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Wang Q, Zhang Y, Chen R, Zhang L, Fu M, Zhang L. Comparative genomic analyses provide insight into the pathogenicity of three Pseudomonas syringae pv. actinidiae strains from Anhui Province, China. BMC Genomics 2024; 25:461. [PMID: 38734623 PMCID: PMC11088785 DOI: 10.1186/s12864-024-10384-1] [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: 12/19/2023] [Accepted: 05/07/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND Pseudomonas syringae pv. actinidiae (Psa) is an important bacterial plant pathogen that causes severe damage to the kiwifruit industry worldwide. Three Psa strains were recently obtained from different kiwifruit orchards in Anhui Province, China. The present study mainly focused on the variations in virulence and genome characteristics of these strains based on the pathogenicity assays and comparative genomic analyses. RESULTS Three strains were identified as biovar 3 (Psa3), along with strain QSY6 showing higher virulence than JZY2 and YXH1 in pathogenicity assays. The whole genome assembly revealed that each of the three strains had a circular chromosome and a complete plasmid. The chromosome sizes ranged from 6.5 to 6.6 Mb with a GC content of approximately 58.39 to 58.46%, and a predicted number of protein-coding sequences ranging from 5,884 to 6,019. The three strains clustered tightly with 8 Psa3 reference strains in terms of average nucleotide identity (ANI), whole-genome-based phylogenetic analysis, and pangenome analysis, while they were evolutionarily distinct from other biovars (Psa1 and Psa5). Variations were observed in the repertoire of effectors of the type III secretion system among all 15 strains. Moreover, synteny analysis of the three sequenced strains revealed eight genomic regions containing 308 genes exclusively present in the highly virulent strain QSY6. Further investigation of these genes showed that 16 virulence-related genes highlight several key factors, such as effector delivery systems (type III secretion systems) and adherence (type IV pilus), which might be crucial for the virulence of QSY6. CONCLUSION Three Psa strains were identified and showed variant virulence in kiwifruit plant. Complete genome sequences and comparative genomic analyses further provided a theoretical basis for the potential pathogenic factors responsible for kiwifruit bacterial canker.
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Affiliation(s)
- Qian Wang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, College of Plant Protection, Anhui Agricultural University, Hefei, China
- State Key Laboratory of Vegetable Biobreeding, Tianjin Academy of Agricultural Sciences, Tianjin, China
| | - Yiju Zhang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, College of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Rui Chen
- State Key Laboratory of Vegetable Biobreeding, Tianjin Academy of Agricultural Sciences, Tianjin, China
| | - Lei Zhang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, College of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Min Fu
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, College of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Lixin Zhang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, College of Plant Protection, Anhui Agricultural University, Hefei, China.
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González AJ, Díaz D, Ciordia M, Landeras E. Occurrence of Pseudomonas syringae pvs. actinidiae, actinidifoliorum and Other P. syringae Strains on Kiwifruit in Northern Spain. Life (Basel) 2024; 14:208. [PMID: 38398717 PMCID: PMC10890144 DOI: 10.3390/life14020208] [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: 12/07/2023] [Revised: 01/24/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
Pseudomonas syringae pv. actinidiae (Psa), the agent causing bacterial canker of kiwifruit, has been present in the Principality of Asturias (PA), Northern Spain, since 2013, although with restricted distribution. In this study, 53 strains collected in kiwifruit orchards in PA during the period 2014-2020 were characterized by a polyphasic approach including biochemical and phylogenetic analysis. Thirty-three strains, previously identified by PCR as Psa, have been found to be a homogeneous group in phylogenetic analysis, which seems to indicate that there have been few introductions of the pathogen into the region. Two strains were confirmed as P. syringae pv. actinidifoliorum (Pfm), so this is the first report of Pfm in the PA. The remaining 18 strains were found to be close to P. avellanae and P. syringae pv. antirrhini or to strains described as Pfm look-alikes. Pathogenicity tests carried out on peppers with a selection of strains have shown that both Psa and Pfm caused clear damage, while the 18 atypical strains caused variable lesions. It would be necessary to carry out pathogenicity testing of atypical strains on kiwifruit plants to study the role of these strains in the kiwifruit pathosystem to evaluate their pathogenic potential in this crop.
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Affiliation(s)
- Ana J. González
- Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Ctra. AS-267, PK 19, 33300 Villaviciosa, Spain; (D.D.); (M.C.)
| | - David Díaz
- Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Ctra. AS-267, PK 19, 33300 Villaviciosa, Spain; (D.D.); (M.C.)
| | - Marta Ciordia
- Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Ctra. AS-267, PK 19, 33300 Villaviciosa, Spain; (D.D.); (M.C.)
| | - Elena Landeras
- Laboratorio de Sanidad Vegetal del Principado de Asturias, C/Lucas Rodríguez Pire, 4-Bajo, 33011 Oviedo, Spain;
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Ishiga T, Sakata N, Usuki G, Nguyen VT, Gomi K, Ishiga Y. Large-Scale Transposon Mutagenesis Reveals Type III Secretion Effector HopR1 Is a Major Virulence Factor in Pseudomonas syringae pv. actinidiae. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010141. [PMID: 36616271 PMCID: PMC9823363 DOI: 10.3390/plants12010141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/11/2022] [Accepted: 12/16/2022] [Indexed: 05/27/2023]
Abstract
Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a serious threat to kiwifruit production worldwide. Four biovars (Psa biovar 1; Psa1, Psa biovar 3; Psa3, Psa biovar 5; Psa5, and Psa biovar 6; Psa6) were reported in Japan, and virulent Psa3 strains spread rapidly to kiwifruit production areas worldwide. Therefore, there is an urgent need to develop critical management strategies for bacterial canker based on dissecting the dynamic interactions between Psa and kiwifruit. To investigate the molecular mechanism of Psa3 infection, we developed a rapid and reliable high-throughput flood-inoculation method using kiwifruit seedlings. Using this inoculation method, we screened 3000 Psa3 transposon insertion mutants and identified 91 reduced virulence mutants and characterized the transposon insertion sites in these mutants. We identified seven type III secretion system mutants, and four type III secretion effectors mutants including hopR1. Mature kiwifruit leaves spray-inoculated with the hopR1 mutant showed significantly reduced virulence compared to Psa3 wild-type, indicating that HopR1 has a critical role in Psa3 virulence. Deletion mutants of hopR1 in Psa1, Psa3, Psa5, and Psa6 revealed that the type III secretion effector HopR1 is a major virulence factor in these biovars. Moreover, hopR1 mutants of Psa3 failed to reopen stomata on kiwifruit leaves, suggesting that HopR1 facilitates Psa entry through stomata into plants. Furthermore, defense related genes were highly expressed in kiwifruit plants inoculated with hopR1 mutant compared to Psa wild-type, indicating that HopR1 suppresses defense-related genes of kiwifruit. These results suggest that HopR1 universally contributes to virulence in all Psa biovars by overcoming not only stomatal-based defense, but also apoplastic defense.
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Affiliation(s)
- Takako Ishiga
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
| | - Nanami Sakata
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
| | - Giyu Usuki
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
| | - Viet Tru Nguyen
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
- Western Highlands Agriculture and Forestry Science Institute, 53 Nguyen Luong Bang Street, Buon Ma Thuot City 630000, Vietnam
| | - Kenji Gomi
- Faculty of Agriculture, Kagawa University, Miki 761-0795, Kagawa, Japan
| | - Yasuhiro Ishiga
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
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Antibacterial mechanism of forsythoside A against Pseudomonas syringae pv. actinidiae. Microb Pathog 2022; 173:105858. [DOI: 10.1016/j.micpath.2022.105858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022]
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Yoon M, Middleditch MJ, Rikkerink EHA. A conserved glutamate residue in RPM1-INTERACTING PROTEIN4 is ADP-ribosylated by the Pseudomonas effector AvrRpm2 to activate RPM1-mediated plant resistance. THE PLANT CELL 2022; 34:4950-4972. [PMID: 36130293 PMCID: PMC9710000 DOI: 10.1093/plcell/koac286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
Gram-negative bacterial plant pathogens inject effectors into their hosts to hijack and manipulate metabolism, eluding surveillance at the battle frontier on the cell surface. The effector AvrRpm1Pma from Pseudomonas syringae pv. maculicola functions as an ADP-ribosyl transferase that modifies RESISTANCE TO P. SYRINGAE PV MACULICOLA1 (RPM1)-INTERACTING PROTEIN4 (RIN4), leading to the activation of Arabidopsis thaliana (Arabidopsis) resistance protein RPM1. Here we confirmed the ADP-ribosyl transferase activity of another bacterial effector, AvrRpm2Psa from P. syringae pv. actinidiae, via sequential inoculation of Pseudomonas strain Pto DC3000 harboring avrRpm2Psa following Agrobacterium-mediated transient expression of RIN4 in Nicotiana benthamiana. We conducted mutational analysis in combination with mass spectrometry to locate the target site in RIN4. A conserved glutamate residue (Glu156) is the most likely target for AvrRpm2Psa, as only Glu156 could be ADP-ribosylated to activate RPM1 among candidate target residues identified from the MS/MS fragmentation spectra. Soybean (Glycine max) and snap bean (Phaseolus vulgaris) RIN4 homologs without glutamate at the positions corresponding to Glu156 of Arabidopsis RIN4 are not ADP-ribosylated by bacterial AvrRpm2Psa. In contrast to the effector AvrB, AvrRpm2Psa does not require the phosphorylation of Thr166 in RIN4 to activate RPM1. Therefore, separate biochemical reactions by different pathogen effectors may trigger the activation of the same resistance protein via distinct modifications of RIN4.
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Affiliation(s)
- Minsoo Yoon
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Martin J Middleditch
- The School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Erik H A Rikkerink
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
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The OmpR-like Transcription Factor as a Negative Regulator of hrpR/S in Pseudomonas syringae pv. actinidiae. Int J Mol Sci 2022; 23:ijms232012306. [PMID: 36293158 PMCID: PMC9602974 DOI: 10.3390/ijms232012306] [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: 07/17/2022] [Revised: 09/28/2022] [Accepted: 10/10/2022] [Indexed: 11/05/2022] Open
Abstract
Bacterial canker of kiwifruit is a devastating disease caused by Pseudomonas syringae pv. actinidiae (Psa). The type III secretion system (T3SS), which translocates effectors into plant cells to subvert plant immunity and promote extracellular bacterial growth, is required for Psa virulence. Despite that the “HrpR/S-HrpL” cascade that sophisticatedly regulates the expression of T3SS and effectors has been well documented, the transcriptional regulators of hrpR/S remain to be determined. In this study, the OmpR-like transcription factor, previously identified by DNA pull-down assay, was found to be involved in the regulation of hrpR/S genes, and its regulatory mechanisms and other functions in Psa were explored through techniques including gene knockout and overexpression, ChIP-seq, and RNA-seq. The OmpR-like transcription factor had binding sites in the promoter region of the hrpR/S, and the transcriptional level of the hrpR/S increased after the deletion of OmpR-like and decreased upon its overexpression in an OmpR-like deletion background. Additionally, OmpR-like overexpression reduced the strain’s capacity to form biofilms and lipopolysaccharides, led to its slow growth in King’s B medium, and reduced its swimming ability, although there was no significant effect on its pathogenicity against kiwifruit hosts. Our results indicated that OmpR-like directly and negatively regulates the transcription of hrpR/S and may be involved in the regulation of multiple biological processes in Psa. Our results provide a basis for further understanding the transcriptional regulation mechanism of hrpR/S in Psa.
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7
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Hemara LM, Jayaraman J, Sutherland PW, Montefiori M, Arshed S, Chatterjee A, Chen R, Andersen MT, Mesarich CH, van der Linden O, Yoon M, Schipper MM, Vanneste JL, Brendolise C, Templeton MD. Effector loss drives adaptation of Pseudomonas syringae pv. actinidiae biovar 3 to Actinidia arguta. PLoS Pathog 2022; 18:e1010542. [PMID: 35622878 PMCID: PMC9182610 DOI: 10.1371/journal.ppat.1010542] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 06/09/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
Abstract
A pandemic isolate of Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) has devastated kiwifruit orchards growing cultivars of Actinidia chinensis. In contrast, A. arguta (kiwiberry) is not a host of Psa3. Resistance is mediated via effector-triggered immunity, as demonstrated by induction of the hypersensitive response in infected A. arguta leaves, observed by microscopy and quantified by ion-leakage assays. Isolates of Psa3 that cause disease in A. arguta have been isolated and analyzed, revealing a 51 kb deletion in the exchangeable effector locus (EEL). This natural EEL-mutant isolate and strains with synthetic knockouts of the EEL were more virulent in A. arguta plantlets than wild-type Psa3. Screening of a complete library of Psa3 effector knockout strains identified increased growth in planta for knockouts of four effectors–AvrRpm1a, HopF1c, HopZ5a, and the EEL effector HopAW1a –suggesting a resistance response in A. arguta. Hypersensitive response (HR) assays indicate that three of these effectors trigger a host species-specific HR. A Psa3 strain with all four effectors knocked out escaped host recognition, but a cumulative increase in bacterial pathogenicity and virulence was not observed. These avirulence effectors can be used in turn to identify the first cognate resistance genes in Actinidia for breeding durable resistance into future kiwifruit cultivars. Clonally propagated monoculture crop plants facilitate the emergence and spread of new diseases. Plant pathogens cause disease by the secretion of effectors that function by repressing the host defense response. While the last few decades have seen a huge increase in our understanding of the role effectors play in mediating plant-pathogen interactions, the combinations of effectors required for the establishment of plant disease and that account for host specificity are less well understood. Breeding genetic resistance is often used to protect plants from disease but it is frequently evaded by rapidly evolving pathogens. Pseudomonas syringae pv. actinidiae (Psa) which causes bacterial canker disease of kiwifruit has spread rapidly throughout the world’s kiwifruit orchards, particularly those growing cultivars of Actinidia chinensis. Other Actinidia species including A. arguta display strong resistance conferred by recognition of effectors delivered by Psa. We explore the depth and dynamics of Psa effector recognition by A. arguta and show that there is a trade-off between losses of effector recognition by A. arguta versus the retention of pathogenicity. Our findings should aid in the understanding of how to breed durable resistance into perennial plants challenged by swiftly evolving pathogens.
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Affiliation(s)
- Lauren M. Hemara
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Bioprotection Aoteoroa, New Zealand
| | - Jay Jayaraman
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
- Bioprotection Aoteoroa, New Zealand
| | - Paul W. Sutherland
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Mirco Montefiori
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Saadiah Arshed
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Abhishek Chatterjee
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Ronan Chen
- The New Zealand Institute for Plant and Food Research Limited, Food Industry Science Centre, Palmerston North, New Zealand
| | - Mark T. Andersen
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Carl H. Mesarich
- Bioprotection Aoteoroa, New Zealand
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Otto van der Linden
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Minsoo Yoon
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Magan M. Schipper
- The New Zealand Institute for Plant and Food Research Limited, Ruakura Campus, Hamilton, New Zealand
| | - Joel L. Vanneste
- The New Zealand Institute for Plant and Food Research Limited, Ruakura Campus, Hamilton, New Zealand
| | - Cyril Brendolise
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
| | - Matthew D. Templeton
- The New Zealand Institute for Plant and Food Research Limited, Mt. Albert Research Centre, Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Bioprotection Aoteoroa, New Zealand
- * E-mail: ,
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Liu Y, Liu M, Hu R, Bai J, He X, Jin Y. Isolation of the Novel Phage PHB09 and Its Potential Use against the Plant Pathogen Pseudomonas syringae pv. actinidiae. Viruses 2021; 13:v13112275. [PMID: 34835081 PMCID: PMC8622976 DOI: 10.3390/v13112275] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 12/26/2022] Open
Abstract
Bacteriophages are viruses that specifically infect target bacteria. Recently, bacteriophages have been considered potential biological control agents for bacterial pathogens due to their host specificity. Pseudomonas syringae pv. actinidiae (Psa) is a reemerging pathogen that causes bacterial canker of kiwifruit (Actinidia sp.). The economic impact of this pest and the development of resistance to antibiotics and copper sprays in Psa and other pathovars have led to investigation of alternative management strategies. Phage therapy may be a useful alternative to conventional treatments for controlling Psa infections. Although the efficacy of bacteriophage φ6 was evaluated for the control of Psa, the characteristics of other DNA bacteriophages infecting Psa remain unclear. In this study, the PHB09 lytic bacteriophage specific to Psa was isolated from kiwifruit orchard soil. Extensive host range testing using Psa isolated from kiwifruit orchards and other Pseudomonas strains showed PHB09 has a narrow host range. It remained stable over a wide range of temperatures (4-50 °C) and pH values (pH 3-11) and maintained stability for 50 min under ultraviolet irradiation. Complete genome sequence analysis indicated PHB09 might belong to a new myovirus genus in Caudoviricetes. Its genome contains a total of 94,844 bp and 186 predicted genes associated with phage structure, packaging, host lysis, DNA manipulation, transcription, and additional functions. The isolation and identification of PHB09 enrich the research on Pseudomonas phages and provide a promising biocontrol agent against kiwifruit bacterial canker.
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Martino G, Holtappels D, Vallino M, Chiapello M, Turina M, Lavigne R, Wagemans J, Ciuffo M. Molecular Characterization and Taxonomic Assignment of Three Phage Isolates from a Collection Infecting Pseudomonas syringae pv. actinidiae and P. syringae pv. phaseolicola from Northern Italy. Viruses 2021; 13:2083. [PMID: 34696512 PMCID: PMC8537276 DOI: 10.3390/v13102083] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 12/27/2022] Open
Abstract
Bacterial kiwifruit vine disease (Pseudomonas syringae pv. actinidiae, Psa) and halo blight of bean (P. syringae pv. phaseolicola, Pph) are routinely treated with copper, leading to environmental pollution and bacterial copper resistance. An alternative sustainable control method could be based on bacteriophages, as phage biocontrol offers high specificity and does not result in the spread of toxic residues into the environment or the food chain. In this research, specific phages suitable for phage-based biocontrol strategies effective against Psa and Pph were isolated and characterized. In total, sixteen lytic Pph phage isolates and seven lytic Psa phage isolates were isolated from soil in Piedmont and Veneto in northern Italy. Genome characterization of fifteen selected phages revealed that the isolated Pph phages were highly similar and could be considered as isolates of a novel species, whereas the isolated Psa phages grouped into four distinct clades, two of which represent putative novel species. No lysogeny-, virulence- or toxin-related genes were found in four phages, making them suitable for potential biocontrol purposes. A partial biological characterization including a host range analysis was performed on a representative subset of these isolates. This analysis was a prerequisite to assess their efficacy in greenhouse and in field trials, using different delivery strategies.
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Affiliation(s)
- Gabriele Martino
- Institute for Sustainable Plant Protection, National Research Council of Italy, I-10135 Torino, Italy; (G.M.); (M.V.); (M.C.); (M.T.)
| | - Dominique Holtappels
- Laboratory of Gene Technology, Department of Biosystems, Katholieke Universiteit Leuven, 3001 Leuven, Belgium; (D.H.); (R.L.); (J.W.)
| | - Marta Vallino
- Institute for Sustainable Plant Protection, National Research Council of Italy, I-10135 Torino, Italy; (G.M.); (M.V.); (M.C.); (M.T.)
| | - Marco Chiapello
- Institute for Sustainable Plant Protection, National Research Council of Italy, I-10135 Torino, Italy; (G.M.); (M.V.); (M.C.); (M.T.)
| | - Massimo Turina
- Institute for Sustainable Plant Protection, National Research Council of Italy, I-10135 Torino, Italy; (G.M.); (M.V.); (M.C.); (M.T.)
| | - Rob Lavigne
- Laboratory of Gene Technology, Department of Biosystems, Katholieke Universiteit Leuven, 3001 Leuven, Belgium; (D.H.); (R.L.); (J.W.)
| | - Jeroen Wagemans
- Laboratory of Gene Technology, Department of Biosystems, Katholieke Universiteit Leuven, 3001 Leuven, Belgium; (D.H.); (R.L.); (J.W.)
| | - Marina Ciuffo
- Institute for Sustainable Plant Protection, National Research Council of Italy, I-10135 Torino, Italy; (G.M.); (M.V.); (M.C.); (M.T.)
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Guardado-Valdivia L, Chacón-López A, Murillo J, Poveda J, Hernández-Flores JL, Xoca-Orozco L, Aguilera S. The Pbo Cluster from Pseudomonas syringae pv. Phaseolicola NPS3121 Is Thermoregulated and Required for Phaseolotoxin Biosynthesis. Toxins (Basel) 2021; 13:toxins13090628. [PMID: 34564632 PMCID: PMC8473136 DOI: 10.3390/toxins13090628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 11/16/2022] Open
Abstract
The bean (Phaseolus vulgaris) pathogen Pseudomonas syringae pv. phaseolicola NPS3121 synthesizes phaseolotoxin in a thermoregulated way, with optimum production at 18 °C. Gene PSPPH_4550 was previously shown to be thermoregulated and required for phaseolotoxin biosynthesis. Here, we established that PSPPH_4550 is part of a cluster of 16 genes, the Pbo cluster, included in a genomic island with a limited distribution in P. syringae and unrelated to the possession of the phaseolotoxin biosynthesis cluster. We identified typical non-ribosomal peptide synthetase, and polyketide synthetase domains in several of the pbo deduced products. RT-PCR and the analysis of polar mutants showed that the Pbo cluster is organized in four transcriptional units, including one monocistronic and three polycistronic. Operons pboA and pboO are both essential for phaseolotoxin biosynthesis, while pboK and pboJ only influence the amount of toxin produced. The three polycistronic units were transcribed at high levels at 18 °C but not at 28 °C, whereas gene pboJ was constitutively expressed. Together, our data suggest that the Pbo cluster synthesizes secondary metabolite(s), which could participate in the regulation of phaseolotoxin biosynthesis.
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Affiliation(s)
- Lizeth Guardado-Valdivia
- Laboratorio Integral de Investigación en Alimentos, Departamento de Química y Bioquímica, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, 63175 Nayarit, Mexico; (L.G.-V.); (A.C.-L.)
| | - Alejandra Chacón-López
- Laboratorio Integral de Investigación en Alimentos, Departamento de Química y Bioquímica, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, 63175 Nayarit, Mexico; (L.G.-V.); (A.C.-L.)
| | - Jesús Murillo
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra (UPNA), Edificio de Agrobiotecnología, Avda. de Pamplona 123, 31192 Mutilva Baja, Spain; (J.M.); (J.P.)
| | - Jorge Poveda
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra (UPNA), Edificio de Agrobiotecnología, Avda. de Pamplona 123, 31192 Mutilva Baja, Spain; (J.M.); (J.P.)
| | - José Luis Hernández-Flores
- Centro de Investigación y Estudios Avanzados del IPN, Departamento de Ingeniería Genética, Irapuato, 36821 Guanajuato, Mexico;
| | - Luis Xoca-Orozco
- Departamento de Ingeniería Bioquímica, Instituto Tecnológico Superior de Purísima del Rincón, Purísima del Rincón, 36413 Guanajuato, Mexico;
| | - Selene Aguilera
- Laboratorio Integral de Investigación en Alimentos, Departamento de Química y Bioquímica, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, 63175 Nayarit, Mexico; (L.G.-V.); (A.C.-L.)
- Correspondence:
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Barrett-Manako K, Andersen M, Martínez-Sánchez M, Jenkins H, Hunter S, Reese-George J, Montefiori M, Wohlers M, Rikkerink E, Templeton M, Nardozza S. Real-Time PCR and Droplet Digital PCR Are Accurate and Reliable Methods To Quantify Pseudomonas syringae pv. actinidiae Biovar 3 in Kiwifruit Infected Plantlets. PLANT DISEASE 2021; 105:1748-1757. [PMID: 33206018 DOI: 10.1094/pdis-08-20-1703-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Pseudomonas syringae pv. actinidiae is the etiological agent of kiwifruit canker disease, causing severe economic losses in kiwifruit production areas around the world. Rapid diagnosis, understanding of bacterial virulence, and rate of infection in kiwifruit cultivars are important in applying effective measures of disease control. P. syringae pv. actinidiae load in kiwifruit is currently determined by a labor-intense colony counting method with no high-throughput and specific quantification method being validated. In this work, we used three alternative P. syringae pv. actinidiae quantification methods in two infected kiwifruit cultivars: start of growth time, quantitative PCR (qPCR), and droplet digital PCR (ddPCR). Method performance in each case was compared with the colony counting method. Methods were validated using calibration curves obtained with serial dilutions of P. syringae pv. actinidiae biovar 3 (Psa3) inoculum and standard growth curves obtained from kiwifruit samples infected with Psa3 inoculum. All three alternative methods showed high correlation (r > 0.85) with the colony counting method. qPCR and ddPCR were very specific, sensitive (5 × 102 CFU/cm2), highly correlated to each other (r = 0.955), and flexible, allowing for sample storage. The inclusion of a kiwifruit biomass marker increased the methods' accuracy. The qPCR method was efficient and allowed for high-throughput processing, and the ddPCR method showed highly accurate results but was more expensive and time consuming. While not ideal for high-throughput processing, ddPCR was useful in developing accurate standard curves for the qPCR method. The combination of the two methods is high-throughput, specific for Psa3 quantification, and useful for research studies (e.g., disease phenotyping and host-pathogen interactions).
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Affiliation(s)
| | - Mark Andersen
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | | | - Heather Jenkins
- New Zealand Institute for Plant and Food Research Limited, Christchurch 8140, New Zealand
| | - Shannon Hunter
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Jonathan Reese-George
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Mirco Montefiori
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Mark Wohlers
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Erik Rikkerink
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Matt Templeton
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Simona Nardozza
- New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
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12
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Ni P, Wang L, Deng B, Jiu S, Ma C, Zhang C, Almeida A, Wang D, Xu W, Wang S. Characterization of a Lytic Bacteriophage against Pseudomonas syringae pv. actinidiae and Its Endolysin. Viruses 2021; 13:631. [PMID: 33917076 PMCID: PMC8067700 DOI: 10.3390/v13040631] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 12/14/2022] Open
Abstract
Pseudomonas syringae pv. actinidiae (Psa) is a phytopathogen that causes canker in kiwifruit. Few conventional control methods are effective against this bacterium. Therefore, alternative approaches, such as phage therapy are warranted. In this study, a lytic bacteriophage (PN09) of Psa was isolated from surface water collected from a river in Hangzhou, China in 2019. Morphologically, PN09 was classified into the Myoviridae family, and could lyse all 29 Psa biovar 3 strains. The optimal temperature and pH ranges for PN09 activity were determined as 25 to 35 ∘C and 6.0 to 9.0, respectively. The complete genome of PN09 was found to be composed of a linear 99,229 bp double-stranded DNA genome with a GC content of 48.16%. The PN09 endolysin (LysPN09) was expressed in vitro and characterized. LysPN09 was predicted to belong to the Muraidase superfamily domain and showed lytic activity against the outer-membrane-permeabilized Psa strains. The lytic activity of LysPN09 was optimal over temperature and pH ranges of 25 to 40 ∘C and 6.0 to 8.0, respectively. When recombinant endolysin LysPN09 was combined with EDTA, Psa strains were effectively damaged. All these characteristics demonstrate that the phage PN09 and its endolysin, LysPN09, are potential candidates for biocontrol of Psa in the kiwifruit industry.
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Affiliation(s)
- Peien Ni
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Lei Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Bohan Deng
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Songtao Jiu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Chao Ma
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Caixi Zhang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Adelaide Almeida
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Dapeng Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Wenping Xu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
| | - Shiping Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; (P.N.); (L.W.); (B.D.); (S.J.); (C.M.); (C.Z.); (D.W.); (S.W.)
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13
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Vandelle E, Colombo T, Regaiolo A, Maurizio V, Libardi T, Puttilli MR, Danzi D, Polverari A. Transcriptional Profiling of Three Pseudomonas syringae pv. actinidiae Biovars Reveals Different Responses to Apoplast-Like Conditions Related to Strain Virulence on the Host. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:376-396. [PMID: 33356409 DOI: 10.1094/mpmi-09-20-0248-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Pseudomonas syringae pv. actinidiae is a phytopathogen that causes devastating bacterial canker in kiwifruit. Among five biovars defined by genetic, biochemical, and virulence traits, P. syringae pv. actinidiae biovar 3 (Psa3) is the most aggressive and is responsible for the most recent reported outbreaks; however, the molecular basis of its heightened virulence is unclear. Therefore, we designed the first P. syringae multistrain whole-genome microarray, encompassing biovars Psa1, Psa2, and Psa3 and the well-established model P. syringae pv. tomato, and analyzed early bacterial responses to an apoplast-like minimal medium. Transcriptomic profiling revealed i) the strong activation in Psa3 of all hypersensitive reaction and pathogenicity (hrp) and hrp conserved (hrc) cluster genes, encoding components of the type III secretion system required for bacterial pathogenicity and involved in responses to environmental signals; ii) potential repression of the hrp/hrc cluster in Psa2; and iii) activation of flagellum-dependent cell motility and chemotaxis genes in Psa1. The detailed investigation of three gene families encoding upstream regulatory proteins (histidine kinases, their cognate response regulators, and proteins with diguanylate cyclase or phosphodiesterase domains) indicated that cyclic di-GMP may be a key regulator of virulence in P. syringae pv. actinidiae biovars. The gene expression data were supported by the quantification of biofilm formation. Our findings suggest that diverse early responses to the host apoplast, even among bacteria belonging to the same pathovar, can lead to different virulence strategies and may explain the differing outcomes of infections. Based on our detailed structural analysis of hrp operons, we also propose a revision of hrp cluster organization and operon regulation in P. syringae.[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)
- Elodie Vandelle
- Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | - Teresa Colombo
- National Research Council of Italy (CNR), Institute of Molecular Biology and Pathology (IBPM) c/o Department of Biochemical Sciences "A. Rossi Fanelli", "Sapienza" University of Rome, Rome, 00185, Italy
| | - Alice Regaiolo
- Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | - Vanessa Maurizio
- Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | - Tommaso Libardi
- Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | | | - Davide Danzi
- Department of Biotechnology, University of Verona, Verona, 37134, Italy
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14
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Mariz-Ponte N, Regalado L, Gimranov E, Tassi N, Moura L, Gomes P, Tavares F, Santos C, Teixeira C. A Synergic Potential of Antimicrobial Peptides against Pseudomonas syringae pv. actinidiae. Molecules 2021; 26:molecules26051461. [PMID: 33800273 PMCID: PMC7962642 DOI: 10.3390/molecules26051461] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas syringae pv. actinidiae (Psa) is the pathogenic agent responsible for the bacterial canker of kiwifruit (BCK) leading to major losses in kiwifruit productions. No effective treatments and measures have yet been found to control this disease. Despite antimicrobial peptides (AMPs) having been successfully used for the control of several pathogenic bacteria, few studies have focused on the use of AMPs against Psa. In this study, the potential of six AMPs (BP100, RW-BP100, CA-M, 3.1, D4E1, and Dhvar-5) to control Psa was investigated. The minimal inhibitory and bactericidal concentrations (MIC and MBC) were determined and membrane damaging capacity was evaluated by flow cytometry analysis. Among the tested AMPs, the higher inhibitory and bactericidal capacity was observed for BP100 and CA-M with MIC of 3.4 and 3.4-6.2 µM, respectively and MBC 3.4-10 µM for both. Flow cytometry assays suggested a faster membrane permeation for peptide 3.1, in comparison with the other AMPs studied. Peptide mixtures were also tested, disclosing the high efficiency of BP100:3.1 at low concentration to reduce Psa viability. These results highlight the potential interest of AMP mixtures against Psa, and 3.1 as an antimicrobial molecule that can improve other treatments in synergic action.
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Affiliation(s)
- Nuno Mariz-Ponte
- Biology Department, Faculty of Science, University of Porto (FCUP), 4169-007 Porto, Portugal; (L.R.); (E.G.); (F.T.); (C.S.)
- LAQV-REQUIMTE, Biology Department, Faculty of Science (FCUP), University of Porto, 4169-007 Porto, Portugal
- CIBIO—Research Centre in Biodiversity and Genetic Resources, In-BIO-Associate Laboratory, Microbial Diversity and Evolution Group, University of Porto (UP), 4485-661 Vairão, Portugal
- Correspondence:
| | - Laura Regalado
- Biology Department, Faculty of Science, University of Porto (FCUP), 4169-007 Porto, Portugal; (L.R.); (E.G.); (F.T.); (C.S.)
- LAQV-REQUIMTE, Biology Department, Faculty of Science (FCUP), University of Porto, 4169-007 Porto, Portugal
| | - Emil Gimranov
- Biology Department, Faculty of Science, University of Porto (FCUP), 4169-007 Porto, Portugal; (L.R.); (E.G.); (F.T.); (C.S.)
- LAQV-REQUIMTE, Biology Department, Faculty of Science (FCUP), University of Porto, 4169-007 Porto, Portugal
| | - Natália Tassi
- LAQV-REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences (FCUP), University of Porto, 4169-007 Porto, Portugal; (N.T.); (P.G.); (C.T.)
| | - Luísa Moura
- CISAS—Centre for Research and Development in Agrifood Systems and Sustainability, Instituto Politécnico de Viana do Castelo, 4900-347 Viana do Castelo, Portugal;
| | - Paula Gomes
- LAQV-REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences (FCUP), University of Porto, 4169-007 Porto, Portugal; (N.T.); (P.G.); (C.T.)
| | - Fernando Tavares
- Biology Department, Faculty of Science, University of Porto (FCUP), 4169-007 Porto, Portugal; (L.R.); (E.G.); (F.T.); (C.S.)
- CIBIO—Research Centre in Biodiversity and Genetic Resources, In-BIO-Associate Laboratory, Microbial Diversity and Evolution Group, University of Porto (UP), 4485-661 Vairão, Portugal
| | - Conceição Santos
- Biology Department, Faculty of Science, University of Porto (FCUP), 4169-007 Porto, Portugal; (L.R.); (E.G.); (F.T.); (C.S.)
- LAQV-REQUIMTE, Biology Department, Faculty of Science (FCUP), University of Porto, 4169-007 Porto, Portugal
| | - Cátia Teixeira
- LAQV-REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences (FCUP), University of Porto, 4169-007 Porto, Portugal; (N.T.); (P.G.); (C.T.)
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15
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Pereira C, Costa P, Pinheiro L, Balcão VM, Almeida A. Kiwifruit bacterial canker: an integrative view focused on biocontrol strategies. PLANTA 2021; 253:49. [PMID: 33502587 DOI: 10.1007/s00425-020-03549-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
Phage-based biocontrol strategies can be an effective alternative to control Psa-induced bacterial canker of kiwifruit. The global production of kiwifruit has been seriously affected by Pseudomonas syringae pv. actinidiae (Psa) over the last decade. Psa damages both Actinidia chinensis var. deliciosa (green kiwifruit) but specially the susceptible Actinidia chinensis var. chinensis (gold kiwifruit), resulting in severe economic losses. Treatments for Psa infections currently available are scarce, involving frequent spraying of the kiwifruit plant orchards with copper products. However, copper products should be avoided since they are highly toxic and lead to the development of bacterial resistance to this metal. Antibiotics are also used in some countries, but bacterial resistance to antibiotics is a serious worldwide problem. Therefore, it is essential to develop new approaches for sustainable agriculture production, avoiding the emergence of resistant Psa bacterial strains. Attempts to develop and establish highly accurate approaches to combat and prevent the occurrence of bacterial canker in kiwifruit plants are currently under study, using specific viruses of bacteria (bacteriophages, or phages) to eliminate the Psa. This review discusses the characteristics of Psa-induced kiwifruit canker, Psa transmission pathways, prevention and control, phage-based biocontrol strategies as a new approach to control Psa in kiwifruit orchards and its advantages over other therapies, together with potential ways to bypass phage inactivation by abiotic factors.
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Affiliation(s)
- Carla Pereira
- Department of Biology and CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Pedro Costa
- Department of Biology and CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Larindja Pinheiro
- Department of Biology and CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Victor M Balcão
- Department of Biology and CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
- PhageLab - Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba, SP, CEP 18023-000, Brazil.
| | - Adelaide Almeida
- Department of Biology and CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
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16
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Hirose K, Ishiga Y, Fujikawa T. Phytotoxin synthesis genes and type III effector genes of Pseudomonas syringae pv. actinidiae biovar 6 are regulated by culture conditions. PeerJ 2020; 8:e9697. [PMID: 32864217 PMCID: PMC7430302 DOI: 10.7717/peerj.9697] [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: 05/04/2020] [Accepted: 07/20/2020] [Indexed: 01/21/2023] Open
Abstract
The kiwifruit bacterial canker (Pseudomonas syringae pv. actinidiae; Psa) causes severe damage to kiwifruit production worldwide. Psa biovar 6 (Psa6), which was isolated in Japan in 2015, produces two types of phytotoxins: coronatine and phaseolotoxin. To elucidate the unique virulence of Psa6, we performed transcriptomic analysis of phytotoxin synthesis genes and type III effector genes in in vitro cultivation using various media. The genes related to phytotoxin synthesis and effectors of Psa6 were strictly regulated in the coronatine-inducing mediums (HS and HSC); 14 of 23 effector genes and a hrpL sigma factor gene were induced at 3 h after transferring to the media (early-inducible genes), and phytotoxin synthesis genes such as argD of phaseolotoxin and cfl of coronatine were induced at 6 and 12 h after transferring to the media (late-inducible genes). In contrast, induction of these genes was not observed in the hrp-inducing medium. Next, to examine whether the changes in gene expression in different media is specific to Psa6, we investigated gene expression in other related bacteria. For Psa biovar 1 (Psa1), biovar 3 (Psa3), and P. s. pv. glycinea (Psg), no clear trends were observed in expression behavior across various culture media and incubation times. Therefore, Psa6 seems to exert its virulence efficiently by using two phytotoxins and effectors according to environmental changes. This is not seen in other biovars and pathovars, so it is thought that Psa6 has acquired its own balance of virulence.
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Affiliation(s)
- Karin Hirose
- Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan.,Faculty of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yasuhiro Ishiga
- Faculty of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takashi Fujikawa
- Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
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17
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Characterization of Bacteriophages against Pseudomonas Syringae pv. Actinidiae with Potential Use as Natural Antimicrobials in Kiwifruit Plants. Microorganisms 2020; 8:microorganisms8070974. [PMID: 32610695 PMCID: PMC7409275 DOI: 10.3390/microorganisms8070974] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/09/2020] [Accepted: 06/12/2020] [Indexed: 02/06/2023] Open
Abstract
Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of a bacterial canker in kiwifruit plants and has caused economic losses worldwide. Currently, the primary strategies to control this pathogen include the use of copper-based compounds and even antibiotics. However, the emergence of isolates of Psa that are resistant to these agrochemicals has raised the need for new alternatives to control this pathogen. Bacteriophages have been proposed as an alternative to control bacterial infections in agriculture, including Psa. Here, we show the isolation and characterization of 13 phages with the potential to control Psa infections in kiwifruit plants. The phages were characterized according to their host range and restriction fragment length polymorphism (RFLP) pattern. Four phages were selected according to their lytic effect on the bacteria and their tolerance to different environmental conditions of pH (4–7), temperature (4–37 °C), and solar radiation exposure (30 and 60 min). The selected phages (CHF1, CHF7, CHF19, and CHF21) were sequenced, revealing a high identity with the podophage of Psa phiPSA2. In vitro assays with kiwifruit leaf samples demonstrated that the mixture of phages reduced the Psa bacterial load within three hours post-application and was able to reduce the damage index in 50% of cases. Similarly, assays with kiwifruit plants maintained in greenhouse conditions showed that these phages were able to reduce the Psa bacterial load in more than 50% of cases and produced a significant decrease in the damage index of treated plants after 30 days. Finally, none of the selected phages were able to infect the other bacteria present in the natural microbiota of kiwifruit plants. These results show that bacteriophages are an attractive alternative to control Psa infections in kiwifruit plants.
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18
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Ishiga T, Sakata N, Nguyen VT, Ishiga Y. Flood inoculation of seedlings on culture medium to study interactions between Pseudomonas syringae pv. actinidiae and kiwifruit. JOURNAL OF GENERAL PLANT PATHOLOGY : JGPP 2020; 86:257-265. [PMID: 32412555 PMCID: PMC7222055 DOI: 10.1007/s10327-020-00916-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/12/2019] [Indexed: 06/01/2023]
Abstract
Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a serious threat to kiwifruit production. Highly virulent strains of Psa biovar3 (Psa3) have spread rapidly to kiwifruit production areas worldwide. Therefore, there is an urgent need to develop critical management strategies for bacterial canker based on dissecting the interactions between Psa and kiwifruit. Here, we developed a rapid and reliable flood-inoculation method using kiwifruit seedlings grown on Murashige and Skoog medium. This method has several advantages over inoculation of conventional soil-grown plants. We demonstrated the utility of a kiwifruit seedling assay to study the virulence of Psa biovars and Psa3 virulence factors, including the type III secretion system (T3SS). Kiwifruit seedlings inoculated with Psa3 developed severe necrosis within 1 week, whereas those inoculated with a T3SS-deficient hrcN mutant of Psa3 did not. This method was also useful for analyzing expression profiles of genes involved in Psa3 virulence during infection, and revealed that the expression of genes encoding the T3SS and type III secreted effectors were strongly induced in planta. Our results indicate that the T3SS has an important role in Psa3 virulence, and the flood-inoculation assay using kiwifruit seedling is suitable for analyzing Psa and kiwifruit interactions.
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Affiliation(s)
- Takako Ishiga
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572 Japan
| | - Nanami Sakata
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572 Japan
| | - Viet Tru Nguyen
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572 Japan
| | - Yasuhiro Ishiga
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572 Japan
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19
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Pinheiro LAM, Pereira C, Barreal ME, Gallego PP, Balcão VM, Almeida A. Use of phage ϕ6 to inactivate Pseudomonas syringae pv. actinidiae in kiwifruit plants: in vitro and ex vivo experiments. Appl Microbiol Biotechnol 2019; 104:1319-1330. [DOI: 10.1007/s00253-019-10301-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/14/2019] [Accepted: 12/08/2019] [Indexed: 12/22/2022]
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