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Tatulli G, Baldassarre F, Schiavi D, Tacconi S, Cognigni F, Costantini F, Balestra GM, Dini L, Pucci N, Rossi M, Scala V, Ciccarella G, Loreti S. Chitosan-Coated Fosetyl-Al Nanocrystals' Efficacy on Nicotiana tabacum Colonized by Xylella fastidiosa. PHYTOPATHOLOGY 2024; 114:1466-1479. [PMID: 38700944 DOI: 10.1094/phyto-04-24-0144-r] [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: 05/05/2024]
Abstract
Xylella fastidiosa (Xf) is a quarantine plant pathogen capable of colonizing the xylem of a wide range of hosts. Currently, there is no cure able to eliminate the pathogen from a diseased plant, but several integrated strategies have been implemented for containing the spread of Xf. Nanotechnology represents an innovative strategy based on the possibility of maximizing the potential antibacterial activity by increasing the surface-to-volume ratio of nanoscale formulations. Nanoparticles based on chitosan and/or fosetyl-Al have shown different in vitro antibacterial efficacy against Xf subsp. fastidiosa (Xff) and pauca (Xfp). This work demonstrated the uptake of chitosan-coated fosetyl-Al nanocrystals (CH-nanoFos) by roots and their localization in the stems and leaves of Olea europaea plants. Additionally, the antibacterial activity of fosetyl-Al, nano-fosetyl, nano-chitosan, and CH-nanoFos was tested on Nicotiana tabacum cultivar SR1 (Petite Havana) inoculated with Xff, Xfp, or Xf subsp. multiplex (Xfm). The bacterial load was evaluated with qPCR, and the results showed that CH-nanoFos was the only treatment able to reduce the colonization of Xff, Xfm, and Xfp in tobacco plants. Additionally, the area under the disease progress curve, used to assess symptom development in tobacco plants inoculated with Xff, Xfm, and Xfp and treated with CH-nanoFos, showed a reduction in symptom development. Furthermore, the twitching assay and bacterial growth under microfluidic conditions confirmed the antibacterial activity of CH-nanoFos.
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Affiliation(s)
- Giuseppe Tatulli
- Council for Agricultural Research and Economics, Research Centre for Plant Protection and Certification of Rome, 00156 Rome, Italy
| | - Francesca Baldassarre
- Department of Biological and Environmental Sciences, UdR INSTM of Lecce University of Salento, Via Monteroni, 73100 Lecce, Italy
- Institute of Nanotechnology, CNR NANOTEC, Consiglio Nazionale delle Ricerche, Via Monteroni, 73100 Lecce, Italy
| | - Daniele Schiavi
- Department of Agriculture and Forest Sciences (DAFNE), University of Tuscia, Via S. Camillo de Lellis, Snc, 01100 Viterbo, Italy
| | - Stefano Tacconi
- CarMeN Laboratory, INSERM 1060-INRAE 1397, Department of Human Nutrition, Lyon Sud Hospital, University of Lyon, Lyon, France
| | - Flavio Cognigni
- Department of Basic and Applied Sciences for Engineering (SBAI), Sapienza University of Rome, Rome, Italy
| | - Francesca Costantini
- Council for Agricultural Research and Economics, Research Centre for Plant Protection and Certification of Rome, 00156 Rome, Italy
- Department of Environmental Biology, Sapienza University of Rome, p.le A. Moro 5, 00185, Rome, Italy
| | - Giorgio Mariano Balestra
- Department of Agriculture and Forest Sciences (DAFNE), University of Tuscia, Via S. Camillo de Lellis, Snc, 01100 Viterbo, Italy
- Phytoparasites Diagnostics (PhyDia) s.r.l. Via S. Camillo Delellis Snc 01100 Viterbo, Italy
| | - Luciana Dini
- Department of Biology and Biotechnology "C. Darwin", Sapienza University of Rome, Rome, Italy
| | - Nicoletta Pucci
- Council for Agricultural Research and Economics, Research Centre for Plant Protection and Certification of Rome, 00156 Rome, Italy
| | - Marco Rossi
- Department of Basic and Applied Sciences for Engineering (SBAI), Sapienza University of Rome, Rome, Italy
- Research Center on Nanotechnology Applied to Engineering of Sapienza (CNIS), Sapienza University of Rome, Rome, Italy
| | - Valeria Scala
- Council for Agricultural Research and Economics, Research Centre for Plant Protection and Certification of Rome, 00156 Rome, Italy
| | - Giuseppe Ciccarella
- Department of Biological and Environmental Sciences, UdR INSTM of Lecce University of Salento, Via Monteroni, 73100 Lecce, Italy
- Institute of Nanotechnology, CNR NANOTEC, Consiglio Nazionale delle Ricerche, Via Monteroni, 73100 Lecce, Italy
| | - Stefania Loreti
- Council for Agricultural Research and Economics, Research Centre for Plant Protection and Certification of Rome, 00156 Rome, Italy
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Burbank L, Gomez L, Shantharaj D, Abdelsamad N, Vasquez K, Burhans A, Ortega B, Rodriguez SH, Strickland J, Krugner R, De La Fuente L, Naegele R. Virulence Comparison of a Comprehensive Panel of Xylella fastidiosa Pierce's Disease Isolates from California. PLANT DISEASE 2024; 108:1555-1564. [PMID: 38105458 DOI: 10.1094/pdis-09-23-1923-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: 12/19/2023]
Abstract
Xylella fastidiosa, the causal agent of Pierce's disease of grapevine, has been found in all major grape-growing regions in California, U.S.A. Large collections of X. fastidiosa isolates are available from these areas, which enable comparative studies of pathogen genetic traits and virulence. Owing to the significant resource requirements for experiments with X. fastidiosa in grapevine, however, most studies use only a single isolate to evaluate disease, and it is not clear how much variability between isolates impacts disease development in experimental or natural settings. In this study, a comprehensive panel of X. fastidiosa isolates from all California grape-growing regions was tested for virulence in susceptible grapevine and in the model host plant, tobacco. Seventy-one isolates were tested, 29 in both grapevine and tobacco. The results of this study highlight the inherent variability of inoculation experiments with X. fastidiosa, including variation in disease severity in plants inoculated with a single isolate, and variability between experimental replicates. There were limited differences in virulence between isolates that were consistent across experimental replicates, or across different host plants. This suggests that choice of isolate within the X. fastidiosa subsp. fastidiosa Pierce's disease group may not make any practical difference when testing in susceptible grape varieties, and that pathogen evolution has not significantly changed virulence of Pierce's disease isolates within California. The location of isolation also did not dictate relative disease severity. This information will inform experimental design for future studies of X. fastidiosa in grapevine and provide important context for genomic research.
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Affiliation(s)
- Lindsey Burbank
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | - Laura Gomez
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL
| | - Deepak Shantharaj
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL
| | - Noor Abdelsamad
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | - Kern Vasquez
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | - Alanna Burhans
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | - Brandon Ortega
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | - Sydney Helm Rodriguez
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | - Jaime Strickland
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | - Rodrigo Krugner
- USDA Agricultural Research Service; Crop Diseases, Pests, and Genetics Research Unit, Parlier, CA
| | | | - Rachel Naegele
- USDA Agricultural Research Service, Sugar Beet and Bean Research Unit, East Lansing, MI
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Ferreira MV, Naranjo E, Denis N, Cobine P, De La Fuente L, Siri MI. Calcium modulation of bacterial wilt disease on potato. Appl Environ Microbiol 2024; 90:e0024224. [PMID: 38690890 PMCID: PMC11107177 DOI: 10.1128/aem.00242-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 03/22/2024] [Indexed: 05/03/2024] Open
Abstract
Ralstonia solanacearum species complex (RSSC) is a phytopathogenic bacterial group that causes bacterial wilt in several crops, being potato (Solanum tuberosum) one of the most important hosts. The relationship between the potato plant ionome (mineral and trace elements composition) and the resistance levels to this pathogen has not been addressed until now. Mineral content of xylem sap, roots, stems and leaves of potato genotypes with different levels of resistance to bacterial wilt was assessed in this work, revealing a positive correlation between divalent calcium (Ca) cation concentrations and genotype resistance. The aim of this study was to investigate the effect of Ca on bacterial wilt resistance, and on the growth and virulence of RSSC. Ca supplementation significantly decreased the growth rate of Ralstonia pseudosolanacearum GMI1000 in minimal medium and affected several virulence traits such as biofilm formation and twitching motility. We also incorporate for the first time the use of microfluidic chambers to follow the pathogen growth and biofilm formation in conditions mimicking the plant vascular system. By using this approach, a reduction in biofilm formation was observed when both, rich and minimal media, were supplemented with Ca. Assessment of the effect of Ca amendments on bacterial wilt progress in potato genotypes revealed a significant delay in disease progress, or a complete absence of wilting symptoms in the case of partially resistant genotypes. This work contributes to the understanding of Ca effect on virulence of this important pathogen and provides new strategies for an integrated control of bacterial wilt on potato. IMPORTANCE Ralstonia solanacearum species complex (RSSC) includes a diverse group of bacterial strains that cause bacterial wilt. This disease is difficult to control due to pathogen aggressiveness, persistence, wide range of hosts, and wide geographic distribution in tropical, subtropical, and temperate regions. RSSC causes considerable losses depending on the pathogen strain, host, soil type, environmental conditions, and cultural practices. In potato, losses of $19 billion per year have been estimated for this pathogen worldwide. In this study, we report for the first time the mineral composition found in xylem sap and plant tissues of potato germplasm with different levels of resistance to bacterial wilt. This study underscores the crucial role of calcium (Ca) concentration in the xylem sap and stem in relation to the resistance of different genotypes. Our in vitro experiments provide evidence of Ca's inhibitory effect on the growth, biofilm formation, and twitching movement of the model RSSC strain R. pseudosolanacearum GMI1000. This study introduces a novel element, the Ca concentration, which should be included into the integrated disease control management strategies for bacterial wilt in potatoes.
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Affiliation(s)
- María Virginia Ferreira
- Área Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Eber Naranjo
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Nicol Denis
- Área Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Paul Cobine
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - María Inés Siri
- Área Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
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Shoukat A, Saqib ZA, Akhtar J, Aslam Z, Pitann B, Hossain MS, Mühling KH. Zinc and Silicon Nano-Fertilizers Influence Ionomic and Metabolite Profiles in Maize to Overcome Salt Stress. PLANTS (BASEL, SWITZERLAND) 2024; 13:1224. [PMID: 38732438 PMCID: PMC11085825 DOI: 10.3390/plants13091224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024]
Abstract
Salinity stress is a major factor affecting the nutritional and metabolic profiles of crops, thus hindering optimal yield and productivity. Recent advances in nanotechnology propose an avenue for the use of nano-fertilizers as a potential solution for better nutrient management and stress mitigation. This study aimed to evaluate the benefits of conventional and nano-fertilizers (nano-Zn/nano-Si) on maize and subcellular level changes in its ionomic and metabolic profiles under salt stress conditions. Zinc and silicon were applied both in conventional and nano-fertilizer-using farms under stress (100 mM NaCl) and normal conditions. Different ions, sugars, and organic acids (OAs) were determined using ion chromatography and inductively coupled plasma mass spectroscopy (ICP-MS). The results revealed significant improvements in different ions, sugars, OAs, and other metabolic profiles of maize. Nanoparticles boosted sugar metabolism, as evidenced by increased glucose, fructose, and sucrose concentrations, and improved nutrient uptake, indicated by higher nitrate, sulfate, and phosphate levels. Particularly, nano-fertilizers effectively limited Na accumulation under saline conditions and enhanced maize's salt stress tolerance. Furthermore, nano-treatments optimized the potassium-to-sodium ratio, a critical factor in maintaining ionic homeostasis under stress conditions. With the growing threat of salinity stress on global food security, these findings highlight the urgent need for further development and implementation of effective solutions like the application of nano-fertilizers in mitigating the negative impact of salinity on plant growth and productivity. However, this controlled environment limits the direct applicability to field conditions and needs future research, particularly long-term field trials, to confirm such results of nano-fertilizers against salinity stress and their economic viability towards sustainable agriculture.
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Affiliation(s)
- Abbas Shoukat
- Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad 38040, Pakistan; (A.S.); (J.A.)
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany; (B.P.); (M.S.H.)
| | - Zulfiqar Ahmad Saqib
- Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad 38040, Pakistan; (A.S.); (J.A.)
| | - Javaid Akhtar
- Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad 38040, Pakistan; (A.S.); (J.A.)
| | - Zubair Aslam
- Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan;
| | - Britta Pitann
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany; (B.P.); (M.S.H.)
| | - Md. Sazzad Hossain
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany; (B.P.); (M.S.H.)
- Department of Agronomy and Haor Agriculture, Faculty of Agriculture, Sylhet Agricultural University, Sylhet 3100, Bangladesh
| | - Karl Hermann Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany; (B.P.); (M.S.H.)
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Román-Écija M, Navas-Cortés JA, Velasco-Amo MP, Arias-Giraldo LF, Gómez LM, Fuente LDL, Landa BB. Two Xylella fastidiosa subsp. multiplex Strains Isolated from Almond in Spain Differ in Plasmid Content and Virulence Traits. PHYTOPATHOLOGY 2023; 113:960-974. [PMID: 36576402 DOI: 10.1094/phyto-06-22-0234-r] [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: 06/17/2023]
Abstract
The plant-pathogenic bacterium Xylella fastidiosa is a major threat to agriculture and the environment worldwide. Recent devastating outbreaks in Europe highlight the potential of this pathogen to cause emergent diseases. X. fastidiosa subsp. multiplex ESVL and IVIA5901 strains that belong to sequence type 6 were isolated from almond orchards within the outbreak area in Alicante province (Spain). Both strains share more than 99% of the chromosomal sequences (average nucleotide identity), but the ESVL strain harbors two plasmids (pXF64-Hb_ESVL and pUCLA-ESVL). Here, virulence phenotypes and genome content were compared between both strains, using three strains from the United States as a reference for the phenotypic analyses. Experiments in microfluidic chambers, used as a simulation of xylem vessels, showed that twitching motility was absent in the IVIA5901 strain, whereas the ESVL strain had reduced twitching motility. In general, both Spanish strains had less biofilm formation, less cell aggregation, and lower virulence in tobacco compared with U.S. reference strains. Genome analysis of the two plasmids from ESVL revealed 51 unique coding sequences that were absent in the chromosome of IVIA5901. Comparison of the chromosomes of both strains showed some unique coding sequences and single-nucleotide polymorphisms in each strain, with potential deleterious mutations. Genomic differences found in genes previously associated with adhesion and motility might explain the differences in the phenotypic traits studied. Although additional studies are necessary to infer the potential role of X. fastidiosa plasmids, our results indicate that the presence of plasmids should be considered in the study of the mechanisms of pathogenicity and adaptation in X. fastidiosa to new environments. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- M Román-Écija
- Department of Crop Protection, Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
| | - J A Navas-Cortés
- Department of Crop Protection, Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
| | - M P Velasco-Amo
- Department of Crop Protection, Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
| | - L F Arias-Giraldo
- Department of Crop Protection, Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
| | - L M Gómez
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, U.S.A
| | - L De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, U.S.A
| | - B B Landa
- Department of Crop Protection, Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
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Shantharaj D, Naranjo E, Merfa MV, Cobine PA, Santra S, De La Fuente L. Zinc Oxide-Based Nanoformulation Zinkicide Mitigates the Xylem-Limited Pathogen Xylella fastidiosa in Tobacco and Southern Highbush Blueberry. PLANT DISEASE 2023; 107:1096-1106. [PMID: 36109877 DOI: 10.1094/pdis-01-22-0246-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: 06/15/2023]
Abstract
The xylem-limited pathogen Xylella fastidiosa causes severe economic losses worldwide, and no effective antimicrobial disease management options are available. The goal of this study was to evaluate the efficacy of a novel ZnO-based nanoparticle formulation, Zinkicide TMN110 (ZnK), against X. fastidiosa in vitro and in planta. In vitro, minimum bactericidal concentration (MBC) of ZnK analyzed in Pierce's Disease 2 medium was estimated at approximately 60 ppm. Time-kill kinetics assay showed a 100% reduction of culturable X. fastidiosa in less than 1 h after ZnK treatment. Microfluidic chambers assays showed that ZnK also inhibits X. fastidiosa cell aggregation and growth under flow conditions. Phytotoxicity assessments in the greenhouse demonstrated that ZnK can be applied as a soil drench in 50 ml at 500 ppm/plant/week up to four times to tobacco and blueberry without causing visible damage. ZnK was also evaluated for disease control in the greenhouse using tobacco infected with X. fastidiosa subsp. fastidiosa strain TemeculaL. ZnK soil drench weekly applications at concentrations of 500 followed by 1,000 ppm (500/1,000) and 500/500/1,000 ppm (in 50 ml each), reduced X. fastidiosa populations by >2 to 3 log10 units and disease severity by approximately 57 and 76%, respectively, compared with the untreated control. Similarly, when blueberry plants infected with X. fastidiosa subsp. multiplex strain AlmaEm3 were soil drenched with ZnK at concentrations 1,000/1,000 ppm and 1,000/1,000/500 ppm (in 200 ml each), the bacterial population was reduced by approximately 1 to 2 log10 units, and disease severity decreased by approximately 39 and 43%, respectively. Overall, this study shows antibacterial activity of ZnK against X. fastidiosa and its effectiveness in plants to reduce disease symptoms under controlled conditions.
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Affiliation(s)
- Deepak Shantharaj
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL
| | - Eber Naranjo
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL
| | - Swadeshmukul Santra
- NanoScience Technology Center, Department of Chemistry, Department of Materials Science and Engineering and Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL
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De La Fuente L, Merfa MV, Cobine PA, Coleman JJ. Pathogen Adaptation to the Xylem Environment. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:163-186. [PMID: 35472277 DOI: 10.1146/annurev-phyto-021021-041716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A group of aggressive pathogens have evolved to colonize the plant xylem. In this vascular tissue, where water and nutrients are transported from the roots to the rest of the plant, pathogens must be able to thrive under acropetal xylem sap flow and scarcity of nutrients while having direct contact only with predominantly dead cells. Nevertheless, a few bacteria have adapted to exclusively live in the xylem, and various pathogens may colonize other plant niches without causing symptoms unless they reach the xylem. Once established, the pathogens modulate its physicochemical conditions to enhance their growth and virulence. Adaptation to the restrictive lifestyle of the xylem leads to genome reduction in xylem-restricted bacteria, as they have a higher proportion of pseudogenes in their genome. The basis of xylem adaptation is not completely understood; therefore, a need still exists for model systems to advance the knowledge on this topic.
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Affiliation(s)
- Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Jeffrey J Coleman
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
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Ge Q, Zhu X, Cobine PA, De La Fuente L. The Copper-Binding Protein CutC Is Involved in Copper Homeostasis and Affects Virulence in the Xylem-Limited Pathogen Xylella fastidiosa. PHYTOPATHOLOGY 2022; 112:1620-1629. [PMID: 35196066 DOI: 10.1094/phyto-11-21-0488-r] [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: 06/14/2023]
Abstract
Copper (Cu) is an essential element that can be toxic if homeostasis is disrupted. Xylella fastidiosa, a xylem-limited plant pathogenic bacterium that causes disease in many economically important crops worldwide, has been exposed to Cu stress caused by wide application of Cu-containing antimicrobials used to control other diseases. However, X. fastidiosa Cu homeostasis mechanisms are still poorly understood. The potentially Cu-related protein CutC, which is involved in Cu tolerance in Escherichia coli and humans, has not been analyzed functionally in plant pathogenic bacteria. We demonstrate that recombinantly expressed X. fastidiosa CutC binds Cu and deletion of cutC gene (PD0586) in X. fastidiosa showed increased sensitivity to Cu-shock compared with wild type (WT) strain TemeculaL. When infecting plants in the greenhouse, cutC mutant showed decreased disease incidence and severity compared with WT but adding Cu exaggerated severity. Interestingly, the inoculation of cutC mutant caused reduced symptoms in the acropetal regions of plants. We hypothesize that X. fastidiosa cutC is involved in Cu homeostasis by binding Cu in cells, leading to Cu detoxification, which is crucial to withstand Cu-shock stress. Unveiling the role of cutC gene in X. fastidiosa facilitates further understanding of Cu homeostasis in bacterial pathogens.
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Affiliation(s)
- Qing Ge
- College of Enology, Northwest A&F University, Yangling, Shaanxi 712100, China
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
| | - Xinyu Zhu
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, U.S.A
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, U.S.A
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
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O'Leary ML, Arias-Giraldo LF, Burbank LP, De La Fuente L, Landa BB. Complete Genome Resources for Xylella fastidiosa Strains AlmaEM3 and BB08-1 Reveal Prophage-Associated Structural Variation Among Blueberry-Infecting Strains. PHYTOPATHOLOGY 2022; 112:732-736. [PMID: 34428919 DOI: 10.1094/phyto-08-21-0317-a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Michael L O'Leary
- United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648, U.S.A
| | - Luis F Arias-Giraldo
- Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas (IAS-CSIC), Córdoba, Spain
| | - Lindsey P Burbank
- United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648, U.S.A
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
| | - Blanca B Landa
- Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas (IAS-CSIC), Córdoba, Spain
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Development of a CAPS Marker and a LAMP Assay for Rapid Detection of Xylella fastidiosa Subsp. multiplex and Differentiation from X. fastidiosa Subsp. fastidiosa on Blueberry. Int J Mol Sci 2022; 23:ijms23041937. [PMID: 35216051 PMCID: PMC8876805 DOI: 10.3390/ijms23041937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 02/05/2023] Open
Abstract
Bacterial leaf scorch (BLS), caused by Xylella fastidiosa (Xf), is a prevalent disease of blueberries in the southeastern United States. Initially, this disease was reported to be caused by X. fastidiosa subsp. multiplex (Xfm). However, a recent survey revealed the presence of another subspecies, X. fastidiosa subsp. fastidiosa (Xff), within naturally infected blueberry plantings in Georgia. Since knowledge regarding the origins of isolates causing Xf outbreaks can impact management recommendations, a routine method for identifying the pathogen at the subspecies level can be beneficial. Several detection strategies are available to identify Xf infection at the subspecies level. However, none of these have been developed for the routine and rapid differentiation of the blueberry-infecting Xf subspecies. Here, we developed two separate straightforward and rapid detection techniques, a cleaved amplified polymorphic sequence (CAPS) marker, and a loop-mediated isothermal amplification (LAMP) assay, targeting the RNA polymerase sigma-70 factor (rpoD) gene sequence of Xfm to discriminate between the two Xf subspecies infecting blueberry. With the CAPS marker, specific detection of Xfm isolates was possible from pure cultures, inoculated greenhouse-grown plant samples, and field infected blueberry samples by restriction digestion of the rpoD gene PCR product (amplified with primers RST31 and RST33) using the BtsI enzyme. The LAMP assay allowed for specific real-time amplification of a 204-bp portion of the XfmrpoD gene from both pure bacterial cultures and infected plant material using the Genie® III system, a result further affirmed by gel electrophoresis and SYBR™ Green I DNA staining for visual observation. These detection strategies have the potential to greatly aid existing diagnostic methods for determining the distribution and prevalence of these Xf subspecies causing bacterial leaf scorch (BLS) in blueberries in the southeastern United States.
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Ge Q, Cobine PA, De La Fuente L. The Influence of Copper Homeostasis Genes copA and copB on Xylella fastidiosa Virulence Is Affected by Sap Copper Concentration. PHYTOPATHOLOGY 2021; 111:1520-1529. [PMID: 33554639 DOI: 10.1094/phyto-12-20-0531-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Xylella fastidiosa is a xylem-limited plant pathogenic bacterium that causes diseases worldwide in crops such as grape, citrus, and olive. Although copper (Cu)-containing compounds are not used for management of X. fastidiosa-caused diseases, they are widely used in X. fastidiosa hosts in vineyards and orchards. The accumulation of Cu in soils and, therefore, plant saps, could be a challenge for X. fastidiosa survival. Here, the molecular basis of Cu homeostasis was studied in relation to virulence. Although homologous Cu-related genes copA (X. fastidiosa loci PD0100) and copB (PD0101) have been characterized in other bacteria, their functions differ among bacterial species. In vitro, both copA and copB mutants were more sensitive to Cu than the wild-type (WT) strain. Interestingly, the copA mutant was more sensitive to Cu shock, while the copB mutant was more sensitive to chronic Cu treatments. In tobacco greenhouse experiments with normal watering, both mutants reduced virulence compared with WT. But when Cu was added as a drench treatment, both copA and copB mutants had increased disease severity approximately 20 and 50% compared with mutants without Cu added, respectively, which were significantly higher than the approximately 5% observed for WT under the same conditions. These results indicate that the pathogen's Cu homeostasis affects virulence and is influenced by Cu concentration in the environment. Understanding Cu homeostasis in X. fastidiosa will help discern the outcome of Cu treatments and the adaptation of this pathogen to the xylem of plants that have been exposed to high Cu concentrations because of agricultural practices.
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Affiliation(s)
- Qing Ge
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL 36849
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12
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Assessment of Ionomic, Phenolic and Flavonoid Compounds for a Sustainable Management of Xylella fastidiosa in Morocco. SUSTAINABILITY 2021. [DOI: 10.3390/su13147818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Morocco belongs to the countries ranked at a high-risk level for entry, establishment, and spread of Xylella fastidiosa, which has recently re-emerged as a plant pathogen of global importance causing olive quick decline syndrome (OQDS). Symptomatic infection by X. fastidiosa leads to devastating diseases and important economic losses. To prevent such losses and damages, countries without current outbreaks like Morocco need to first understand their host plant responses to X. fastidiosa. The assessment of the macro and micro-elements content (ionome) in leaves can give basic and useful information along with being a powerful tool for the sustainable management of diseases caused by this devastating pathogen. Herein, we compare the leaf ionome of four important autochthonous Moroccan olive cultivars (‘Picholine Marocaine’, ‘Haouzia’, ‘Menara’, and ‘Meslalla’), and eight Mediterranean varieties introduced in Morocco (‘Arbequina’, ‘Arbosana’, ‘Leccino’, ‘Ogliarola salentina’, ‘Cellina di Nardo’, ‘Frantoio’, ‘Leucocarpa’, and ‘Picholine de Languedoc’), to develop hypotheses related to the resistance or susceptibility of the Moroccan olive trees to X. fastidiosa infection. Leaf ionomes, mainly Ca, Cu, Fe, Mg, Mn, Na, Zn, and P, were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). These varieties were also screened for their total phenolics and flavonoids content. Data were then involved in a comparative scheme to determine the plasticity of the pathogen. Our results showed that the varieties ‘Leccino’, ’Arbosana’, ‘Arbequina’ consistently contained higher Mn, Cu, and Zn and lower Ca and Na levels compared with the higher pathogen-sensitive ‘Ogliarola salentina’ and ‘Cellina di Nardò’. Our findings suggest that ‘Arbozana’, ‘Arbiquina’, ‘Menara’, and ‘Haouzia’ may tolerate the infection by X. fastidiosa to varying degrees, provides additional support for ‘Leccino’ having resistance to X. fastidiosa, and suggests that both ‘Ogliarola salentina’ and ‘Cellina di Nardö’ are likely sensitive to X. fastidiosa infection.
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Di Genova D, Lewis KJ, Oliver JE. Natural Infection of Southern Highbush Blueberry ( Vaccinium corymbosum Interspecific Hybrids) by Xylella fastidiosa subsp. fastidiosa. PLANT DISEASE 2020; 104:2598-2605. [PMID: 32795247 DOI: 10.1094/pdis-11-19-2477-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Xylella fastidiosa (Xf) is an emerging insect-vectored, xylem-limited bacterium that can cause disease on several economically important fruit and tree crops including almond, blueberry, citrus, grapevine, peach, and pecan. On blueberry, Xf causes bacterial leaf scorch (BLS), which is prevalent in the southeastern United States. This disease, previously reported to be caused by Xf subsp. multiplex (Xfm), can result in rapid plant decline and death of southern highbush (SHB) blueberry cultivars. In 2017, a survey of blueberry plantings in southern Georgia (U.S.A.) confirmed the presence of Xf-infected plants in eight of nine sites examined, and seven isolates were cultured from infected plants. Genetic characterization of these isolates through single-locus and multilocus sequence analysis revealed that three isolates from two sites belonged to Xf subsp. fastidiosa (Xff), with significant similarity to isolates from grapevine. After these three isolates were artificially inoculated onto greenhouse-grown SHB blueberries (cv. 'Rebel'), symptoms typical of BLS developed, and Xff infection was confirmed through genetic characterization and reisolation of the bacterium to fulfill Koch's postulates. Because all previously reported Xf isolates from blueberry have been characterized as Xfm, this is the first time that isolation of Xff has been reported from naturally infected blueberry plantings. The potential impact of Xff isolates on disease management in blueberry requires further exploration. Furthermore, given that isolates from both Xfm and Xff were obtained within a single naturally infected blueberry planting, blueberry in southern Georgia may provide opportunities for intersubspecific recombination between Xff and Xfm isolates.
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Affiliation(s)
- Dario Di Genova
- Department of Crop and Soil Sciences, University of Georgia, Tifton Campus, Tifton, GA 31793, U.S.A
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, 35020 Legnaro, Italy
| | - Kippy J Lewis
- Department of Plant Pathology, University of Georgia, Tifton Campus, Tifton, GA 31793, U.S.A
| | - Jonathan E Oliver
- Department of Plant Pathology, University of Georgia, Tifton Campus, Tifton, GA 31793, U.S.A
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de Souza JB, Almeida-Souza HO, Zaini PA, Alves MN, de Souza AG, Pierry PM, da Silva AM, Goulart LR, Dandekar AM, Nascimento R. Xylella fastidiosa subsp. pauca Strains Fb7 and 9a5c from Citrus Display Differential Behavior, Secretome, and Plant Virulence. Int J Mol Sci 2020; 21:E6769. [PMID: 32942709 PMCID: PMC7555403 DOI: 10.3390/ijms21186769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/12/2020] [Accepted: 09/13/2020] [Indexed: 12/20/2022] Open
Abstract
Xylella fastidiosa colonizes the xylem of various cultivated and native plants worldwide. Citrus production in Brazil has been seriously affected, and major commercial varieties remain susceptible to Citrus Variegated Chlorosis (CVC). Collective cellular behaviors such as biofilm formation influence virulence and insect transmission of X. fastidiosa. The reference strain 9a5c produces a robust biofilm compared to Fb7 that remains mostly planktonic, and both were isolated from symptomatic citrus trees. This work deepens our understanding of these distinct behaviors at the molecular level, by comparing the cellular and secreted proteomes of these two CVC strains. Out of 1017 identified proteins, 128 showed differential abundance between the two strains. Different protein families were represented such as proteases, hemolysin-like proteins, and lipase/esterases, among others. Here we show that the lipase/esterase LesA is among the most abundant secreted proteins of CVC strains as well, and demonstrate its functionality by complementary activity assays. More severe symptoms were observed in Nicotiana tabacum inoculated with strain Fb7 compared to 9a5c. Our results support that systemic symptom development can be accelerated by strains that invest less in biofilm formation and more in plant colonization. This has potential application in modulating the bacterial-plant interaction and reducing disease severity.
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Affiliation(s)
- Jessica Brito de Souza
- Institute of Biotechnology, Federal University of Uberlandia, Av. Amazonas, Bloco 2E, Campus Umuarama, Uberlandia MG 38400-902, Brazil; (J.B.d.S.); (H.O.A.-S.); (A.G.d.S.); (L.R.G.); (R.N.)
| | - Hebréia Oliveira Almeida-Souza
- Institute of Biotechnology, Federal University of Uberlandia, Av. Amazonas, Bloco 2E, Campus Umuarama, Uberlandia MG 38400-902, Brazil; (J.B.d.S.); (H.O.A.-S.); (A.G.d.S.); (L.R.G.); (R.N.)
| | - Paulo Adriano Zaini
- Department of Plant Sciences, College of Agriculture and Environmental Sciences, University of California, Davis, 1 Shields Ave, Davis, CA 95616, USA;
| | - Mônica Neli Alves
- Department of Technology, School of Agricultural and Veterinary Studies, São Paulo State University (FCAV/UNESP), Via de Acesso Prof. Paulo Donato Castellane, Jaboticabal SP 14884-900, Brazil;
- Citriculture Defense Fund (Fundecitrus), Av. Dr. Adhemar Pereira de Barros 201, Araraquara SP 14807-040, Brazil
| | - Aline Gomes de Souza
- Institute of Biotechnology, Federal University of Uberlandia, Av. Amazonas, Bloco 2E, Campus Umuarama, Uberlandia MG 38400-902, Brazil; (J.B.d.S.); (H.O.A.-S.); (A.G.d.S.); (L.R.G.); (R.N.)
| | - Paulo Marques Pierry
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo SP 05508-000, Brazil; (P.M.P.); (A.M.d.S.)
| | - Aline Maria da Silva
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo SP 05508-000, Brazil; (P.M.P.); (A.M.d.S.)
| | - Luiz Ricardo Goulart
- Institute of Biotechnology, Federal University of Uberlandia, Av. Amazonas, Bloco 2E, Campus Umuarama, Uberlandia MG 38400-902, Brazil; (J.B.d.S.); (H.O.A.-S.); (A.G.d.S.); (L.R.G.); (R.N.)
| | - Abhaya M. Dandekar
- Department of Plant Sciences, College of Agriculture and Environmental Sciences, University of California, Davis, 1 Shields Ave, Davis, CA 95616, USA;
| | - Rafael Nascimento
- Institute of Biotechnology, Federal University of Uberlandia, Av. Amazonas, Bloco 2E, Campus Umuarama, Uberlandia MG 38400-902, Brazil; (J.B.d.S.); (H.O.A.-S.); (A.G.d.S.); (L.R.G.); (R.N.)
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15
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Vergine M, Nicolì F, Sabella E, Aprile A, De Bellis L, Luvisi A. Secondary Metabolites in Xylella fastidiosa-Plant Interaction. Pathogens 2020; 9:pathogens9090675. [PMID: 32825425 PMCID: PMC7559865 DOI: 10.3390/pathogens9090675] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/12/2020] [Accepted: 08/18/2020] [Indexed: 12/24/2022] Open
Abstract
During their evolutionary history, plants have evolved the ability to synthesize and accumulate small molecules known as secondary metabolites. These compounds are not essential in the primary cell functions but play a significant role in the plants’ adaptation to environmental changes and in overcoming stress. Their high concentrations may contribute to the resistance of the plants to the bacterium Xylella fastidiosa, which has recently re-emerged as a plant pathogen of global importance. Although it is established in several areas globally and is considered one of the most dangerous plant pathogens, no cure has been developed due to the lack of effective bactericides and the difficulties in accessing the xylem vessels where the pathogen grows and produces cell aggregates and biofilm. This review highlights the role of secondary metabolites in the defense of the main economic hosts of X. fastidiosa and identifies how knowledge about biosynthetic pathways could improve our understanding of disease resistance. In addition, current developments in non-invasive techniques and strategies of combining molecular and physiological techniques are examined, in an attempt to identify new metabolic engineering options for plant defense.
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16
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The Multi-Millennial Olive Agroecosystem of Salento (Apulia, Italy) Threatened by Xylella Fastidiosa Subsp. Pauca: A Working Possibility of Restoration. SUSTAINABILITY 2020. [DOI: 10.3390/su12176700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In Salento, the olive agro-ecosystem has lasted more than 4000 years, and represents an invaluable local heritage for landscape, trade, and social traditions. The quarantine bacterium Xylella fastidiosa subsp. pauca was introduced in the area from abroad and has been widely threatening olive groves in the area. The successful eradication of quarantine phytopathogens requires a prompt identification of the causative agent at the new site, a restricted infected area, a highly effective local organization for crop uprooting and biological features of the micro-organism that would guarantee its complete elimination. However, at the time of the first record, these criteria were not met. Interdisciplinary studies showed that a zinc-copper-citric acid biocomplex allowed a consistent reduction of field symptoms and pathogen cell concentration within infected olive trees. In this perspective article, it is briefly described the implementation of control strategies in some olive farms of Salento. The protocol includes spray treatment with the biocomplex during spring and summer, regular pruning of the trees and mowing of soil between February and April to reduce the juvenile of the insect vector(s). Thus far, more than 500 ha have begun to follow this eco-friendly strategy within the “infected” and “containment” areas of Salento.
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17
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Naranjo E, Merfa MV, Santra S, Ozcan A, Johnson E, Cobine PA, De La Fuente L. Zinkicide Is a ZnO-Based Nanoformulation with Bactericidal Activity against Liberibacter crescens in Batch Cultures and in Microfluidic Chambers Simulating Plant Vascular Systems. Appl Environ Microbiol 2020; 86:e00788-20. [PMID: 32561578 PMCID: PMC7414956 DOI: 10.1128/aem.00788-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/12/2020] [Indexed: 01/09/2023] Open
Abstract
Phloem-limited bacterial "Candidatus Liberibacter" species are associated with incurable plant diseases worldwide. Antimicrobial treatments for these pathogens are challenging due to the difficulty of reaching the vascular tissue they occupy at bactericidal concentrations. Here, in vitro antimicrobial mechanisms of Zinkicide TMN110 (ZnK), a nonphytotoxic zinc oxide (ZnO)-based nanoformulation, were compared to those of bulk ZnO (b-ZnO) using as a model the only culturable species of the genus, Liberibacter crescens Minimum bactericidal concentration (MBC) determination and time-kill assays showed that ZnK has a bactericidal effect against L. crescens, whereas b-ZnO is bacteriostatic. When ZnK was used at the MBC (150 ppm), its antimicrobial mechanisms included an increase in Zn solubility, generation of intracellular reactive oxygen species, lipid peroxidation, and cell membrane disruption; all of these were of greater intensity than those of b-ZnO. Inhibition of biofilms, which are important during insect vector colonization, was stronger by ZnK than by b-ZnO at concentrations between 2.5 and 10 ppm in batch cultures; however, neither ZnK nor b-ZnO removed L. crescens preformed biofilms when applied between 100 and 400 ppm. In microfluidic chambers simulating source-to-sink phloem movement, ZnK significantly outperformed b-ZnO in Zn mobilization and bactericidal activity against L. crescens planktonic cells in sink reservoirs. In microfluidic chamber assays assessing antibiofilm activity, ZnK displayed a significantly enhanced bactericidal activity against L. crescens individual attached cells as well as preformed biofilms compared to that of b-ZnO. The superior mobility and antimicrobial activity of ZnK in microenvironments make this formulation a promising product to control plant diseases caused by "Candidatus Liberibacter" species and other plant vascular pathogens.IMPORTANCE "Candidatus Liberibacter" species are associated with incurable plant diseases that have caused billions of dollars of losses for United States and world agriculture. Chemical control of these pathogens is complicated, because their life cycle combines intracellular vascular stages in plant hosts with transmission by highly mobile insect vectors. To date, "Candidatus Liberibacter" species are mostly unculturable, except for Liberibacter crescens, a member of the genus that has been used as a model for in vitro assays. Here, we evaluated the potential of Zinkicide (ZnK) as an antimicrobial against "Candidatus Liberibacter" species in batch cultures and under flow conditions, using L. crescens as a biological model. ZnK displayed bactericidal activity against L. crescens in batch cultures and showed increased mobility and bactericidal activity in microfluidic devices resembling "Candidatus Liberibacter" species natural habitats. ZnK performance observed here against L. crescens makes this compound a promising candidate to control plant diseases caused by vascular pathogens.
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Affiliation(s)
- Eber Naranjo
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Swadeshmukul Santra
- NanoScience Technology Center, University of Central Florida, Orlando, Florida, USA
- Department of Chemistry, University of Central Florida, Orlando, Florida, USA
- Department of Materials Science and Engineering, University of Central Florida, Orlando, Florida, USA
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida, USA
| | - Ali Ozcan
- NanoScience Technology Center, University of Central Florida, Orlando, Florida, USA
- Department of Chemistry, University of Central Florida, Orlando, Florida, USA
- Vocational School of Technical Sciences, Karamanoglu Mehmetbey University, Karaman, Turkey
| | - Evan Johnson
- Citrus Research and Education Center, University of Florida, Lake Alfred, Florida, USA
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
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18
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Del Coco L, Migoni D, Girelli CR, Angilè F, Scortichini M, Fanizzi FP. Soil and Leaf Ionome Heterogeneity in Xylella fastidiosa Subsp. Pauca-Infected, Non-Infected and Treated Olive Groves in Apulia, Italy. PLANTS (BASEL, SWITZERLAND) 2020; 9:E760. [PMID: 32560583 PMCID: PMC7356509 DOI: 10.3390/plants9060760] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
Xylella fastidiosa subsp. pauca is responsible for the "olive quick decline syndrome" (OQDS) in Salento (Apulia). The main epidemiological aspects of the syndrome are related to the pathogen spread and survival in the area, and to the biology of the insect vector. The assessment of the macro and microelements content (i.e., ionome) in soil and leaves could provide basic and useful information. Indeed, knowledge of host ionomic composition and the possibility of its modification could represent a potential tool for the management of diseases caused by X. fastidiosa. Therefore, soil and leaf ionomes of naturally infected, not infected, and zinc-copper-citric acid biocomplex treated trees of different areas of Apulia and the bordering Basilicata regions were compared. We observed that soil and leaf ionomic composition of olive farms growing in the pathogen-free areas north of the Salento Barletta-Andria-Trani BAT (Apulia) and Potenza PZ (Basilicata, Apulia bordering region) provinces is significantly different from that shown by the infected olive groves of the Salento areas (LE, BR, TA provinces). In particular, a higher content of zinc and copper both in soil and leaves was found in the studied northern areas in comparison to the southern areas. This finding could partly explain the absence of OQDS in those areas. In the infected Salento areas, the leaf ionomic profile resulted as being markedly different for the biocomplex treated compared to the untreated trees. A higher zinc content in leaves characterized treated with respect to untreated trees. On the other hand, among the not-infected trees, Xylella-resistant Leccino showed higher manganese content when compared with the higher pathogen sensitive Ogliarola salentina and Cellina di Nardò. According to these results, soil and olive leaf ionome could provide basic information for the epidemiologic study and possible control of X. f. subsp. pauca in Apulia.
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Affiliation(s)
- Laura Del Coco
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Prov.le Lecce-Monteroni, I-73100 Lecce, Italy; (L.D.C.); (D.M.); (C.R.G.); (F.A.)
| | - Danilo Migoni
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Prov.le Lecce-Monteroni, I-73100 Lecce, Italy; (L.D.C.); (D.M.); (C.R.G.); (F.A.)
| | - Chiara Roberta Girelli
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Prov.le Lecce-Monteroni, I-73100 Lecce, Italy; (L.D.C.); (D.M.); (C.R.G.); (F.A.)
| | - Federica Angilè
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Prov.le Lecce-Monteroni, I-73100 Lecce, Italy; (L.D.C.); (D.M.); (C.R.G.); (F.A.)
| | - Marco Scortichini
- Council for Agricultural Research and Economics-Research Centre for Olive, Fruit Trees and Citrus Crops, Via di Fioranello, 52, I-00134 Roma, Italy;
| | - Francesco Paolo Fanizzi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Prov.le Lecce-Monteroni, I-73100 Lecce, Italy; (L.D.C.); (D.M.); (C.R.G.); (F.A.)
- University of Salento Local Unit of Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici (CIRCMSB), Via Celso Ulpiani, 27-70126 Bari, Italy
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19
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Ge Q, Cobine PA, De La Fuente L. Copper Supplementation in Watering Solution Reaches the Xylem But Does Not Protect Tobacco Plants Against Xylella fastidiosa Infection. PLANT DISEASE 2020; 104:724-730. [PMID: 31961767 DOI: 10.1094/pdis-08-19-1748-re] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Xylella fastidiosa is a xylem-limited plant pathogenic bacterium that causes disease in many crops worldwide. Copper (Cu) is an antimicrobial agent widely used on X. fastidiosa hosts to control other diseases. Although the effects of Cu for control of foliar pathogens are well known, it is less studied on xylem-colonizing pathogens. Previous results from our group showed that low concentrations of CuSO4 increased biofilm formation, whereas high concentrations inhibited biofilm formation and growth in vitro. In this study, we conducted in planta experiments to determine the influence of Cu in X. fastidiosa infection using tobacco as a model. X. fastidiosa-infected and noninfected plants were watered with tap water or with water supplemented with 4 mM or 8 mM of CuSO4. Symptom progression was assessed, and sap and leaf ionome analysis was performed by inductively coupled plasma with optical emission spectroscopy. Cu uptake was confirmed by increased concentrations of Cu in the sap of plants treated with CuSO4-amended water. Leaf scorch symptoms in Cu-supplemented plants showed a trend toward more severe at later time points. Quantification of total and viable X. fastidiosa in planta indicated that CuSO4-amended treatments did not inhibit but slightly increased the growth of X. fastidiosa. Cu in sap was in the range of concentrations that promote X. fastidiosa biofilm formation according to our previous in vitro study. Based on these results, we proposed that the plant Cu homeostasis machinery controls the level of Cu in the xylem, preventing it from becoming elevated to a level that would lead to bacterial inhibition.
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Affiliation(s)
- Qing Ge
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL 36849
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20
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Doblas-Ibáñez P, Deng K, Vasquez MF, Giese L, Cobine PA, Kolkman JM, King H, Jamann TM, Balint-Kurti P, De La Fuente L, Nelson RJ, Mackey D, Smith LG. Dominant, Heritable Resistance to Stewart's Wilt in Maize Is Associated with an Enhanced Vascular Defense Response to Infection with Pantoea stewartii. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1581-1597. [PMID: 31657672 DOI: 10.1094/mpmi-05-19-0129-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Vascular wilt bacteria such as Pantoea stewartii, the causal agent of Stewart's bacterial wilt of maize (SW), are destructive pathogens that are difficult to control. These bacteria colonize the xylem, where they form biofilms that block sap flow leading to characteristic wilting symptoms. Heritable forms of SW resistance exist and are used in maize breeding programs but the underlying genes and mechanisms are mostly unknown. Here, we show that seedlings of maize inbred lines with pan1 mutations are highly resistant to SW. However, current evidence suggests that other genes introgressed along with pan1 are responsible for resistance. Genomic analyses of pan1 lines were used to identify candidate resistance genes. In-depth comparison of P. stewartii interaction with susceptible and resistant maize lines revealed an enhanced vascular defense response in pan1 lines characterized by accumulation of electron-dense materials in xylem conduits visible by electron microscopy. We propose that this vascular defense response restricts P. stewartii spread through the vasculature, reducing both systemic bacterial colonization of the xylem network and consequent wilting. Though apparently unrelated to the resistance phenotype of pan1 lines, we also demonstrate that the effector WtsE is essential for P. stewartii xylem dissemination, show evidence for a nutritional immunity response to P. stewartii that alters xylem sap composition, and present the first analysis of maize transcriptional responses to P. stewartii infection.
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Affiliation(s)
- Paula Doblas-Ibáñez
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Kaiyue Deng
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Miguel F Vasquez
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Laura Giese
- Department of Horticulture and Crop Sciences, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, U.S.A
| | - Judith M Kolkman
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Helen King
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
| | - Tiffany M Jamann
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, U.S.A
| | - Peter Balint-Kurti
- United States Department of Agriculture-Agricultural Research Service, Plant Science Research Unit, Raleigh, NC 27695, U.S.A. and Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, U.S.A
| | | | - Rebecca J Nelson
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - David Mackey
- Department of Horticulture and Crop Sciences, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Laurie G Smith
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093, U.S.A
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Cabot C, Martos S, Llugany M, Gallego B, Tolrà R, Poschenrieder C. A Role for Zinc in Plant Defense Against Pathogens and Herbivores. FRONTIERS IN PLANT SCIENCE 2019; 10:1171. [PMID: 31649687 PMCID: PMC6794951 DOI: 10.3389/fpls.2019.01171] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 08/27/2019] [Indexed: 05/17/2023]
Abstract
Pests and diseases pose a threat to food security, which is nowadays aggravated by climate change and globalization. In this context, agricultural policies demand innovative approaches to more effectively manage resources and overcome the ecological issues raised by intensive farming. Optimization of plant mineral nutrition is a sustainable approach to ameliorate crop health and yield. Zinc is a micronutrient essential for all living organisms with a key role in growth, development, and defense. Competition for Zn affects the outcome of the host-attacker interaction in both plant and animal systems. In this review, we provide a clear framework of the different strategies involving low and high Zn concentrations launched by plants to fight their enemies. After briefly introducing the most relevant macro- and micronutrients for plant defense, the functions of Zn in plant protection are summarized with special emphasis on superoxide dismutases (SODs) and zinc finger proteins. Following, we cover recent meaningful studies identifying Zn-related passive and active mechanisms for plant protection. Finally, Zn-based strategies evolved by pathogens and pests to counteract plant defenses are discussed.
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Affiliation(s)
- Catalina Cabot
- Departament of Biology, Universitat de les Illes Balears, Palma, Spain
| | - Soledad Martos
- Plant Physiology Laboratory, Bioscience Faculty, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mercè Llugany
- Plant Physiology Laboratory, Bioscience Faculty, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Berta Gallego
- Plant Physiology Laboratory, Bioscience Faculty, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Roser Tolrà
- Plant Physiology Laboratory, Bioscience Faculty, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Charlotte Poschenrieder
- Plant Physiology Laboratory, Bioscience Faculty, Universitat Autònoma de Barcelona, Barcelona, Spain
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Potnis N, Kandel PP, Merfa MV, Retchless AC, Parker JK, Stenger DC, Almeida RPP, Bergsma-Vlami M, Westenberg M, Cobine PA, De La Fuente L. Patterns of inter- and intrasubspecific homologous recombination inform eco-evolutionary dynamics of Xylella fastidiosa. THE ISME JOURNAL 2019; 13:2319-2333. [PMID: 31110262 PMCID: PMC6776109 DOI: 10.1038/s41396-019-0423-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 11/09/2022]
Abstract
High rates of homologous recombination (HR) in the bacterial plant pathogen Xylella fastidiosa have been previously detected. This study aimed to determine the extent and explore the ecological significance of HR in the genomes of recombinants experimentally generated by natural transformation and wild-type isolates. Both sets of strains displayed widespread HR and similar average size of recombined fragments consisting of random events (2-10 kb) of inter- and intrasubspecific recombination. A significantly higher proportion and greater lengths (>10 kb, maximum 31.5 kb) of recombined fragments were observed in subsp. morus and in strains isolated in Europe from intercepted coffee plants shipped from the Americas. Such highly recombinant strains pose a serious risk of emergence of novel variants, as genetically distinct and formerly geographically isolated genotypes are brought in close proximity by global trade. Recently recombined regions in wild-type strains included genes involved in regulation and signaling, host colonization, nutrient acquisition, and host evasion, all fundamental traits for X. fastidiosa ecology. Identification of four recombinant loci shared between wild-type and experimentally generated recombinants suggests potential hotspots of recombination in this naturally competent pathogen. These findings provide insights into evolutionary forces possibly affecting the adaptive potential to colonize the host environments of X. fastidiosa.
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Affiliation(s)
- Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
| | - Prem P Kandel
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, USA
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
| | - Adam C Retchless
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jennifer K Parker
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Drake C Stenger
- United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, USA
| | - Rodrigo P P Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Maria Bergsma-Vlami
- Dutch National Plant Protection Organization (NPPO-NL), P.O. Box. 9102, Wageningen, 6700 HC, The Netherlands
| | - Marcel Westenberg
- Dutch National Plant Protection Organization (NPPO-NL), P.O. Box. 9102, Wageningen, 6700 HC, The Netherlands
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA.
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Nicolas O, Charles MT, Jenni S, Toussaint V, Parent SÉ, Beaulieu C. The Ionomics of Lettuce Infected by Xanthomonas campestris pv. vitians. FRONTIERS IN PLANT SCIENCE 2019; 10:351. [PMID: 30984219 PMCID: PMC6448033 DOI: 10.3389/fpls.2019.00351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/07/2019] [Indexed: 05/31/2023]
Abstract
Bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vitians (Xcv) places a major constraint on lettuce production worldwide. The most sustainable strategy known to date for controlling BLS is the use of resistant cultivars. The nutrient elemental signature (ionome) of ten lettuce cultivars with three levels of resistance was analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) to determine which nutrient balances are linked to resistance to BLS, and to assess the effect of Xcv infection on the ionome. The elemental concentrations were preprocessed with isometric log-ratios to define nutrient balances. Using this approach, 4 out of 11 univariate nutrient balances were found to significantly influence the resistance of lettuce cultivars to BLS (P < 0.05). These significant balances were the overall nutritional status balancing all measured nutrients with their complementary in the dry mass, as well as balances [Mn | Zn,Cu], [Zn | Cu], and [S,N | P]. Moreover, the infection of lettuce cultivars mostly affected the lettuce ionome on the [N,S | P] balance, where infection tended to lean the balance toward the N,S part relatively to P. This study shows that nutrient uptake in lettuce can be affected by BLS infection and that nutrient status influences resistance to BLS infection.
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Affiliation(s)
- Olbert Nicolas
- Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
- Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu Research and Development Centre, Saint-Jean-sur-Richelieu, QC, Canada
| | - Marie Thérèse Charles
- Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu Research and Development Centre, Saint-Jean-sur-Richelieu, QC, Canada
| | - Sylvie Jenni
- Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu Research and Development Centre, Saint-Jean-sur-Richelieu, QC, Canada
| | - Vicky Toussaint
- Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu Research and Development Centre, Saint-Jean-sur-Richelieu, QC, Canada
| | - Serge-Étienne Parent
- Department of Soils and Agri-Food Engineering, Université Laval, Quebec City, QC, Canada
| | - Carole Beaulieu
- Département de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
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Saponari M, Giampetruzzi A, Loconsole G, Boscia D, Saldarelli P. Xylella fastidiosa in Olive in Apulia: Where We Stand. PHYTOPATHOLOGY 2019; 109:175-186. [PMID: 30376439 DOI: 10.1094/phyto-08-18-0319-fi] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A dramatic outbreak of Xylella fastidiosa decimating olive was discovered in 2013 in Apulia, Southern Italy. This pathogen is a quarantine bacterium in the European Union (EU) and created unprecedented turmoil for the local economy and posed critical challenges for its management. With the new emerging threat to susceptible crops in the EU, efforts were devoted to gain basic knowledge on the pathogen biology, host, and environmental interactions (e.g., bacterial strain(s) and pathogenicity, hosts, vector(s), and fundamental drivers of its epidemics) in order to find means to control or mitigate the impacts of the infections. Field surveys, greenhouse tests, and laboratory analyses proved that a single bacterial introduction occurred in the area, with a single genotype, belonging to the subspecies pauca, associated with the epidemic. Infections caused by isolates of this genotype turned to be extremely aggressive on the local olive cultivars, causing a new disease termed olive quick decline syndrome. Due to the initial extension of the foci and the rapid spread of the infections, eradication measures (i.e., pathogen elimination from the area) were soon replaced by containment measures including intense border surveys of the contaminated area, removal of infected trees, and mandatory vector control. However, implementation of containment measures encountered serious difficulties, including public reluctance to accept control measures, poor stakeholder cooperation, misinformation from some media outlets, and lack of robust responses by some governmental authorities. This scenario delayed and limited containment efforts and allowed the bacterium to continue its rapid dissemination over more areas in the region, as shown by the continuous expansion of the official borders of the infected area. At the research level, the European Commission and regional authorities are now supporting several programs aimed to find effective methods to mitigate and contain the impact of X. fastidiosa on olives, the predominant host affected in this epidemic. Preliminary evidence of the presence of resistance in some olive cultivars represents a promising approach currently under investigation for long-term management strategies. The present review describes the current status of the epidemic and major research achievements since 2013.
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Affiliation(s)
- M Saponari
- First, fourth, and fifth author: Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Bari, via Amendola 122/D, Bari, Italy; and second and third author: Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, via Amendola 165/A, Bari, Italy
| | - A Giampetruzzi
- First, fourth, and fifth author: Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Bari, via Amendola 122/D, Bari, Italy; and second and third author: Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, via Amendola 165/A, Bari, Italy
| | - G Loconsole
- First, fourth, and fifth author: Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Bari, via Amendola 122/D, Bari, Italy; and second and third author: Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, via Amendola 165/A, Bari, Italy
| | - D Boscia
- First, fourth, and fifth author: Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Bari, via Amendola 122/D, Bari, Italy; and second and third author: Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, via Amendola 165/A, Bari, Italy
| | - P Saldarelli
- First, fourth, and fifth author: Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Bari, via Amendola 122/D, Bari, Italy; and second and third author: Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, via Amendola 165/A, Bari, Italy
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25
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Kandel PP, Chen H, De La Fuente L. A Short Protocol for Gene Knockout and Complementation in Xylella fastidiosa Shows that One of the Type IV Pilin Paralogs (PD1926) Is Needed for Twitching while Another (PD1924) Affects Pilus Number and Location. Appl Environ Microbiol 2018; 84:e01167-18. [PMID: 29980551 PMCID: PMC6121978 DOI: 10.1128/aem.01167-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 06/29/2018] [Indexed: 11/20/2022] Open
Abstract
Twitching motility is one of the major virulence factors of the plant-pathogenic bacterium Xylella fastidiosa, and it is mediated by type IV pili (TFP) that are present at one of the cell poles. Genome analysis of X. fastidiosa showed the presence of at least four paralogs of the gene pilA, which encodes the TFP major pilin subunit. However, whether all of these paralogs have a functional role in TFP structure and function is unknown. Here, using a short and reliable protocol based on overlap extension PCR and natural transformation, deletion mutants of two pilA paralogs (pilA1 PD1924 and pilA2 PD1926) were generated in two X. fastidiosa subsp. fastidiosa strains, WM1-1 and TemeculaL, followed by assessment of twitching motility and biofilm formation. Deletion of pilA2 caused loss of twitching motility, whereas deletion of pilA1 did not influence twitching motility but caused hyperpiliation and extended distribution of TFP along the sides of the cell. Loss of twitching motility due to pilA2 deletion was restored when a wild-type copy of the pilA2 gene was added at a neutral site in the genome of mutants in both wild-type backgrounds. This study demonstrates that PCR templates generated by overlap extension PCR can be successfully used to rapidly generate gene knockouts and perform genetic complementation in X. fastidiosa, and that twitching motility in X. fastidiosa is controlled by regulating the transcription of the major pilin subunit, pilA2IMPORTANCE The bacterial plant pathogen Xylella fastidiosa causes incurable diseases in multiple hosts, including grape, citrus, and blueberry. Historically restricted to the Americas, it was recently found to cause epidemics in olives in Italy and to infect other hosts in Europe and Asia. In this study, we report a short protocol to create deletion and complemented mutants using fusion PCR and natural transformation. We also determined the distinct function of two pilin paralogs, the main structural component of TFP involved in twitching motility, which allows this bacterium to move inside the xylem vessels against the flow. One of the paralogs is needed for twitching movement, whereas the other does not have an effect on motility but influences the number and position of TFP. Since twitching motility is fundamental for the virulence of this xylem-limited bacterium, this study contributes to the understanding of the regulation of virulence by this pathogen.
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Affiliation(s)
- Prem P Kandel
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Hongyu Chen
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
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26
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Stevison LS, Sefick S, Rushton C, Graze RM. Recombination rate plasticity: revealing mechanisms by design. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160459. [PMID: 29109222 PMCID: PMC5698621 DOI: 10.1098/rstb.2016.0459] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2017] [Indexed: 12/13/2022] Open
Abstract
For over a century, scientists have known that meiotic recombination rates can vary considerably among individuals, and that environmental conditions can modify recombination rates relative to the background. A variety of external and intrinsic factors such as temperature, age, sex and starvation can elicit 'plastic' responses in recombination rate. The influence of recombination rate plasticity on genetic diversity of the next generation has interesting and important implications for how populations evolve. Further, many questions remain regarding the mechanisms and molecular processes that contribute to recombination rate plasticity. Here, we review 100 years of experimental work on recombination rate plasticity conducted in Drosophila melanogaster We categorize this work into four major classes of experimental designs, which we describe via classic studies in D. melanogaster Based on these studies, we highlight molecular mechanisms that are supported by experimental results and relate these findings to studies in other systems. We synthesize lessons learned from this model system into experimental guidelines for using recent advances in genotyping technologies, to study recombination rate plasticity in non-model organisms. Specifically, we recommend (1) using fine-scale genome-wide markers, (2) collecting time-course data, (3) including crossover distribution measurements, and (4) using mixed effects models to analyse results. To illustrate this approach, we present an application adhering to these guidelines from empirical work we conducted in Drosophila pseudoobscuraThis article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
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Affiliation(s)
- Laurie S Stevison
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Stephen Sefick
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Chase Rushton
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Rita M Graze
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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27
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Chen H, Kandel PP, Cruz LF, Cobine PA, De La Fuente L. The Major Outer Membrane Protein MopB Is Required for Twitching Movement and Affects Biofilm Formation and Virulence in Two Xylella fastidiosa strains. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:896-905. [PMID: 28800709 DOI: 10.1094/mpmi-07-17-0161-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
MopB is a major outer membrane protein (OMP) in Xylella fastidiosa, a bacterial plant pathogen that causes losses on many economically important crops. Based on in silico analysis, the uncharacterized MopB protein of X. fastidiosa contains a β-barrel structure with an OmpA-like domain and a predicted calcium-binding motif. Here, MopB function was studied by mutational analysis taking advantage of the natural competence of X. fastidiosa. Mutants of mopB were constructed in two different X. fastidiosa strains, the type strain Temecula and the more virulent WM1-1. Deletion of the mopB gene impaired cell-to-cell aggregation, surface attachment, and biofilm formation in both strains. Interestingly, mopB deletion completely abolished twitching motility. Electron microscopy of the bacterial cell surface revealed that mopB deletion eliminated type IV and type I pili formation, potentially caused by destabilization of the outer membrane. Both mopB mutants showed reduced virulence using tobacco (Nicotiana tabacum) as a host under greenhouse conditions. These results suggest that MopB has pleiotropic functions in biofilm formation and twitching motility and is important for virulence of X. fastidiosa.
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Affiliation(s)
- Hongyu Chen
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A.; and
| | - Prem P Kandel
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A.; and
| | - Luisa F Cruz
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A.; and
| | - Paul A Cobine
- 2 Department of Biological Sciences, Auburn University
| | - Leonardo De La Fuente
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A.; and
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Kandel PP, Almeida RPP, Cobine PA, De La Fuente L. Natural Competence Rates Are Variable Among Xylella fastidiosa Strains and Homologous Recombination Occurs In Vitro Between Subspecies fastidiosa and multiplex. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:589-600. [PMID: 28459171 DOI: 10.1094/mpmi-02-17-0053-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Xylella fastidiosa, an etiological agent of emerging crop diseases around the world, is naturally competent for the uptake of DNA from the environment that is incorporated into its genome by homologous recombination. Homologous recombination between subspecies of X. fastidiosa was inferred by in silico studies and was hypothesized to cause disease emergence. However, no experimental data are available on the degree to which X. fastidiosa strains are capable of competence and whether recombination can be experimentally demonstrated between subspecies. Here, using X. fastidiosa strains from different subspecies, natural competence in 11 of 13 strains was confirmed with plasmids containing antibiotic markers flanked by homologous regions and, in three of five strains, with dead bacterial cells used as source of donor DNA. Recombination frequency differed among strains and was correlated to growth rate and twitching motility. Moreover, intersubspecific recombination occurred readily between strains of subsp. fastidiosa and multiplex, as demonstrated by movement of antibiotic resistance and green fluorescent protein from donor to recipient cells and confirmed by DNA sequencing of the flanking arms of recombinant strains. Results demonstrate that natural competence is widespread among X. fastidiosa strains and could have an impact in pathogen adaptation and disease development.
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Affiliation(s)
- Prem P Kandel
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, U.S.A
| | - Rodrigo P P Almeida
- 2 Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, U.S.A.; and
| | - Paul A Cobine
- 3 Department of Biological Sciences, Auburn University
| | - Leonardo De La Fuente
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, U.S.A
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Whidden M, Cogan N, Donahue M, Navarrete F, De La Fuente L. A Two-Dimensional Multiphase Model of Biofilm Formation in Microfluidic Chambers. Bull Math Biol 2015; 77:2161-79. [PMID: 26621357 DOI: 10.1007/s11538-015-0115-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 10/15/2015] [Indexed: 10/22/2022]
Abstract
The bacterial pathogen Xylella fastidiosa is the causal agent of many pathological conditions of economically important agricultural crops. There is no known cure for X. fastidiosa diseases, and management of the problem is based solely in controlling the population of insect vectors, which is somewhat effective. The bacterium causes disease by forming biofilms inside the vascular system of the plant, a process that is poorly understood. In microfluidic chambers, used as artificial xylem vessels, this bacterium has been observed to reproducibly cluster into a distinct, regular pattern of aggregates, spatially separated by channels of non-biofilm components. We develop a multiphase model in two dimensions, which recapitulates this spatial patterning, suggesting that bacterial growth and attachment/detachment processes are strongly influential modulators of these patterns. This indicates plausible strategies, such as the addition of metals and chelators, for mitigating the severity of diseases induced by this bacterial pathogen.
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Affiliation(s)
- Mark Whidden
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Nick Cogan
- Department of Mathematics, Florida State University, Tallahassee, FL, USA
| | - Matt Donahue
- Department of Mathematics, University of Tulsa, Tulsa, OK, USA
| | - Fernando Navarrete
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
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Oliver JE, Cobine PA, De La Fuente L. Xylella fastidiosa Isolates from Both subsp. multiplex and fastidiosa Cause Disease on Southern Highbush Blueberry (Vaccinium sp.) Under Greenhouse Conditions. PHYTOPATHOLOGY 2015; 105:855-862. [PMID: 25738552 DOI: 10.1094/phyto-11-14-0322-fi] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Xylella fastidiosa is a xylem-limited gram-negative plant pathogen that affects numerous crop species, including grape, citrus, peach, pecan, and almond. Recently, X. fastidiosa has also been found to be the cause of bacterial leaf scorch on blueberry in the southeastern United States. Thus far, all X. fastidiosa isolates obtained from infected blueberry have been classified as X. fastidiosa subsp. multiplex; however, X. fastidiosa subsp. fastidiosa isolates are also present in the southeastern United States and commonly cause Pierce's disease of grapevines. In this study, seven southeastern U.S. isolates of X. fastidiosa, including three X. fastidiosa subsp. fastidiosa isolates from grape, one X. fastidiosa subsp. fastidiosa isolate from elderberry, and three X. fastidiosa subsp. multiplex isolates from blueberry, were used to infect the southern highbush blueberry 'Rebel'. Following inoculation, all isolates colonized blueberry, and isolates from both X. fastidiosa subsp. multiplex and X. fastidiosa subsp. fastidiosa caused symptoms, including characteristic stem yellowing and leaf scorch symptoms as well as dieback of the stem tips. Two X. fastidiosa subsp. multiplex isolates from blueberry caused more severe symptoms than the other isolates examined, and infection with these two isolates also had a significant impact on host mineral nutrient content in sap and leaves. These findings have potential implications for understanding X. fastidiosa host adaptation and expansion and the development of emerging diseases caused by this bacterium.
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Affiliation(s)
- J E Oliver
- First and third authors: Department of Entomology and Plant Pathology, and second author: Department of Biological Sciences, Auburn University, Auburn, AL 36830
| | - P A Cobine
- First and third authors: Department of Entomology and Plant Pathology, and second author: Department of Biological Sciences, Auburn University, Auburn, AL 36830
| | - L De La Fuente
- First and third authors: Department of Entomology and Plant Pathology, and second author: Department of Biological Sciences, Auburn University, Auburn, AL 36830
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Navarrete F, De La Fuente L. Zinc Detoxification Is Required for Full Virulence and Modification of the Host Leaf Ionome by Xylella fastidiosa. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:497-507. [PMID: 25561271 DOI: 10.1094/mpmi-07-14-0221-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Zinc (Zn) is an essential element for all forms of life because it is a structural or catalytic cofactor of many proteins, but it can have toxic effects at high concentrations; thus, microorganisms must tightly regulate its levels. Here, we evaluated the role of Zn homeostasis proteins in the virulence of the xylem-limited bacterium Xylella fastidiosa, causal agent of Pierce's disease of grapevine, among other diseases. Two mutants of X. fastidiosa 'Temecula' affected in genes which regulate Zn homeostasis (zur) and Zn detoxification (czcD) were constructed. Both knockouts showed increased sensitivity to Zn at physiologically relevant concentrations and increased intracellular accumulation of this metal compared with the wild type. Increased Zn sensitivity was correlated with decreased growth in grapevine xylem sap, reduced twitching motility, and downregulation of exopolysaccharide biosynthetic genes. Tobacco plants inoculated with either knockout mutant showed reduced foliar symptoms and a much reduced (czcD) or absent (zur) modification of the leaf ionome (i.e., the mineral nutrient and trace element composition), as well as reduced bacterial populations. The results show that detoxification of Zn is crucial for the virulence of X. fastidiosa and verifies our previous findings that modification of the host leaf ionome correlates with bacterial virulence.
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Affiliation(s)
- Fernando Navarrete
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
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