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Zheng Y, Zhang R, Chen M, Zhou Q, Wu Y, Xue W. Design, Synthesis, and Antibacterial Evaluation of Novel Isoindolin-1-ones Derivatives Containing Piperidine Fragments. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:12434-12444. [PMID: 38775141 DOI: 10.1021/acs.jafc.3c09928] [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: 06/06/2024]
Abstract
A series of novel isoindoline-1-one derivatives containing piperidine moiety were designed and synthesized using natural compounds as raw materials, and their biological activities were tested for three bacterial and three fungal pathogens. These derivatives exhibited good against phytopathogenic bacteria activities against Pseudomonas syringae pv actinidiae (Psa) and Xanthomonas axonopodis pv.citri (Xac). Some compounds exhibited excellent antibacterial activities against Xanthomonas oryzae pv oryzae (Xoo). The dose of Y8 against Xoo (the maximum half lethal effective concentration (EC50) = 21.3 μg/mL) was better than that of the thiediazole copper dose (EC50 = 53.3 μg/mL). Excitingly, further studies have shown that the molecular docking of Y8 with 2FBW indicates that it can fully locate the interior of the binding pocket through hydrogen bonding and hydrophobic interactions, thereby enhancing its anti-Xoo activity. Scanning electron microscopy (SEM) studies revealed that Y8 induced the Xoo cell membrane collapse. Moreover, the proteomic results also indicate that Y8 may be a multifunctional candidate as it affects the formation of bacterial Xoo biofilms, thereby exerting antibacterial effects.
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Affiliation(s)
- Yuguo Zheng
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemical of Guizhou University, Huaxi District Guiyang 550025, China
- The Key Laboratory of Chemical Synthesis and Environmental Pollution Control-Remediation Technology of Guizhou Province, Xingyi Normal University for Nationalities, Xingyi 562400, China
| | - Renfeng Zhang
- The Key Laboratory of Chemical Synthesis and Environmental Pollution Control-Remediation Technology of Guizhou Province, Xingyi Normal University for Nationalities, Xingyi 562400, China
| | - Mei Chen
- The Key Laboratory of Chemical Synthesis and Environmental Pollution Control-Remediation Technology of Guizhou Province, Xingyi Normal University for Nationalities, Xingyi 562400, China
| | - Qing Zhou
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemical of Guizhou University, Huaxi District Guiyang 550025, China
| | - Yongjun Wu
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemical of Guizhou University, Huaxi District Guiyang 550025, China
| | - Wei Xue
- State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemical of Guizhou University, Huaxi District Guiyang 550025, China
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Alexandrino AV, Barcelos MP, Federico LB, da Silva TG, Cavalca LB, de Moraes CHA, Ferreira H, Taft CA, Behlau F, de Paula Silva CHT, Novo-Mansur MTM. GDP-mannose pyrophosphorylase is an efficient target in Xanthomonas citri for citrus canker control. Microbiol Spectr 2024; 12:e0367323. [PMID: 38722158 DOI: 10.1128/spectrum.03673-23] [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: 10/25/2023] [Accepted: 03/20/2024] [Indexed: 06/06/2024] Open
Abstract
Xanthomonas citri subsp. citri (Xcc) is a bacterium that causes citrus canker, an economically important disease that results in premature fruit drop and reduced yield of fresh fruit. In this study, we demonstrated the involvement of XanB, an enzyme with phosphomannose isomerase (PMI) and guanosine diphosphate-mannose pyrophosphorylase (GMP) activities, in Xcc pathogenicity. Additionally, we found that XanB inhibitors protect the host against Xcc infection. Besides being deficient in motility, biofilm production, and ultraviolet resistance, the xanB deletion mutant was unable to cause disease, whereas xanB complementation restored wild-type phenotypes. XanB homology modeling allowed in silico virtual screening of inhibitors from databases, three of them being suitable in terms of absorption, distribution, metabolism, excretion, and toxicity (ADME/Tox) properties, which inhibited GMP (but not PMI) activity of the Xcc recombinant XanB protein in more than 50%. Inhibitors reduced citrus canker severity up to 95%, similarly to copper-based treatment. xanB is essential for Xcc pathogenicity, and XanB inhibitors can be used for the citrus canker control. IMPORTANCE Xcc causes citrus canker, a threat to citrus production, which has been managed with copper, being required a more sustainable alternative for the disease control. XanB was previously found on the surface of Xcc, interacting with the host and displaying PMI and GMP activities. We demonstrated by xanB deletion and complementation that GMP activity plays a critical role in Xcc pathogenicity, particularly in biofilm formation. XanB homology modeling was performed, and in silico virtual screening led to carbohydrate-derived compounds able to inhibit XanB activity and reduce disease symptoms by 95%. XanB emerges as a promising target for drug design for control of citrus canker and other economically important diseases caused by Xanthomonas sp.
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Affiliation(s)
- André Vessoni Alexandrino
- Laboratório de Bioquímica e Biologia Molecular Aplicada (LBBMA), Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
- Programa de Pós-Graduação em Biotecnologia (PPGBiotec), Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Mariana Pegrucci Barcelos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Leonardo Bruno Federico
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Tamiris Garcia da Silva
- Departamento de Pesquisa e Desenvolvimento, Fundo de Defesa da Citricultura, Fundecitrus, Araraquara, São Paulo, Brazil
| | - Lúcia Bonci Cavalca
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, UNESP, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Carlos Henrique Alves de Moraes
- Laboratório de Bioquímica e Biologia Molecular Aplicada (LBBMA), Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Henrique Ferreira
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, UNESP, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | | | - Franklin Behlau
- Departamento de Pesquisa e Desenvolvimento, Fundo de Defesa da Citricultura, Fundecitrus, Araraquara, São Paulo, Brazil
| | | | - Maria Teresa Marques Novo-Mansur
- Laboratório de Bioquímica e Biologia Molecular Aplicada (LBBMA), Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
- Programa de Pós-Graduação em Biotecnologia (PPGBiotec), Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular (PPGGEv), Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
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Ramamoorthy S, Pena M, Ghosh P, Liao YY, Paret M, Jones JB, Potnis N. Transcriptome profiling of type VI secretion system core gene tssM mutant of Xanthomonas perforans highlights regulators controlling diverse functions ranging from virulence to metabolism. Microbiol Spectr 2024; 12:e0285223. [PMID: 38018859 PMCID: PMC10782981 DOI: 10.1128/spectrum.02852-23] [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: 07/14/2023] [Accepted: 10/20/2023] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE T6SS has received attention due to its significance in mediating interorganismal competition through contact-dependent release of effector molecules into prokaryotic and eukaryotic cells. Reverse-genetic studies have indicated the role of T6SS in virulence in a variety of plant pathogenic bacteria, including the one studied here, Xanthomonas. However, it is not clear whether such effect on virulence is merely due to a shift in the microbiome-mediated protection or if T6SS is involved in a complex virulence regulatory network. In this study, we conducted in vitro transcriptome profiling in minimal medium to decipher the signaling pathways regulated by tssM-i3* in X. perforans AL65. We show that TssM-i3* regulates the expression of a suite of genes associated with virulence and metabolism either directly or indirectly by altering the transcription of several regulators. These findings further expand our knowledge on the intricate molecular circuits regulated by T6SS in phytopathogenic bacteria.
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Affiliation(s)
- Sivakumar Ramamoorthy
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Michelle Pena
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Palash Ghosh
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Ying-Yu Liao
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Mathews Paret
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
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Qiu Y, Wei F, Meng H, Peng M, Zhang J, He Y, Wei L, Ahmed W, Ji G. Whole-genome sequencing and comparative genome analysis of Xanthomonas fragariae YM2 causing angular leaf spot disease in strawberry. FRONTIERS IN PLANT SCIENCE 2023; 14:1267132. [PMID: 38192696 PMCID: PMC10773614 DOI: 10.3389/fpls.2023.1267132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024]
Abstract
Background Angular leaf spot disease caused by plant pathogenic bacterium Xanthomonas fragariae seriously threatens strawberry crop production globally. Methods In this study, we sequenced the whole genome of X. fragariae YM2, isolated from Yunnan Province, China. In addition, we performed a comparative genome analysis of X. fragariae YM2 with two existing strains of X. fragariae YL19 and SHQP01 isolated from Liaoning and Shanghai, respectively. Results The results of Nanopore sequencing showed that X. fragariae YM2 comprises one single chromosome with a contig size of 4,263,697 bp, one plasmid contig size of 0.39 Mb, a GC content ratio of 62.27%, and 3,958 predicted coding genes. The genome of YM2 comprises gum, hrp, rpf, and xps gene clusters and lipopolysaccharide (LPS), which are typical virulence factors in Xanthomonas species. By performing a comparative genomic analysis between X. fragariae strains YM2, YL19, and SHQP01, we found that strain YM2 is similar to YL19 and SHQP01 regarding genome size and GC contents. However, there are minor differences in the composition of major virulence factors and homologous gene clusters. Furthermore, the results of collinearity analysis demonstrated that YM2 has lower similarity and longer evolutionary distance with YL19 and SHQP01, but YL19 is more closely related to SHQP01. Conclusions The availability of this high-quality genetic resource will serve as a basic tool for investigating the biology, molecular pathogenesis, and virulence of X. fragariae YM2. In addition, unraveling the potential vulnerabilities in its genetic makeup will aid in developing more effective disease suppression control measures.
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Affiliation(s)
- Yue Qiu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- College of Agriculture, Anshun University, Anshun, Guizhou, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Fangjun Wei
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Han Meng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Menglin Peng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Jinhao Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Yilu He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Lanfang Wei
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Agricultural Foundation Experiment Teaching Center, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Waqar Ahmed
- College of Plant Protection, South China Agricultural University, Guangzhou, Guangdong, China
| | - Guanghai Ji
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
- Key Laboratory of Agro-Biodiversity and Pest Management of Ministry of Education, Yunnan Agricultural University, Kunming, Yunnan, China
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Jiang S, Wang W, Mou C, Zou J, Jin Z, Hao G, Chi YR. Facile access to benzofuran derivatives through radical reactions with heteroatom-centered super-electron-donors. Nat Commun 2023; 14:7381. [PMID: 37968279 PMCID: PMC10651860 DOI: 10.1038/s41467-023-43198-y] [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: 12/22/2022] [Accepted: 11/03/2023] [Indexed: 11/17/2023] Open
Abstract
The development of suitable electron donors is critical to single-electron-transfer (SET) processes. The use of heteroatom-centered anions as super-electron-donors (SEDs) for direct SET reactions has rarely been studied. Here we show that heteroatom anions can be applied as SEDs to initiate radical reactions for facile synthesis of 3-substituted benzofurans. Phosphines, thiols and anilines bearing different substitution patterns work well in this inter-molecular radical coupling reaction and the 3-functionalized benzofuran products bearing heteroatomic functionalities are given in moderate to excellent yields. The reaction mechanism is elucidated via control experiments and computational methods. The afforded products show promising applications in both organic synthesis and pesticide development.
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Affiliation(s)
- Shichun Jiang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang, 550025, China
| | - Wei Wang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang, 550025, China
| | - Chengli Mou
- Guizhou University of Traditional Chinese Medicine, Guiyang, 550025, China
| | - Juan Zou
- Guizhou University of Traditional Chinese Medicine, Guiyang, 550025, China
| | - Zhichao Jin
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang, 550025, China.
| | - Gefei Hao
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang, 550025, China.
| | - Yonggui Robin Chi
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang, 550025, China.
- School of Chemistry, Chemical Engineering, and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore.
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Bianco MI, Ponso MA, Garita-Cambronero J, Conforte VP, Galván TE, Dunger G, Morales GM, Vojnov AA, Romero AM, Cubero J, Yaryura PM. Genomic and phenotypic insight into Xanthomonas vesicatoria strains with different aggressiveness on tomato. Front Microbiol 2023; 14:1185368. [PMID: 37440880 PMCID: PMC10333488 DOI: 10.3389/fmicb.2023.1185368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/09/2023] [Indexed: 07/15/2023] Open
Abstract
Xanthomonas vesicatoria is one of the causal agents of bacterial spot, a disease that seriously affects the production of tomato (Solanum lycopersicum) and pepper (Capsicum annum) worldwide. In Argentina, bacterial spot is found in all tomato producing areas, with X. vesicatoria being one of the main species detected in the fields. Previously, we isolated three X. vesicatoria strains BNM 208, BNM 214, and BNM 216 from tomato plants with bacterial spot, and found they differed in their ability to form biofilm and in their degree of aggressiveness. Here, the likely causes of those differences were explored through genotypic and phenotypic studies. The genomes of the three strains were sequenced and assembled, and then compared with each other and also with 12 other publicly available X. vesicatoria genomes. Phenotypic characteristics (mainly linked to biofilm formation and virulence) were studied in vitro. Our results show that the differences observed earlier between BNM 208, BNM 214, and BNM 216 may be related to the structural characteristics of the xanthan gum produced by each strain, their repertoire of type III effectors (T3Es), the presence of certain genes associated with c-di-GMP metabolism and type IV pili (T4P). These findings on the pathogenicity mechanisms of X. vesicatoria could be useful for developing bacterial spot control strategies aimed at interfering with the infection processes.
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Affiliation(s)
- María Isabel Bianco
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigación en Medicina y Ciencias de la Salud, Facultad de Medicina, Universidad del Salvador, Buenos Aires, Argentina
| | - María Agustina Ponso
- Instituto Multidisciplinario de Investigación y Transferencia Agroalimentario y Biotecnológica (IMITAB, UNVM-CONICET), Instituto Académico Pedagógico de Ciencias Básicas y Aplicadas, Universidad Nacional de Villa María, Villa María, Argentina
| | | | - Valeria Paola Conforte
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigación en Medicina y Ciencias de la Salud, Facultad de Medicina, Universidad del Salvador, Buenos Aires, Argentina
| | - Tadeo E. Galván
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Germán Dunger
- Facultad de Ciencias Agrarias, Instituto de Ciencias Agropecuarias del Litoral, CONICET, Universidad Nacional del Litoral, Esperanza, Argentina
| | - Gustavo M. Morales
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados, Universidad Nacional de Rio Cuarto – CONICET, Rio Cuarto, Argentina
| | - Adrián Alberto Vojnov
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigación en Medicina y Ciencias de la Salud, Facultad de Medicina, Universidad del Salvador, Buenos Aires, Argentina
| | - Ana María Romero
- Cátedra de Fitopatología, Departamento de Producción Vegetal, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jaime Cubero
- Laboratorio de Bacteriología, Departamento de Protección Vegetal, Instituto Nacional de Investigación y Tecnología Agraria/Consejo Superior de Investigaciones Científicas (INIA/CSIC), Madrid, Spain
| | - Pablo Marcelo Yaryura
- Instituto Multidisciplinario de Investigación y Transferencia Agroalimentario y Biotecnológica (IMITAB, UNVM-CONICET), Instituto Académico Pedagógico de Ciencias Básicas y Aplicadas, Universidad Nacional de Villa María, Villa María, Argentina
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Martin AP, Martínez MF, Chiesa MA, Garcia L, Gerhardt N, Uviedo F, Torres PS, Marano MR. Priming crop plants with rosemary (Salvia rosmarinus Spenn, syn Rosmarinus officinalis L.) extract triggers protective defense response against pathogens. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 197:107644. [PMID: 36996636 DOI: 10.1016/j.plaphy.2023.107644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/28/2023] [Accepted: 03/13/2023] [Indexed: 06/19/2023]
Abstract
Plant bioactive compounds provide novel straightforward approaches to control plant diseases. Rosemary (Salvia rosmarinus)-derived extracts carry many prominent pharmacological activities, including antimicrobial and antioxidant, mainly due to its phenolic compounds, rosmarinic acid (RA), carnosic acid and carnosol. However, the effects of these extracts on plant diseases are still unknown, which constrains its potential application as bioprotectant in the agricultural production. In this study we demonstrate the antiviral effect of the aqueous rosemary extract (ARE) against tobacco necrosis virus strain A (TNVA) in ARE-treated tobacco (Nicotiana tabacum) plants. Our results show that ARE-treatment enhances plant defense response, contributing to reduce virus replication and systemic movement in tobacco plants. RA, the main phenolic compound detected in this extract, is one of the main inducers of TNVA control. The ARE-induced protection in TNVA-infected plants was characterized by the expression of H2O2 scavengers and defense-related genes, involving salicylic acid- and jasmonic acid-regulated pathways. Furthermore, treatment with ARE in lemon (Citrus limon) and soybean (Glycine max) leaves protects the plants against Xanthomonas citri subsp. citri and Diaporthe phaseolorum var. meridionalis, respectively. Additionally, ARE treatment also promotes growth and development, suggesting a biostimulant activity in soybean. These results open the way for the potential use of ARE as a bioprotective agent in disease management.
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Affiliation(s)
- Ana Paula Martin
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2002 FHN, Rosario, Argentina; Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Suipacha 590, S2002LRK, Rosario, Argentina
| | - María Florencia Martínez
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2002 FHN, Rosario, Argentina
| | - María Amalia Chiesa
- Laboratorio de Eco-Fisiología Vegetal (LEFIVE), Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-UNR/CONICET, Parque Villarino S/N, 2125, Zavalla, Santa Fe, Argentina
| | - Lucila Garcia
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2002 FHN, Rosario, Argentina; Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Suipacha 590, S2002LRK, Rosario, Argentina
| | - Nadia Gerhardt
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2002 FHN, Rosario, Argentina; Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Suipacha 590, S2002LRK, Rosario, Argentina
| | - Facundo Uviedo
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2002 FHN, Rosario, Argentina
| | - Pablo S Torres
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2002 FHN, Rosario, Argentina
| | - María Rosa Marano
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2002 FHN, Rosario, Argentina; Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Suipacha 590, S2002LRK, Rosario, Argentina.
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Cell Density-Regulated Adhesins Contribute to Early Disease Development and Adhesion in Ralstonia solanacearum. Appl Environ Microbiol 2023; 89:e0156522. [PMID: 36688670 PMCID: PMC9973027 DOI: 10.1128/aem.01565-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Adhesins (adhesive proteins) help bacteria stick to and colonize diverse surfaces and often contribute to virulence. The genome of the bacterial wilt pathogen Ralstonia solanacearum (Rs) encodes dozens of putative adhesins, some of which are upregulated during plant pathogenesis. Little is known about the role of these proteins in bacterial wilt disease. During tomato colonization, three putative Rs adhesin genes were upregulated in a ΔphcA quorum-sensing mutant that cannot respond to high cell densities: radA (Ralstonia adhesin A), rcpA (Ralstonia collagen-like protein A), and rcpB. Based on this differential gene expression, we hypothesized that adhesins repressed by PhcA contribute to early disease stages when Rs experiences a low cell density. During root colonization, Rs upregulated rcpA and rcpB, but not radA, relative to bacteria in the stem at mid-disease. Root attachment assays and confocal microscopy with ΔrcpA/B and ΔradA revealed that all three adhesins help Rs attach to tomato seedling roots. Biofilm assays on abiotic surfaces found that Rs does not require RadA, RcpA, or RcpB for interbacterial attachment (cohesion), but these proteins are essential for anchoring aggregates to a surface (adhesion). However, Rs did not require the adhesins for later disease stages in planta, including colonization of the root endosphere and stems. Interestingly, all three adhesins were essential for full competitive fitness in planta. Together, these infection stage-specific assays identified three proteins that contribute to adhesion and the critical first host-pathogen interaction in bacterial wilt disease. IMPORTANCE Every microbe must balance its need to attach to surfaces with the biological imperative to move and spread. The high-impact plant-pathogenic bacterium Ralstonia solanacearum can stick to biotic and abiotic substrates, presumably using some of the dozens of putative adhesins encoded in its genome. We confirmed the functions and identified the biological roles of multiple afimbrial adhesins. By assaying the competitive fitness and the success of adhesin mutants in three different plant compartments, we identified the specific disease stages and host tissues where three previously cryptic adhesins contribute to success in plants. Combined with tissue-specific regulatory data, this work indicates that R. solanacearum deploys distinct adhesins that help it succeed at different stages of plant pathogenesis.
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Shahbaz E, Ali M, Shafiq M, Atiq M, Hussain M, Balal RM, Sarkhosh A, Alferez F, Sadiq S, Shahid MA. Citrus Canker Pathogen, Its Mechanism of Infection, Eradication, and Impacts. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010123. [PMID: 36616252 PMCID: PMC9824702 DOI: 10.3390/plants12010123] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/14/2022] [Accepted: 12/13/2022] [Indexed: 05/16/2023]
Abstract
Citrus canker is a ravaging bacterial disease threatening citrus crops. Its major types are Asiatic Canker, Cancrosis B, and Cancrosis C, caused by Xanthomonas citri pv. citri (Xcc), Xanthomonas citri pv. aurantifolii pathotype-B (XauB), and pathotype-C (XauC), respectively. The bacterium enters its host through stomata and wounds, from which it invades the intercellular spaces in the apoplast. It produces erumpent corky necrotic lesions often surrounded by a chlorotic halo on the leaves, young stems, and fruits, which causes dark spots, defoliation, reduced photosynthetic rate, rupture of leaf epidermis, dieback, and premature fruit drop in severe cases. Its main pathogenicity determinant gene is pthA, whose variants are present in all citrus canker-causing pathogens. Countries where citrus canker is not endemic adopt different methods to prevent the introduction of the pathogen into the region, eradicate the pathogen, and minimize its dissemination, whereas endemic regions require an integrated management program to control the disease. The main aim of the present manuscript is to shed light on the pathogen profile, its mechanism of infection, and fruitful strategies for disease management. Although an adequate method to completely eradicate citrus canker has not been introduced so far, many new methods are under research to abate the disease.
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Affiliation(s)
- Esha Shahbaz
- Department of Food Sciences, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Mobeen Ali
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Shafiq
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Atiq
- Department of Plant Pathology, University of Agriculture, Faisalabad 38000, Pakistan
| | - Mujahid Hussain
- Horticultural Science Department, North Florida Research and Education Center, University of Florida/IFAS, Quincy, FL 32351, USA
| | - Rashad Mukhtar Balal
- Department of Horticulture, College of Agriculture, University of Sargodha, Sargodha 40100, Pakistan
| | - Ali Sarkhosh
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Fernando Alferez
- Horticultural Science Department, Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee, FL 34142, USA
| | - Saleha Sadiq
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Adnan Shahid
- Horticultural Science Department, North Florida Research and Education Center, University of Florida/IFAS, Quincy, FL 32351, USA
- Correspondence:
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10
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Sena-Vélez M, Ferragud E, Redondo C, Graham JH, Cubero J. Chemotactic Responses of Xanthomonas with Different Host Ranges. Microorganisms 2022; 11:microorganisms11010043. [PMID: 36677335 PMCID: PMC9866238 DOI: 10.3390/microorganisms11010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/05/2022] [Accepted: 12/19/2022] [Indexed: 12/25/2022] Open
Abstract
Xanthomonas citri pv. citri (Xcc) (X. citri subsp. citri) type A is the causal agent of citrus bacterial canker (CBC) on most Citrus spp. and close relatives. Two narrow-host-range strains of Xcc, Aw and A*, from Florida and Southwest Asia, respectively, infect only Mexican lime (Citrus aurantifolia) and alemow (C. macrophylla). In the initial stage of infection, these xanthomonads enter via stomata to reach the apoplast. Herein, we investigated the differences in chemotactic responses for wide and narrow-host-range strains of Xcc A, X. euvesicatoria pv. citrumelonis (X. alfalfae subsp. citrumelonis), the causal agent of citrus bacterial spot, and X. campestris pv. campestris, the crucifer black rot pathogen. These strains of Xanthomonas were compared for carbon source use, the chemotactic responses toward carbon compounds, chemotaxis sensor content, and responses to apoplastic fluids from Citrus spp. and Chinese cabbage (Brassica pekinensis). Different chemotactic responses occurred for carbon sources and apoplastic fluids, depending on the Xanthomonas strain and the host plant from which the apoplastic fluid was derived. Differential chemotactic responses to carbon sources and citrus apoplasts suggest that these Xanthomonas strains sense host-specific signals that facilitate their location and entry of stomatal openings or wounds.
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Affiliation(s)
- Marta Sena-Vélez
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC) EA 1207, L’institut National de Recherche pour L’agriculture, L’alimentation et L’environneme (INRAE) USC1328, Orléans University, BP 6759, CEDEX 2, 45067 Orléans, France
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
| | - Elisa Ferragud
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
| | - Cristina Redondo
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
| | - James H. Graham
- Citrus Research and Education Center (CREC), University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850-2299, USA
| | - Jaime Cubero
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
- Correspondence: ; Tel.: +34-913474162
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11
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Qiao P, Zhao M, Guan W, Walcott R, Ye Y, Yang Y, Zhao T. A putative multi-sensor hybrid histidine kinase, BarA Ac , inhibits the expression of the type III secretion system regulator HrpG in Acidovorax citrulli. Front Microbiol 2022; 13:1064577. [PMID: 36532489 PMCID: PMC9748350 DOI: 10.3389/fmicb.2022.1064577] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 11/14/2022] [Indexed: 07/30/2023] Open
Abstract
Bacterial fruit blotch (BFB), caused by Acidovorax citrulli, severely damages watermelon, melon, and other cucurbit crops worldwide. Although many virulence determinants have been identified in A. citrulli, including swimming motility, twitching motility, biofilm formation, and the type III secretion system (T3SS), research on their regulation is lacking. To study virulence regulation mechanisms, we found a putative histidine kinase BarA Ac that may be related to the T3SS regulator HrpG in A. citrulli. We deleted and characterized barAAc (Aave_2063) in A. citrulli Aac5 strain. Compared to the wild-type Aac5, virulence and early proliferation of barAAc mutant in host watermelon cotyledons were significantly increased, and induction of hypersensitive response in non-host tobacco was accelerated, while biofilm formation and swimming motility were significantly reduced. In addition, the transcriptomic analysis revealed that the expression of many T3SS-related genes was upregulated in the ΔbarAAc deletion mutant when cultured in KB medium. Meanwhile, the ΔbarAAc deletion mutant showed increased accumulation of the T3SS regulator HrpG in KB medium, which may account for the increased deployment of T3SS. This suggests that the putative histidine kinase BarA Ac is able to repress the T3SS expression by inhibiting HrpG in the KB medium, which appears to be important for rational energy allocation. In summary, our research provides further understanding of the regulatory network of A. citrulli virulence.
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Affiliation(s)
- Pei Qiao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mei Zhao
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Department of Plant Pathology, University of Georgia, Athens, GA, United States
| | - Wei Guan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ron Walcott
- Department of Plant Pathology, University of Georgia, Athens, GA, United States
| | - Yunfeng Ye
- Horticultural Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Yuwen Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Tingchang Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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12
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Garcia L, Molina MC, Padgett-Pagliai KA, Torres PS, Bruna RE, García Véscovi E, González CF, Gadea J, Marano MR. A serralysin-like protein of Candidatus Liberibacter asiaticus modulates components of the bacterial extracellular matrix. Front Microbiol 2022; 13:1006962. [DOI: 10.3389/fmicb.2022.1006962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Huanglongbing (HLB), the current major threat for Citrus species, is caused by intracellular alphaproteobacteria of the genus Candidatus Liberibacter (CaL), with CaL asiaticus (CLas) being the most prevalent species. This bacterium inhabits phloem cells and is transmitted by the psyllid Diaphorina citri. A gene encoding a putative serralysin-like metalloprotease (CLIBASIA_01345) was identified in the CLas genome. The expression levels of this gene were found to be higher in citrus leaves than in psyllids, suggesting a function for this protease in adaptation to the plant environment. Here, we study the putative role of CLas-serralysin (Las1345) as virulence factor. We first assayed whether Las1345 could be secreted by two different surrogate bacteria, Rhizobium leguminosarum bv. viciae A34 (A34) and Serratia marcescens. The protein was detected only in the cellular fraction of A34 and S. marcescens expressing Las1345, and increased protease activity of those bacteria by 2.55 and 4.25-fold, respectively. In contrast, Las1345 expressed in Nicotiana benthamiana leaves did not show protease activity nor alterations in the cell membrane, suggesting that Las1345 do not function as a protease in the plant cell. Las1345 expression negatively regulated cell motility, exopolysaccharide production, and biofilm formation in Xanthomonas campestris pv. campestris (Xcc). This bacterial phenotype was correlated with reduced growth and survival on leaf surfaces as well as reduced disease symptoms in N. benthamiana and Arabidopsis. These results support a model where Las1345 could modify extracellular components to adapt bacterial shape and appendages to the phloem environment, thus contributing to virulence.
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13
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Wang T, Huang Q, An X, Yang Y, Guan W, Zhao T. Type III secretion system genes hrcJ and hrpE affect virulence, hypersensitive response and biofilm formation of group II strains of Acidovorax citrulli. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2022. [DOI: 10.3389/fsufs.2022.995894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bacterial fruit blotch (BFB) caused by Acidovorax citrulli is a worldwide threat to watermelon and melon production. The type III secretion system (T3SS) plays an important role in the virulence of A. citrulli in its host plants and to induce hypersensitive response (HR) in its non-host plants. Little is known, however, about the contribution of the T3SS to biofilm formation in A. citrulli. We mutated two T3SS-related genes hrcJ and hrpE, respectively, and compared the mutants with their wild-type strain Aac-5 of A. citrulli, and their complementation strains on virulence, HR, and biofilm formation. Both mutants significantly reduced virulence in watermelon and melon seedlings and their ability to induce HR in tobacco leaves. Such reduction phenotypes were significantly recovered to the wild-type level, when the mutant strains were complemented with the wild-type hrcJ and hrpE genes. Interestingly, the two T3SS-related gene mutants also displayed enhanced ability to form biofilm, suggesting a different role of biofilm in the virulence of the group II stains of A. citrulli.
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14
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Long Y, Luo R, Xu Z, Cheng S, Li L, Ma H, Bao M, Li M, Ouyang Z, Wang N, Duan S. A Fluorescent Reporter-Based Evaluation Assay for Antibacterial Components Against Xanthomonas citri subsp. citri. Front Microbiol 2022; 13:864963. [PMID: 35602035 PMCID: PMC9114712 DOI: 10.3389/fmicb.2022.864963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Xanthomonas citri subsp. citri (Xcc) is the agent of citrus bacterial canker (CBC) disease, which has significantly reduced citrus quantity and quality in many producing areas worldwide. Copper-based bactericides are the primary products for CBC control and management, but the problems derived from copper-resistant and environmental contamination have become issues of anxiety. Thus, there is a need to find alternative antibacterial products instead of relying on a single type of agent. This study developed a method to evaluate the inhibition of antibacterial agents using the fluorescence-labeled recombinant Xcc strain (Xcc-eYFP). The optimization of timelines and parameters for the evaluation of antibacterial agents involved the use of a Spark™ multimode microplate reader. This evaluation and screening method can be applied to bactericides, cocktail-mixture formulations, antagonistic bacteria, and derived metabolites. The results showed that the minimum inhibitory concentration (MIC) of commercial bactericides determined by fluorescence agrees with the MIC values determined by the conventional method. A screened cocktail-mixture bactericide presents more activity than the individual agents during the protective effects. Notably, this method has been further developed in the screening of Xcc-antagonistic bacterial strains. In summary, we provide a validated strategy for screening and evaluation of different antibacterial components for inhibition against Xcc for CBC control and management.
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Affiliation(s)
- Yunfei Long
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Ruifang Luo
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Zhou Xu
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Shuyuan Cheng
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Ling Li
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Haijie Ma
- College of Agricultural and Food Sciences, Zhejiang A&F University, Hangzhou, China
| | - Minli Bao
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Min Li
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Zhigang Ouyang
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Nian Wang
- Department of Microbiology and Cell Science, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Shuo Duan
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
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15
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Morinière L, Mirabel L, Gueguen E, Bertolla F. A Comprehensive Overview of the Genes and Functions Required for Lettuce Infection by the Hemibiotrophic Phytopathogen Xanthomonas hortorum pv. vitians. mSystems 2022; 7:e0129021. [PMID: 35311560 PMCID: PMC9040725 DOI: 10.1128/msystems.01290-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 02/07/2022] [Indexed: 12/25/2022] Open
Abstract
The successful infection of a host plant by a phytopathogenic bacterium depends on a finely tuned molecular cross talk between the two partners. Thanks to transposon insertion sequencing techniques (Tn-seq), whole genomes can now be assessed to determine which genes are important for the fitness of several plant-associated bacteria in planta. Despite its agricultural relevance, the dynamic molecular interaction established between the foliar hemibiotrophic phytopathogen Xanthomonas hortorum pv. vitians and its host, lettuce (Lactuca sativa), remains completely unknown. To decipher the genes and functions mobilized by the pathogen throughout the infection process, we conducted a Tn-seq experiment in lettuce leaves to mimic the selective pressure occurring during natural infection. This genome-wide screening identified 170 genes whose disruption caused serious fitness defects in lettuce. A thorough examination of these genes using comparative genomics and gene set enrichment analyses highlighted that several functions and pathways were highly critical for the pathogen's survival. Numerous genes involved in amino acid, nucleic acid, and exopolysaccharide biosynthesis were critical. The xps type II secretion system operon, a few TonB-dependent transporters involved in carbohydrate or siderophore scavenging, and multiple genes of the carbohydrate catabolism pathways were also critical, emphasizing the importance of nutrition systems in a nutrient-limited environment. Finally, several genes implied in camouflage from the plant immune system and resistance to immunity-induced oxidative stress were strongly involved in host colonization. As a whole, these results highlight some of the central metabolic pathways and cellular functions critical for Xanthomonas host adaptation and pathogenesis. IMPORTANCE Xanthomonas hortorum was recently the subject of renewed interest, as several studies highlighted that its members were responsible for diseases in a wide range of plant species, including crops of agricultural relevance (e.g., tomato and carrot). Among X. hortorum variants, X. hortorum pv. vitians is a reemerging foliar hemibiotrophic phytopathogen responsible for severe outbreaks of bacterial leaf spot of lettuce all around the world. Despite recent findings, sustainable and practical means of disease control remain to be developed. Understanding the host-pathogen interaction from a molecular perspective is crucial to support these efforts. The genes and functions mobilized by X. hortorum pv. vitians during its interaction with lettuce had never been investigated. Our study sheds light on these processes by screening the whole pathogen genome for genes critical for its fitness during the infection process, using transposon insertion sequencing and comparative genomics.
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Affiliation(s)
- Lucas Morinière
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
| | - Laurène Mirabel
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
| | - Erwan Gueguen
- Université Lyon, Université Claude Bernard Lyon 1, INSA, CNRS, UMR Microbiologie, Adaptation, Pathogénie, Villeurbanne, France
| | - Franck Bertolla
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
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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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Shi Y, Yang X, Ye X, Feng J, Cheng T, Zhou X, Liu DX, Xu L, Wang J. The Methyltransferase HemK Regulates the Virulence and Nutrient Utilization of the Phytopathogenic Bacterium Xanthomonas citri Subsp. citri. Int J Mol Sci 2022; 23:ijms23073931. [PMID: 35409293 PMCID: PMC8999716 DOI: 10.3390/ijms23073931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 11/18/2022] Open
Abstract
Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xcc), seriously affects fruit quality and yield, leading to significant economic losses around the world. Understanding the mechanism of Xcc virulence is important for the effective control of Xcc infection. In this report, we investigate the role of a protein named HemK in the regulation of the virulence traits of Xcc. The hemK gene was deleted in the Xcc jx-6 background, and the ΔhemK mutant phenotypically displayed significantly decreased motility, biofilm formation, extracellular enzymes, and polysaccharides production, as well as increased sensitivity to oxidative stress and high temperatures. In accordance with the role of HemK in the regulation of a variety of virulence-associated phenotypes, the deletion of hemK resulted in reduced virulence on citrus plants as well as a compromised hypersensitive response on a non-host plant, Nicotiana benthamiana. These results indicated that HemK is required for the virulence of Xcc. To characterize the regulatory effect of hemK deletion on gene expression, RNA sequencing analysis was conducted using the wild-type Xcc jx-6 strain and its isogenic ΔhemK mutant strain, grown in XVM2 medium. Comparative transcriptome analysis of these two strains revealed that hemK deletion specifically changed the expression of several virulence-related genes associated with the bacterial secretion system, chemotaxis, and quorum sensing, and the expression of various genes related to nutrient utilization including amino acid metabolism, carbohydrate metabolism, and energy metabolism. In conclusion, our results indicate that HemK plays an essential role in virulence, the regulation of virulence factor synthesis, and the nutrient utilization of Xcc.
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Affiliation(s)
- Yu Shi
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
| | - Xiaobei Yang
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
| | - Xiaoxin Ye
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
| | - Jiaying Feng
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
| | - Tianfang Cheng
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
| | - Xiaofan Zhou
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
| | - Ding Xiang Liu
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
| | - Linghui Xu
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
- Correspondence: (L.X.); (J.W.)
| | - Junxia Wang
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (Y.S.); (X.Y.); (X.Y.); (J.F.); (T.C.); (X.Z.); (D.X.L.)
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
- Correspondence: (L.X.); (J.W.)
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18
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Nascimento CA, Teixeira-Silva NS, Caserta R, Marques MOM, Takita MA, de Souza AA. Overexpression of CsSAMT in Citrus sinensis Induces Defense Response and Increases Resistance to Xanthomonas citri subsp. citri. FRONTIERS IN PLANT SCIENCE 2022; 13:836582. [PMID: 35401588 PMCID: PMC8988300 DOI: 10.3389/fpls.2022.836582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Citrus canker is a destructive disease caused by Xanthomonas citri subsp. citri, which affects all commercial sweet orange (Citrus sinensis [L.] Osbeck) cultivars. Salicylic acid (SA) and systemic-acquired resistance (SAR) have been demonstrated to have a crucial role in mediating plant defense responses against this phytopathogen. To induce SAR, SA is converted to methyl salicylate (MeSA) by an SA-dependent methyltransferase (SAMT) and translocated systemically to prime noninfected distal tissues. Here, we generated sweet orange transgenic plants (based on cvs. Hamlin and Valencia) overexpressing the SAMT gene from Citrus (CsSAMT) and evaluated their resistance to citrus canker. We obtained four independent transgenic lines and confirmed their significantly higher MeSA volatilization compared to wild-type controls. Plants overexpressing CsSAMT showed reduced symptoms of citrus canker and bacterial populations in all transgenic lines without compromising plant development. One representative transgenic line (V44SAMT) was used to evaluate resistance response in primary and secondary sites. Without inoculation, V44SAMT modulated CsSAMT, CsNPR1, CsNPR3, and CsWRKY22 expression, indicating that this plant is in a primed defense status. The results demonstrate that MeSA signaling prompts the plant to respond more efficiently to pathogen attacks and induces immune responses in transgenic plants at both primary and secondary infection sites.
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Affiliation(s)
- Cesar Augusto Nascimento
- Citrus Research Center “Sylvio Moreira”, Agronomic Institute – IAC, Cordeirópolis, Brazil
- Department of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas – UNICAMP, Campinas, Brazil
| | | | - Raquel Caserta
- Citrus Research Center “Sylvio Moreira”, Agronomic Institute – IAC, Cordeirópolis, Brazil
| | | | - Marco Aurelio Takita
- Citrus Research Center “Sylvio Moreira”, Agronomic Institute – IAC, Cordeirópolis, Brazil
| | - Alessandra A. de Souza
- Citrus Research Center “Sylvio Moreira”, Agronomic Institute – IAC, Cordeirópolis, Brazil
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19
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de Souza-Neto RR, Carvalho IGB, Martins PMM, Picchi SC, Tomaz JP, Caserta R, Takita MA, de Souza AA. MqsR toxin as a biotechnological tool for plant pathogen bacterial control. Sci Rep 2022; 12:2794. [PMID: 35181693 PMCID: PMC8857320 DOI: 10.1038/s41598-022-06690-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 12/23/2021] [Indexed: 11/09/2022] Open
Abstract
Type II toxin-antitoxin (TA) systems are widespread in bacteria and are involved in important cell features, such as cell growth inhibition and antimicrobial tolerance, through the induction of persister cells. Overall, these characteristics are associated with bacterial survival under stress conditions and represent a significant genetic mechanism to be explored for antibacterial molecules. We verified that even though Xylella fastidiosa and Xanthomonas citri subsp. citri share closely related genomes, they have different Type II TA system contents. One important difference is the absence of mqsRA in X. citri. The toxin component of this TA system has been shown to inhibit the growth of X. fastidiosa. Thus, the absence of mqsRA in X. citri led us to explore the possibility of using the MqsR toxin to impair X. citri growth. We purified MqsR and confirmed that the toxin was able to inhibit X. citri. Subsequently, transgenic citrus plants producing MqsR showed a significant reduction in citrus canker and citrus variegated chlorosis symptoms caused, respectively, by X. citri and X. fastidiosa. This study demonstrates that the use of toxins from TA systems is a promising strategy to be explored aiming bacterial control.
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Affiliation(s)
- Reinaldo Rodrigues de Souza-Neto
- Citrus Research Center, Agronomic Institute - IAC, Cordeirópolis, SP, Brazil.,Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas - UNICAMP, Campinas, SP, Brazil
| | | | | | | | - Juarez Pires Tomaz
- Rural Development Institute of Parana - IAPAR-EMATER, Londrina, PR, Brazil
| | - Raquel Caserta
- Citrus Research Center, Agronomic Institute - IAC, Cordeirópolis, SP, Brazil
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20
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Preliminary characterization and phylogeny of sphingomonads occurring on Stone and Pome Fruit Trees in Northern Iran. Biologia (Bratisl) 2021. [DOI: 10.1007/s11756-021-00895-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zhang Y, Andrade MO, Wang W, Teper D, Romeo T, Wang N. Examination of the Global Regulon of CsrA in Xanthomonas citri subsp. citri Using Quantitative Proteomics and Other Approaches. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1236-1249. [PMID: 34282945 DOI: 10.1094/mpmi-05-21-0113-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The RNA-binding protein CsrA is a global posttranscriptional regulator and controls many physiological processes and virulence traits. Deletion of csrA caused loss of virulence, reduced motility and production of xanthan gum and substantial increase in glycogen accumulation, as well as enhanced bacterial aggregation and cell adhesion in Xanthomonas spp. How CsrA controls these traits is poorly understood. In this study, an isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomic analysis was conducted to compare the protein profile of wild-type strain Xanthomonas citri subsp. citri and the isogenic ΔcsrA strain. A total of 2,374 proteins were identified, and 284 were considered to be differentially expressed proteins (DEPS), among which 151 proteins were up-regulated and 133 were down-regulated in the ΔcsrA strain with respect to the wild-type strain. Enrichment analysis and a protein-protein interaction network analysis showed that CsrA regulates bacterial secretion systems, flagella, and xanthan gum biosynthesis. Several proteins encoded by the gumB operon were down-regulated, whereas proteins associated with flagellum assembly and the type IV secretion system were up-regulated in the ΔcsrA strain relative to the Xcc306 strain. These results were confirmed by β-glucuronidase assay or Western blot. RNA secondary structure prediction and a gel-shift assay indicated that CsrA binds to the Shine-Dalgarno sequence of virB5. In addition, the iTRAQ analysis identified 248 DEPs that were not previously identified in transcriptome analyses. Among them, CsrA regulates levels of eight regulatory proteins (ColR, GacA, GlpR, KdgR, MoxR, PilH, RecX, and YgiX), seven TonB-dependent receptors, four outer membrane proteins, and two ferric enterobactin receptors. Taken together, this study greatly expands understanding of the regulatory network of CsrA in X. citri subsp. citri.[Formula: see text] Copyright © 2021 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)
- Yanan Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
- Center for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing, Yunnan, 655011, China
| | - Maxuel O Andrade
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Wenting Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
- Department of Plant Pathology, University of Florida, Gainesville FL 32611, U.S.A
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
| | - Tony Romeo
- Department of Microbiology and Cell Sciences, University of Florida, Gainesville FL 32611, U.S.A
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
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Bashir I, War AF, Rafiq I, Reshi ZA, Rashid I, Shouche YS. Phyllosphere microbiome: Diversity and functions. Microbiol Res 2021; 254:126888. [PMID: 34700185 DOI: 10.1016/j.micres.2021.126888] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/15/2021] [Accepted: 09/30/2021] [Indexed: 12/28/2022]
Abstract
Phyllosphere or aerial surface of plants represents the globally largest and peculiar microbial habitat that inhabits diverse and rich communities of bacteria, fungi, viruses, cyanobacteria, actinobacteria, nematodes, and protozoans. These hyperdiverse microbial communities are related to the host's specific functional traits and influence the host's physiology and the ecosystem's functioning. In the last few years, significant advances have been made in unravelling several aspects of phyllosphere microbiology, including diversity and microbial community composition, dynamics, and functional interactions. This review highlights the current knowledge about the assembly, structure, and composition of phyllosphere microbial communities across spatio-temporal scales, besides functional significance of different microbial communities to the plant host and the surrounding environment. The knowledge will help develop strategies for modelling and manipulating these highly beneficial microbial consortia for furthering scientific inquiry into their interactions with the host plants and also for their useful and economic utilization.
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Affiliation(s)
- Iqra Bashir
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India.
| | - Aadil Farooq War
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
| | - Iflah Rafiq
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
| | - Zafar A Reshi
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
| | - Irfan Rashid
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
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Teper D, Xu J, Pandey SS, Wang N. PthAW1, a Transcription Activator-Like Effector of Xanthomonas citri subsp. citri, Promotes Host-Specific Immune Responses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1033-1047. [PMID: 33970668 DOI: 10.1094/mpmi-01-21-0026-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Citrus canker disease caused by Xanthomonas citri subsp. citri is one of the most destructive diseases in citrus. X. citri subsp. citri pathotypes display different host ranges. X. citri subsp. citri strain A (XccA) causes canker disease in most commercial citrus varieties, whereas strain AW (XccAW), which is genetically similar to XccA, infects only lime and alemow. Understanding the mechanism that determines the host range of pathogens is critical to investigating and utilizing host resistance. We hypothesized that XccAW would undergo mutations in genes that restrict its host range when artificially inoculated into incompatible citrus varieties. To test this hypothesis, we used an experimental evolution approach to identify phenotypic traits and genetic loci associated with the adaptation of XccAW to incompatible sweet orange. Repeated inoculation and reisolation cycles improved the ability of three independent XccAW strains to colonize sweet orange. Adapted XccAW strains displayed increased expression of type III secretion system and effector genes. Genome sequencing analysis indicated that two of the adapted strains harbored mutations in pthAW1, a transcription activator-like effector (TALE) gene, that corresponded to the removal of one or two repeats from the central DNA-binding repeat region. Introduction of the original but not the adapted pthAW1 variants into XccA abolished its ability to cause canker symptoms in sweet orange, Meyer lemon, and clementine but not in other XccAW-resistant citrus varieties. The original pthAW1, when expressed in XccA, induced ion leakage and the expression of pathogenesis-related genes but had no effect on CsLOB1 expression in sweet orange. Our study has identified a novel host-specific avirulence TALE and demonstrated active adaptive rearrangements of the TALE repeat array during host adaptation.[Formula: see text] Copyright © 2021 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)
- Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
| | - Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, U.S.A
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Biofilm formation by strains of Burkholderia cenocepacia lineages IIIA and IIIB and B. gladioli pv. alliicola associated with onion bacterial scale rot. Braz J Microbiol 2021; 52:1665-1675. [PMID: 34351603 DOI: 10.1007/s42770-021-00564-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/27/2021] [Indexed: 10/20/2022] Open
Abstract
The Burkholderia genus has high ecological and nutritional versatility, having species capable of causing diseases in animals, humans, and plants. During chronic infections in humans, biofilm formation is a characteristic often associated with strains from different species of this genus. However, there is still no information on the formation of biofilms by plant pathogenic strains of B. cenocepacia (Bce) lineages IIIA and IIIB and B. gladioli pv. alliicola (Bga), which are associated with onion bacterial scale rot in the semi-arid region of northeast Brazil. In this study, we performed an in vitro characterization of biofilm formation ability in different culture media by the phytopathogenic strains of Bce and Bga and investigated its relationship with swarming motility. Our results indicated the existence of an intraspecific variation in biofilm formation capacity in vitro by these bacteria and the existence of a negative correlation between swarming motility and biofilm formation for strains of Bce lineage IIIB. In addition, histopathological analyses performed using optical microscopy and scanning electron microscopy revealed the formation of biofilm in vivo by Bce strains in onion tissues.
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Tano J, Ripa MB, Tondo ML, Carrau A, Petrocelli S, Rodriguez MV, Ferreira V, Siri MI, Piskulic L, Orellano EG. Light modulates important physiological features of Ralstonia pseudosolanacearum during the colonization of tomato plants. Sci Rep 2021; 11:14531. [PMID: 34267245 PMCID: PMC8282871 DOI: 10.1038/s41598-021-93871-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 06/25/2021] [Indexed: 02/06/2023] Open
Abstract
Ralstonia pseudosolanacearum GMI1000 (Rpso GMI1000) is a soil-borne vascular phytopathogen that infects host plants through the root system causing wilting disease in a wide range of agro-economic interest crops, producing economical losses. Several features contribute to the full bacterial virulence. In this work we study the participation of light, an important environmental factor, in the regulation of the physiological attributes and infectivity of Rpso GMI1000. In silico analysis of the Rpso genome revealed the presence of a Rsp0254 gene, which encodes a putative blue light LOV-type photoreceptor. We constructed a mutant strain of Rpso lacking the LOV protein and found that the loss of this protein and light, influenced characteristics involved in the pathogenicity process such as motility, adhesion and the biofilms development, which allows the successful host plant colonization, rendering bacterial wilt. This protein could be involved in the adaptive responses to environmental changes. We demonstrated that light sensing and the LOV protein, would be used as a location signal in the host plant, to regulate the expression of several virulence factors, in a time and tissue dependent way. Consequently, bacteria could use an external signal and Rpsolov gene to know their location within plant tissue during the colonization process.
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Affiliation(s)
- Josefina Tano
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina
| | - María Belén Ripa
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina
| | - María Laura Tondo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Analía Carrau
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina
| | - Silvana Petrocelli
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - María Victoria Rodriguez
- Área Biología Vegetal, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Virginia Ferreira
- Área Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - María Inés Siri
- Área Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Laura Piskulic
- Área Estadística y Procesamiento de datos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Elena Graciela Orellano
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas (IBR-FBIOyF), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario (CONICET-UNR), Suipacha 531, S2002LRK, Rosario, Argentina.
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de Sousa LP. Bacterial communities of indoor surface of stingless bee nests. PLoS One 2021; 16:e0252933. [PMID: 34242231 PMCID: PMC8270128 DOI: 10.1371/journal.pone.0252933] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/25/2021] [Indexed: 12/15/2022] Open
Abstract
Microbes have been identified as fundamental for the good health of bees, acting as pathogens, protective agent against infection/inorganic toxic compounds, degradation of recalcitrant secondary plant metabolites, definition of social group membership, carbohydrate metabolism, honey and bee pollen production. However, study of microbiota associated with bees have been largely confined to the honeybees and solitary bees. Here, I characterized the microbiota of indoor surface nest of four brazilian stingless bee species (Apidae: Meliponini) with different construction behaviors and populations. Bees that use predominantly plant material to build the nest (Frieseomelitta varia and Tetragonisca angustula) have a microbiome dominated by bacteria found in the phylloplane and flowers such as Pseudomonas sp. and Sphingomonas sp. Species that use mud and feces (Trigona spinipes) possess a microbiome dominated by coliforms such as Escherichia coli and Alcaligenes faecalis. Melipona quadrifasciata, which uses both mud / feces and plant resin, showed a hybrid microbiome with microbes found in soil, feces and plant material. These findings indicate that indoor surface microbiome varies widely among bees and reflects the materials used in the construction of the nests.
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Affiliation(s)
- Leandro Pio de Sousa
- Department of Genetic, Evolution, Microbiology and Immunology, Institute of Biology, State University of Campinas, Campinas, Brazil
- * E-mail:
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27
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Mitre LK, Teixeira‐Silva NS, Rybak K, Magalhães DM, de Souza‐Neto RR, Robatzek S, Zipfel C, de Souza AA. The Arabidopsis immune receptor EFR increases resistance to the bacterial pathogens Xanthomonas and Xylella in transgenic sweet orange. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:1294-1296. [PMID: 33991397 PMCID: PMC8313127 DOI: 10.1111/pbi.13629] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 05/06/2021] [Indexed: 05/22/2023]
Affiliation(s)
- Letícia Kuster Mitre
- Centro de Citricultura Sylvio Moreira – IACCordeirópolisSPBrazil
- University of CampinasCampinasSPBrazil
| | | | - Katarzyna Rybak
- LMU BiocenterLudwig‐Maximilians‐Universität MünchenMartinsriedGermany
| | - Diogo Maciel Magalhães
- Centro de Citricultura Sylvio Moreira – IACCordeirópolisSPBrazil
- University of CampinasCampinasSPBrazil
| | | | - Silke Robatzek
- LMU BiocenterLudwig‐Maximilians‐Universität MünchenMartinsriedGermany
| | - Cyril Zipfel
- Institute of Plant and Microbial Biology and Zürich‐Basel Plant Science CenterUniversity of ZürichZürichSwitzerland
- The Sainsbury LaboratoryUniversity of East AngliaNorwich Research Park, NorwichUK
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Picchi SC, Granato LM, Franzini MJF, Andrade MO, Takita MA, Machado MA, de Souza AA. Modified Monosaccharides Content of Xanthan Gum Impairs Citrus Canker Disease by Affecting the Epiphytic Lifestyle of Xanthomonas citri subsp. citri. Microorganisms 2021; 9:microorganisms9061176. [PMID: 34072545 PMCID: PMC8229982 DOI: 10.3390/microorganisms9061176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 11/16/2022] Open
Abstract
Xanthomonas citri subsp. citri (X. citri) is a plant pathogenic bacterium causing citrus canker disease. The xanA gene encodes a phosphoglucomutase/phosphomannomutase protein that is a key enzyme required for the synthesis of lipopolysaccharides and exopolysaccharides in Xanthomonads. In this work, firstly we isolated a xanA transposon mutant (xanA::Tn5) and analyzed its phenotypes as biofilm formation, xanthan gum production, and pathogenesis on the sweet orange host. Moreover, to confirm the xanA role in the impaired phenotypes we further produced a non-polar deletion mutant (ΔxanA) and performed the complementation of both xanA mutants. In addition, we analyzed the percentages of the xanthan gum monosaccharides produced by X. citri wild-type and xanA mutant. The mutant strain had higher ratios of mannose, galactose, and xylose and lower ratios of rhamnose, glucuronic acid, and glucose than the wild-type strain. Such changes in the saccharide composition led to the reduction of xanthan yield in the xanA deficient strain, affecting also other important features in X. citri, such as biofilm formation and sliding motility. Moreover, we showed that xanA::Tn5 caused no symptoms on host leaves after spraying, a method that mimetics the natural infection condition. These results suggest that xanA plays an important role in the epiphytical stage on the leaves that is essential for the successful interaction with the host, including adaptive advantage for bacterial X. citri survival and host invasion, which culminates in pathogenicity.
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Affiliation(s)
- Simone Cristina Picchi
- Biotechnology Lab, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 1349070, Brazil; (S.C.P.); (M.J.F.F.); (M.A.T.); (M.A.M.)
| | - Laís Moreira Granato
- Biotechnology Lab, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 1349070, Brazil; (S.C.P.); (M.J.F.F.); (M.A.T.); (M.A.M.)
- Correspondence: (L.M.G.); (A.A.d.S.)
| | - Maria Júlia Festa Franzini
- Biotechnology Lab, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 1349070, Brazil; (S.C.P.); (M.J.F.F.); (M.A.T.); (M.A.M.)
| | - Maxuel Oliveira Andrade
- Bioscience National Lab, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo 13083100, Brazil;
| | - Marco Aurélio Takita
- Biotechnology Lab, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 1349070, Brazil; (S.C.P.); (M.J.F.F.); (M.A.T.); (M.A.M.)
| | - Marcos Antonio Machado
- Biotechnology Lab, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 1349070, Brazil; (S.C.P.); (M.J.F.F.); (M.A.T.); (M.A.M.)
| | - Alessandra Alves de Souza
- Biotechnology Lab, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 1349070, Brazil; (S.C.P.); (M.J.F.F.); (M.A.T.); (M.A.M.)
- Correspondence: (L.M.G.); (A.A.d.S.)
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29
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Caccalano MN, Dilarri G, Zamuner CFC, Domingues DS, Ferreira H. Hexanoic acid: a new potential substitute for copper-based agrochemicals against citrus canker. J Appl Microbiol 2021; 131:2488-2499. [PMID: 34008224 DOI: 10.1111/jam.15125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/29/2021] [Accepted: 04/11/2021] [Indexed: 01/16/2023]
Abstract
AIMS The aim of the study is to evaluate hexanoic acid (HA) as an alternative to manage citrus canker. METHODS AND RESULTS The minimal growth inhibitory concentration of HA against Xanthomonas citri subsp. citri was determined at 2·15 mmol l-1 using a respiratory activity assay. Growth curves at different pH values showed that growth inhibition was not due to media acidification induced by HA. The germination rate and root elongation of Lactuca sativa seeds exposed to different concentrations of HA (varying from 0·86 to 5·16 mmol l-1 ) were assessed to screen for phytotoxicity. The acid exhibited low phytotoxicity for L. sativa at 1·29 and 2·58 mmol l-1 . To evaluate the ability of HA to protect citrus against X. citri infection, leaves of Citrus sinensis were sprayed with the acid and subsequently challenged with X. citri. HA at 3·44 mmol l-1 was able to protect citrus against infection, showing a reduction of three orders of magnitude in the number of citrus canker lesions per cm2 when compared to the untreated negative control. CONCLUSION HA is a potential alternative to copper for citrus canker management. SIGNIFICANCE AND IMPACT OF THE STUDY HA inhibits X. citri growth, exhibits low phytotoxicity and is an alternative to copper for the protection of citrus plants against bacterial infection.
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Affiliation(s)
- M N Caccalano
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - G Dilarri
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - C F C Zamuner
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - D S Domingues
- Department of Biodiversity, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - H Ferreira
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
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Bacteriophage-Mediated Control of Phytopathogenic Xanthomonads: A Promising Green Solution for the Future. Microorganisms 2021; 9:microorganisms9051056. [PMID: 34068401 PMCID: PMC8153558 DOI: 10.3390/microorganisms9051056] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/05/2021] [Accepted: 05/11/2021] [Indexed: 12/21/2022] Open
Abstract
Xanthomonads, members of the family Xanthomonadaceae, are economically important plant pathogenic bacteria responsible for infections of over 400 plant species. Bacteriophage-based biopesticides can provide an environmentally friendly, effective solution to control these bacteria. Bacteriophage-based biocontrol has important advantages over chemical pesticides, and treatment with these biopesticides is a minor intervention into the microflora. However, bacteriophages’ agricultural application has limitations rooted in these viruses’ biological properties as active substances. These disadvantageous features, together with the complicated registration process of bacteriophage-based biopesticides, means that there are few products available on the market. This review summarizes our knowledge of the Xanthomonas-host plant and bacteriophage-host bacterium interaction’s possible influence on bacteriophage-based biocontrol strategies and provides examples of greenhouse and field trials and products readily available in the EU and the USA. It also details the most important advantages and limitations of the agricultural application of bacteriophages. This paper also investigates the legal background and industrial property right issues of bacteriophage-based biopesticides. When appropriately applied, bacteriophages can provide a promising tool against xanthomonads, a possibility that is untapped. Information presented in this review aims to explore the potential of bacteriophage-based biopesticides in the control of xanthomonads in the future.
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Beyond the Wall: Exopolysaccharides in the Biofilm Lifestyle of Pathogenic and Beneficial Plant-Associated Pseudomonas. Microorganisms 2021; 9:microorganisms9020445. [PMID: 33670010 PMCID: PMC7926942 DOI: 10.3390/microorganisms9020445] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/12/2021] [Accepted: 02/18/2021] [Indexed: 11/16/2022] Open
Abstract
The formation of biofilms results from a multicellular mode of growth, in which bacteria remain enwrapped by an extracellular matrix of their own production. Many different bacteria form biofilms, but among the most studied species are those that belong to the Pseudomonas genus due to the metabolic versatility, ubiquity, and ecological significance of members of this group of microorganisms. Within the Pseudomonas genus, biofilm studies have mainly focused on the opportunistic human pathogen Pseudomonas aeruginosa due to its clinical importance. The extracellular matrix of P. aeruginosa is mainly composed of exopolysaccharides, which have been shown to be important for the biofilm architecture and pathogenic features of this bacterium. Notably, some of the exopolysaccharides recurrently used by P. aeruginosa during biofilm formation, such as the alginate and polysaccharide synthesis loci (Psl) polysaccharides, are also used by pathogenic and beneficial plant-associated Pseudomonas during their interaction with plants. Interestingly, their functions are multifaceted and seem to be highly dependent on the bacterial lifestyle and genetic context of production. This paper reviews the functions and significance of the exopolysaccharides produced by plant-associated Pseudomonas, particularly the alginate, Psl, and cellulose polysaccharides, focusing on their equivalents produced in P. aeruginosa within the context of pathogenic and beneficial interactions.
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Shafiei SNS, Ahmad K, Ikhsan NFM, Ismail SI, Sijam K. Suppression of Xanthomonas oryzae pv. oryzae biofilm formation by Acacia mangium methanol leaf extract. BRAZ J BIOL 2021; 81:11-17. [PMID: 32074168 DOI: 10.1590/1519-6984.206124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 09/05/2019] [Indexed: 01/27/2023] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo), a pathogen responsible for rice bacterial leaf blight, produces biofilm to protect viable Xoo cells from antimicrobial agents. A study was conducted to determine the potency of Acacia mangium methanol (AMMH) leaf extract as a Xoo biofilm inhibitor. Four concentrations (3.13, 6.25, 9.38, and 12.5 mg/mL) of AMMH leaf extract were tested for their ability to inhibit Xoo biofilm formation on a 96-well microtiter plate. The results showed that the negative controls had the highest O.D. values from other treatments, indicating the intense formation of biofilm. This was followed by the positive control (Streptomycin sulfate, 0.2 mg/mL) and AMMH leaf extract at concentration 3.13 mg/mL, which showed no significant differences in their O.D. values (1.96 and 1.57, respectively). All other treatments at concentrations of 6.25, 9.38, and 12.5 mg/mL showed no significant differences in their O.D. values (0.91, 0.79, and 0.53, respectively). For inhibition percentages, treatment with concentration 12.5 mg/mL gave the highest result (81.25%) followed by treatment at concentrations 6.25 and 9.38 mg/mL that showed no significant differences in their inhibition percentage (67.75% and 72.23%, respectively). Concentration 3.13 mg/mL resulted in 44.49% of biofilm inhibition and the positive control resulted in 30.75% of biofilm inhibition. Confocal laser scanning microscopy (CLSM) analysis of Xoo biofilm inhibition and breakdown showed the presence of non-viable Xoo cells and changes in aggregation size due to increase in AMMH leaf extract concentration. Control slides showed the absence of Xoo dead cells.
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Affiliation(s)
- S N Sarah Shafiei
- Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia
| | - K Ahmad
- Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia.,Institute of Plantation Studies - IKP, Universiti Putra Malaysia, Selangor, Malaysia
| | - N F M Ikhsan
- Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia
| | - S I Ismail
- Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia
| | - K Sijam
- Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, Selangor, Malaysia
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Chaudhry V, Runge P, Sengupta P, Doehlemann G, Parker JE, Kemen E. Shaping the leaf microbiota: plant-microbe-microbe interactions. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:36-56. [PMID: 32910810 PMCID: PMC8210630 DOI: 10.1093/jxb/eraa417] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 09/07/2020] [Indexed: 05/28/2023]
Abstract
The aerial portion of a plant, namely the leaf, is inhabited by pathogenic and non-pathogenic microbes. The leaf's physical and chemical properties, combined with fluctuating and often challenging environmental factors, create surfaces that require a high degree of adaptation for microbial colonization. As a consequence, specific interactive processes have evolved to establish a plant leaf niche. Little is known about the impact of the host immune system on phyllosphere colonization by non-pathogenic microbes. These organisms can trigger plant basal defenses and benefit the host by priming for enhanced resistance to pathogens. In most disease resistance responses, microbial signals are recognized by extra- or intracellular receptors. The interactions tend to be species specific and it is unclear how they shape leaf microbial communities. In natural habitats, microbe-microbe interactions are also important for shaping leaf communities. To protect resources, plant colonizers have developed direct antagonistic or host manipulation strategies to fight competitors. Phyllosphere-colonizing microbes respond to abiotic and biotic fluctuations and are therefore an important resource for adaptive and protective traits. Understanding the complex regulatory host-microbe-microbe networks is needed to transfer current knowledge to biotechnological applications such as plant-protective probiotics.
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Affiliation(s)
- Vasvi Chaudhry
- Department of Microbial Interactions, IMIT/ZMBP, University of
Tübingen, Tübingen, Germany
| | - Paul Runge
- Department of Microbial Interactions, IMIT/ZMBP, University of
Tübingen, Tübingen, Germany
- Max Planck Institute for Plant Breeding Research, Köln, Germany
| | - Priyamedha Sengupta
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences
(CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne,
Germany
| | - Gunther Doehlemann
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences
(CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne,
Germany
| | - Jane E Parker
- Max Planck Institute for Plant Breeding Research, Köln, Germany
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences
(CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne,
Germany
| | - Eric Kemen
- Department of Microbial Interactions, IMIT/ZMBP, University of
Tübingen, Tübingen, Germany
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Pal G, Mehta D, Singh S, Magal K, Gupta S, Jha G, Bajaj A, Ramu VS. Foliar Application or Seed Priming of Cholic Acid-Glycine Conjugates can Mitigate/Prevent the Rice Bacterial Leaf Blight Disease via Activating Plant Defense Genes. FRONTIERS IN PLANT SCIENCE 2021; 12:746912. [PMID: 34630495 PMCID: PMC8497891 DOI: 10.3389/fpls.2021.746912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 08/25/2021] [Indexed: 05/06/2023]
Abstract
Xanthomonas Oryzae pv. oryzae (Xoo) causes bacterial blight and Rhizoctonia solani (R. solani) causes sheath blight in rice accounting for >75% of crop losses. Therefore, there is an urgent need to develop strategies for the mitigation of these pathogen infections. In this study, we report the antimicrobial efficacy of Cholic Acid-Glycine Conjugates (CAGCs) against Xoo and R. solani. We show that CAGC C6 is a broad-spectrum antimicrobial and is also able to degrade biofilms. The application of C6 did not hamper plant growth and showed minimal effect on the plant cell membranes. Exogenous application of C6 on pre-infection or post-infection of Xoo on rice susceptible genotype Taichung native (TN1) can mitigate the bacterial load and improve resistance through upregulation of plant defense genes. We further demonstrate that C6 can induce plant defense responses when seeds were primed with C6 CAGC. Therefore, this study demonstrates the potential of CAGCs as effective antimicrobials for crop protection that can be further explored for field applications.
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Affiliation(s)
- Garima Pal
- Laboratory of Plant Functional Genomics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Devashish Mehta
- Laboratory of Nanotechnology and Chemical Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Saurabh Singh
- Laboratory of Plant Microbe Interactions, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Kalai Magal
- Laboratory of Plant Functional Genomics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Siddhi Gupta
- Laboratory of Nanotechnology and Chemical Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Gopaljee Jha
- Laboratory of Plant Microbe Interactions, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Avinash Bajaj
- Laboratory of Nanotechnology and Chemical Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
- *Correspondence: Avinash Bajaj
| | - Vemanna S. Ramu
- Laboratory of Plant Functional Genomics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
- Vemanna S. Ramu
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Qiao K, Liu Q, Xia Y, Zhang S. Evaluation of a Small-Molecule Compound, N-Acetylcysteine, for the Management of Bacterial Spot of Tomato Caused by Copper-Resistant Xanthomonas perforans. PLANT DISEASE 2021; 105:108-113. [PMID: 33175655 DOI: 10.1094/pdis-05-20-0928-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bacterial spot caused by Xanthomonas spp. is one of the major diseases in tomato. Xanthomonas perforans is the main pathogen of bacterial spot on tomato in Florida. Currently, application of copper fungicides is the primary measure used to manage this disease. However, the development of copper resistance in X. perforans and accumulation of copper in the environment are major concerns for excessive use of copper-based products in agriculture. Due to its antibacterial properties and low environmental impact, N-acetylcysteine (NAC), a small molecule commonly used in medicine for human bacterial diseases, has been studied in agriculture for the control of plant bacterial pathogens, including X. citri and Xylella fastidiosa. This study evaluated the effect of NAC alone and in combination with copper on a copper-resistant X. perforans strain in vitro and its ability to control bacterial spot of tomato under greenhouse and field conditions. In vitro, the minimum inhibitory concentration of NAC against the X. perforans strain was 2,048 mg liter-1. NAC increased sensitivity of the copper-resistant X. perforans to copper in vitro when application of NAC was followed by copper application after 6 h. In greenhouse assays, NAC applied alone or in combination with copper significantly (P < 0.05) reduced the disease severity of bacterial spot on tomato compared with the untreated control. NAC at 100 mg liter-1 + copper at 300 mg liter-1 consistently exhibited synergistic effects against bacterial spot. In the field trials, NAC at 1,000 mg liter-1 + copper at 150 mg liter-1 significantly reduced disease severity compared with the untreated control. Results from this study demonstrated that NAC significantly reduced the disease severity of bacterial spot of tomato and enhanced the efficacy of copper against copper-resistant X. perforans, indicating that NAC could be applied for the effective management of bacterial spot of tomato.
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Affiliation(s)
- Kang Qiao
- Tropical Research and Education Center, Department of Plant Pathology, University of Florida, IFAS, Homestead, FL 33031, U.S.A
- Key Laboratory of Pesticide Toxicology & Application Technique, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P.R. China
| | - Qingchun Liu
- Tropical Research and Education Center, Department of Plant Pathology, University of Florida, IFAS, Homestead, FL 33031, U.S.A
| | - Ye Xia
- Department of Plant Pathology, Ohio State University, Columbus, OH 43210, U.S.A
| | - Shouan Zhang
- Tropical Research and Education Center, Department of Plant Pathology, University of Florida, IFAS, Homestead, FL 33031, U.S.A
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Favaro MA, Molina MC, Roeschlin RA, Gadea J, Gariglio N, Marano MR. Different Responses in Mandarin Cultivars Uncover a Role of Cuticular Waxes in the Resistance to Citrus Canker. PHYTOPATHOLOGY 2020; 110:1791-1801. [PMID: 32573348 DOI: 10.1094/phyto-02-20-0053-r] [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
'Okitsu' is a mandarin cultivar showing substantial resistance to X. citri subsp. citri (X. citri). We have previously shown that this cultivar has significantly lower canker incidence and severity than 'Clemenules', particularly during early stages of leaf development in the field. This differential response is only seen when the leaves are inoculated by spraying, suggesting that leaf surface contributes to resistance. In this work, we have studied structural and chemical properties of leaf surface barriers of both cultivars. Ultrastructural analysis showed a thicker cuticle covering epidermal surface and guard cells in young 'Okitsu' leaves than in 'Clemenules'. This thicker cuticle was associated with a smaller stomatal aperture and reduced cuticle permeability. These findings correlated with an accumulation of cuticular wax components, including primary alcohols, alkanes, and fatty acids. None of these differences were observed in mature leaves, where both cultivars are equally resistant to the bacterium. Remarkably, mechanical alteration of cuticular thickness of young 'Okitsu' leaves allows canker development. Furthermore, cuticular waxes extracted from young 'Okitsu' leaves have higher antibacterial activity against X. citri than 'Clemenules'. Taken together, these data suggest that a faster development of epicuticular waxes in 'Okitsu' leaves play a central role in its resistance to X. citri.
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Affiliation(s)
- María A Favaro
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2000FHN Rosario, Argentina
- Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 590, S2002LRK Rosario, Argentina
- Instituto de Ciencias Agropecuarias del Litoral, Universidad Nacional del Litoral, CONICET, Facultad de Ciencias Agrarias, Kreder 2805, 3080 HOF Esperanza, Santa Fe, Argentina
| | - María C Molina
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2000FHN Rosario, Argentina
- Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 590, S2002LRK Rosario, Argentina
| | - Roxana A Roeschlin
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2000FHN Rosario, Argentina
- Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 590, S2002LRK Rosario, Argentina
| | - José Gadea
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-CSIC, Ingeniero Fausto Elio, S/N, 46022 Valencia, España
| | - Norberto Gariglio
- Instituto de Ciencias Agropecuarias del Litoral, Universidad Nacional del Litoral, CONICET, Facultad de Ciencias Agrarias, Kreder 2805, 3080 HOF Esperanza, Santa Fe, Argentina
| | - María R Marano
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ocampo y Esmeralda S/N, S2000FHN Rosario, Argentina
- Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 590, S2002LRK Rosario, Argentina
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Virulence Genetics of an Erwinia amylovora Putative Polysaccharide Transporter Family Member. J Bacteriol 2020; 202:JB.00390-20. [PMID: 32839177 DOI: 10.1128/jb.00390-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/07/2020] [Indexed: 01/26/2023] Open
Abstract
The Gram-negative enterobacterium Erwinia amylovora causes fire blight disease in apple and pear trees. Lipopolysaccharides and the exopolysaccharide amylovoran are essential E. amylovora virulence factors. We found that mutations in rfbX disrupted amylovoran production and virulence in apple fruits and tree shoots and that the deletion of yibD suppressed the rfbX mutant phenotype. The level of expression of yibD was about 10-fold higher in the ΔrfbX mutant than the wild type. A forward genetic suppressor screen in the ΔrfbX mutant uncovered multiple mutations in yibD and supported the conclusion that the virulence defect of rfbX mutants is due to reduced amylovoran production. The yibD and rfbX genes are expressed as a two-gene operon, yibD rfbX The rfbX gene encodes a previously uncharacterized putative polysaccharide subunit transporter, while yibD encodes a predicted glycosyltransferase. Mutation of rfbX did not have a detectable effect on lipopolysaccharide patterns; however, the overexpression of yibD in both the wild-type and ΔyibD ΔrfbX genetic backgrounds disrupted both amylovoran and lipopolysaccharide production. Additionally, the overexpression of yibD in the ΔyibD ΔrfbX mutant inhibited bacterial growth in amylovoran-inducing medium. This growth inhibition phenotype was used in a forward genetic suppressor screen and reverse-genetics tests to identify several genes involved in lipopolysaccharide production, which, when mutated, restored the ability of the ΔyibD ΔrfbX mutant overexpressing yibD to grow in amylovoran-inducing medium. Remarkably, all the lipopolysaccharide gene mutants tested were defective in lipopolysaccharide and amylovoran production. These results reveal a genetic connection between amylovoran and lipopolysaccharide production in E. amylovora IMPORTANCE This study discovered previously unknown genetic connections between exopolysaccharide and lipopolysaccharide production in the fire blight pathogen Erwinia amylovora This represents a step forward in our understanding of the biology underlying the production of these two macromolecules. Fire blight is an economically important disease that impacts the production of apples and pears worldwide. Few fire blight control measures are available, and growers rely heavily on antibiotic applications at bloom time. Both exopolysaccharide and lipopolysaccharide are E. amylovora virulence factors. Our results indicate that the overexpression of the yibD gene in E. amylovora disrupts both lipopolysaccharide production and exopolysaccharide production. This effect could potentially be used as the basis for the development of an antivirulence treatment for the prevention of fire blight disease.
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Morão LG, Lorenzoni ASG, Chakraborty P, Ayusso GM, Cavalca LB, Santos MB, Marques BC, Dilarri G, Zamuner C, Regasini LO, Ferreira H, Scheffers DJ. Investigating the Modes of Action of the Antimicrobial Chalcones BC1 and T9A. Molecules 2020; 25:molecules25204596. [PMID: 33050236 PMCID: PMC7587203 DOI: 10.3390/molecules25204596] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/29/2020] [Accepted: 10/06/2020] [Indexed: 02/02/2023] Open
Abstract
Xanthomonas citri subsp. citri (X. citri) is an important phytopathogen and causes Asiatic Citrus Canker (ACC). To control ACC, copper sprays are commonly used. As copper is an environmentally damaging heavy metal, new antimicrobials are needed to combat citrus canker. Here, we explored the antimicrobial activity of chalcones, specifically the methoxychalcone BC1 and the hydroxychalcone T9A, against X. citri and the model organism Bacillus subtilis. BC1 and T9A prevented growth of X. citri and B. subtilis in concentrations varying from 20 µg/mL to 40 µg/mL. BC1 and T9A decreased incorporation of radiolabeled precursors of DNA, RNA, protein, and peptidoglycan in X. citri and B. subtilis. Both compounds mildly affected respiratory activity in X. citri, but T9A strongly decreased respiratory activity in B. subtilis. In line with that finding, intracellular ATP decreased strongly in B. subtilis upon T9A treatment, whereas BC1 increased intracellular ATP. In X. citri, both compounds resulted in a decrease in intracellular ATP. Cell division seems not to be affected in X. citri, and, although in B. subtilis the formation of FtsZ-rings is affected, a FtsZ GTPase activity assay suggests that this is an indirect effect. The chalcones studied here represent a sustainable alternative to copper for the control of ACC, and further studies are ongoing to elucidate their precise modes of action.
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Affiliation(s)
- Luana G. Morão
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, 130506-900 SP Rio Claro, Brazil; (L.G.M.); (G.D.); (C.Z.)
| | - André S. G. Lorenzoni
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands; (A.S.G.L.); (P.C.); (L.B.C.)
| | - Parichita Chakraborty
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands; (A.S.G.L.); (P.C.); (L.B.C.)
| | - Gabriela M. Ayusso
- Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, 15054-000 SP São José do Rio Preto, Brazil; (G.M.A.); (M.B.S.); (B.C.M.); (L.O.R.)
| | - Lucia B. Cavalca
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands; (A.S.G.L.); (P.C.); (L.B.C.)
| | - Mariana B. Santos
- Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, 15054-000 SP São José do Rio Preto, Brazil; (G.M.A.); (M.B.S.); (B.C.M.); (L.O.R.)
| | - Beatriz C. Marques
- Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, 15054-000 SP São José do Rio Preto, Brazil; (G.M.A.); (M.B.S.); (B.C.M.); (L.O.R.)
| | - Guilherme Dilarri
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, 130506-900 SP Rio Claro, Brazil; (L.G.M.); (G.D.); (C.Z.)
| | - Caio Zamuner
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, 130506-900 SP Rio Claro, Brazil; (L.G.M.); (G.D.); (C.Z.)
| | - Luis O. Regasini
- Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, 15054-000 SP São José do Rio Preto, Brazil; (G.M.A.); (M.B.S.); (B.C.M.); (L.O.R.)
| | - Henrique Ferreira
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, 130506-900 SP Rio Claro, Brazil; (L.G.M.); (G.D.); (C.Z.)
- Correspondence: (H.F.); (D.-J.S.); Tel.: +31-50-3632319 (D.-J.S.)
| | - Dirk-Jan Scheffers
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands; (A.S.G.L.); (P.C.); (L.B.C.)
- Correspondence: (H.F.); (D.-J.S.); Tel.: +31-50-3632319 (D.-J.S.)
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An SQ, Potnis N, Dow M, Vorhölter FJ, He YQ, Becker A, Teper D, Li Y, Wang N, Bleris L, Tang JL. Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogen Xanthomonas. FEMS Microbiol Rev 2020; 44:1-32. [PMID: 31578554 PMCID: PMC8042644 DOI: 10.1093/femsre/fuz024] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/29/2019] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health.
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Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centre (NBIC), Biological Sciences, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Rouse Life Science Building, Auburn University, Auburn AL36849, USA
| | - Max Dow
- School of Microbiology, Food Science & Technology Building, University College Cork, Cork T12 K8AF, Ireland
| | | | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
| | - Anke Becker
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Yi Li
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Leonidas Bleris
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX75080, USA
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
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40
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Identification and characterization of virulence-attenuated mutants in Ralstonia solanacearum as potential biocontrol agents against bacterial wilt of Pogostemon cablin. Microb Pathog 2020; 147:104418. [PMID: 32739402 DOI: 10.1016/j.micpath.2020.104418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/30/2020] [Accepted: 07/23/2020] [Indexed: 12/31/2022]
Abstract
Ralstonia solanacearum is a soil-borne pathogen that causes bacterial wilt worldwide. The virulence-attenuated mutants were able to combat the soil-borne plant diseases. In this study, we screened the virulence-attenuated mutant PRS-84-4-49 of Ralstonia solanacearum and demonstrated that this strain showed a significant biocontrol effect against patchouli bacterial wilt. Three putative virulence-attenuated mutants obtained in our previous preliminary screen were individually tested for their pathogenicity to patchouli plants. Mutant PRS-84-4-49 showed significantly less virulence to patchouli plants than the other investigated mutants. The virulence-attenuated mutant PRS-84-4-49 was then evaluated for its potential to control patchouli bacterial wilt. The results revealed that the biocontrol treatment significantly reduced disease severity compared with the inoculated control plants, their highest disease incidence were 33% and 63%, respectively, at 5 days post-inoculation. Mutant PRS-84-4-49 exhibited less motility and produced fewer biofilms than the wild-type strain. Therefore, our results demonstrate that virulence-attenuated mutant of Ralstonia solanacearum has potential as biological control agent capable of suppressing patchouli bacterial wilt.
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41
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Zhang J, Wei C, Li S, Hu D, Song B. Discovery of novel bis-sulfoxide derivatives bearing acylhydrazone and benzothiazole moieties as potential antibacterial agents. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 167:104605. [PMID: 32527439 DOI: 10.1016/j.pestbp.2020.104605] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
On the basis of the active substructure combination principle, 24 novel synthesis of novel bis-sulfoxide derivatives bearing acylhydrazone and benzothiazole moieties as potential antibacterial agents were designed and synthesized. The bioactivity assay results showed that many compounds had significant in vitro inhibitory effects against Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas citri pv. citri (Xac). Notably, compound 4b had the best in vitro antibacterial activity against Xoo at an half-maximal effective concentration value of 11.4 μg/mL, which was superior to those of thiodiazole copper (TDC) and bismerthiazol (BMT). Compared with TDC and BMT, compound 4b was more effective in vivo controlling rice bacterial leaf blight with curative and protection activities of 42.5% and 40.3%, respectively. In addition, compound 4b can influence biofilm formation, inhibit extracellular polysaccharide production, and ultimately reduce the pathogenicity of Xoo. All the results indicated that bis-sulfoxide derivatives bearing acylhydrazone and benzothiazole moieties can be used for the development of small-molecule pesticides with high antibacterial activity.
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Affiliation(s)
- Jianhong Zhang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Chunle Wei
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Shaoyuan Li
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Deyu Hu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Baoan Song
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China..
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42
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Fu H, Zhao M, Xu J, Tan L, Han J, Li D, Wang M, Xiao S, Ma X, Deng Z. Citron C-05 inhibits both the penetration and colonization of Xanthomonas citri subsp. citri to achieve resistance to citrus canker disease. HORTICULTURE RESEARCH 2020; 7:58. [PMID: 32377349 PMCID: PMC7193574 DOI: 10.1038/s41438-020-0278-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 02/05/2020] [Accepted: 02/12/2020] [Indexed: 06/11/2023]
Abstract
Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a serious bacterial disease that affects citrus production worldwide. Citron C-05 (Citrus medica) is the only germplasm in the Citrus genus that has been identified to exhibit strong resistance to Xcc. However, it has not been determined when, where, and how Xcc is restricted in the tissues of Citron C-05 during the infection process. In the present study, we investigated the spatiotemporal growth dynamics of an eGFP-labeled virulent Xcc (eGFP-Xcc) strain in Citron C-05 along with five susceptible biotypes (i.e., lemon, pummelo, sour orange, sweet orange, and ponkan mandarin) upon inoculation via the spraying or leaf infiltration of a bacterial suspension. The results from extensive confocal laser scanning microscopy analyses showed that while Xcc grew rapidly in plants of all five susceptible genotypes, Xcc was severely restricted in the epidermal and mesophyll cell layers of the leaves of Citron C-05 in the early stage of infection. Not surprisingly, resistance against Xcc in Citron C-05 was found to be associated with the production of reactive oxygen species and hypersensitive response-like cell death, as well as greater upregulation of several defense-related genes, including a pathogenesis-related gene (PR1) and a glutathione S-transferase gene (GST1), compared with sweet orange as a susceptible control. Taken together, our results not only provide further valuable details of the spatiotemporal dynamics of the host entry, propagation, and spread of Xcc in both resistant and susceptible citrus plants but also suggest that resistance to Xcc in Citron C-05 may be attributed to the activation of multiple defense mechanisms.
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Affiliation(s)
- Hongyan Fu
- College of Horticulture, Hunan Agricultural University, 410128 Changsha, Hunan China
- National Center for Citrus Improvement, 410128 Changsha, Hunan China
| | - Mingming Zhao
- College of Horticulture, Hunan Agricultural University, 410128 Changsha, Hunan China
- National Center for Citrus Improvement, 410128 Changsha, Hunan China
| | - Jing Xu
- College of Horticulture, Hunan Agricultural University, 410128 Changsha, Hunan China
- National Center for Citrus Improvement, 410128 Changsha, Hunan China
| | - Limei Tan
- National Center for Citrus Improvement, 410128 Changsha, Hunan China
| | - Jian Han
- Hunan Horticultural Research Institute, 410125 Changsha, Hunan China
| | - Dazhi Li
- College of Horticulture, Hunan Agricultural University, 410128 Changsha, Hunan China
- National Center for Citrus Improvement, 410128 Changsha, Hunan China
| | - Meijun Wang
- College of Horticulture, Hunan Agricultural University, 410128 Changsha, Hunan China
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology Research & Department of Plant Sciences and Landscape Architecture, University of Maryland College Park, Rockville, MD 20850 USA
| | - Xianfeng Ma
- College of Horticulture, Hunan Agricultural University, 410128 Changsha, Hunan China
- National Center for Citrus Improvement, 410128 Changsha, Hunan China
| | - Ziniu Deng
- College of Horticulture, Hunan Agricultural University, 410128 Changsha, Hunan China
- National Center for Citrus Improvement, 410128 Changsha, Hunan China
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Guan W, Wang T, Huang Q, Tian E, Liu B, Yang Y, Zhao T. A LuxR-type regulator, AcrR, regulates flagellar assembly and contributes to virulence, motility, biofilm formation, and growth ability of Acidovorax citrulli. MOLECULAR PLANT PATHOLOGY 2020; 21:489-501. [PMID: 31943660 PMCID: PMC7060138 DOI: 10.1111/mpp.12910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 12/05/2019] [Accepted: 12/20/2019] [Indexed: 05/26/2023]
Abstract
LuxR-type regulators regulate many bacterial processes and play important roles in bacterial motility and virulence. Acidovorax citrulli is a seedborne bacterial pathogen responsible for bacterial fruit blotch, which causes great losses in melon and watermelon worldwide. We identified a LuxR-type, nonquorum sensing-related regulator, AcrR, in the group II strain Aac-5 of A. citrulli. We found that the acrR mutant lost twitching and swimming motilities, and flagellar formation. It also showed reduced virulence, but increased biofilm formation and growth ability. Transcriptomic analysis revealed that 394 genes were differentially expressed in the acrR mutant of A. citrulli, including 33 genes involved in flagellar assembly. Our results suggest that AcrR may act as a global regulator affecting multiple important biological functions of A. citrulli.
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Affiliation(s)
- Wei Guan
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Tielin Wang
- State Key Laboratory Breeding Base of Dao‐di HerbsNational Resource Center for Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijingChina
| | - Qi Huang
- Floral and Nursery Plants Research UnitU.S. Department of AgricultureAgricultural Research ServiceBeltsvilleMDUSA
| | - Eryuan Tian
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Bo Liu
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Yuwen Yang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Tingchang Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
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Fan Z, Shi J, Luo N, Ding M, Bao X. Synthesis, Crystal Structure, and Agricultural Antimicrobial Evaluation of Novel Quinazoline Thioether Derivatives Incorporating the 1,2,4-Triazolo[4,3- a]pyridine Moiety. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:11598-11606. [PMID: 31560195 DOI: 10.1021/acs.jafc.9b04733] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A total of 22 quinazoline thioether derivatives incorporating a 1,2,4-triazolo[4,3-a]pyridine moiety were designed, synthesized, and evaluated as antimicrobial agents in agriculture. Among these compounds, the chemical structure of compound 6l was further confirmed via single-crystal X-ray diffraction analysis. The bioassay results revealed that some of the compounds possessed noticeable in vitro antibacterial activities against the tested phytopathogenic bacteria. For example, compounds 6b and 6g had EC50 values as low as 10.0 and 24.7 μg/mL against Xanthomonas axonopodis pv. citri (Xac), respectively, which were significantly better than that of the commercial agrobactericide bismerthiazol (56.9 μg/mL). Particularly, compound 6b was also found to be capable of suppressing the pathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo) approximately 12-fold more potent than control bismerthiazol, in terms of their EC50 values (7.2 versus 89.8 μg/mL). Importantly, the most active compound 6b turned out to be one with the highest hydrophilicity and the lowest molecular weight within the series. In vivo bioassays further showed the application prospect of 6b as a promising plant bactericide for controlling Xoo. Additionally, in vitro antifungal activities of these compounds were also evaluated at the concentration of 50 μg/mL. Overall, the present study demonstrated the potential of 1,2,4-triazolo[4,3-a]pyridine-bearing quinazoline thioether derivatives as efficient agricultural antibacterial agents for crop protection.
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Affiliation(s)
- Zhijiang Fan
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Centre for Research and Development of Fine Chemicals , Guizhou University , Guiyang 550025 , P. R. China
| | - Jun Shi
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Centre for Research and Development of Fine Chemicals , Guizhou University , Guiyang 550025 , P. R. China
| | - Na Luo
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Centre for Research and Development of Fine Chemicals , Guizhou University , Guiyang 550025 , P. R. China
| | - Muhan Ding
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Centre for Research and Development of Fine Chemicals , Guizhou University , Guiyang 550025 , P. R. China
| | - Xiaoping Bao
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Centre for Research and Development of Fine Chemicals , Guizhou University , Guiyang 550025 , P. R. China
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45
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Grinberg M, Orevi T, Steinberg S, Kashtan N. Bacterial survival in microscopic surface wetness. eLife 2019; 8:e48508. [PMID: 31610846 PMCID: PMC6824842 DOI: 10.7554/elife.48508] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/20/2019] [Indexed: 01/06/2023] Open
Abstract
Plant leaves constitute a huge microbial habitat of global importance. How microorganisms survive the dry daytime on leaves and avoid desiccation is not well understood. There is evidence that microscopic surface wetness in the form of thin films and micrometer-sized droplets, invisible to the naked eye, persists on leaves during daytime due to deliquescence - the absorption of water until dissolution - of hygroscopic aerosols. Here, we study how such microscopic wetness affects cell survival. We show that, on surfaces drying under moderate humidity, stable microdroplets form around bacterial aggregates due to capillary pinning and deliquescence. Notably, droplet-size increases with aggregate-size, and cell survival is higher the larger the droplet. This phenomenon was observed for 13 bacterial species, two of which - Pseudomonas fluorescens and P. putida - were studied in depth. Microdroplet formation around aggregates is likely key to bacterial survival in a variety of unsaturated microbial habitats, including leaf surfaces.
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Affiliation(s)
- Maor Grinberg
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
| | - Tomer Orevi
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
| | - Shifra Steinberg
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
| | - Nadav Kashtan
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food, and EnvironmentHebrew UniversityRehovotIsrael
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46
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Garcia-Cruz A, Aguilar-Gonzalez CN, Rincon-Enriquez G, Ilyina A, Guizar-Gonzalez C, Mtz-Enriquez AI, Diaz-Jimenez L, Quinones-Aguilar EE, Enriquez-Vara J, Ramos-Gonzalez R. BactericidalIn-VitroEffect of Zinc Ferrite Nanoparticles and the Orange Wax Extracts on Three Phytopathogen Microorganisms. IEEE Trans Nanobioscience 2019; 18:528-534. [DOI: 10.1109/tnb.2019.2937840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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47
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The ecnA Antitoxin Is Important Not Only for Human Pathogens: Evidence of Its Role in the Plant Pathogen Xanthomonas citri subsp. citri. J Bacteriol 2019; 201:JB.00796-18. [PMID: 31358614 DOI: 10.1128/jb.00796-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 07/24/2019] [Indexed: 11/20/2022] Open
Abstract
Xanthomonas citri subsp. citri causes citrus canker disease worldwide in most commercial varieties of citrus. Its transmission occurs mainly by wind-driven rain. Once X. citri reaches a leaf, it can epiphytically survive by forming a biofilm, which enhances the persistence of the bacteria under different environmental stresses and plays an important role in the early stages of host infection. Therefore, the study of genes involved in biofilm formation has been an important step toward understanding the bacterial strategy for survival in and infection of host plants. In this work, we show that the ecnAB toxin-antitoxin (TA) system, which was previously identified only in human bacterial pathogens, is conserved in many Xanthomonas spp. We further show that in X. citri, ecnA is involved in important processes, such as biofilm formation, exopolysaccharide (EPS) production, and motility. In addition, we show that ecnA plays a role in X. citri survival and virulence in host plants. Thus, this mechanism represents an important bacterial strategy for survival under stress conditions.IMPORTANCE Very little is known about TA systems in phytopathogenic bacteria. ecnAB, in particular, has only been studied in bacterial human pathogens. Here, we showed that it is present in a wide range of Xanthomonas sp. phytopathogens; moreover, this is the first work to investigate the functional role of this TA system in Xanthomonas citri biology, suggesting an important new role in adaptation and survival with implications for bacterial pathogenicity.
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48
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Pruvost O, Boyer K, Ravigné V, Richard D, Vernière C. Deciphering how plant pathogenic bacteria disperse and meet: Molecular epidemiology of Xanthomonas citri pv. citri at microgeographic scales in a tropical area of Asiatic citrus canker endemicity. Evol Appl 2019; 12:1523-1538. [PMID: 31462912 PMCID: PMC6708428 DOI: 10.1111/eva.12788] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/25/2019] [Accepted: 02/24/2019] [Indexed: 12/15/2022] Open
Abstract
Although some plant pathogenic bacteria represent a significant threat to agriculture, the determinants of their ecological success and evolutionary potential are still poorly understood. Refining our understanding of bacterial strain circulation at small spatial scales and the biological significance and evolutionary consequences of co-infections are key questions. The study of bacterial population biology can be challenging, because it requires high-resolution markers that can be genotyped with a high throughput. Here, we overcame this difficulty for Xanthomonas citri pv. citri, a genetically monomorphic bacterium causing Asiatic citrus canker (ACC). Using a genotyping method that did not require cultivating the bacterium or purifying DNA, we deciphered the pathogen's spatial genetic structure at several microgeographic scales, down to single lesion, in a situation of ACC endemicity. In a grove where copper was recurrently applied for ACC management, copper-susceptible and copper-resistant X. citri pv. citri coexisted and the bacterial population structured as three genetic clusters, suggesting a polyclonal contamination. The range of spatial dependency, estimated for the two largest clusters, was four times greater for the cluster predominantly composed of copper-resistant bacteria. Consistently, the evenness value calculated for this cluster was indicative of increased transmission. Linkage disequilibrium was high even at a tree scale, probably due to a combination of clonality and admixture. Approximately 1% of samples exhibited within-lesion multilocus polymorphism, explained at least in part by polyclonal infections. Canker lesions, which are of major biological significance as an inoculum source, may also represent a preferred niche for horizontal gene transfer. This study points out the potential of genotyping data for estimating the range of spatial dependency of plant bacterial pathogens, an important parameter for guiding disease management strategies.
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Affiliation(s)
| | | | | | - Damien Richard
- CIRADUMR PVBMTSaint Pierre, La RéunionFrance
- ANSESSaint Pierre, La RéunionFrance
- Université de la RéunionUMR PVBMTSaint Denis, La RéunionFrance
| | - Christian Vernière
- CIRADUMR PVBMTSaint Pierre, La RéunionFrance
- CIRADUMR BGPIMontpellierFrance
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49
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Garita-Cambronero J, Sena-Vélez M, Ferragud E, Sabuquillo P, Redondo C, Cubero J. Xanthomonas citri subsp. citri and Xanthomonas arboricola pv. pruni: Comparative analysis of two pathogens producing similar symptoms in different host plants. PLoS One 2019; 14:e0219797. [PMID: 31318915 PMCID: PMC6639005 DOI: 10.1371/journal.pone.0219797] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/01/2019] [Indexed: 01/06/2023] Open
Abstract
Comparative studies in Xanthomonas have provided a vast amount of data that enabled to deepen in the knowledge of those factors associated with virulence and Xanthomonas plant interaction. The species of this genus present a wide range of host plants and a large number of studies have been focused to elucidate which mechanism are involved in this characteristic. In this study, comparative genomic and phenotypic analysis were performed between X. citri subsp. citri (Xcc), one of the most studied pathogens within Xanthomonas, and X. arboricola pv. pruni (Xap), a pathogen which has aroused great interest in recent time. The work was aimed to find those elements that contribute to their host divergence despite the convergence in the symptoms that each species cause on Citrus spp. and Prunus spp., respectively. This study reveals a set of genes that could be putatively associated with the adaptation of these pathogens to their hosts, being the most remarkable those involved in environmental sensing systems such as the case of the TonB-dependent transporters, the sensors of the two-component system and the methyl accepting chemotaxis proteins. Other important variants were found in processes related to the decomposition of the cell wall as could be appreciated by their dissimilar set of cell-wall degrading enzymes. Type three effectors, as one of the most important factors in delineating the host specificity in Xanthomonas, also showed a different array when comparing both species, being some of them unique to each pathogen. On the other hand, only small variations could be connected to other features such as the motility appendages and surface adhesion proteins, but these differences were accompanied by a dissimilar capacity to attach on host and non-host leaf surface. The molecular factors found in this work provide the basis to perform a more in-depth functional analyses that unveil those actual factors associated with pathogenesis and host specificity in Xcc and Xap.
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Affiliation(s)
- Jerson Garita-Cambronero
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain.,Centro de Investigación de Biocombustibles y Bioproductos, Instituto Tecnológico Agrario de Castilla y León (ITACyL), Villarejo de Órbigo, Leon, Spain
| | - Marta Sena-Vélez
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain.,Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Elisa Ferragud
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
| | - Pilar Sabuquillo
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
| | - Cristina Redondo
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
| | - Jaime Cubero
- Departamento de Protección Vegetal, Laboratorio Bacteriología, Instituto Nacional de Investigación y Tecnología Agraria (INIA), Madrid, Spain
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50
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The Xanthomonas citri pv. citri Type VI Secretion System is Induced During Epiphytic Colonization of Citrus. Curr Microbiol 2019; 76:1105-1111. [PMID: 31289847 DOI: 10.1007/s00284-019-01735-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 07/01/2019] [Indexed: 12/26/2022]
Abstract
Xanthomonas citri pv. citri (X. citri pv. citri) is the causal agent of Asiatic citrus canker and infects economically important citrus crops. X. citri pv. citri contains one type VI secretion system (T6SS) required for resistance to predation by the soil amoeba Dictyostelium discoideum and induced by the ECF sigma factor EcfK in the presence of amoeba. In this work, we describe the analysis of T6SS gene expression during interaction with host plants. We show that T6SS genes and the cognate positive regulator ecfK are upregulated during growth in the plant surface (epiphytic) and maintain low expression levels during growth inside plant mesophyll. In addition, expression of the virulence-associated T3SS is also induced during epiphytic growth and shows a temporal induction pattern during growth inside plant leaves. The T6SS is not required for adhesion to leaf surface and biofilm formation during the first stages of plant colonization nor for killing of yeasts cells. Since the phyllosphere is colonized by eukaryotic predators of bacteria, induction of the X. citri pv. citri anti-amoeba T6SS during epiphytic growth suggests the presence of an environmental signal that triggers the resistance phenotype.
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