crop Pest Integrated Pest Management on Crop in Northwestern Loess Plateau, Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Crop Pest Integrated Pest Management on Crop in Northwestern Loess Plateau, Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Nan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Crop Pest Integrated Pest Management on Crop in Northwestern Loess Plateau, Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Yunfeng Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Crop Pest Integrated Pest Management on Crop in Northwestern Loess Plateau, Ministry of Agriculture, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
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Maejima K, Iwai R, Himeno M, Komatsu K, Kitazawa Y, Fujita N, Ishikawa K, Fukuoka M, Minato N, Yamaji Y, Oshima K, Namba S. Recognition of floral homeotic MADS domain transcription factors by a phytoplasmal effector, phyllogen, induces phyllody. Plant J 2014; 78:541-54. [PMID: 24597566 PMCID: PMC4282529 DOI: 10.1111/tpj.12495] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/14/2014] [Accepted: 02/19/2014] [Indexed: 05/18/2023]
Abstract
Plant pathogens alter the course of plant developmental processes, resulting in abnormal morphology in infected host plants. Phytoplasmas are unique plant-pathogenic bacteria that transform plant floral organs into leaf-like structures and cause the emergence of secondary flowers. These distinctive symptoms have attracted considerable interest for many years. Here, we revealed the molecular mechanisms of the floral symptoms by focusing on a phytoplasma-secreted protein, PHYL1, which induces morphological changes in flowers that are similar to those seen in phytoplasma-infected plants. PHYL1 is a homolog of the phytoplasmal effector SAP54 that also alters floral development. Using yeast two-hybrid and in planta transient co-expression assays, we found that PHYL1 interacts with and degrades the floral homeotic MADS domain proteins SEPALLATA3 (SEP3), APETALA1 (AP1) and CAULIFLOWER (CAL). This degradation of MADS domain proteins was dependent on the ubiquitin-proteasome pathway. The expression of floral development genes downstream of SEP3 and AP1 was disrupted in 35S::PHYL1 transgenic plants. PHYL1 was genetically and functionally conserved among other phytoplasma strains and species. We designate PHYL1, SAP54 and their homologs as members of the phyllody-inducing gene family of 'phyllogens'.
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Affiliation(s)
- Kensaku Maejima
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Ryo Iwai
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Misako Himeno
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Ken Komatsu
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Yugo Kitazawa
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Naoko Fujita
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Kazuya Ishikawa
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Misato Fukuoka
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Nami Minato
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Yasuyuki Yamaji
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Kenro Oshima
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
| | - Shigetou Namba
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo1–1–1 Yayoi, Bunkyo–ku, Tokyo, 113–8657, Japan
- * For correspondence (e-mail )
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Sugio A, MacLean AM, Hogenhout SA. The small phytoplasma virulence effector SAP11 contains distinct domains required for nuclear targeting and CIN-TCP binding and destabilization. New Phytol 2014; 202:838-848. [PMID: 24552625 PMCID: PMC4235307 DOI: 10.1111/nph.12721] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 01/04/2014] [Indexed: 05/20/2023]
Abstract
Phytoplasmas are insect-transmitted bacterial phytopathogens that secrete virulence effectors and induce changes in the architecture and defense response of their plant hosts. We previously demonstrated that the small (± 10 kDa) virulence effector SAP11 of Aster Yellows phytoplasma strain Witches' Broom (AY-WB) binds and destabilizes Arabidopsis CIN (CINCINNATA) TCP (TEOSINTE-BRANCHED, CYCLOIDEA, PROLIFERATION FACTOR 1 AND 2) transcription factors, resulting in dramatic changes in leaf morphogenesis and increased susceptibility to phytoplasma insect vectors. SAP11 contains a bipartite nuclear localization signal (NLS) that targets this effector to plant cell nuclei. To further understand how SAP11 functions, we assessed the involvement of SAP11 regions in TCP binding and destabilization using a series of mutants. SAP11 mutants lacking the entire N-terminal domain, including the NLS, interacted with TCPs but did not destabilize them. SAP11 mutants lacking the C-terminal domain were impaired in both binding and destabilization of TCPs. These SAP11 mutants did not alter leaf morphogenesis. A SAP11 mutant that did not accumulate in plant nuclei (SAP11ΔNLS-NES) was able to bind and destabilize TCP transcription factors, but instigated weaker changes in leaf morphogenesis than wild-type SAP11. Overall the results suggest that phytoplasma effector SAP11 has a modular organization in which at least three domains are required for efficient CIN-TCP destabilization in plants.
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Affiliation(s)
- Akiko Sugio
- Cell and Developmental Biology, The John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Allyson M MacLean
- Cell and Developmental Biology, The John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Saskia A Hogenhout
- Cell and Developmental Biology, The John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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Siewert C, Luge T, Duduk B, Seemüller E, Büttner C, Sauer S, Kube M. Analysis of expressed genes of the bacterium 'Candidatus phytoplasma Mali' highlights key features of virulence and metabolism. PLoS One 2014; 9:e94391. [PMID: 24728201 PMCID: PMC3984173 DOI: 10.1371/journal.pone.0094391] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 03/14/2014] [Indexed: 11/19/2022] Open
Abstract
'Candidatus Phytoplasma mali' is a phytopathogenic bacterium of the family Acholeplasmataceae assigned to the class Mollicutes. This causative agent of the apple proliferation colonizes in Malus domestica the sieve tubes of the plant phloem resulting in a range of symptoms such as witches'--broom formation, reduced vigor and affecting size and quality of the crop. The disease is responsible for strong economical losses in Europe. Although the genome sequence of the pathogen is available, there is only limited information on expression of selected genes and metabolic key features that have not been examined on the transcriptomic or proteomic level so far. This situation is similar to many other phytoplasmas. In the work presented here, RNA-Seq and mass spectrometry shotgun techniques were applied on tissue samples from Nicotiana occidentalis infected by 'Ca. P. mali' strain AT providing insights into transcriptome and proteome of the pathogen. Data analysis highlights expression of 208 genes including 14 proteins located in the terminal inverted repeats of the linear chromosome. Beside a high portion of house keeping genes, the recently discussed chaperone GroES/GroEL is expressed. Furthermore, gene expression involved in formation of a type IVB and of the Sec-dependent secretion system was identified as well as the highly expressed putative pathogenicity-related SAP11-like effector protein. Metabolism of phytoplasmas depends on the uptake of spermidine/putescine, amino acids, co-factors, carbohydrates and in particular malate/citrate. The expression of these transporters was confirmed and the analysis of the carbohydrate cycle supports the suggested alternative energy-providing pathway for phytoplasmas releasing acetate and providing ATP. The phylogenetic analyses of malate dehydrogenase and acetate kinase in phytoplasmas show a closer relatedness to the Firmicutes in comparison to Mycoplasma species indicating an early divergence of the Acholeplasmataceae from the Mollicutes.
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Affiliation(s)
- Christin Siewert
- Division Phytomedicine, Department of Crop and Animal Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Toni Luge
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Bojan Duduk
- Institute of Pesticides and Environmental Protection, Belgrade, Serbia
| | - Erich Seemüller
- Julius Kuehn Institute, Federal Research Centre for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture, Dossenheim, Germany
| | - Carmen Büttner
- Division Phytomedicine, Department of Crop and Animal Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sascha Sauer
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Michael Kube
- Division Phytomedicine, Department of Crop and Animal Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
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Kakizawa S, Kamagata Y. A Multiplex-PCR Method for Strain Identification and Detailed Phylogenetic Analysis of AY-Group Phytoplasmas. Plant Dis 2014; 98:299-305. [PMID: 30708443 DOI: 10.1094/pdis-03-13-0216-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phytoplasmas are plant pathogenic bacteria that cause devastating losses in the yield of diverse crops worldwide. Specific detection and strain identification of phytoplasmas is important to prevent the spread of phytoplasma-induced diseases. Hence, methods to rapidly detect these organisms are important for pest control. Polymerase chain reaction (PCR) methods using phytoplasma-specific primers are widely used to detect phytoplasmas from infected plants and insects because they are highly sensitive, easily handled, and have a variety of analytical secondary applications. The phytoplasma 16S rDNA was widely used as a target of the PCR detection method; however, further target genes and more rapid methods have been required for more specific detection of phytoplasmas. Here, we developed a multiplex-PCR system to amplify several phytoplasma genes. We designed 36 primers, based on the genome sequence of 'Candidatus Phytoplasma asteris', to amplify 18 single-copy genes covering wide regions of the phytoplasma genome. Nine genes could be simultaneously amplified in a single PCR. This multiplex-PCR was applied to DNAs from 10 phytoplasma strains belonging to the AY-group, and different amplification patterns were obtained between strains, suggesting that this method would allow us to differentiate phytoplasmas at the strain level. Direct sequencing was also possible after the multiplex-PCR amplification by a modified sequencing method. Detailed phylogenetic analysis was performed using concatenated sequences, and evolutionary relationships among four Japanese isolates were revealed, where these strains could not be distinguished by their 16S rDNA. Thus, this multiplex-PCR system is useful for rapid strain identification and detailed phylogenetic analysis of phytoplasmas.
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Affiliation(s)
- Shigeyuki Kakizawa
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan
| | - Yoichi Kamagata
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan
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Mitrović J, Siewert C, Duduk B, Hecht J, Mölling K, Broecker F, Beyerlein P, Büttner C, Bertaccini A, Kube M. Generation and analysis of draft sequences of 'stolbur' phytoplasma from multiple displacement amplification templates. J Mol Microbiol Biotechnol 2013; 24:1-11. [PMID: 24158016 DOI: 10.1159/000353904] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Phytoplasma-associated diseases are reported for more than 1,000 plant species worldwide. Only a few genome sequences are available in contrast to the economical importance of these bacterial pathogens. A new strategy was used to retrieve phytoplasma strain-specific genome data. Multiple displacement amplification was performed on DNA obtained from <3 g of plant tissue from tobacco and parsley samples infected with 'stolbur' strains. Random hexamers and Phi29 polymerase were evaluated with and without supplementation by group-assigned oligonucleotides providing templates for Illumina's sequencing approach. Metagenomic drafts derived from individual and pooled strain-specific de novo assemblies were analyzed. Supplementation of the Phi29 reaction with the group-assigned oligonucleotides resulted in an about 2-fold enrichment of the percentage of phytoplasma-assigned reads and thereby improved assembly results. The obtained genomic drafts represent the largest datasets available from 'stolbur' phytoplasmas. Sequences of the two strains (558 kb, 448 proteins and 516 kb, 346 proteins, respectively) were annotated allowing the identification of prominent membrane proteins and reconstruction of core pathways. Analysis of a putative truncated sucrose phosphorylase provides hints on sugar degradation. Furthermore, it is shown that drafts obtained from repetitive-rich genomes allow only limited analysis on multicopy regions and genome completeness.
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Affiliation(s)
- Jelena Mitrović
- Laboratory of Applied Phytopathology, Institute of Pesticides and Environmental Protection, Belgrade, Serbia
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Kube M, Siewert C, Migdoll AM, Duduk B, Holz S, Rabus R, Seemüller E, Mitrovic J, Müller I, Büttner C, Reinhardt R. Analysis of the complete genomes of Acholeplasma brassicae, A. palmae and A. laidlawii and their comparison to the obligate parasites from 'Candidatus Phytoplasma'. J Mol Microbiol Biotechnol 2013; 24:19-36. [PMID: 24158107 DOI: 10.1159/000354322] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Analysis of the completely determined genomes of the plant-derived Acholeplasma brassicae strain O502 and A. palmae strain J233 revealed that the circular chromosomes are 1,877,792 and 1,554,229 bp in size, have a G + C content of 36 and 29%, and encode 1,690 and 1,439 proteins, respectively. Comparative analysis of these sequences and previously published genomes of A. laidlawii strain PG-8, 'Candidatus Phytoplasma asteris' strains, 'Ca. P. australiense' and 'Ca. P. mali' show a limited shared basic genetic repertoire. The acholeplasma genomes are characterized by a low number of rearrangements, duplication and integration events. Exceptions are the unusual duplication of rRNA operons in A. brassicae and an independently introduced second gene for a single-stranded binding protein in both genera. In contrast to phytoplasmas, the acholeplasma genomes differ by encoding the cell division protein FtsZ, a wide variety of ABC transporters, the F0F1 ATP synthase, the Rnf-complex, SecG of the Sec-dependent secretion system, a richly equipped repertoire for carbohydrate metabolism, fatty acid, isoprenoid and partial amino acid metabolism. Conserved metabolic proteins encoded in phytoplasma genomes such as the malate dehydrogenase SfcA, several transporters and proteins involved in host-interaction, and virulence-associated effectors were not predicted for the acholeplasmas.
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Affiliation(s)
- Michael Kube
- Division Phytomedicine, Department of Crop and Animal Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
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Firrao G, Martini M, Ermacora P, Loi N, Torelli E, Foissac X, Carle P, Kirkpatrick BC, Liefting L, Schneider B, Marzachì C, Palmano S. Genome wide sequence analysis grants unbiased definition of species boundaries in "Candidatus Phytoplasma". Syst Appl Microbiol 2013; 36:539-48. [PMID: 24034865 DOI: 10.1016/j.syapm.2013.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Revised: 07/08/2013] [Accepted: 07/18/2013] [Indexed: 10/26/2022]
Abstract
The phytoplasmas are currently named using the Candidatus category, as the inability to grow them in vitro prevented (i) the performance of tests, such as DNA-DNA hybridization, that are regarded as necessary to establish species boundaries, and (ii) the deposition of type strains in culture collections. The recent accession to complete or nearly complete genome sequence information disclosed the opportunity to apply to the uncultivable phytoplasmas the same taxonomic approaches used for other bacteria. In this work, the genomes of 14 strains, belonging to the 16SrI, 16SrIII, 16SrV and 16SrX groups, including the species "Ca. P. asteris", "Ca. P. mali", "Ca. P. pyri", "Ca. P. pruni", and "Ca. P. australiense" were analyzed along with Acholeplasma laidlawi, to determine their taxonomic relatedness. Average nucleotide index (ANIm), tetranucleotide signature frequency correlation index (Tetra), and multilocus sequence analysis of 107 shared genes using both phylogenetic inference of concatenated (DNA and amino acid) sequences and consensus networks, were carried out. The results were in large agreement with the previously established 16S rDNA based classification schemes. Moreover, the taxonomic relationships within the 16SrI, 16SrIII and 16SrX groups, that represent clusters of strains whose relatedness could not be determined by 16SrDNA analysis, could be comparatively evaluated with non-subjective criteria. "Ca. P. mali" and "Ca. P. pyri" were found to meet the genome characteristics for the retention into two different, yet strictly related species; representatives of subgroups 16SrI-A and 16SrI-B were also found to meet the standards used in other bacteria to distinguish separate species; the genomes of the strains belonging to 16SrIII were found more closely related, suggesting that their subdivision into Candidatus species should be approached with caution.
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Affiliation(s)
- Giuseppe Firrao
- Dipartimento di Scienze Agrarie ed Ambientali, Università di Udine, Udine, Italy; Istituto Nazionale di Biostrutture e Biosistemi, Interuniversity Consortium, Italy.
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Chung WC, Chen LL, Lo WS, Lin CP, Kuo CH. Comparative analysis of the peanut witches'-broom phytoplasma genome reveals horizontal transfer of potential mobile units and effectors. PLoS One 2013; 8:e62770. [PMID: 23626855 PMCID: PMC3633829 DOI: 10.1371/journal.pone.0062770] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 03/25/2013] [Indexed: 11/18/2022] Open
Abstract
Phytoplasmas are a group of bacteria that are associated with hundreds of plant diseases. Due to their economical importance and the difficulties involved in the experimental study of these obligate pathogens, genome sequencing and comparative analysis have been utilized as powerful tools to understand phytoplasma biology. To date four complete phytoplasma genome sequences have been published. However, these four strains represent limited phylogenetic diversity. In this study, we report the shotgun sequencing and evolutionary analysis of a peanut witches'-broom (PnWB) phytoplasma genome. The availability of this genome provides the first representative of the 16SrII group and substantially improves the taxon sampling to investigate genome evolution. The draft genome assembly contains 13 chromosomal contigs with a total size of 562,473 bp, covering ∼90% of the chromosome. Additionally, a complete plasmid sequence is included. Comparisons among the five available phytoplasma genomes reveal the differentiations in gene content and metabolic capacity. Notably, phylogenetic inferences of the potential mobile units (PMUs) in these genomes indicate that horizontal transfer may have occurred between divergent phytoplasma lineages. Because many effectors are associated with PMUs, the horizontal transfer of these transposon-like elements can contribute to the adaptation and diversification of these pathogens. In summary, the findings from this study highlight the importance of improving taxon sampling when investigating genome evolution. Moreover, the currently available sequences are inadequate to fully characterize the pan-genome of phytoplasmas. Future genome sequencing efforts to expand phylogenetic diversity are essential in improving our understanding of phytoplasma evolution.
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Affiliation(s)
- Wan-Chia Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Ling-Ling Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Wen-Sui Lo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Chan-Pin Lin
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
- * E-mail:
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