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Zecharia N, Miri V, Dror O, Hatib K, Holland D, Dani S, Bahar O. Seasonal Dynamics and Distribution of Xylella fastidiosa in Infected Almond Trees. PHYTOPATHOLOGY 2024; 114:1186-1195. [PMID: 38105220 DOI: 10.1094/phyto-07-23-0240-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: 12/19/2023]
Abstract
This research focused on studying the dynamics of the bacterial pathogen Xylella fastidiosa in almond trees across different developmental stages. The objective was to understand the seasonal distribution and concentration of X. fastidiosa within almond trees. Different tree organs, including leaves, shoots, branches, fruits, flowers, and roots, from 10 X. fastidiosa-infected almond trees were sampled over 2 years. The incidence and concentration of X. fastidiosa were determined using qPCR and isolation. Throughout the study, X. fastidiosa was consistently absent from fruits, flowers, and roots, whereas it was detected in leaves as well as in shoots and branches. We demonstrate that the absence of X. fastidiosa in the roots is likely linked to the inability of this isolate to infect the peach-almond hybrid rootstock GF677. X. fastidiosa incidence in shoots and branches remained consistent throughout the year, whereas in leaf petioles, it varied across developmental stages, with lower detection during the early and late stages of the season. Similarly, viable X. fastidiosa cells were isolated from shoots and branches at all developmental stages, but no successful isolations were achieved from leaf petioles during the vegetative and nut growth stage. Studying the progression of almond leaf scorch symptoms in trees with initial infections showed that once symptoms emerged on one branch, symptomless branches were likely already infected by the bacterium. Therefore, selectively pruning symptomatic branches is unlikely to cure the tree. This study enhances our understanding of X. fastidiosa dynamics in almond trees and may have practical applications for its detection and control.
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Affiliation(s)
- Noa Zecharia
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Vanunu Miri
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Orit Dror
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Kamel Hatib
- Newe Ya'ar Research Center, Agricultural Research Organization, Volcani Center, Ramat Yishay, Israel
| | - Doron Holland
- Newe Ya'ar Research Center, Agricultural Research Organization, Volcani Center, Ramat Yishay, Israel
| | - Shtienberg Dani
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Ofir Bahar
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
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De La Fuente L, Navas-Cortés JA, Landa BB. Ten Challenges to Understanding and Managing the Insect-Transmitted, Xylem-Limited Bacterial Pathogen Xylella fastidiosa. PHYTOPATHOLOGY 2024; 114:869-884. [PMID: 38557216 DOI: 10.1094/phyto-12-23-0476-kc] [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: 04/04/2024]
Abstract
An unprecedented plant health emergency in olives has been registered over the last decade in Italy, arguably more severe than what occurred repeatedly in grapes in the United States in the last 140 years. These emergencies are epidemics caused by a stealthy pathogen, the xylem-limited, insect-transmitted bacterium Xylella fastidiosa. Although these epidemics spurred research that answered many questions about the biology and management of this pathogen, many gaps in knowledge remain. For this review, we set out to represent both the U.S. and European perspectives on the most pressing challenges that need to be addressed. These are presented in 10 sections that we hope will stimulate discussion and interdisciplinary research. We reviewed intrinsic problems that arise from the fastidious growth of X. fastidiosa, the lack of specificity for insect transmission, and the economic and social importance of perennial mature woody plant hosts. Epidemiological models and predictions of pathogen establishment and disease expansion, vital for preparedness, are based on very limited data. Most of the current knowledge has been gathered from a few pathosystems, whereas several hundred remain to be studied, probably including those that will become the center of the next epidemic. Unfortunately, aspects of a particular pathosystem are not always transferable to others. We recommend diversification of research topics of both fundamental and applied nature addressing multiple pathosystems. Increasing preparedness through knowledge acquisition is the best strategy to anticipate and manage diseases caused by this pathogen, described as "the most dangerous plant bacterium known worldwide."
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Affiliation(s)
- Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
| | - Juan A Navas-Cortés
- Department of Crop Protection. Institute for Sustainable Agriculture (IAS), Consejo Superior de Investigaciones Científicas (CSIC), Córdoba, Spain
| | - Blanca B Landa
- Department of Crop Protection. Institute for Sustainable Agriculture (IAS), Consejo Superior de Investigaciones Científicas (CSIC), Córdoba, Spain
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Bleve G, Trivellin N, Chirizzi D, Tarantini A, Orlandi VT, Milano F. Sensitivity of Xylella fastidiosa subsp. pauca Salento-1 to light at 410 nm. Photochem Photobiol Sci 2024; 23:793-801. [PMID: 38578539 DOI: 10.1007/s43630-024-00556-z] [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: 11/07/2023] [Accepted: 02/14/2024] [Indexed: 04/06/2024]
Abstract
All over the world, from America to the Mediterranean Sea, the plant pathogen Xylella fastidiosa represents one of the most difficult challenges with many implications at ecological, agricultural, and economic levels. X. fastidiosa is a rod-shaped Gram-negative bacterium belonging to the family of Xanthomonadaceae. It grows at very low rates and infects a wide range of plants thanks to different vectors. Insects, through their stylets, suck a sap rich in nutrients and inject bacteria into xylem vessels. Since, until now, no antimicrobial treatment has been successfully applied to kill X. fastidiosa and/or prevent its diffusion, in this study, antimicrobial blue light (aBL) was explored as a potential anti-Xylella tool. Xylella fastidiosa subsp. pauca Salento-1, chosen as a model strain, showed a certain degree of sensitivity to light at 410 nm. The killing effect was light dose dependent and bacterial concentration dependent. These preliminary results support the potential of blue light in decontamination of agricultural equipment and/or plant surface; however, further investigations are needed for in vivo applications.
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Affiliation(s)
- Gianluca Bleve
- Istituto di Scienze delle Produzioni Alimentari (ISPA), Consiglio Nazionale delle Ricerche (CNR), SP Lecce-Monteroni, 73100, Lecce, Italy
| | - Nicola Trivellin
- Department of Industrial Engineering, University of Padua, via Venezia, 1, 35131, Padova, Italy
| | - Daniela Chirizzi
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, via Manfredonia 20, 71100, Foggia, Italy
| | - Annamaria Tarantini
- Istituto di Scienze delle Produzioni Alimentari (ISPA), Consiglio Nazionale delle Ricerche (CNR), SP Lecce-Monteroni, 73100, Lecce, Italy
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti (Di.S.S.P.A), Università di Bari, via G. Amendola, 165/A, Bari, 70126, Italy
| | - Viviana Teresa Orlandi
- Departemnt of Biotechnologies and Life Sciences, University of Insubria, via J. H. Dunant, 3, 21100, Varese, Italy.
| | - Francesco Milano
- Istituto di Scienze delle Produzioni Alimentari (ISPA), Consiglio Nazionale delle Ricerche (CNR), SP Lecce-Monteroni, 73100, Lecce, Italy
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Lindow S, Koutsoukis R, Meyer K, Baccari C. Control of Pierce's Disease of Grape with Paraburkholderia phytofirmans PsJN in the Field. PHYTOPATHOLOGY 2024; 114:503-511. [PMID: 37913631 DOI: 10.1094/phyto-06-23-0219-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Replicated field studies were conducted to evaluate the factors that could influence the efficacy of Paraburkholderia phytofirmans PsJN for the control of Pierce's disease of grape, as well as to determine the extent to which disease control was systemic within plants. Topical applications of PsJN with an organosilicon surfactant was an effective way to introduce this bacterium under field conditions and provided similar levels of disease control as its mechanical inoculation. Disease incidence in inoculated shoots was often reduced two- to threefold when PsJN was inoculated a single time as much as 3 weeks before Xylella fastidiosa and up to 5 weeks after the pathogen. Inoculation of a shoot with PsJN greatly decreased the probability of any symptoms rather than reducing the severity of disease, suggesting a systemic protective response of individual shoots. Although the likelihood of disease symptoms on shoots inoculated with the pathogen on PsJN-treated plants was lower than on control plants inoculated only with the pathogen, the protection conferred by PsJN was not experienced by all shoots on a given plant. This suggested that any systemic resistance was spatially limited. Whereas the population size of PsJN increased to more than 106 cells/g and spread more than 1 m within 12 weeks after its inoculation alone into grape, its population size subsequently decreased greatly after about 5 weeks, and its distal dispersal in stems was restricted when co-inoculated with X. fastidiosa. PsJN may experience collateral damage from apparent host responses induced when both species are present.
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Affiliation(s)
- Steven Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Renee Koutsoukis
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Kyle Meyer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Clelia Baccari
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
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Feitosa-Junior OR, Lubbe A, Kosina SM, Martins-Junior J, Barbosa D, Baccari C, Zaini PA, Bowen BP, Northen TR, Lindow SE, da Silva AM. The Exometabolome of Xylella fastidiosa in Contact with Paraburkholderia phytofirmans Supernatant Reveals Changes in Nicotinamide, Amino Acids, Biotin, and Plant Hormones. Metabolites 2024; 14:82. [PMID: 38392974 PMCID: PMC10890622 DOI: 10.3390/metabo14020082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 02/25/2024] Open
Abstract
Microbial competition within plant tissues affects invading pathogens' fitness. Metabolomics is a great tool for studying their biochemical interactions by identifying accumulated metabolites. Xylella fastidiosa, a Gram-negative bacterium causing Pierce's disease (PD) in grapevines, secretes various virulence factors including cell wall-degrading enzymes, adhesion proteins, and quorum-sensing molecules. These factors, along with outer membrane vesicles, contribute to its pathogenicity. Previous studies demonstrated that co-inoculating X. fastidiosa with the Paraburkholderia phytofirmans strain PsJN suppressed PD symptoms. Here, we further investigated the interaction between the phytopathogen and the endophyte by analyzing the exometabolome of wild-type X. fastidiosa and a diffusible signaling factor (DSF) mutant lacking quorum sensing, cultivated with 20% P. phytofirmans spent media. Liquid chromatography-mass spectrometry (LC-MS) and the Method for Metabolite Annotation and Gene Integration (MAGI) were used to detect and map metabolites to genomes, revealing a total of 121 metabolites, of which 25 were further investigated. These metabolites potentially relate to host adaptation, virulence, and pathogenicity. Notably, this study presents the first comprehensive profile of X. fastidiosa in the presence of a P. phytofirmans spent media. The results highlight that P. phytofirmans and the absence of functional quorum sensing affect the ratios of glutamine to glutamate (Gln:Glu) in X. fastidiosa. Additionally, two compounds with plant metabolism and growth properties, 2-aminoisobutyric acid and gibberellic acid, were downregulated when X. fastidiosa interacted with P. phytofirmans. These findings suggest that P. phytofirmans-mediated disease suppression involves modulation of the exometabolome of X. fastidiosa, impacting plant immunity.
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Affiliation(s)
- Oseias R Feitosa-Junior
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo 05508-900, SP, Brazil
- The DOE Joint Genome Institute, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Andrea Lubbe
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Suzanne M Kosina
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Joaquim Martins-Junior
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo 05508-900, SP, Brazil
| | - Deibs Barbosa
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo 05508-900, SP, Brazil
| | - Clelia Baccari
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Paulo A Zaini
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Benjamin P Bowen
- The DOE Joint Genome Institute, Berkeley, CA 94720, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Trent R Northen
- The DOE Joint Genome Institute, Berkeley, CA 94720, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Steven E Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Aline M da Silva
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo 05508-900, SP, Brazil
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Castro C, Ndukwe I, Heiss C, Black I, Ingel BM, Guevara M, Sun Y, Azadi P, Sun Q, Roper MC. Xylella fastidiosa modulates exopolysaccharide polymer length and the dynamics of biofilm development with a β-1,4-endoglucanase. mBio 2023; 14:e0139523. [PMID: 37830811 PMCID: PMC10653819 DOI: 10.1128/mbio.01395-23] [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: 06/06/2023] [Accepted: 08/30/2023] [Indexed: 10/14/2023] Open
Abstract
IMPORTANCE It is well established that exopolysaccharide (EPS) is an integral structural component of bacterial biofilms necessary for assembly and maintenance of the three-dimensional architecture of the biofilm. However, the process and role of EPS turnover within a developing biofilm is not fully understood. Here, we demonstrated that Xylella fastidiosa uses a self-produced endoglucanase to enzymatically process its own EPS to modulate EPS polymer length. This enzymatic processing of EPS dictates the early stages of X. fastidiosa's biofilm development, which, in turn, affects its behavior in planta. A deletion mutant that cannot produce the endoglucanase was hypervirulent, thereby linking enzymatic processing of EPS to attenuation of virulence in symptomatic hosts, which may be a vestige of X. fastidiosa's commensal behavior in many of its other non-symptomatic hosts.
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Affiliation(s)
- Claudia Castro
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Ikenna Ndukwe
- Complex Carbohydrate Research Center, University of Georgia, Athens, USA
| | - Christian Heiss
- Complex Carbohydrate Research Center, University of Georgia, Athens, USA
| | - Ian Black
- Complex Carbohydrate Research Center, University of Georgia, Athens, USA
| | - Brian M. Ingel
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Matthew Guevara
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Yuling Sun
- Department of Computer Science, Wellesley College, Wellesley, Massachusetts, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, USA
| | - Qiang Sun
- Department of Biology, University of Wisconsin, Stevens Point, Wisconsin, USA
| | - M. Caroline Roper
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
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Scortichini M, Manetti G, Brunetti A, Lumia V, Sciarroni L, Pilotti M. Xylella fastidiosa subsp. pauca, Neofusicoccum spp. and the Decline of Olive Trees in Salento (Apulia, Italy): Comparison of Symptoms, Possible Interactions, Certainties and Doubts. PLANTS (BASEL, SWITZERLAND) 2023; 12:3593. [PMID: 37896056 PMCID: PMC10609838 DOI: 10.3390/plants12203593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 09/27/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023]
Abstract
Xylella fastidiosa subsp. pauca (XFP), Neofusicoccum mediterraneum, N. stellenboschiana and other fungi have been found in olive groves of Salento (Apulia, Italy) that show symptoms of severe decline. XFP is well known to be the cause of olive quick decline syndrome (OQDS). It has also been assessed that Neofusicoccum spp. causes a distinct disease syndrome, namely, branch and twig dieback (BTD). All these phytopathogens incite severe symptoms that can compromise the viability of large canopy sectors or the whole tree. However, their specific symptoms are not easily distinguished, especially during the final stages of the disease when branches are definitively desiccated. By contrast, they can be differentiated during the initial phases of the infection when some facets of the diseases are typical, especially wood discoloration, incited solely by fungi. Here, we describe the typical symptomatological features of OQDS and BTD that can be observed in the field and that have been confirmed by Koch postulate experiments. Similar symptoms, caused by some abiotic adverse conditions and even by additional biotic factors, are also described. Thus, this review aims at: (i) raising the awareness that declining olive trees in Salento do not have to be linked a priori to XFP; (ii) defining the guidelines for a correct symptomatic diagnosis to orient proper laboratory analyses, which is crucial for the application of effective control measures. The possibility that bacterium and fungi could act as a polyspecies and in conjunction with predisposing abiotic stresses is also widely discussed.
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Affiliation(s)
- Marco Scortichini
- Research Centre for Olive, Fruit Trees and Citrus Crops (CREA-OFA), Council for Agricultural Research and Economics (CREA), 00134 Rome, Italy;
| | - Giuliano Manetti
- Research Centre for Plant Protection and Certification (CREA-DC), Council for Agricultural Research and Economics (CREA), 00156 Rome, Italy; (G.M.); (A.B.); (V.L.); (L.S.)
| | - Angela Brunetti
- Research Centre for Plant Protection and Certification (CREA-DC), Council for Agricultural Research and Economics (CREA), 00156 Rome, Italy; (G.M.); (A.B.); (V.L.); (L.S.)
| | - Valentina Lumia
- Research Centre for Plant Protection and Certification (CREA-DC), Council for Agricultural Research and Economics (CREA), 00156 Rome, Italy; (G.M.); (A.B.); (V.L.); (L.S.)
| | - Lorenzo Sciarroni
- Research Centre for Plant Protection and Certification (CREA-DC), Council for Agricultural Research and Economics (CREA), 00156 Rome, Italy; (G.M.); (A.B.); (V.L.); (L.S.)
| | - Massimo Pilotti
- Research Centre for Plant Protection and Certification (CREA-DC), Council for Agricultural Research and Economics (CREA), 00156 Rome, Italy; (G.M.); (A.B.); (V.L.); (L.S.)
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Leisner CP, Potnis N, Sanz-Saez A. Crosstalk and trade-offs: Plant responses to climate change-associated abiotic and biotic stresses. PLANT, CELL & ENVIRONMENT 2023; 46:2946-2963. [PMID: 36585762 DOI: 10.1111/pce.14532] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/07/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
As sessile organisms, plants are constantly challenged by a dynamic growing environment. This includes fluctuations in temperature, water availability, light levels, and changes in atmospheric constituents such as carbon dioxide (CO2 ) and ozone (O3 ). In concert with changes in abiotic conditions, plants experience changes in biotic stress pressures, including plant pathogens and herbivores. Human-induced increases in atmospheric CO2 levels have led to alterations in plant growth environments that impact their productivity and nutritional quality. Additionally, it is predicted that climate change will alter the prevalence and virulence of plant pathogens, further challenging plant growth. A knowledge gap exists in the complex interplay between plant responses to biotic and abiotic stress conditions. Closing this gap is crucial for developing climate resilient crops in the future. Here, we briefly review the physiological responses of plants to elevated CO2 , temperature, tropospheric O3 , and drought conditions, as well as the interaction of these abiotic stress factors with plant pathogen pressure. Additionally, we describe the crosstalk and trade-offs involved in plant responses to both abiotic and biotic stress, and outline targets for future work to develop a more sustainable future food supply considering future climate change.
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Affiliation(s)
- Courtney P Leisner
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Alvaro Sanz-Saez
- Department of Crop, Soil and Environmental Science, Auburn University, Auburn, Alabama, USA
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Bodino N, Cavalieri V, Dongiovanni C, Saponari M, Bosco D. Bioecological Traits of Spittlebugs and Their Implications for the Epidemiology and Control of the Xylella fastidiosa Epidemic in Apulia (Southern Italy). PHYTOPATHOLOGY 2023; 113:1647-1660. [PMID: 36945728 DOI: 10.1094/phyto-12-22-0460-ia] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Spatial-temporal dynamics of spittlebug populations, together with transmission biology, are of major importance to outline the disease epidemiology of Xylella fastidiosa subsp. pauca in Apulian olive groves. The spread rate of X. fastidiosa is mainly influenced by (i) the pathogen colonization of the host plant; (ii) the acquisition of the pathogen by the vector from an infected plant, and its inoculation to healthy plants; (iii) the vector population dynamics and abundance at different spatial scales; and (iv) the dispersal of the vector. In this contribution we summarize the recent advances in research on insect vectors' traits-points ii, iii, and iv-focusing on those most relevant to X. fastidiosa epidemic in Apulia. Among the vectors' bioecological traits influencing the X. fastidiosa epidemic in olive trees, we emphasize the following: natural infectivity and transmission efficiency, phenological timing of both nymphal and adult stage, the role of seminatural vegetation as a vector reservoir in the agroecosystem and landscape, and preferential and directional dispersal capabilities. Despite the research on X. fastidiosa vectors carried out in Europe in the last decade, key uncertainties on insect vectors remain, hampering a thorough understanding of pathogen epidemiology and the development of effective and targeted management strategies. Our goal is to provide a structured and contextualized review of knowledge on X. fastidiosa vectors' key traits in the Apulian epidemic, highlighting information gaps and stimulating novel research pathways on X. fastidiosa pathosystems in Europe. [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)
- Nicola Bodino
- CNR-Istituto per la Protezione Sostenibile delle Piante, 10135 Torino, Italy
| | - Vincenzo Cavalieri
- CNR-Istituto per la Protezione Sostenibile delle Piante, SS Bari, 70126 Bari, Italy
| | - Crescenza Dongiovanni
- CRSFA-Centro di Ricerca, Sperimentazione e Formazione in Agricoltura Basile Caramia, 70010 Locorotondo (BA), Italy
| | - Maria Saponari
- CNR-Istituto per la Protezione Sostenibile delle Piante, SS Bari, 70126 Bari, Italy
| | - Domenico Bosco
- CNR-Istituto per la Protezione Sostenibile delle Piante, 10135 Torino, Italy
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università degli Studi di Torino, 10095 Grugliasco (TO), Italy
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Roddee J, Backus EA, Cervantes FA, Hanboonsong Y. Xylella fastidiosa inoculation behaviors (EPG X wave) are performed differently by blue-green sharpshooters based on infection status of prior probing host. JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:697-712. [PMID: 36988102 DOI: 10.1093/jee/toad043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/22/2022] [Accepted: 02/17/2023] [Indexed: 06/14/2023]
Abstract
Does Xylella fastidiosa, a bacterial plant pathogen with noncirculative foregut-borne transmission, manipulate behavior of its sharpshooter vector to facilitate its own inoculation? To answer this question, blue-green sharpshooters, Graphocephala atropunctata (Signoret), were reared on basil to clean their foreguts, then removed from the colony and given one of four pre-electropenetrography (EPG) treatments: i) old colony adults on basil, ii) young colony adults on basil, iii) young colony adults held on healthy grapevine for 4 days, and iv) young colony adults held on Xf-infected (symptomatic) grapevine for 4 days. After treatments, stylet probing behaviors were recorded on healthy grapevine via AC-DC electropenetrography. Waveforms representing putative Xf inoculation (XB1 [salivation and rinsing egestion] and XC1 [discharging egestion]) and other behaviors were statistically compared among treatments. Mean number of events per insect and 'total' duration per insect of XB1 and XC1 were highest for insects from healthy grape, lowest for basil (regardless of insect age), and intermediate for Xf-infected grape. The surprising results showed that prior exposure to healthy grapevines had a stronger effect on subsequent performance of inoculation behaviors on healthy grapevine than did prior exposure to Xf-infected grapevine. It is hypothesized that non-Xf microbes were acquired from healthy grapevine, causing greater clogging of the precibarium, leading to more performance of inoculation behaviors. This study shows for the first time that presence of noncirculative, foregut-borne microbes can directly manipulate a vector's behavior to increase inoculation. Also, EPG can uniquely visualize the dynamic interactions between vectors and the microbes they carry.
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Affiliation(s)
- Jariya Roddee
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Khon Kaen University, 40002, Khon Kaen, Thailand
| | - Elaine A Backus
- USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA 93648 - 9757, USA
| | - Felix A Cervantes
- USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA 93648 - 9757, USA
| | - Yupa Hanboonsong
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Khon Kaen University, 40002, Khon Kaen, Thailand
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Carluccio G, Greco D, Sabella E, Vergine M, De Bellis L, Luvisi A. Xylem Embolism and Pathogens: Can the Vessel Anatomy of Woody Plants Contribute to X. fastidiosa Resistance? Pathogens 2023; 12:825. [PMID: 37375515 DOI: 10.3390/pathogens12060825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
The maintenance of an intact water column in the xylem lumen several meters above the ground is essential for woody plant viability. In fact, abiotic and biotic factors can lead to the formation of emboli in the xylem, interrupting sap flow and causing consequences on the health status of the plant. Anyway, the tendency of plants to develop emboli depends on the intrinsic features of the xylem, while the cyto-histological structure of the xylem plays a role in resistance to vascular pathogens, as in the case of the pathogenic bacterium Xylella fastidiosa. Analysis of the scientific literature suggests that on grapevine and olive, some xylem features can determine plant tolerance to vascular pathogens. However, the same trend was not reported in citrus, indicating that X. fastidiosa interactions with host plants differ by species. Unfortunately, studies in this area are still limited, with few explaining inter-cultivar insights. Thus, in a global context seriously threatened by X. fastidiosa, a deeper understanding of the relationship between the physical and mechanical characteristics of the xylem and resistance to stresses can be useful for selecting cultivars that may be more resistant to environmental changes, such as drought and vascular pathogens, as a way to preserve agricultural productions and ecosystems.
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Affiliation(s)
- Giambattista Carluccio
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Davide Greco
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Erika Sabella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Marzia Vergine
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Luigi De Bellis
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Andrea Luvisi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
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12
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Illuminating the signalomics of microbial biofilm on plant surfaces. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Sun Q. Structural variation and spatial polysaccharide profiling of intervessel pit membranes in grapevine. ANNALS OF BOTANY 2022; 130:595-609. [PMID: 35869610 PMCID: PMC9510951 DOI: 10.1093/aob/mcac096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Intervessel pit membranes (PMs) are important cell wall structures in the vessel system that may impact a plant's water transport and its susceptibility to vascular diseases. Functional roles of intervessel PMs largely depend on their structure and polysaccharide composition, which are the targets of this study. METHODS With grapevine used as a model plant, this study applied an immunogold-scanning electron microscopy technique to simultaneously analyse at high resolution intervessel PM structures and major pectic and hemicellulosic polysaccharides that make up intervessel PMs. KEY RESULTS Intervessel PMs in functional xylem showed significant structural variation, with about 90 % of them being structurally intact with smooth or relatively smooth surfaces and the remaining 10 % with progressively degraded structures. The results also elucidated details of the removal process of cell wall materials from the intervessel PM surface toward its depth during its natural degradation. Four groups of pectic and hemicellulosic polysaccharides were immunolocalized in intervessel PMs and differed in their spatial distribution and abundance. Weakly methyl-esterified homogalacturonans (WMe-HGs, detected by JIM5) were abundant in the surface layer, heavily methyl-esterified homogalacturonans (HMe-HGs, detected by JIM7) and xylans detected by CCRC-M140 were mostly found in deeper layers, and fucosylated xyloglucans (F-XyGs, detected by CCRC-M1) were more uniformly distributed at different depths of the intervessel PM. CONCLUSIONS Intervessel PMs displayed diverse structural variations in grapevine. They contained certain major groups of pectic and hemicellulosic polysaccharides with different spatial distributions and abundance. This information is crucial to reveal the polysaccharide profiling of the primary cell wall and to understand the roles of intervessel PMs in the regulation of water transport as well as in a plant's susceptibility to vascular diseases.
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14
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Fanton AC, Furze ME, Brodersen CR. Pathogen-induced hydraulic decline limits photosynthesis and starch storage in grapevines (Vitis sp.). PLANT, CELL & ENVIRONMENT 2022; 45:1829-1842. [PMID: 35297057 DOI: 10.1111/pce.14312] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/11/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
Xylella fastidiosa (Xf) is the bacterial pathogen responsible for Pierce's Disease (PD) in grapevine (Vitis vinifera L.) and numerous diseases in agriculturally and ecologically important species. Current theory suggests that localized inoculations via insect feeding lead to bacterial spread through the xylem, reducing water transport capacity, leading to declines in productivity, and ultimately death. Yet, the underlying mechanisms of Xf-induced mortality are not fully understood. In this study, we documented the development of PD symptoms over 12-13 weeks postinoculation. Subsequently assessed photosynthetic capacity, starch storage, and stem hydraulics in four grapevine genotypes (two PD-resistant and two PD-susceptible), comparing those physiological changes to control plants. PD-susceptible genotypes showed a coordinated decline in photosynthesis, starch storage, and stem hydraulics, whereas Xf-inoculation led to no change in starch and stem hydraulics in the PD-resistant genotypes. Together these data support the idea of a link between loss of hydraulic conductivity due to tylosis production with a downstream photosynthetic decline and starch depletion in the PD-susceptible genotypes. Our data support the theory that hydraulic failure and carbon starvation underlie plant mortality resulting from PD.
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Affiliation(s)
- Ana Clara Fanton
- School of the Environment, Yale University, New Haven, Connecticut, USA
| | - Morgan E Furze
- School of the Environment, Yale University, New Haven, Connecticut, USA
- Department of Viticulture and Enology, University of California, Davis, Davis, California, USA
| | - Craig R Brodersen
- School of the Environment, Yale University, New Haven, Connecticut, USA
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15
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Cervantes K, Hilton AE, Stamler RA, Heerema RJ, Bock C, Wang X, Jo YK, Grauke LJ, Randall JJ. Evidence for Seed Transmission of Xylella fastidiosa in Pecan ( Carya illinoinensis). FRONTIERS IN PLANT SCIENCE 2022; 13:780335. [PMID: 35463450 PMCID: PMC9024359 DOI: 10.3389/fpls.2022.780335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Pecan bacterial leaf scorch, caused by Xylella fastidiosa subsp. multiplex, is an economically significant disease of pecan with known detrimental effects on the yield of susceptible cultivars. In this study, endosperm was harvested from developing pecan seeds, and direct qPCR and sequencing were used to detect and confirm the presence of X. fastidiosa. DNA was isolated from mature seeds originating from seven trees, revealing a positivity rate up to 90%, and transmission of X. fastidiosa from infected seed to the germinated seedlings was found to be over 80%. Further epidemiological analyses were performed to determine where X. fastidiosa localizes in mature seed and seedlings. The highest concentrations of X. fastidiosa DNA were found in the hilum and outer integument of the seeds and the petioles, respectively. High-, medium-, and low-density seeds were harvested to determine the impact of the bacterium on seed density and seedling growth rate. The growth rate of seedlings originating from low-density seeds was significantly reduced compared to the medium- and high-density seeds. Despite the increased growth and germination rates, the high-density seed group had a greater proportion of samples that tested positive for the presence of X. fastidiosa by qPCR. The results demonstrate the ability of X. fastidiosa to colonize developing seeds and be efficiently transmitted from well-developed seeds to germinated seedlings. Continued research is needed to understand the plant-microbe interactions involved in the colonization of pecan seeds by X. fastidiosa and to develop effective phytosanitary approaches to reduce the risks posed by seed transmission.
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Affiliation(s)
- Kimberly Cervantes
- Molecular Biology and Interdisciplinary Life Sciences, New Mexico State University, Las Cruces, NM, United States
| | - Angelyn E. Hilton
- United States Department of Agriculture, Southern Plains Agricultural Research Center, Pecan Breeding and Genetics, Somerville, TX, United States
| | - Rio A. Stamler
- Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM, United States
| | - Richard J. Heerema
- Extension Plant Sciences, New Mexico State University, Las Cruces, NM, United States
| | - Clive Bock
- United States Department of Agriculture, Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA, United States
| | - Xinwang Wang
- United States Department of Agriculture, Southern Plains Agricultural Research Center, Pecan Breeding and Genetics, Somerville, TX, United States
| | - Young-Ki Jo
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
| | - L. J. Grauke
- United States Department of Agriculture, Southern Plains Agricultural Research Center, Pecan Breeding and Genetics, Somerville, TX, United States
| | - Jennifer J. Randall
- Molecular Biology and Interdisciplinary Life Sciences, New Mexico State University, Las Cruces, NM, United States
- Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM, United States
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16
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Duan S, Long Y, Cheng S, Li J, Ouyang Z, Wang N. Rapid Evaluation of the Resistance of Citrus Germplasms Against Xanthomonas citri subsp. citri. PHYTOPATHOLOGY 2022; 112:765-774. [PMID: 34495678 DOI: 10.1094/phyto-04-21-0175-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus bacterial canker (CBC), one of the most devastating citrus diseases. Most commercial citrus varieties are susceptible to CBC. However, some citrus varieties and wild citrus germplasms are CBC resistant and are promising in genetic increases in citrus resistance against CBC. We aimed to evaluate citrus germplasms for resistance against CBC. First, we developed a rapid evaluation method based on enhanced yellow fluorescent protein (eYFP)-labeled Xcc. The results demonstrated that eYFP does not affect the growth and virulence of Xcc. Xcc-eYFP allows measurement of bacterial titers but is more efficient and rapid than the plate colony counting method. Next, we evaluated citrus germplasms collected in China. Based on symptoms and bacterial titers, we identified that two citrus germplasms ('Ichang' papeda and 'Huapi' kumquat) are resistant, whereas eight citrus germplasms ('Chongyi' wild mandarin, 'Mangshan' wild mandarin, 'Ledong' kumquat, 'Dali' citron, 'Yiliang' citron, 'Longyan' kumquat, 'Bawang' kumquat, and 'Daoxian' wild mandarin) are tolerant. In summary, we have developed a rapid evaluation method to test the resistance of citrus plants against CBC. This method was successfully used to identify two highly canker-resistant citrus germplasms and eight citrus germplasms with canker tolerance. These results could be leveraged in traditional breeding contexts or be used to identify canker resistance genes to increase the disease resistance of commercial citrus varieties via biotechnological approaches.
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Affiliation(s)
- Shuo Duan
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Yunfei Long
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Shuyuan Cheng
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Zhigang Ouyang
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850, U.S.A
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17
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Falsini S, Tani C, Sambuco G, Papini A, Faraoni P, Campigli S, Ghelardini L, Bleve G, Rizzo D, Ricciolini M, Scarpelli I, Drosera L, Gnerucci A, Hand FP, Marchi G, Schiff S. Anatomical and biochemical studies of Spartium junceum infected by Xylella fastidiosa subsp. multiplex ST 87. PROTOPLASMA 2022; 259:103-115. [PMID: 33860374 PMCID: PMC8752565 DOI: 10.1007/s00709-021-01640-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Spartium junceum L. is a typical species of Mediterranean shrubland areas, also grown in gardens and parks as an ornamental. In recent years in Europe, S. junceum has been recurrently found to be infected by different subspecies and genotypes of the quarantine regulated bacterium Xylella fastidiosa (Xf). This work presents for the first time the anatomy of S. junceum plants that we found, by means of genetic and immunochemistry analysis, to be naturally infected by Xf subsp. multiplex ST87 (XfmST87) in Monte Argentario (Grosseto, Tuscany, Italy), a new outbreak area within the EU. Our anatomical observations showed that bacteria colonized exclusively the xylem conductive elements and moved horizontally to adjacent vessels through pits. Interestingly, a pink/violet matrix was observed with Toluidine blue staining in infected conduits indicating a high content of acidic polysaccharides. In particular, when this pink-staining matrix was observed, bacterial cells were either absent or degenerated, suggesting that the matrix was produced by the host plant as a defense response against bacterial spread. In addition, a blue-staining phenolic material was found in the vessels and, at high concentration, in the pits and inter-vessels. SEM micrographs confirmed that polysaccharide and phenolic components showed different structures, which appear to be related to two different morphologies: fibrillary and granular, respectively. Moreover, our LM observations revealed bacterial infection in xylem conductive elements of green shoots and leaves only, and not in those of other plant organs such as roots and flowers.
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Affiliation(s)
- S Falsini
- Dipartimento di Biologia, Università degli studi di Firenze, via P.A. Micheli 3, 50121, Firenze, Italy.
| | - C Tani
- Dipartimento di Biologia, Università degli studi di Firenze, via P.A. Micheli 3, 50121, Firenze, Italy
| | - G Sambuco
- Dipartimento di Biologia, Università degli studi di Firenze, via P.A. Micheli 3, 50121, Firenze, Italy
| | - A Papini
- Dipartimento di Biologia, Università degli studi di Firenze, via P.A. Micheli 3, 50121, Firenze, Italy
| | - P Faraoni
- Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Università degli Studi di Firenze, viale G. Pieraccini 6, 50139, Firenze, Italy
| | - S Campigli
- Dipartimento di Scienze delle Produzioni Agroalimentari e dell'Ambiente, Università degli Studi di Firenze, Piazzale delle Cascine 28, 50100, Firenze, Italy
| | - L Ghelardini
- Dipartimento di Scienze delle Produzioni Agroalimentari e dell'Ambiente, Università degli Studi di Firenze, Piazzale delle Cascine 28, 50100, Firenze, Italy
| | - G Bleve
- Istituto di Scienze delle Produzioni Alimentari, Consiglio Nazionale delle Ricerche, Lecce, Italy
| | - D Rizzo
- Regione Toscana, Servizio Fitosanitario Regionale e di Vigilanza e Controllo Agroforestale, Via A. Manzoni 16, 50121, Firenze, Italy
| | - M Ricciolini
- Regione Toscana, Servizio Fitosanitario Regionale e di Vigilanza e Controllo Agroforestale, Via A. Manzoni 16, 50121, Firenze, Italy
| | - I Scarpelli
- Regione Toscana, Servizio Fitosanitario Regionale e di Vigilanza e Controllo Agroforestale, Via A. Manzoni 16, 50121, Firenze, Italy
| | - L Drosera
- Regione Toscana, Servizio Fitosanitario Regionale e di Vigilanza e Controllo Agroforestale, Via A. Manzoni 16, 50121, Firenze, Italy
| | - A Gnerucci
- Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Università degli Studi di Firenze, viale G. Pieraccini 6, 50139, Firenze, Italy
- Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, 50019, Sesto Fiorentino, (FI), Italy
| | - F Peduto Hand
- Department of Plant Pathology, Ohio State University, Columbus, OH, 43220, USA
| | - G Marchi
- Dipartimento di Scienze delle Produzioni Agroalimentari e dell'Ambiente, Università degli Studi di Firenze, Piazzale delle Cascine 28, 50100, Firenze, Italy
| | - S Schiff
- Dipartimento di Biologia, Università degli studi di Firenze, via P.A. Micheli 3, 50121, Firenze, Italy.
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18
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Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression. Microbiol Spectr 2021; 9:e0159121. [PMID: 34787465 PMCID: PMC8597638 DOI: 10.1128/spectrum.01591-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial cold shock-domain proteins are conserved nucleic acid binding chaperones that play important roles in stress adaptation and pathogenesis. Csp1 is a temperature-independent cold shock protein homolog in Xylella fastidiosa, a bacterial plant pathogen of grapevine and other economically important crops. Csp1 contributes to stress tolerance and virulence in X. fastidiosa. However, besides general single-stranded nucleic acid binding activity, little is known about the specific function(s) of Csp1. To further investigate the role(s) of Csp1, we compared phenotypic differences and transcriptome profiles between the wild type and a csp1 deletion mutant (Δcsp1). Csp1 contributes to attachment and long-term survival and influences gene expression. We observed reduced cell-to-cell attachment and reduced attachment to surfaces with the Δcsp1 strain compared to those with the wild type. Transmission electron microscopy imaging revealed that Δcsp1 was deficient in pili formation compared to the wild type and complemented strains. The Δcsp1 strain also showed reduced survival after long-term growth in vitro. Long-read nanopore transcriptome sequencing (RNA-Seq) analysis revealed changes in expression of several genes important for attachment and biofilm formation in Δcsp1 compared to that in the wild type. One gene of interest, pilA1, which encodes a type IV pili subunit protein, was upregulated in Δcsp1. Deleting pilA1 in X. fastidiosa strain Stag's Leap increased surface attachment in vitro and reduced virulence in grapevines. X. fastidiosa virulence depends on bacterial attachment to host tissue and movement within and between xylem vessels. Our results show that the impact of Csp1 on virulence may be due to changes in expression of attachment genes. IMPORTANCE Xylella fastidiosa is a major threat to the worldwide agriculture industry. Despite its global importance, many aspects of X. fastidiosa biology and pathogenicity are poorly understood. There are currently few effective solutions to suppress X. fastidiosa disease development or eliminate bacteria from infected plants. Recently, disease epidemics due to X. fastidiosa have greatly expanded, increasing the need for better disease prevention and control strategies. Our studies show a novel connection between cold shock protein Csp1 and pili abundance and attachment, which have not been reported for X. fastidiosa. Understanding how pathogenesis-related gene expression is regulated can aid in developing novel pathogen and disease control strategies. We also streamlined a bioinformatics protocol to process and analyze long-read nanopore bacterial RNA-Seq data, which will benefit the research community, particularly those working with non-model bacterial species.
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19
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Picciotti U, Lahbib N, Sefa V, Porcelli F, Garganese F. Aphrophoridae Role in Xylella fastidiosa subsp. pauca ST53 Invasion in Southern Italy. Pathogens 2021; 10:1035. [PMID: 34451499 PMCID: PMC8399165 DOI: 10.3390/pathogens10081035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 12/03/2022] Open
Abstract
The Philaenus spumarius L. (Hemiptera Aphrophoridae) is a xylem-sap feeder vector that acquires Xylella fastidiosa subsp. pauca ST53 during feeding on infected plants. The bacterium is the plant pathogen responsible for olive quick decline syndrome that has decimated olive trees in Southern Italy. Damage originates mainly from the insect vector attitude that multiplies the pathogen potentialities propagating Xf in time and space. The principal action to manage insect-borne pathogens and to contain the disease spread consists in vector and transmission control. The analysis of an innovative and sustainable integrated pest management quantitative strategy that targets the vector and the infection by combining chemical and physical control means demonstrates that it is possible to stop the Xylella invasion. This review updates the available topics addressing vectors' identification, bionomics, infection management, and induced disease by Xylella invasion to discuss major available tools to mitigate the damage consequent to the disease.
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Affiliation(s)
- Ugo Picciotti
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari Aldo Moro, 70126 Bari, Italy; (U.P.); (N.L.); (V.S.); (F.G.)
- Department of Marine Science and Applied Biology, Laboratory of Plant Pathology, University of Alicante, 03080 Alicante, Spain
| | - Nada Lahbib
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari Aldo Moro, 70126 Bari, Italy; (U.P.); (N.L.); (V.S.); (F.G.)
- Faculty of Sciences of Tunis, University of Tunis El-Manar, Tunis 1068, Tunisia
- INRAT—National Institute of Agronomic Research of Tunisia, Laboratory of Plant Protection, Rue Hédi Karray, Ariana 2049, Tunisia
| | - Valdete Sefa
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari Aldo Moro, 70126 Bari, Italy; (U.P.); (N.L.); (V.S.); (F.G.)
| | - Francesco Porcelli
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari Aldo Moro, 70126 Bari, Italy; (U.P.); (N.L.); (V.S.); (F.G.)
- CIHEAM—Centre International de Hautes Etudes Agronomiques Méditerranéennes, Mediterranean Agronomic Institute of Bari, 70010 Valenzano, BA, Italy
| | - Francesca Garganese
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari Aldo Moro, 70126 Bari, Italy; (U.P.); (N.L.); (V.S.); (F.G.)
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20
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Fanton AC, Brodersen C. Hydraulic consequences of enzymatic breakdown of grapevine pit membranes. PLANT PHYSIOLOGY 2021; 186:1919-1931. [PMID: 33905519 PMCID: PMC8331172 DOI: 10.1093/plphys/kiab191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
Xylella fastidiosa (Xf) is the xylem-dwelling bacterial agent associated with Pierce's disease (PD), which leads to significant declines in productivity in agriculturally important species like grapevine (Vitis vinifera). Xf spreads through the xylem network by digesting the pit membranes (PMs) between adjacent vessels, thereby potentially changing the hydraulic properties of the stem. However, the effects of Xf on water transport vary depending on the plant host and the infection stage, presenting diverse outcomes. Here, we investigated the effects of polygalacturonase, an enzyme known to be secreted by Xf when it produces biofilm on the PM surface, on stem hydraulic conductivity, and PM integrity. Experiments were performed on six grapevine genotypes with varying levels of PD resistance, with the expectation that PM resistance to degradation by polygalacturonase may play a role in PD resistance. Our objective was to study a single component of this pathosystem in isolation to better understand the mechanisms behind reported changes in hydraulics, thereby excluding the biological response of the plant to the presence of Xf in the vascular system. PM damage only occurred in stems perfused with polygalacturonase. Although the damaged PM area was small (2%-9% of the total pit aperture area), membrane digestion led to significant changes in the median air-seeding thresholds, and most importantly, shifted frequency distribution. Finally, enzyme perfusion also resulted in a universal reduction in stem hydraulic conductivity, suggesting the development of tyloses may not be the only contributing factor to reduced hydraulic conductivity in infected grapevine.
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Affiliation(s)
- Ana Clara Fanton
- School of the Environment, Yale University, New Haven, Connecticut 06511, USA
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, Connecticut 06511, USA
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21
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Petit G, Bleve G, Gallo A, Mita G, Montanaro G, Nuzzo V, Zambonini D, Pitacco A. Susceptibility to Xylella fastidiosa and functional xylem anatomy in Olea europaea: revisiting a tale of plant-pathogen interaction. AOB PLANTS 2021; 13:plab027. [PMID: 34316336 PMCID: PMC8300559 DOI: 10.1093/aobpla/plab027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/19/2021] [Indexed: 05/09/2023]
Abstract
Xylella fastidiosa is a xylem-limited bacterium causing the Olive Quick Decline Syndrome, which is currently devastating the agricultural landscape of Southern Italy. The bacterium is injected into the xylem vessels of leaf petioles after the penetration of the insect vector's stylet. From here, it is supposed to colonize the xylem vasculature moving against water flow inside conductive vessels. Widespread vessel clogging following the bacterial infection and causing the failure of water transport seemed not to fully supported by the recent empirical xylem anatomical observations in infected olive trees. We tested the hypothesis that the higher susceptibility to the X. fastidiosa's infection in Cellina di Nardò compared with Leccino is associated to the higher vulnerability to air embolism of its larger vessels. Such hypothesis is motivated by the recognized ability of X. fastidiosa in degrading pit membranes and also because air embolism would possibly provide microenvironmental conditions more favourable to its more efficient aerobic metabolism. We revised the relevant literature on bacterium growth and xylem physiology, and carried out empirical field, mid-summer measurements of xylem anatomy and native embolism in olive cultivars with high (Cellina di Nardò) and low susceptibility (Leccino) to the infection by X. fastidiosa. Both cultivars had similar shoot mass traits and vessel length (~80 cm), but the highly susceptible one had larger vessels and a lower number of vessels supplying a given leaf mass. Native air embolism reduced mean xylem hydraulic conductance by ~58 % (Cellina di Nardò) and ~38 % (Leccino). The higher air-embolism vulnerability of the larger vessels in Cellina di Nardò possibly facilitates the X. fastidiosa's infection compared to Leccino. Some important characteristics of the vector-pathogen-plant interactions still require deep investigations acknowledging both the pathogen metabolic pathways and the biophysical principles of xylem hydraulics.
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Affiliation(s)
- Giai Petit
- Department of Land, Environment, Agriculture and Forestry (LEAF/TESAF), University of Padua, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Gianluca Bleve
- Institute of Sciences of Food Production, National research Council (ISPA-CNR), via Provinciale Lecce-Monteroni 73100 Lecce, Italy
| | - Antonia Gallo
- Institute of Sciences of Food Production, National research Council (ISPA-CNR), via Provinciale Lecce-Monteroni 73100 Lecce, Italy
| | - Giovanni Mita
- Institute of Sciences of Food Production, National research Council (ISPA-CNR), via Provinciale Lecce-Monteroni 73100 Lecce, Italy
| | - Giuseppe Montanaro
- Department of European and Mediterranean Culture (DiCEM), University of Basilicata, Via Lanera, 20, 75100 Matera, Italy
| | - Vitale Nuzzo
- Department of European and Mediterranean Culture (DiCEM), University of Basilicata, Via Lanera, 20, 75100 Matera, Italy
| | - Dario Zambonini
- Department of Land, Environment, Agriculture and Forestry (LEAF/TESAF), University of Padua, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Andrea Pitacco
- Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padua, Viale dell’Università 16, 35020 Legnaro (PD), Italy
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22
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Mullens A, Jamann TM. Colonization and Movement of Green Fluorescent Protein-Labeled Clavibacter nebraskensis in Maize. PLANT DISEASE 2021; 105:1422-1431. [PMID: 33190611 DOI: 10.1094/pdis-08-20-1823-re] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Clavibacter nebraskensis causes Goss's bacterial wilt and leaf blight, a major disease of maize. Infected crop residue is the primary inoculum source and infection can occur via wounds or natural openings, such as stomata or hydathodes. The use of resistant hybrids is the primary control method for Goss's wilt. In this study, colonization and movement patterns of C. nebraskensis during infection were examined using green fluorescent protein (GFP)-labeled bacterial strains. We successfully introduced a plasmid to C. nebraskensis via electroporation, which resulted in GFP accumulation. Fluorescence microscopy revealed that in the absence of wounding, bacteria colonize leaf tissue via entry through the hydathodes when guttation droplets are present. Stomatal penetration was not observed under natural conditions. Bacteria initially colonize the xylem and subsequently the mesophyll, which creates the freckles that are characteristic of the disease. Bacteria infiltrated into the mesophyll did not cause disease symptoms, could not enter the vasculature, and did not spread from the initial inoculation point. Bacteria were observed exuding through stomata onto the leaf surface, resulting in the characteristic sheen of diseased leaves. Resistant maize lines exhibited decreased bacterial spread in the vasculature and the mesophyll. These tools to examine C. nebraskensis movement offer opportunities and new insights into the pathogenesis process and can form the basis for improved Goss's wilt management through host resistance.
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Affiliation(s)
- Alexander Mullens
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801
| | - Tiffany M Jamann
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801
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23
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Santos RB, Figueiredo A. Two sides of the same story in grapevine-pathogen interactions. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3367-3380. [PMID: 33631010 DOI: 10.1093/jxb/erab091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Proteases are an integral part of plant defence systems, and their role in plant-pathogen interactions is unequivocal. Emerging evidence suggests that different protease families contribute to the establishment not only of hypersensitive response, priming, and signalling, but also of recognition events through complex proteolytic cascades. Moreover, they play a crucial role in pathogen/microbe-associated molecular pattern (PAMP/MAMP)-triggered immunity as well as in effector-triggered immunity. However, despite important advances in our understanding of the role of proteases in plant defence, the contribution of proteases to pathogen defence in grapevine remains poorly understood. In this review, we summarize current knowledge of the main grapevine pathosystems and explore the role of serine, cysteine, and aspartic proteases from both the host and pathogen point of views.
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Affiliation(s)
- Rita B Santos
- Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
| | - Andreia Figueiredo
- Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
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24
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Riefolo C, Antelmi I, Castrignanò A, Ruggieri S, Galeone C, Belmonte A, Muolo MR, Ranieri NA, Labarile R, Gadaleta G, Nigro F. Assessment of the Hyperspectral Data Analysis as a Tool to Diagnose Xylella fastidiosa in the Asymptomatic Leaves of Olive Plants. PLANTS 2021; 10:plants10040683. [PMID: 33916301 PMCID: PMC8065538 DOI: 10.3390/plants10040683] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 11/16/2022]
Abstract
Xylella fastidiosa is a bacterial pathogen affecting many plant species worldwide. Recently, the subspecies pauca (Xfp) has been reported as the causal agent of a devastating disease on olive trees in the Salento area (Apulia region, southeastern Italy), where centenarian and millenarian plants constitute a great agronomic, economic, and landscape trait, as well as an important cultural heritage. It is, therefore, important to develop diagnostic tools able to detect the disease early, even when infected plants are still asymptomatic, to reduce the infection risk for the surrounding plants. The reference analysis is the quantitative real time-Polymerase-Chain-Reaction (qPCR) of the bacterial DNA. The aim of this work was to assess whether the analysis of hyperspectral data, using different statistical methods, was able to select with sufficient accuracy, which plants to analyze with PCR, to save time and economic resources. The study area was selected in the Municipality of Oria (Brindisi). Partial Least Square Regression (PLSR) and Canonical Discriminant Analysis (CDA) indicated that the most important bands were those related to the chlorophyll function, water, lignin content, as can also be seen from the wilting symptoms in Xfp-infected plants. The confusion matrix of CDA showed an overall accuracy of 0.67, but with a better capability to discriminate the infected plants. Finally, an unsupervised classification, using only spectral data, was able to discriminate the infected plants at a very early stage of infection. Then, in phase of testing qPCR should be performed only on the plants predicted as infected from hyperspectral data, thus, saving time and financial resources.
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Affiliation(s)
- Carmela Riefolo
- Research Centre for Agriculture and Environment, Council for Agricultural Research and Economics (CREA-AA), 70125 Bari, Italy;
- Correspondence: (C.R.); (F.N.)
| | - Ilaria Antelmi
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi Aldo Moro, Via Amendola 165/A, 70126 Bari, Italy; (I.A.); (R.L.)
| | - Annamaria Castrignanò
- Department of Engineering and Geology (InGeo), Università degli Studi Gabriele D’Annunzio, Chieti-Pescara, 66013 Chieti, Italy;
| | - Sergio Ruggieri
- Research Centre for Agriculture and Environment, Council for Agricultural Research and Economics (CREA-AA), 70125 Bari, Italy;
| | - Ciro Galeone
- Water Research Institute, National Research Council (CNR-IRSA), 70125 Bari, Italy;
| | - Antonella Belmonte
- Institute for Electromagnetic Sensing of the Environment, National Research Council (CNR-IREA), 70126 Bari, Italy;
| | - Maria Rita Muolo
- Servizi di Informazione Territoriale S.r.l., 70015 Noci, Italy; (M.R.M.); (N.A.R.)
| | - Nicola A. Ranieri
- Servizi di Informazione Territoriale S.r.l., 70015 Noci, Italy; (M.R.M.); (N.A.R.)
| | - Rossella Labarile
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi Aldo Moro, Via Amendola 165/A, 70126 Bari, Italy; (I.A.); (R.L.)
| | | | - Franco Nigro
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi Aldo Moro, Via Amendola 165/A, 70126 Bari, Italy; (I.A.); (R.L.)
- Correspondence: (C.R.); (F.N.)
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25
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Monteiro MP, Hernandez-Montelongo J, Sahoo PK, Hernández Montelongo R, de Oliveira DS, Piazzeta MHO, García Sandoval JP, de Souza AA, Gobbi AL, Cotta MA. Functionalized microchannels as xylem-mimicking environment: Quantifying X. fastidiosa cell adhesion. Biophys J 2021; 120:1443-1453. [PMID: 33607085 DOI: 10.1016/j.bpj.2021.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 01/27/2021] [Accepted: 02/08/2021] [Indexed: 11/28/2022] Open
Abstract
Microchannels can be used to simulate xylem vessels and investigate phytopathogen colonization under controlled conditions. In this work, we explore surface functionalization strategies for polydimethylsiloxane and glass microchannels to study microenvironment colonization by Xylella fastidiosa subsp. pauca cells. We closely monitored cell initial adhesion, growth, and motility inside microfluidic channels as a function of chemical environments that mimic those found in xylem vessels. Carboxymethylcellulose (CMC), a synthetic cellulose, and an adhesin that is overexpressed during early stages of X. fastidiosa biofilm formation, XadA1 protein, were immobilized on the device's internal surfaces. This latter protocol increased bacterial density as compared with CMC. We quantitatively evaluated the different X. fastidiosa attachment affinities to each type of microchannel surface using a mathematical model and experimental observations acquired under constant flow of culture medium. We thus estimate that bacterial cells present ∼4 and 82% better adhesion rates in CMC- and XadA1-functionalized channels, respectively. Furthermore, variable flow experiments show that bacterial adhesion forces against shear stresses approximately doubled in value for the XadA1-functionalized microchannel as compared with the polydimethylsiloxane and glass pristine channels. These results show the viability of functionalized microchannels to mimic xylem vessels and corroborate the important role of chemical environments, and particularly XadA1 adhesin, for early stages of X. fastidiosa biofilm formation, as well as adhesivity modulation along the pathogen life cycle.
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Affiliation(s)
- Moniellen P Monteiro
- Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Jacobo Hernandez-Montelongo
- Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Prasana K Sahoo
- Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil
| | - Rosaura Hernández Montelongo
- Departamento de Electrónica, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Guadalajara, Jalisco, México
| | - Douglas S de Oliveira
- Campus Avançado de Jandaia do Sul, Universidade Federal do Paraná, Jandaia do Sul, Paraná, Brasil
| | - Maria H O Piazzeta
- Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais/CNPEM, Campinas, São Paulo, Brasil
| | - Juan P García Sandoval
- Departamento de Ingeniería Química, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Guadalajara, Jalisco, México
| | - Alessandra A de Souza
- Instituto Agronômico de Campinas, Centro de Citricultura Sylvio Moreira, Cordeirópolis, São Paulo, Brasil
| | - Angelo L Gobbi
- Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais/CNPEM, Campinas, São Paulo, Brasil
| | - Mônica A Cotta
- Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
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26
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Riaz S, Tenscher AC, Heinitz CC, Huerta-Acosta KG, Walker MA. Genetic analysis reveals an east-west divide within North American Vitis species that mirrors their resistance to Pierce's disease. PLoS One 2020; 15:e0243445. [PMID: 33338052 PMCID: PMC7748146 DOI: 10.1371/journal.pone.0243445] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/22/2020] [Indexed: 11/26/2022] Open
Abstract
Pierce’s disease (PD) caused by the bacterium Xylella fastidiosa is a deadly disease of grapevines. This study used 20 SSR markers to genotype 326 accessions of grape species collected from the southeastern and southwestern United States, Mexico and Costa Rica. Two hundred sixty-six of these accessions, and an additional 12 PD resistant hybrid cultivars developed from southeastern US grape species, were evaluated for PD resistance. Disease resistance was evaluated by quantifying the level of bacteria in stems and measuring PD symptoms on the canes and leaves. Both Bayesian clustering and principal coordinate analyses identified two groups with an east-west divide: group 1 consisted of grape species from the southeastern US and Mexico, and group 2 consisted of accessions collected from the southwestern US and Mexico. The Sierra Madre Oriental mountain range appeared to be a phylogeographic barrier. The state of Texas was identified as a potential hybridization zone. The hierarchal STRUCTURE analysis on each group showed clustering of unique grape species. An east-west divide was also observed for PD resistance. With the exception of Vitis candicans and V. cinerea accessions collected from Mexico, all other grape species as well as the resistant southeastern hybrid cultivars were susceptible to the disease. Southwestern US grape accessions from drier desert regions showed stronger resistance to the disease. Strong PD resistance was observed within three distinct genetic clusters of V. arizonica which is adapted to drier environments and hybridizes freely with other species across its wide range.
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Affiliation(s)
- Summaira Riaz
- Department of Viticulture and Enology, University of California, Davis, California, United States of America
| | - Alan C. Tenscher
- Department of Viticulture and Enology, University of California, Davis, California, United States of America
| | - Claire C. Heinitz
- Department of Viticulture and Enology, University of California, Davis, California, United States of America
| | - Karla G. Huerta-Acosta
- Department of Viticulture and Enology, University of California, Davis, California, United States of America
| | - M. Andrew Walker
- Department of Viticulture and Enology, University of California, Davis, California, United States of America
- * E-mail:
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27
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Phenotypic Characterization and Transformation Attempts Reveal Peculiar Traits of Xylella fastidiosa Subspecies pauca Strain De Donno. Microorganisms 2020; 8:microorganisms8111832. [PMID: 33233703 PMCID: PMC7699976 DOI: 10.3390/microorganisms8111832] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/19/2022] Open
Abstract
Xylella fastidiosa subsp. pauca strain De Donno has been recently identified as the causal agent of a severe disease affecting olive trees in a wide area of the Apulia Region (Italy). While insights on the genetics and epidemiology of this virulent strain have been gained, its phenotypic and biological traits remained to be explored. We investigated in vitro behavior of the strain and compare its relevant biological features (growth rate, biofilm formation, cell-cell aggregation, and twitching motility) with those of the type strain Temecula1. The experiments clearly showed that the strain De Donno did not show fringe on the agar plates, produced larger amounts of biofilm and had a more aggregative behavior than the strain Temecula1. Repeated attempts to transform, by natural competence, the strain De Donno failed to produce a GFP-expressing and a knockout mutant for the rpfF gene. Computational prediction allowed us to identify potentially deleterious sequence variations most likely affecting the natural competence and the lack of fringe formation. GFP and rpfF- mutants were successfully obtained by co-electroporation in the presence of an inhibitor of the type I restriction-modification system. The availability of De Donno mutant strains will open for new explorations of its interactions with hosts and insect vectors.
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28
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Sisterson MS, Burbank LP, Krugner R, Haviland D, Stenger DC. Xylella fastidiosa and Glassy-Winged Sharpshooter Population Dynamics in the Southern San Joaquin Valley of California. PLANT DISEASE 2020; 104:2994-3001. [PMID: 32852243 DOI: 10.1094/pdis-01-20-0066-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Xylella fastidiosa is a vector-transmitted bacterial plant pathogen that affects a wide array of perennial crops, including grapevines (Pierce's disease). In the southern San Joaquin Valley of California, epidemics of Pierce's disease of grapevine were associated with the glassy-winged sharpshooter, Homalodisca vitripennis. During the growing season, rates of X. fastidiosa spread in vineyards are affected by changes in pathogen distribution within chronically infected grapevines and by vector population dynamics. Grapevines chronically infected with X. fastidiosa rarely tested positive for the pathogen prior to July, suggesting vector acquisition of X. fastidiosa from grapevines increases as the season progresses. This hypothesis was supported by an increase in number of X. fastidiosa-positive glassy-winged sharpshooters collected from vineyards during July through September. Analysis of insecticide records indicated that vineyards in the study area were typically treated with a systemic neonicotinoid in spring of each year. As a result, abundance of glassy-winged sharpshooters was typically low in late spring and early summer, with abundance of glassy-winged sharpshooter adults increasing in late June and early July of each year. Collectively, the results suggest that late summer is a crucial time for X. fastidiosa secondary spread in vineyards in the southern San Joaquin Valley, because glassy-winged sharpshooter abundance, number of glassy-winged sharpshooters testing positive for X. fastidiosa, and grapevines with detectable pathogen populations were all greatest during this period.
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Affiliation(s)
- Mark S Sisterson
- USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648-9757
| | - Lindsey P Burbank
- USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648-9757
| | - Rodrigo Krugner
- USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648-9757
| | - David Haviland
- University of California Cooperative Extension, Bakersfield, CA 93307
| | - Drake C Stenger
- USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648-9757
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29
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Sabella E, Moretti S, Gärtner H, Luvisi A, De Bellis L, Vergine M, Saurer M, Cherubini P. Increase in ring width, vessel number and δ18O in olive trees infected with Xylella fastidiosa. TREE PHYSIOLOGY 2020; 40:1583-1594. [PMID: 32705131 DOI: 10.1093/treephys/tpaa095] [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] [Received: 03/30/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
Xylella fastidiosa (Xf) Wells, Raju et al., 1986 is a bacterium that causes plant diseases in the Americas. In Europe, it was first detected on the Salento Peninsula (Italy), where it was found to be associated with the olive quick decline syndrome. Here, we present the results of the first tree-ring study of infected and uninfected olive trees (Olea europaea L.) of two different cultivars, one resistant and one susceptible, to establish the effects induced by the spread of the pathogen inside the tree. Changes in wood anatomical characteristics, such as an increase in the number of vessels and in ring width, were observed in the infected plants of both the cultivars Cellina di Nardò (susceptible to Xf infection) and Leccino (resistant to Xf infection). Thus, whether infection affects the mortality of the tree or not, the tree shows a reaction to it. The presence of occlusions was detected in the wood of both 4-year-old branches and the tree stem core. As expected, the percentage of occluded vessels in the Xf-susceptible cultivar Cellina di Nardò was significantly higher than in the Xf-resistant cultivar Leccino. The δ 18O of the 4-year-old branches was significantly higher in infected trees of both cultivars than in noninfected trees, while no variations in δ 13C were observed. This suggests a reduction in leaf transpiration rates during infection and seems to be related to the occlusions observed in rings of the 4-year-old branches. Such occlusions can determine effects at leaf level that could influence stomatal activity. On the other hand, the significant increase in the number of vessels in infected trees could be related to the tree's attempt to enhance water conductivity in response to the pathogen-induced vessel occlusions.
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Affiliation(s)
- Erika Sabella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, Lecce, 73100, Italy
| | - Samuele Moretti
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
- Laboratoire Vigne, Biotechnologies et Environnement (LVBE, EA 3991), Université de Haute-Alsace, 33 rue de Herrlisheim, 68008 Colmar Cedex, France
| | - Holger Gärtner
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Andrea Luvisi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, Lecce, 73100, Italy
| | - Luigi De Bellis
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, Lecce, 73100, Italy
| | - Marzia Vergine
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, Lecce, 73100, Italy
| | - Matthias Saurer
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Paolo Cherubini
- WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
- Department of Forest and Conservation Sciences, University of British Columbia, 3041 - 2424 Main Mall, Vancouver, BC, Canada
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30
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Huang W, Reyes-Caldas P, Mann M, Seifbarghi S, Kahn A, Almeida RPP, Béven L, Heck M, Hogenhout SA, Coaker G. Bacterial Vector-Borne Plant Diseases: Unanswered Questions and Future Directions. MOLECULAR PLANT 2020; 13:1379-1393. [PMID: 32835885 PMCID: PMC7769051 DOI: 10.1016/j.molp.2020.08.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 06/01/2023]
Abstract
Vector-borne plant diseases have significant ecological and economic impacts, affecting farm profitability and forest composition throughout the world. Bacterial vector-borne pathogens have evolved sophisticated strategies to interact with their hemipteran insect vectors and plant hosts. These pathogens reside in plant vascular tissue, and their study represents an excellent opportunity to uncover novel biological mechanisms regulating intracellular pathogenesis and to contribute to the control of some of the world's most invasive emerging diseases. In this perspective, we highlight recent advances and major unanswered questions in the realm of bacterial vector-borne disease, focusing on liberibacters, phytoplasmas, spiroplasmas, and Xylella fastidiosa.
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Affiliation(s)
- Weijie Huang
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Paola Reyes-Caldas
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA
| | - Marina Mann
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Shirin Seifbarghi
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA
| | - Alexandra Kahn
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Rodrigo P P Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Laure Béven
- UMR 1332 Biologie du Fruit et Pathologie, Univ. Bordeaux, INRAE, Villenave d'Ornon 33882 France
| | - Michelle Heck
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; Boyce Thompson Institute, Ithaca, NY 14853, USA; Emerging Pests and Pathogens Research Unit, Robert W. Holley Center, USDA ARS, Ithaca, NY 14853, USA
| | - Saskia A Hogenhout
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK; School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA.
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31
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Grapevine phenolic compounds influence cell surface adhesion of Xylella fastidiosa and bind to lipopolysaccharide. PLoS One 2020; 15:e0240101. [PMID: 33007036 PMCID: PMC7531785 DOI: 10.1371/journal.pone.0240101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 09/19/2020] [Indexed: 12/14/2022] Open
Abstract
Bacterial phytopathogen Xylella fastidiosa specifically colonizes the plant vascular tissue through a complex process of cell adhesion, biofilm formation, and dispersive movement. Adaptation to the chemical environment of the xylem is essential for bacterial growth and progression of infection. Grapevine xylem sap contains a range of plant secondary metabolites such as phenolics, which fluctuate in response to pathogen infection and plant physiological state. Phenolic compounds are often involved in host-pathogen interactions and influence infection dynamics through signaling activity, antimicrobial properties, and alteration of bacterial phenotypes. The effect of biologically relevant concentrations of phenolic compounds coumaric acid, gallic acid, epicatechin, and resveratrol on growth of X. fastidiosa was assessed in vitro. None of these compounds inhibited bacterial growth, but epicatechin and gallic acid reduced cell-surface adhesion. Cell-cell aggregation decreased with resveratrol treatment, but the other phenolic compounds tested had minimal effect on aggregation. Expression of attachment (xadA) and aggregation (fimA) related genes were altered by presence of the phenolic compounds, consistent with observed phenotypes. All four of the phenolic compounds bound to purified X. fastidiosa lipopolysaccharide (LPS), a major cell-surface component. Information regarding the impact of chemical environment on pathogen colonization in plants is important for understanding the infection process and factors associated with host susceptibility.
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32
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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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Andrade MO, Pang Z, Achor DS, Wang H, Yao T, Singer BH, Wang N. The flagella of 'Candidatus Liberibacter asiaticus' and its movement in planta. MOLECULAR PLANT PATHOLOGY 2020; 21:109-123. [PMID: 31721403 PMCID: PMC6913195 DOI: 10.1111/mpp.12884] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Citrus huanglongbing (HLB) is the most devastating citrus disease worldwide. 'Candidatus Liberibacter asiaticus' (Las) is the most prevalent HLB causal agent that is yet to be cultured. Here, we analysed the flagellar genes of Las and Rhizobiaceae and observed two characteristics unique to the flagellar proteins of Las: (i) a shorter primary structure of the rod capping protein FlgJ than other Rhizobiaceae bacteria and (ii) Las contains only one flagellin-encoding gene flaA (CLIBASIA_02090), whereas other Rhizobiaceae species carry at least three flagellin-encoding genes. Only flgJAtu but not flgJLas restored the swimming motility of Agrobacterium tumefaciens flgJ mutant. Pull-down assays demonstrated that FlgJLas interacts with FlgB but not with FliE. Ectopic expression of flaALas in A. tumefaciens mutants restored the swimming motility of ∆flaA mutant and ∆flaAD mutant, but not that of the null mutant ∆flaABCD. No flagellum was observed for Las in citrus and dodder. The expression of flagellar genes was higher in psyllids than in planta. In addition, western blotting using flagellin-specific antibody indicates that Las expresses flagellin protein in psyllids, but not in planta. The flagellar features of Las in planta suggest that Las movement in the phloem is not mediated by flagella. We also characterized the movement of Las after psyllid transmission into young flush. Our data support a model that Las remains inside young flush after psyllid transmission and before the flush matures. The delayed movement of Las out of young flush after psyllid transmission provides opportunities for targeted treatment of young flush for HLB control.
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Affiliation(s)
- Maxuel O. Andrade
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Zhiqian Pang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Diann S. Achor
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Han Wang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
| | - Tingshan Yao
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
- National Engineering Research Center for Citrus, Citrus Research Institute, Southwest UniversityChongqing400712People’s Republic of China
| | - Burton H. Singer
- Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
| | - Nian Wang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of Florida/Institute of Food and Agricultural SciencesLake AlfredFLUSA
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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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Sicard A, Merfa MV, Voeltz M, Zeilinger AR, De La Fuente L, Almeida RPP. Discriminating between viable and membrane-damaged cells of the plant pathogen Xylella fastidiosa. PLoS One 2019; 14:e0221119. [PMID: 31442247 PMCID: PMC6707623 DOI: 10.1371/journal.pone.0221119] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/30/2019] [Indexed: 12/31/2022] Open
Abstract
Xylella fastidiosa is a plant pathogenic bacterium with devastating consequences to several crops of economic importance across the world. While this pathogen has been studied for over a century in the United States, several aspects of its biology remain to be investigated. Determining the physiological state of bacteria is essential to understand the effects of its interactions with different biotic and abiotic factors on cell viability. Although X. fastidiosa is culturable, its slow growing nature makes this technique cumbersome to assess the physiological state of cells present in a given environment. PMA-qPCR, i.e. the use of quantitative PCR combined with the pre-treatment of cells with the dye propidium monoazide, has been successfully used in a number of studies on human pathogens to calculate the proportion of viable cells, but has less frequently been tested on plant pathogens. We found that the use of a version of PMA, PMAxx, facilitated distinguishing between viable and non-viable cells based on cell membrane integrity in vitro and in planta. Additional experiments comparing the number of culturable, viable, and total cells in planta would help further confirm our initial results. Enhancers, intended to improve the efficacy of PMAxx, were not effective and appeared to be slightly toxic to X. fastidiosa.
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Affiliation(s)
- Anne Sicard
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
| | - Marcus V. Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Michael Voeltz
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
| | - Adam R. Zeilinger
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Rodrigo P. P. Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
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Feitosa-Junior OR, Stefanello E, Zaini PA, Nascimento R, Pierry PM, Dandekar AM, Lindow SE, da Silva AM. Proteomic and Metabolomic Analyses of Xylella fastidiosa OMV-Enriched Fractions Reveal Association with Virulence Factors and Signaling Molecules of the DSF Family. PHYTOPATHOLOGY 2019; 109:1344-1353. [PMID: 30973310 DOI: 10.1094/phyto-03-19-0083-r] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Xylella fastidiosa releases outer membrane vesicles (OMVs) known to play a role in the systemic dissemination of this pathogen. OMVs inhibit bacterial attachment to xylem wall and traffic lipases/esterases that act on the degradation of plant cell wall. Here, we extended the characterization of X. fastidiosa OMVs by identifying proteins and metabolites potentially associated with OMVs produced by Temecula1, a Pierce's disease strain, and by 9a5c and Fb7, two citrus variegated chlorosis strains. These results strengthen that one of the OMVs multiple functions is to carry determinants of virulence, such as lipases/esterases, adhesins, proteases, porins, and a pectin lyase-like protein. For the first time, we show that the two citrus variegated chlorosis strains produce X. fastidiosa diffusible signaling factor 2 (DSF2) and citrus variegated chlorosis-DSF (likewise, Temecula1) and most importantly, that these compounds of the DSF (X. fastidiosa DSF) family are associated with OMV-enriched fractions. Altogether, our findings widen the potential functions of X. fastidiosa OMVs in intercellular signaling and host-pathogen interactions.
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Affiliation(s)
- Oséias R Feitosa-Junior
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Eliezer Stefanello
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Paulo A Zaini
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
- 2Department of Plant Sciences, University of California, Davis, CA 95616, U.S.A
| | - Rafael Nascimento
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
- 3Instituto de Genética e Bioquímica, Universidade Federal de Uberlândia, Uberlândia, MG 38400-902, Brazil
| | - Paulo M Pierry
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Abhaya M Dandekar
- 2Department of Plant Sciences, University of California, Davis, CA 95616, U.S.A
| | - Steven E Lindow
- 4Department Plant and Microbial Biology, University of California, Berkeley, CA 94720, U.S.A
| | - Aline M da Silva
- 1Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
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Sabella E, Aprile A, Genga A, Siciliano T, Nutricati E, Nicolì F, Vergine M, Negro C, De Bellis L, Luvisi A. Xylem cavitation susceptibility and refilling mechanisms in olive trees infected by Xylella fastidiosa. Sci Rep 2019; 9:9602. [PMID: 31270378 PMCID: PMC6610111 DOI: 10.1038/s41598-019-46092-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/19/2019] [Indexed: 01/09/2023] Open
Abstract
In olive trees, Xylella fastidiosa colonizes xylem vessels and compromises water transport causing the olive quick decline syndrome (OQDS). The loss of hydraulic conductivity could be attributed to vessel occlusions induced both by the bacteria biofilm and by plant responses (tyloses, gums, etc.) that could trigger embolism. The ability of the infected plants to detect embolism and to respond, by activating mechanisms to restore the hydraulic conductivity, can influence the severity of the disease symptomatology. In order to investigate these mechanisms in the X. fastidiosa-resistant olive cultivar Leccino and in the susceptible Cellina di Nardò, sections of healthy olive stems were analysed by laser scanning microscope to calculate the cavitation vulnerability index. Findings indicated that the cultivar Leccino seems to be constitutively less susceptible to cavitation than the susceptible one. Among the vascular refilling mechanisms, starch hydrolysis is a well-known strategy to refill xylem vessels that suffered cavitation and it is characterized by a dense accumulation of starch grains in the xylem parenchima; SEM-EDX analysis of stem cross-sections of infected plants revealed an aggregation of starch grains in the Leccino xylem vessels. These observations could indicate that this cultivar, as well as being anatomically less susceptible to cavitation, it also could be able to activate more efficient refilling mechanisms, restoring vessel's hydraulic conductivity. In order to verify this hypothesis, we analysed the expression levels of some genes belonging to families involved in embolism sensing and refilling mechanisms: aquaporins, sucrose transporters, carbohydrate metabolism and enzymes related to starch breakdown, alpha and beta-amylase. The obtained genes expression patterns suggested that the infected plants of the cultivar Leccino strongly modulates the genes involved in embolism sensing and refilling.
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Affiliation(s)
- Erika Sabella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Alessio Aprile
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy.
| | - Alessandra Genga
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Tiziana Siciliano
- Department of Physic and Math, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Eliana Nutricati
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Francesca Nicolì
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Marzia Vergine
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Carmine Negro
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Luigi De Bellis
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
| | - Andrea Luvisi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov.le Monteroni 165, 73100, Lecce, Italy
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Novelli S, Gismondi A, Di Marco G, Canuti L, Nanni V, Canini A. Plant defense factors involved in Olea europaea resistance against Xylella fastidiosa infection. JOURNAL OF PLANT RESEARCH 2019; 132:439-455. [PMID: 30993555 DOI: 10.1007/s10265-019-01108-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
Olive quick decline syndrome (OQDS) is a dangerous plant disease, caused by the bacterium Xylella fastidiosa, which targets olive (Olea europaea). Since field observations suggested that some olive cultivars (i.e. Leccino) were more resistant to OQDS than others (i.e. Cellina di Nardò), the plant defense strategies adopted by olive to contrast X. fastidiosa infection were investigated. In the present study, ELISA and genetic approaches were used to confirm plant infection, while microbial colonization mechanism and distribution in host plant tissues and reactive oxygen species (ROS) levels were examined by light, scanning electron and confocal microscopy analyses. Spectrophotometric and chromatographic techniques were performed to measure secondary metabolites content and qPCR assay was carried out for monitoring plant gene expression variation. Our analysis showed that X. fastidiosa caused accumulation of ROS in Leccino samples compared to Cellina di Nardò. Moreover, the infection induced the up-regulation of defense-related genes, such as NADPH oxidase, some protein kinases, pathogen plant response factors and metabolic enzymes. We also found that Leccino plants enhanced the production of specific antioxidant and antimicrobial molecules, to fight the pathogen and avoid its spreading into xylem vessels. We provided new information on OQDS resistance mechanism applied by Leccino cultivar. In particular, we evidenced that high concentrations of ROS, switching on plant defence signalling pathways, may represent a key factor in fighting X. fastidiosa infection.
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Affiliation(s)
- Silvia Novelli
- Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica 1, Rome, 00133, Italy
| | - Angelo Gismondi
- Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica 1, Rome, 00133, Italy
| | - Gabriele Di Marco
- Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica 1, Rome, 00133, Italy
| | - Lorena Canuti
- Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica 1, Rome, 00133, Italy
| | - Valentina Nanni
- Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica 1, Rome, 00133, Italy
| | - Antonella Canini
- Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica 1, Rome, 00133, Italy.
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Pereira WEL, Ferreira CB, Caserta R, Melotto M, de Souza AA. Xylella fastidiosa subsp. pauca and fastidiosa Colonize Arabidopsis Systemically and Induce Anthocyanin Accumulation in Infected Leaves. PHYTOPATHOLOGY 2019; 109:225-232. [PMID: 30277118 DOI: 10.1094/phyto-05-18-0155-fi] [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: 06/08/2023]
Abstract
The bacterium Xylella fastidiosa is a multihost pathogen that affects perennial crops such as grapevine, sweet orange, and olive tree worldwide. It is inherently difficult to study these pathosystems owing to the long-term growth habit of the host plant. Thus, the availability of model plants becomes essential to accelerate discoveries with economic impact. In this study, we uncovered evidence that the model plant Arabidopsis thaliana can be colonized by two different X. fastidiosa subspecies, pauca and fastidiosa. We observed that these bacteria are able to move away from the inoculation point as high bacterial populations were found in distant tissues. In addition, confocal laser scanning microscopy analysis of bacterial movement inside the petiole revealed the ability of the bacterium to move against the net xylem flow during the time course of colonization forming biofilm. These findings provide evidence for the capacity of X. fastidiosa to colonize Arabidopsis. Furthermore, leaves inoculated with X. fastidiosa showed a significant accumulation of anthocyanin. We propose that the X. fastidiosa subsp. pauca or fastidiosa colonization pattern and anthocyanin accumulation in the Arabidopsis ecotype Col-0 can be used as marker phenotypes to facilitate further studies aimed at improving genetic components involved in X. fastidiosa-host interaction.
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Affiliation(s)
- W E L Pereira
- First, second, third, and fifth authors: Centro de Citricultura Sylvio Moreira-Instituto Agronômico, Cordeirópolis, SP, Brazil; first and second authors: Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brazil; and first and fourth authors: Department of Plant Sciences, University of California, Davis
| | - C B Ferreira
- First, second, third, and fifth authors: Centro de Citricultura Sylvio Moreira-Instituto Agronômico, Cordeirópolis, SP, Brazil; first and second authors: Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brazil; and first and fourth authors: Department of Plant Sciences, University of California, Davis
| | - R Caserta
- First, second, third, and fifth authors: Centro de Citricultura Sylvio Moreira-Instituto Agronômico, Cordeirópolis, SP, Brazil; first and second authors: Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brazil; and first and fourth authors: Department of Plant Sciences, University of California, Davis
| | - M Melotto
- First, second, third, and fifth authors: Centro de Citricultura Sylvio Moreira-Instituto Agronômico, Cordeirópolis, SP, Brazil; first and second authors: Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brazil; and first and fourth authors: Department of Plant Sciences, University of California, Davis
| | - A A de Souza
- First, second, third, and fifth authors: Centro de Citricultura Sylvio Moreira-Instituto Agronômico, Cordeirópolis, SP, Brazil; first and second authors: Universidade Estadual de Campinas (Unicamp), Campinas, SP, Brazil; and first and fourth authors: Department of Plant Sciences, University of California, Davis
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Baccari C, Antonova E, Lindow S. Biological Control of Pierce's Disease of Grape by an Endophytic Bacterium. PHYTOPATHOLOGY 2019; 109:248-256. [PMID: 30540526 DOI: 10.1094/phyto-07-18-0245-fi] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Effective preventive measures and therapies are lacking for control of Pierce's disease of grape caused by the xylem-colonizing bacterium Xylella fastidiosa responsible for serious losses in grape production. In this study we explored the potential for endophytic bacteria to alter the disease process. While most endophytic bacteria found within grape did not grow or multiply when inoculated into mature grape vines, Paraburkholderia phytofirmans strain PsJN achieved population sizes as large as 106 cells/g and moved 1 m or more within 4 weeks after inoculation into vines. While X. fastidiosa achieved large population sizes and moved extensively in grape when inoculated alone, few viable cells were recovered from plants in which it was co-inoculated with strain PsJN and the incidence of leaves exhibiting scorching symptoms typical of Pierce's disease was consistently greatly reduced from that in control plants. Suppression of disease symptoms occurred not only when strain PsJN was co-inoculated with the pathogen by puncturing stems in the same site in plants, but also when inoculated at the same time but at different sites in the plant. Large population sizes of strain PsJN could be established in both leaf lamina and petioles by topical application of cell suspensions in 0.2% of an organo-silicon surfactant conferring low surface tension, and such treatments were as effective as direct puncture inoculations of this biocontrol strain in reducing disease severity. While inoculation of strain PsJN into plants by either method at the same time as or even 4 weeks after that of the pathogen resulted in large reductions in disease severity, much less disease control was conferred by inoculation of PsJN 4 weeks prior to that of the pathogen. The expression of grapevine PR1 and ETR1 within 3 weeks of inoculation was substantially higher in plants inoculated with both X. fastidiosa and strain PsJN compared with that in plants inoculated only with the pathogen or strain PsJN, suggesting that this biological control agent reduces disease by priming expression of innate disease resistance pathways in plants that otherwise would have exhibited minimal responses to the pathogen. Strain PsJN thus appears highly efficacious for the control of Pierce's disease when used as an eradicant treatment that can be easily made even by spray application.
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Affiliation(s)
- Clelia Baccari
- Department of Plant and Microbial Biology, University of California, Berkeley 94720
| | - Elena Antonova
- Department of Plant and Microbial Biology, University of California, Berkeley 94720
| | - Steven Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley 94720
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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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Stable Expression of Modified Green Fluorescent Protein in Group B Streptococci To Enable Visualization in Experimental Systems. Appl Environ Microbiol 2018; 84:AEM.01262-18. [PMID: 30006391 DOI: 10.1128/aem.01262-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 07/04/2018] [Indexed: 12/17/2022] Open
Abstract
Group B streptococcus (GBS) is a Gram-positive bacterium associated with various diseases in humans and animals. Many studies have examined GBS physiology, virulence, and microbe-host interactions using diverse imaging approaches, including fluorescence microscopy. Strategies to label and visualize GBS using fluorescence biomarkers have been limited to antibody-based methods or nonspecific stains that bind DNA or protein; an effective plasmid-based system to label GBS with a fluorescence biomarker would represent a useful visualization tool. In this study, we developed and validated a green fluorescent protein (GFP)-variant-expressing plasmid, pGU2664, which can be applied as a marker to visualize GBS in experimental studies. The synthetic constitutively active CP25 promoter drives strong and stable expression of the GFPmut3 biomarker in GBS strains carrying pGU2664. GBS maintains GFPmut3 activity at different phases of growth. The application of fluorescence polarization enables easy discrimination of GBS GFPmut3 activity from the autofluorescence of culture media commonly used to grow GBS. Differential interference contrast microscopy, in combination with epifluorescence microscopy to detect GFPmut3 in GBS, enabled visualization of bacterial attachment to live human epithelial cells in real time. Plasmid pGU2664 was also used to visualize phenotypic differences in the adherence of wild-type GBS and an isogenic gene-deficient mutant strain lacking CovR (the control of virulence regulator) in adhesion assays. The system for GFPmut3 expression in GBS described in this study provides a new tool for the visualization of this organism in diverse research applications. We discuss the advantages and consider the limitations of this fluorescent biomarker system developed for GBS.IMPORTANCE Group B streptococcus (GBS) is a bacterium associated with various diseases in humans and animals. This study describes the development of a strategy to label and visualize GBS using a fluorescence biomarker, termed GFPmut3. We show that this biomarker can be successfully applied to track the growth of bacteria in liquid medium, and it enables the detailed visualization of GBS in the context of live human cells in real-time microscopic analysis. The system for GFPmut3 expression in GBS described in this study provides a new tool for the visualization of this organism in diverse research applications.
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Jeger M, Caffier D, Candresse T, Chatzivassiliou E, Dehnen-Schmutz K, Gilioli G, Grégoire JC, Jaques Miret JA, MacLeod A, Navajas Navarro M, Niere B, Parnell S, Potting R, Rafoss T, Rossi V, Urek G, Van Bruggen A, Van der Werf W, West J, Winter S, Almeida R, Bosco D, Jacques MA, Landa B, Purcell A, Saponari M, Czwienczek E, Delbianco A, Stancanelli G, Bragard C. Updated pest categorisation of Xylella fastidiosa. EFSA J 2018; 16:e05357. [PMID: 32625990 PMCID: PMC7009507 DOI: 10.2903/j.efsa.2018.5357] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Following a request from the European Commission, the EFSA Plant Health Panel updated its pest categorisation of Xylella fastidiosa, previously delivered as part of the pest risk assessment published in 2015. X. fastidiosa is a Gram‐negative bacterium, responsible for various plant diseases, including Pierce's disease, phony peach disease, citrus variegated chlorosis, olive quick decline syndrome, almond leaf scorch and various other leaf scorch diseases. The pathogen is endemic in the Americas and is present in Iran. In the EU, it is reported in southern Apulia in Italy, on the island of Corsica and in the Provence‐Alpes‐Côte d'Azur region in France, as well as in the Autonomous region of Madrid, the province of Alicante and the Balearic Islands in Spain. The reported status is ‘transient, under eradication’, except for the Balearic Islands, Corsica and southern of Apulia, where the status is ‘present with a restricted distribution, under containment’. The pathogen is regulated under Council Directive 2000/29/EC and through emergency measures under http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32015D0789 (as amended http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32017D2352). The pest could enter the EU via host plants for planting and via infectious insect vectors. The host range includes hundreds of host species listed in the EFSA host plant database. In the EU, host plants are widely distributed and climatic conditions are favourable for its establishment. X. fastidiosa can spread by movement of host plants for planting and infectious insect vectors. X. fastidiosa is known to cause severe direct damage to major crops including almonds, citrus, grapevines, olives, stone fruits and also forest trees, landscape and ornamental trees, with high impacts. The criteria assessed by the Panel for consideration as a potential Union quarantine pest are met (the pathogen is present in the EU, but it has a restricted distribution and is under official control). X. fastidiosa is not considered as a regulated non‐quarantine pest (RNQP) as the pathogen may spread also via insect vector transmission.
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Rapicavoli J, Ingel B, Blanco‐Ulate B, Cantu D, Roper C. Xylella fastidiosa: an examination of a re-emerging plant pathogen. MOLECULAR PLANT PATHOLOGY 2018; 19:786-800. [PMID: 28742234 PMCID: PMC6637975 DOI: 10.1111/mpp.12585] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 07/13/2017] [Accepted: 07/19/2017] [Indexed: 05/10/2023]
Abstract
UNLABELLED Xylella fastidiosa is a Gram-negative bacterial plant pathogen with an extremely wide host range. This species has recently been resolved into subspecies that correlate with host specificity. This review focuses on the status of X. fastidiosa pathogenic associations in plant hosts in which the bacterium is either endemic or has been recently introduced. Plant diseases associated with X. fastidiosa have been documented for over a century, and much about what is known in the context of host-pathogen interactions is based on these hosts, such as grape and citrus, in which this pathogen has been well described. Recent attention has focused on newly emerging X. fastidiosa diseases, such as in olives. TAXONOMY Bacteria; Gammaproteobacteria; family Xanthomonadaceae; genus Xylella; species fastidiosa. MICROBIOLOGICAL PROPERTIES Gram-negative rod (0.25-0.35 × 0.9-3.5 μm), non-flagellate, motile via Type IV pili-mediated twitching, fastidious. HOST RANGE Xylella fastidiosa has a broad host range that includes ornamental, ecological and agricultural plants belonging to over 300 different species in 63 different families. To date, X. fastidiosa has been found to be pathogenic in over 100 plant species. In addition, it can establish non-symptomatic associations with many plants as a commensal endophyte. Here, we list the four distinct subspecies of X. fastidiosa and some of the agriculturally relevant diseases caused by them: X. fastidiosa ssp. fastidiosa causes Pierce's disease (PD) of grapevine (Vitis vinifera); X. fastidiosa ssp. multiplex causes almond leaf scorch (ALS) and diseases on other nut and shade tree crops; X. fastidiosa ssp. pauca causes citrus variegated chlorosis (CVC) (Citrus spp.), coffee leaf scorch and olive quick decline syndrome (OQDS) (Olea europaea); X. fastidiosa ssp. sandyi causes oleander leaf scorch (OLS) (Nerium oleander). Significant host specificity seemingly exists for some of the subspecies, although this could be a result of technical biases based on the limited number of plants tested, whereas some subspecies are not as stringent in their host range and can infect several plant hosts. DISEASE SYMPTOMS Most X. fastidiosa-related diseases appear as marginal leaf necrosis and scorching of the leaves. In the case of PD, X. fastidiosa can also cause desiccation of berries (termed 'raisining'), irregular periderm development and abnormal abscission of petioles. In olive trees affected with OQDS, leaves exhibit marginal necrosis and defoliation, and overall tree decline occurs. Plants with ALS and OLS also exhibit the characteristic leaf scorch symptoms. Not all X. fastidiosa-related diseases exhibit the typical leaf scorch symptoms. These include CVC and Phony Peach disease, amongst others. In the case of CVC, symptoms include foliar wilt and interveinal chlorosis on the upper surfaces of the leaves (similar to zinc deficiency), which correspond to necrotic, gum-like regions on the undersides of the leaves. Additional symptoms of CVC include defoliation, dieback and hardening of fruits. Plants infected with Phony Peach disease exhibit a denser, more compact canopy (as a result of shortened internodes, darker green leaves and delayed leaf senescence), premature bloom and reduced fruit size. Some occlusions occur in the xylem vessels, but there are no foliar wilting, chlorosis or necrosis symptoms . USEFUL WEBSITES: http://www.piercesdisease.org/; https://pubmlst.org/xfastidiosa/; http://www.xylella.lncc.br/; https://nature.berkeley.edu/xylella/; https://ec.europa.eu/food/plant/plant_health_biosecurity/legislation/emergency_measures/xylella-fastidiosa_en.
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Affiliation(s)
- Jeannette Rapicavoli
- Department of Plant Pathology and MicrobiologyUniversity of CaliforniaRiversideCA 92521USA
| | - Brian Ingel
- Department of Plant Pathology and MicrobiologyUniversity of CaliforniaRiversideCA 92521USA
| | | | - Dario Cantu
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCA 95616USA
| | - Caroline Roper
- Department of Plant Pathology and MicrobiologyUniversity of CaliforniaRiversideCA 92521USA
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Cardinale M, Luvisi A, Meyer JB, Sabella E, De Bellis L, Cruz AC, Ampatzidis Y, Cherubini P. Specific Fluorescence in Situ Hybridization (FISH) Test to Highlight Colonization of Xylem Vessels by Xylella fastidiosa in Naturally Infected Olive Trees ( Olea europaea L.). FRONTIERS IN PLANT SCIENCE 2018; 9:431. [PMID: 29681910 PMCID: PMC5897508 DOI: 10.3389/fpls.2018.00431] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 03/21/2018] [Indexed: 05/11/2023]
Abstract
The colonization behavior of the Xylella fastidiosa strain CoDiRO, the causal agent of olive quick decline syndrome (OQDS), within the xylem of Olea europaea L. is still quite controversial. As previous literature suggests, even if xylem vessel occlusions in naturally infected olive plants were observed, cell aggregation in the formation of occlusions had a minimal role. This observation left some open questions about the whole behavior of the CoDiRO strain and its actual role in OQDS pathogenesis. In order to evaluate the extent of bacterial infection in olive trees and the role of bacterial aggregates in vessel occlusions, we tested a specific fluorescence in situ hybridization (FISH) probe (KO 210) for X. fastidiosa and quantified the level of infection and vessel occlusion in both petioles and branches of naturally infected and non-infected olive trees. All symptomatic petioles showed colonization by X. fastidiosa, especially in the larger innermost vessels. In several cases, the vessels appeared completely occluded by a biofilm containing bacterial cells and extracellular matrix and the frequent colonization of adjacent vessels suggested a horizontal movement of the bacteria. Infected symptomatic trees had 21.6 ± 10.7% of petiole vessels colonized by the pathogen, indicating an irregular distribution in olive tree xylem. Thus, our observations point out the primary role of the pathogen in olive vessel occlusions. Furthermore, our findings indicate that the KO 210 FISH probe is suitable for the specific detection of X. fastidiosa.
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Affiliation(s)
- Massimiliano Cardinale
- Institute of Applied Microbiology, Research Center for BioSystems, Land Use, and Nutrition, Justus-Liebig-University Giessen, Giessen, Germany
| | - Andrea Luvisi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
- *Correspondence: Andrea Luvisi,
| | - Joana B. Meyer
- WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - Erika Sabella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - Luigi De Bellis
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - Albert C. Cruz
- Department of Computer and Electrical Engineering and Computer Science, California State University, Bakersfield, CA, United States
| | - Yiannis Ampatzidis
- Department of Agricultural and Biological Engineering, Southwest Florida Research and Education Center, University of Florida, Gainesville, FL, United States
| | - Paolo Cherubini
- WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
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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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Burbank LP, Van Horn CR. Conjugative Plasmid Transfer in Xylella fastidiosa Is Dependent on tra and trb Operon Functions. J Bacteriol 2017; 199:e00388-17. [PMID: 28808128 PMCID: PMC5626953 DOI: 10.1128/jb.00388-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/05/2017] [Indexed: 12/16/2022] Open
Abstract
The insect-transmitted plant pathogen Xylella fastidiosa is capable of efficient horizontal gene transfer (HGT) and recombination. Natural transformation occurs at high rates in X. fastidiosa, but there also is evidence that certain strains of X. fastidiosa carry native plasmids equipped with transfer and mobilization genes, suggesting conjugation as an additional mechanism of HGT in some instances. Two operons, tra and trb, putatively encoding a conjugative type IV secretion system, are found in some but not all X. fastidiosa isolates, often on native plasmids. X. fastidiosa strains that carry the conjugative transfer genes can belong to different subspecies and frequently differ in host ranges. Using X. fastidiosa strain M23 (X. fastidiosa subsp. fastidiosa) or Dixon (X. fastidiosa subsp. multiplex) as the donor strain and Temecula (X. fastidiosa subsp. fastidiosa) as the recipient strain, plasmid transfer was characterized using the mobilizable broad-host-range vector pBBR5pemIK. Transfer of plasmid pBBR5pemIK was observed under in vitro conditions with both donor strains and was dependent on both tra and trb operon functions. A conjugative mechanism likely contributes to gene transfer between diverse strains of X. fastidiosa, possibly facilitating adaptation to new environments or different hosts.IMPORTANCEXylella fastidiosa is an important plant pathogen worldwide, infecting a wide range of different plant species. The emergence of new diseases caused by X. fastidiosa, or host switching of existing strains, is thought to be primarily due to the high frequency of HGT and recombination in this pathogen. Transfer of plasmids by a conjugative mechanism enables movement of larger amounts of genetic material at one time, compared with other routes of gene transfer such as natural transformation. Establishing the prevalence and functionality of this mechanism in X. fastidiosa contributes to a better understanding of HGT, adaptation, and disease emergence in this diverse pathogen.
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Affiliation(s)
- Lindsey P Burbank
- U.S. Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, California, USA
| | - Christopher R Van Horn
- U.S. Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, California, USA
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Stiffness signatures along early stages of Xylella fastidiosa biofilm formation. Colloids Surf B Biointerfaces 2017; 159:174-182. [DOI: 10.1016/j.colsurfb.2017.07.075] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/19/2017] [Accepted: 07/26/2017] [Indexed: 01/05/2023]
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