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Cieniewicz E, Schnabel E, Powell G, Snipes Z, Schnabel G. Detection and Characterization of Xylella fastidiosa subsp. fastidiosa in Rabbiteye Blueberry in South Carolina. PLANT DISEASE 2024; 108:1476-1480. [PMID: 38254326 DOI: 10.1094/pdis-11-23-2392-sc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Xylella fastidiosa causes bacterial leaf scorch in southern highbush (Vaccinium corymbosum interspecific hybrids) and is also associated with a distinct disease phenotype in rabbiteye blueberry (V. virgatum) cultivars in the southeastern United States. Both X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. multiplex have been reported to cause problems in southern highbush blueberry, but so far only X. fastidiosa subsp. multiplex has been reported in rabbiteye cultivars in Louisiana. In this study, we report detection of X. fastidiosa in rabbiteye blueberry plants in association with symptoms of foliar reddening and shoot dieback. High throughput sequencing of an X. fastidiosa-positive plant sample and comparative analyses identified the strain in one of these plants as being X. fastidiosa subsp. fastidiosa. We briefly discuss the implications of these findings, which may spur research into blueberry as a potential inoculum source that could enable spread to other susceptible fruit crops in South Carolina.
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Affiliation(s)
- Elizabeth Cieniewicz
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634
| | - Elise Schnabel
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634
| | - Garner Powell
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634
| | - Zachary Snipes
- Clemson Cooperative Extension, Charleston County Cooperative Extension Office, Charleston, SC 29401
| | - Guido Schnabel
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634
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Su CC, Fung JA, Chang RJ, Chang CJ, Jan FJ, Shih HT, Chen J. TaqMan Quantitative PCR Detection of Xylella taiwanensis in Taiwan. PLANT DISEASE 2023; 107:3051-3056. [PMID: 36890125 DOI: 10.1094/pdis-01-23-0064-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Xylella taiwanensis (Xt) is a nutritionally fastidious bacterial pathogen causing pear leaf scorch disease (PLSD) in Taiwan. The disease causes early defoliation, loss of tree vigor, and reduction in fruit yield and quality. No cure for PLSD is available. The only option for growers to control the disease is to use pathogen-free propagation material, which requires early and accurate detection of Xt. Currently, only one simplex PCR method is available for the diagnosis of PLSD. We developed five Xt-specific TaqMan quantitative PCR (TaqMan qPCR) systems (primers-probe sets) for the detection of Xt. The PCR systems target three conserved genomic loci commonly used in bacterial pathogen detection: the 16S rRNA gene (rrs), the 16S-23S rRNA intergenic transcribed sequence (16S-23S rRNA ITS), and the DNA gyrase gene (gyrB). BLAST analysis using the GenBank nr sequence database, including whole genome sequences of 88 Xanthomonas campestris pv. campestris (Xcc) strains, 147 X. fastidiosa (Xf) strains, and 32 Xt strains, showed that all primer and probe sequences were specific only to Xt. Single nucleotide polymorphisms (SNPs) provided the primer/probe specificity to Xt. The PCR systems were evaluated by using DNA samples from pure cultures of two Xt strains, one Xf strain, one Xcc strain, and 140 plant samples collected from 23 pear orchards in four counties in Taiwan. The two-copy rrs and 16S-23S rRNA ITS-based PCR systems (Xt803-F/R, Xt731-F/R, and Xt16S-F/R) showed higher detection sensitivity than the two single-copy gyrB-based systems (XtgB1-F/R and XtgB2-F/R). A metagenomic analysis of a representative PLSD leaf sample detected the presence of non-Xt proteobacteria and fungal pathogens that should be taken into consideration in PLSD, as they might interfere with diagnosis.
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Affiliation(s)
- Chiou-Chu Su
- Division of Pesticide Application, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, Wufeng, Taichung 41358, Taiwan
| | - Jie-An Fung
- Division of Pesticide Application, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, Wufeng, Taichung 41358, Taiwan
| | - Ruey-Jang Chang
- Division of Pesticide Application, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, Wufeng, Taichung 41358, Taiwan
| | - Chung-Jan Chang
- Department of Plant Pathology, University of Georgia, Griffin, GA 30223, U.S.A
| | - Fuh-Jyh Jan
- Department of Plant Pathology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Hsien-Tzung Shih
- Applied Zoology Division, Taiwan Agricultural Research Institute, Council of Agriculture, Wufeng, Taichung 41362, Taiwan
| | - Jianchi Chen
- USDA-ARS, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648, U.S.A
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Bragard C, Baptista P, Chatzivassiliou E, Di Serio F, Gonthier P, Jaques Miret JA, Justesen AF, MacLeod A, Magnusson CS, Milonas P, Navas‐Cortes JA, Parnell S, Potting R, Stefani E, Thulke H, Van der Werf W, Civera AV, Yuen J, Zappalà L, Chen J, Migheli Q, Vloutoglou I, Streissl F, Reignault PL. Pest categorisation of Xylella taiwanensis. EFSA J 2023; 21:e07736. [PMID: 36698497 PMCID: PMC9854164 DOI: 10.2903/j.efsa.2023.7736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The EFSA Plant Health Panel performed a pest categorisation of Xylella taiwanensis, a Gram-negative bacterium belonging to the Xanthomonadaceae. The pathogen is a well-defined taxonomic entity, and it is the causal agent of the pear leaf scorch. X. taiwanensis is present in subtropical and temperate areas of the island of Taiwan, where it affects low chilling pear cultivars of the species Pyrus pyrifolia (Asian pear). No other plant species are reported to be affected by the pathogen. The pathogen is not known to be present in the EU territory and it is not included in the Commission Implementing Regulation (EU) 2019/2072. The main pathway for the entry of the pathogen into the EU territory is host plants for planting (except seeds); another possible pathway might be represented by putative insect vectors, though their identity remains unknown. The cultivated area of P. pyrifolia in the EU territory is very limited. Conversely, the genetically related P. communis is widely cultivated in most EU Member States and there is no information so far on the susceptibility of its several cultivars. Should the pest establish in the EU, economic impact is expected, provided that suitable insect vectors are present and P. communis is as susceptible to infection as P. pyrifolia. Phytosanitary measures are available to prevent the introduction and spread of the pathogen into the EU, since plants for planting from Taiwan is a closed pathway; nonetheless, putative vectors, if confirmed and identified, may represent an additional risk of the pathogen's introduction and spread. The lack of knowledge on whether X. taiwanensis can infect P. communis, the identity and presence of suitable vectors in the EU lead to key uncertainties on entry, establishment, spread and impact. X. taiwanensis satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.
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Cheng YI, Lin YC, Leu JY, Kuo CH, Chu HA. Comparative analysis reveals distinctive genomic features of Taiwan hot-spring cyanobacterium Thermosynechococcus sp. TA-1. Front Microbiol 2022; 13:932840. [PMID: 36033852 PMCID: PMC9403480 DOI: 10.3389/fmicb.2022.932840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Thermosynechococcus is a genus of thermophilic unicellular cyanobacteria that dominates microbial mats in Asian non-acidic hot springs. These cyanobacteria are the major primary producers in their ecological niches and are promising sources of thermostable enzymes for biotechnology applications. To improve our understanding of these organisms, we conducted whole-genome sequencing of a novel strain for comparative analysis with other representatives in the same genus. This newly characterized strain, Thermosynechococcus sp. TA-1, was isolated from the Taian hot springs in Taiwan. Analyses based on average nucleotide identity (ANI) and genome-scale phylogeny suggested that TA-1 and another Taiwanese strain CL-1 belong to a novel species-level taxon. Two metagenome-assembled genomes (MAGs) originated from India represent the sister group, and Thermosynechococcus elongatus PKUAC-SCTE542 from China is the next closest lineage. All cultivated strains and MAGs from Japan form a separate monophyletic clade and could be classified into two species-level taxa. Intriguingly, although TA-1 and CL-1 share 97.0% ANI, the genome alignment identified at least 16 synteny breakpoints that are mostly associated with transposase genes, which illustrates the dynamic nature of their chromosomal evolution. Gene content comparisons identified multiple features distinct at species- or strain-level among these Thermosynechococcus representatives. Examples include genes involved in bicarbonate transportation, nitric oxide protection, urea utilization, kanamycin resistance, restriction-modification system, and chemotaxis. Moreover, we observed the insertion of type II inteins in multiple genes of the two Taiwanese strains and inferred putative horizontal transfer of an asparagine synthase gene (asnB) associated with exopolysaccharides gene cluster. Taken together, while previous work suggested that strains in this genus share a highly conserved genomic core and no clear genetic differentiation could be linked to environmental factors, we found that the overall pattern of gene content divergence is largely congruent with core genome phylogeny. However, it is difficult to distinguish between the roles of phylogenetic relatedness and geographic proximity in shaping the genetic differentiation. In conclusion, knowledge of the genomic differentiation among these strains provides valuable resources for future functional characterization.
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Affiliation(s)
- Yen-I Cheng
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Chen Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Jyh-Yih Leu
- Department of Life Science, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- *Correspondence: Chih-Horng Kuo,
| | - Hsiu-An Chu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Hsiu-An Chu,
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Landa BB, Saponari M, Feitosa-Junior OR, Giampetruzzi A, Vieira FJD, Mor E, Robatzek S. Xylella fastidiosa's relationships: the bacterium, the host plants, and the plant microbiome. THE NEW PHYTOLOGIST 2022; 234:1598-1605. [PMID: 35279849 DOI: 10.1111/nph.18089] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Xylella fastidiosa is the causal agent of important crop diseases and is transmitted by xylem-sap-feeding insects. The bacterium colonizes xylem vessels and can persist with a commensal or pathogen lifestyle in more than 500 plant species. In the past decade, reports of X. fastidiosa across the globe have dramatically increased its known occurrence. This raises important questions: How does X. fastidiosa interact with the different host plants? How does the bacterium interact with the plant immune system? How does it influence the host's microbiome? We discuss recent strain genetic typing and plant transcriptome and microbiome analyses, which have advanced our understanding of factors that are important for X. fastidiosa plant infection.
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Affiliation(s)
- Blanca B Landa
- Institute for Sustainable Agriculture, CSIC, Alameda del Obispo S/N, Córdoba, 14004, Spain
| | - Maria Saponari
- CNR - Institute for Sustainable Plant Protection (IPSP), Via Amendola 165/A, Bari, 70126, Italy
| | | | - Annalisa Giampetruzzi
- CNR - Institute for Sustainable Plant Protection (IPSP), Via Amendola 165/A, Bari, 70126, Italy
| | - Filipe J D Vieira
- Genetics, LMU Biocentre, Grosshadener Strasse 4, Planegg, 82152, Germany
| | - Eliana Mor
- Genetics, LMU Biocentre, Grosshadener Strasse 4, Planegg, 82152, Germany
| | - Silke Robatzek
- Genetics, LMU Biocentre, Grosshadener Strasse 4, Planegg, 82152, Germany
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Pronk LJU, Medema MH. Whokaryote: distinguishing eukaryotic and prokaryotic contigs in metagenomes based on gene structure. Microb Genom 2022; 8. [PMID: 35503723 PMCID: PMC9465069 DOI: 10.1099/mgen.0.000823] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Metagenomics has become a prominent technology to study the functional potential of all organisms in a microbial community. Most studies focus on the bacterial content of these communities, while ignoring eukaryotic microbes. Indeed, many metagenomics analysis pipelines silently assume that all contigs in a metagenome are prokaryotic, likely resulting in less accurate annotation of eukaryotes in metagenomes. Early detection of eukaryotic contigs allows for eukaryote-specific gene prediction and functional annotation. Here, we developed a classifier that distinguishes eukaryotic from prokaryotic contigs based on foundational differences between these taxa in terms of gene structure. We first developed Whokaryote, a random forest classifier that uses intergenic distance, gene density and gene length as the most important features. We show that, with an estimated recall, precision and accuracy of 94, 96 and 95 %, respectively, this classifier with features grounded in biology can perform almost as well as the classifiers EukRep and Tiara, which use k-mer frequencies as features. By retraining our classifier with Tiara predictions as an additional feature, the weaknesses of both types of classifiers are compensated; the result is Whokaryote+Tiara, an enhanced classifier that outperforms all individual classifiers, with an F1 score of 0.99 for both eukaryotes and prokaryotes, while still being fast. In a reanalysis of metagenome data from a disease-suppressive plant endospheric microbial community, we show how using Whokaryote+Tiara to select contigs for eukaryotic gene prediction facilitates the discovery of several biosynthetic gene clusters that were missed in the original study. Whokaryote (+Tiara) is wrapped in an easily installable package and is freely available from https://github.com/LottePronk/whokaryote.
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Affiliation(s)
- Lotte J U Pronk
- Bioinformatics Group, Wageningen University, Wageningen, The Netherlands
| | - Marnix H Medema
- Bioinformatics Group, Wageningen University, Wageningen, The Netherlands
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Castillo AI, Tsai CW, Su CC, Weng LW, Lin YC, Cho ST, Almeida RPP, Kuo CH. Genetic differentiation of Xylella fastidiosa following the introduction into Taiwan. Microb Genom 2021; 7:000727. [PMID: 34898423 PMCID: PMC8767338 DOI: 10.1099/mgen.0.000727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 10/22/2021] [Indexed: 12/15/2022] Open
Abstract
The economically important plant pathogen Xylella fastidiosa has been reported in multiple regions of the globe during the last two decades, threatening a growing list of plants. Particularly, X. fastidiosa subspecies fastidiosa causes Pierce's disease (PD) of grapevines, which is a problem in the USA, Spain, and Taiwan. In this work, we studied PD-causing subsp. fastidiosa populations and compared the genome sequences of 33 isolates found in Central Taiwan with 171 isolates from the USA and two from Spain. Phylogenetic relationships, haplotype networks, and genetic diversity analyses confirmed that subsp. fastidiosa was recently introduced into Taiwan from the Southeast USA (i.e. the PD-I lineage). Recent core-genome recombination events were detected among introduced subsp. fastidiosa isolates in Taiwan and contributed to the development of genetic diversity. The genetic diversity observed includes contributions through recombination from unknown donors, suggesting that higher genetic diversity exists in the region. Nevertheless, no recombination event was detected between X. fastidiosa subsp. fastidiosa and the endemic sister species Xylella taiwanensis, which is the causative agent of pear leaf scorch disease. In summary, this study improved our understanding of the genetic diversity of an important plant pathogenic bacterium after its invasion to a new region.
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Affiliation(s)
- Andreina I. Castillo
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Chi-Wei Tsai
- Department of Entomology, National Taiwan University, Taipei 106, Taiwan, ROC
| | - Chiou-Chu Su
- Division of Pesticide Application, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Taichung 413, Taiwan, ROC
| | - Ling-Wei Weng
- Department of Entomology, National Taiwan University, Taipei 106, Taiwan, ROC
| | - Yu-Chen Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Shu-Ting Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Rodrigo P. P. Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan, ROC
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