title: Characterization of Novel Bacteriophages for Biocontrol of Bacterial Blight in Leek Caused by Pseudomonas syringae pv. porri.
abstract: Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum), is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4, and vB_PsyM_KIL5), and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b). Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the "KIL-like viruses," related to the Felixounalikevirus genus, together with phage phiPsa374 from P. syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods.
authors.affiliation: Laboratory of Gene Technology, Department of Biosystems, KU LeuvenLeuven, Belgium; Unit Plant- Crop Protection, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium.
authors.forename: Sofie
authors.initials: S
authors.lastname: Rombouts
authors.affiliation: Vegetable Research Centre (PCG) Kruishoutem, Belgium.
authors.forename: Anneleen
authors.initials: A
authors.lastname: Volckaert
authors.affiliation: Research Station for Vegetable Production Sint-Katelijne-Waver, Belgium.
authors.forename: Sofie
authors.initials: S
authors.lastname: Venneman
authors.affiliation: Inagro Rumbeke, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Declercq
authors.affiliation: Laboratory of Applied Microbiology and Biotechnology, Department of Bioscience Engineering, University of Antwerp Antwerpen, Belgium.
authors.forename: Dieter
authors.initials: D
authors.lastname: Vandenheuvel
authors.affiliation: Laboratory of Applied Microbiology and Biotechnology, Department of Bioscience Engineering, University of Antwerp Antwerpen, Belgium.
authors.forename: Camille N
authors.initials: CN
authors.lastname: Allonsius
authors.affiliation: Unit Plant- Crop Protection, Institute for Agricultural and Fisheries Research Merelbeke, Belgium.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Van Malderghem
authors.affiliation: Laboratory of Gene Technology, Department of Biosystems, KU Leuven Leuven, Belgium.
authors.forename: Ho B
authors.initials: HB
authors.lastname: Jang
authors.affiliation: Laboratory of Gene Technology, Department of Biosystems, KU LeuvenLeuven, Belgium; Laboratory of Applied Biotechnology, Department of Applied Biosciences, Ghent UniversityGhent, Belgium.
authors.forename: Yves
authors.initials: Y
authors.lastname: Briers
authors.affiliation: School of Life Sciences, Biomedical Research Institute and Transnational University Limburg, Hasselt University Diepenbeek, Belgium.
authors.forename: Jean P
authors.initials: JP
authors.lastname: Noben
authors.affiliation: Institute of Food, Nutrition and Health, ETH Zurich Zurich, Switzerland.
authors.forename: Jochen
authors.initials: J
authors.lastname: Klumpp
authors.affiliation: Unit Plant- Crop Protection, Institute for Agricultural and Fisheries Research Merelbeke, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Van Vaerenbergh
authors.affiliation: Unit Plant- Crop Protection, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium; Lab. of Microbiology, Department of Biochemistry and Microbiology, Ghent UniversityGent, Belgium.
authors.forename: Martine
authors.initials: M
authors.lastname: Maes
authors.affiliation: Laboratory of Gene Technology, Department of Biosystems, KU Leuven Leuven, Belgium.
authors.forename: Rob
authors.initials: R
authors.lastname: Lavigne
keywords: KIL-like viruses; Pseudomonas syringae pv. porri; leek bacterial blight; phage therapy; phylogenomics