title: The filamentous phage XacF1 causes loss of virulence in Xanthomonas axonopodis pv. citri, the causative agent of citrus canker disease.
abstract: In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac) strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 600 nm long. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs), some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII), ORF2 (pV), ORF6 (pIII), and ORF8 (pVI). XacF1 showed a relatively wide host range, infecting seven out of 11 strains tested in this study. Frequently, XacF1 was found to be integrated into the genome of Xac strains. This integration occurred at the host dif site (attB) and was mediated by the host XerC/D recombination system. The attP sequence was identical to that of Xanthomonas phage Cf1c. Interestingly, infection by XacF1 phage caused several physiological changes to the bacterial host cells, including lower levels of extracellular polysaccharide production, reduced motility, slower growth rate, and a dramatic reduction in virulence. In particular, the reduction in virulence suggested possible utilization of XacF1 as a biological control agent against citrus canker disease.
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University Higashi-Hiroshima, Japan.
authors: Abdelmonim Ali
authors: AA
authors: Ahmad
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University Higashi-Hiroshima, Japan ; Department of Microbiology, Faculty of Science, Zagazig University Zagazig, Sharkia, Egypt.
authors: Ahmed
authors: A
authors: Askora
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University Higashi-Hiroshima, Japan.
authors: Takeru
authors: T
authors: Kawasaki
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University Higashi-Hiroshima, Japan.
authors: Makoto
authors: M
authors: Fujie
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University Higashi-Hiroshima, Japan.
authors: Takashi
authors: T
authors: Yamada
keywords: biocontrol; citrus canker; filamentous phage; loss of virulence