Short Communication

Complete Genome Sequencing of Three Clade-1 Xanthomonads Reveals Genetic Determinants for a Lateral Flagellin and the Biosynthesis of Coronatine-Like Molecules in Xanthomonas

    Authors and Affiliations
    • Chloé Peduzzi1
    • Angeliki Sagia1 2
    • Daiva Burokienė3
    • Ildikó Katalin Nagy4
    • Marion Fischer-Le Saux5
    • Perrine Portier5
    • Alexis Dereeper2
    • Sébastien Cunnac2
    • Veronica Roman-Reyna6 7
    • Jonathan M. Jacobs6 7
    • Claude Bragard1
    • Ralf Koebnik2
    1. 1Earth & Life Institute, UCLouvain, Louvain-la-Neuve, Belgium
    2. 2Plant Health Institute of Montpellier (PHIM), University of Montpellier, Cirad, INRAE, Institut Agro, IRD, Montpellier, France
    3. 3Nature Research Centre, Institute of Botany, Laboratory of Plant Pathology, Vilnius, Lithuania
    4. 4Enviroinvest Corp., Pécs, Hungary
    5. 5Univ. Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, F-49000 Angers, France
    6. 6Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A.
    7. 7Infectious Disease Institute, The Ohio State University, Columbus, OH 43210, U.S.A.

    Evolutionarily, early-branching xanthomonads, also referred to as clade-1 xanthomonads, include major plant pathogens, most of which colonize monocotyledonous plants. Seven species have been validly described, among them the two sugarcane pathogens Xanthomonas albilineans and Xanthomonas sacchari, as well as Xanthomonas translucens, which infects small-grain cereals and diverse grasses but also asparagus and pistachio trees. Single-gene sequencing and genomic approaches have indicated that this clade likely contains more, yet-undescribed species. In this study, we sequenced representative strains of three novel species using long-read sequencing technology. Xanthomonas campestris pv. phormiicola strain CFBP 8444 causes bacterial streak on New Zealand flax, another monocotyledonous plant. Xanthomonas sp. strain CFBP 8443 has been isolated from common bean, and Xanthomonas sp. strain CFBP 8445 originated from banana. Complete assemblies of the chromosomes confirmed their unique phylogenetic position within clade 1 of Xanthomonas. Genome mining revealed novel genetic features, hitherto undescribed in other members of the Xanthomonas genus. In strain CFBP 8444, we identified genes related to the synthesis of coronatine-like compounds, a phytotoxin produced by several pseudomonads, which raises interesting questions about the evolution and pathogenicity of this pathogen. Furthermore, strain CFBP 8444 was found to contain a second, atypical flagellar gene cluster in addition to the canonical flagellar gene cluster. Overall, this research represents an important step toward better understanding the evolutionary history and biology of early-branching xanthomonads.

    Literature Cited