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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 Dis 2024:PDIS09231923RE. [PMID: 38105458 DOI: 10.1094/pdis-09-23-1923-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [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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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 Dis 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] [What about the content of this article? (0)] [Affiliation(s)] [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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El Handi K, Sabri M, Valentini F, De Stradis A, Achbani EH, Hafidi M, El Moujabber M, Elbeaino T. Exploring Active Peptides with Antimicrobial Activity In Planta against Xylella fastidiosa. Biology 2022; 11:1685. [DOI: 10.3390/biology11111685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022]
Abstract
Xylella fastidiosa (Xf) is a xylem-limited quarantine plant bacterium and one of the most harmful agricultural pathogens across the world. Despite significant research efforts, neither a direct treatment nor an efficient strategy has yet been developed for combatting Xylella-associated diseases. Antimicrobial peptides (AMPs) have been gaining interest as a promising sustainable tool to control pathogens due to their unique mechanism of action, broad spectrum of activity, and low environmental impact. In this study, we disclose the bioactivity of nine AMPs reported in the literature to be efficient against human and plant pathogen bacteria, i.e., Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, against Xf, through in vitro and in vivo experiments. Based on viable-quantitative PCR (v-qPCR), fluorescence microscopy (FM), optical density (OD), and transmission electron microscopy (TEM) assays, peptides Ascaphin-8 (GF19), DASamP1 (FF13), and DASamP2 (IL14) demonstrated the highest bactericidal and antibiofilm activities and were more efficient than the peptide PB178 (KL29), reported as one of the most potent AMPs against Xf at present. Furthermore, these AMPs showed low to no toxicity when tested on eukaryotic cells. In in planta tests, no Xf disease symptoms were noticed in Nicotiana tabacum plants treated with the AMPs 40 days post inoculation. This study highlighted the high antagonistic activity of newly tested AMP candidates against Xf, which could lead to the development of promising eco-friendly management of Xf-related diseases.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Moll L, Badosa E, Planas M, Feliu L, Montesinos E, Bonaterra A. Antimicrobial Peptides With Antibiofilm Activity Against Xylella fastidiosa. Front Microbiol 2021; 12:753874. [PMID: 34819923 PMCID: PMC8606745 DOI: 10.3389/fmicb.2021.753874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/04/2021] [Indexed: 11/26/2022] Open
Abstract
Xylella fastidiosa is a plant pathogen that was recently introduced in Europe and is causing havoc to its agriculture. This Gram-negative bacterium invades the host xylem, multiplies, and forms biofilm occluding the vessels and killing its host. In spite of the great research effort, there is no method that effectively prevents or cures hosts from infections. The main control strategies up to now are eradication, vector control, and pathogen-free plant material. Antimicrobial peptides have arisen as promising candidates to combat this bacterium due to their broad spectrum of activity and low environmental impact. In this work, peptides previously reported in the literature and newly designed analogs were studied for its bactericidal and antibiofilm activity against X. fastidiosa. Also, their hemolytic activity and effect on tobacco leaves when infiltrated were determined. To assess the activity of peptides, the strain IVIA 5387.2 with moderate growth, able to produce biofilm and susceptible to antimicrobial peptides, was selected among six representative strains found in the Mediterranean area (DD1, CFBP 8173, Temecula, IVIA 5387.2, IVIA 5770, and IVIA 5901.2). Two interesting groups of peptides were identified with bactericidal and/or antibiofilm activity and low-moderate toxicity. The peptides 1036 and RIJK2 with dual (bactericidal–antibiofilm) activity against the pathogen and moderate toxicity stand out as the best candidates to control X. fastidiosa diseases. Nevertheless, peptides with only antibiofilm activity and low toxicity are also promising agents as they could prevent the occlusion of xylem vessels caused by the pathogen. The present work contributes to provide novel compounds with antimicrobial and antibiofilm activity that could lead to the development of new treatments against diseases caused by X. fastidiosa.
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Affiliation(s)
- Luís Moll
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Esther Badosa
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Marta Planas
- LIPPSO, Department of Chemistry, University of Girona, Girona, Spain
| | - Lidia Feliu
- LIPPSO, Department of Chemistry, University of Girona, Girona, Spain
| | - Emilio Montesinos
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Anna Bonaterra
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Ge Q, Liu R, Cobine PA, Potnis N, De La Fuente L. Phenotypic and Phylogenetic Characterization of Cu Homeostasis among Xylella fastidiosa Strains. Pathogens 2021; 10:pathogens10040495. [PMID: 33924015 PMCID: PMC8073393 DOI: 10.3390/pathogens10040495] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/16/2021] [Accepted: 04/18/2021] [Indexed: 12/17/2022] Open
Abstract
Xylella fastidiosa is a bacterial pathogen causing severe diseases and asymptomatic colonization in more than 600 plants worldwide. Copper (Cu) is a widely used antimicrobial treatment for various plant diseases, including those affecting X. fastidiosa hosts. Cu homeostasis among X. fastidiosa strains from different geographical locations and host species has not been characterized. Here, we assessed minimum inhibitory concentration (MIC) of Cu for 54 X. fastidiosa strains. We observed strain-level variation in MIC values within each subspecies. We hypothesized that these differences could be explained by sequence variation in Cu homeostasis genes. Phylogenies based on copA, copB, copL, and cutC were created using 74 genomes (including 43 strains used in vitro) of X. fastidiosa, showing that the phylogenetic clustering of Cu homeostasis associated with clustering was based on core genome phylogenies, rather than on pattern of MIC. No association was found among Cu MIC, subspecies classification, and host and location of isolation, probably due to uneven and limited group of strains whose genomes are available. Further analysis focused on a subgroup of isolates from Georgia’s vineyards that shared similar Cu-related phenotypes. Further research is needed to better understand the distribution of Cu homeostasis for this pathogen.
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Affiliation(s)
- Qing Ge
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (Q.G.); (R.L.); (N.P.)
| | - Ranlin Liu
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (Q.G.); (R.L.); (N.P.)
| | - Paul A. Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA;
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (Q.G.); (R.L.); (N.P.)
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (Q.G.); (R.L.); (N.P.)
- Correspondence: ; Tel.: +1-334-844-2582
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Machini W, Oliveira-brett A. In situ electrochemical investigation of the interaction between bacteria Xylella fastidiosa DNA and copper(II) using DNA-electrochemical biosensors. Electrochem commun 2021; 125:106975. [DOI: 10.1016/j.elecom.2021.106975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Tatulli G, Modesti V, Pucci N, Scala V, L’Aurora A, Lucchesi S, Salustri M, Scortichini M, Loreti S. Further In Vitro Assessment and Mid-Term Evaluation of Control Strategy of Xylella fastidiosa subsp. pauca in Olive Groves of Salento (Apulia, Italy). Pathogens 2021; 10:85. [PMID: 33478174 PMCID: PMC7835972 DOI: 10.3390/pathogens10010085] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/13/2022] Open
Abstract
During recent years; Xylella fastidiosa subsp. pauca (Xfp) has spread in Salento causing relevant damage to the olive groves. Measures to contain the spreading of the pathogen include the monitoring of the areas bordering the so-called "infected" zone and the tree eradication in case of positive detection. In order to provide a control strategy aimed to maintain the tree productivity in the infected areas, we further evaluated the in vitro and in planta mid-term effectiveness of a zinc-copper-citric acid biocomplex. The compound showed an in vitro bactericidal activity and inhibited the biofilm formation in representative strains of X. fastidiosa subspecies, including Xfp isolated in Apulia from olive trees. The field mid-term evaluation of the control strategy assessed by quantitative real-time PCR in 41 trees of two olive groves of the "infected" area revealed a low concentration of Xfp over the seasons upon the regular spraying of the biocomplex over 3 or 4 consecutive years. In particular, the bacterial concentration lowered in July and October with respect to March, after six consecutive treatments. The trend was not affected by the cultivar and it was similar either in the Xfp-sensitive cultivars Ogliarola salentina and Cellina di Nardò or in the Xfp-resistant Leccino. Moreover, the scoring of the number of wilted twigs over the seasons confirmed the trend. The efficacy of the treatment in the management of olive groves subjected to a high pathogen pressure is highlighted by the yielded a good oil production.
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Affiliation(s)
- Giuseppe Tatulli
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, 00156 Roma, Italy; (G.T.); (V.M.); (N.P.); (V.S.); (A.L.); (S.L.)
| | - Vanessa Modesti
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, 00156 Roma, Italy; (G.T.); (V.M.); (N.P.); (V.S.); (A.L.); (S.L.)
| | - Nicoletta Pucci
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, 00156 Roma, Italy; (G.T.); (V.M.); (N.P.); (V.S.); (A.L.); (S.L.)
| | - Valeria Scala
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, 00156 Roma, Italy; (G.T.); (V.M.); (N.P.); (V.S.); (A.L.); (S.L.)
| | - Alessia L’Aurora
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, 00156 Roma, Italy; (G.T.); (V.M.); (N.P.); (V.S.); (A.L.); (S.L.)
| | - Simone Lucchesi
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, 00156 Roma, Italy; (G.T.); (V.M.); (N.P.); (V.S.); (A.L.); (S.L.)
| | - Manuel Salustri
- Dipartimento di Biologia Ambientale, Sapienza University of Rome, 00185 Roma, Italy;
| | - Marco Scortichini
- Council for Agricultural Research and Economics (CREA), Research Centre for Olive, Fruit and Citrus Crops, 00134 Roma, Italy
| | - Stefania Loreti
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, 00156 Roma, Italy; (G.T.); (V.M.); (N.P.); (V.S.); (A.L.); (S.L.)
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Gómez LM, Teixeira-Silva NS, Caserta R, Takita MA, Marques MOM, de Souza AA. Overexpression of Citrus reticulata SAMT in Nicotiana tabacum increases MeSA volatilization and decreases Xylella fastidiosa symptoms. Planta 2020; 252:103. [PMID: 33185761 DOI: 10.1007/s00425-020-03511-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 11/03/2020] [Indexed: 06/11/2023]
Abstract
MAIN CONCLUSION Nicotiana tabacum overexpressing CrSAMT from Citrus reticulata increased production of MeSA, which works as an airborne signal in neighboring wild-type plants, inducing PR1 and increasing resistance to the pathogen Xylella fastidiosa. Xylella fastidiosa is one of the major threats to plant health worldwide, affecting yield in many crops. Despite many efforts, the development of highly productive resistant varieties has been challenging. In studying host plant resistance, the S-adenosyl-L-methionine: salicylic acid carboxyl methyltransferase gene (SAMT) from Citrus reticulata, a X. fastidiosa resistant species, was upregulated in response to pathogen infection. SAMT is involved with the catalysis and production of methyl salicylate (MeSA), an airborne signal responsible for triggering systemic acquired resistance. Here we used tobacco as a model system and generated transgenic plants overexpressing C. reticulata SAMT (CrSAMT). We performed an in silico structural characterization of CrSAMT and investigated its biotechnological potential in modulating the immune system in transgenic plants. The increase of MeSA production in transgenic lines was confirmed by gas chromatography (GC-MS). The transgenic lines showed upregulation of PR1, and their incubation with neighboring wild-type plants activated PR1 expression, indicating that MeSA worked as an airborne signal. In addition, transgenic plants showed significantly fewer symptoms when challenged with X. fastidiosa. Altogether, these data suggest that CrSAMT plays a role in host defense response and can be used in biotechnology approaches to confer resistance against X. fastidiosa.
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Affiliation(s)
- Laura M Gómez
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
- Entomology and Plant Pathology Department, Auburn University, Auburn, AL, USA
| | - Natália S Teixeira-Silva
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
| | - Raquel Caserta
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
| | - Marco A Takita
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil
| | - Márcia O M Marques
- Departamento de Fitoquímica/IAC, Avenida Doutor Theodureto Almeida Camargo 1500, Campinas, SP, 13012970, Brazil
| | - Alessandra A de Souza
- Centro de Citricultura Sylvio Moreira/IAC, Rodovia Anhanguera, km 158, PO Box 04, Cordeirópolis, SP, 13490-970, Brazil.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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