title: Assessment of the genetic and phenotypic diversity among rhizogenic Agrobacterium biovar 1 strains infecting solanaceous and cucurbit crops.
abstract: Rhizogenic Agrobacterium biovar 1 strains have been found to cause extensive root proliferation on hydroponically grown Cucurbitaceae and Solanaceae crops, resulting in substantial economic losses. As these agrobacteria live under similar ecological conditions, infecting a limited number of crops, it may be hypothesized that genetic and phenotypic variation among such strains is relatively low. In this study we assessed the phenotypic diversity as well as the phylogenetic and evolutionary relationships of several rhizogenic Agrobacterium biovar 1 strains from cucurbit and solanaceous crops. A collection of 41 isolates was subjected to a number of phenotypic assays and characterized by MLSA targeting four housekeeping genes (16S rRNA gene, recA, rpoB and trpE) and two loci from the root-inducing Ri-plasmid (part of rolB and virD2). Besides phenotypic variation, remarkable genotypic diversity was observed, especially for some chromosomal loci such as trpE. In contrast, genetic diversity was lower for the plasmid-borne loci, indicating that the studied chromosomal housekeeping genes and Ri-plasmid-borne loci might not exhibit the same evolutionary history. Furthermore, phylogenetic and network analyses and several recombination tests suggested that recombination could be contributing in some extent to the evolutionary dynamics of rhizogenic Agrobacterium populations. Finally, a genomospecies-level identification analysis revealed that at least four genomospecies may occur on cucurbit and tomato crops (G1, G3, G8 and G9). Together, this study gives a first glimpse at the genetic and phenotypic diversity within this economically important plant pathogenic bacterium.
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (MS), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium.
authors.forename: Lien
authors.initials: L
authors.lastname: Bosmans
authors.affiliation: Department of Animal Health, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, E-28040 Madrid, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Álvarez-Pérez
authors.affiliation: Research Centre Hoogstraten vzw, B-2328 Meerle, Belgium.
authors.forename: Rob
authors.initials: R
authors.lastname: Moerkens
authors.affiliation: Research Station for Vegetable Production vzw, B-2860 Sint-Katelijne-Waver, Belgium.
authors.forename: Lieve
authors.initials: L
authors.lastname: Wittemans
authors.affiliation: Research Station for Vegetable Production vzw, B-2860 Sint-Katelijne-Waver, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Van Calenberge
authors.affiliation: Scientia Terrae vzw, B-2860 Sint-Katelijne-Waver, Belgium.
authors.forename: Stefan Van
authors.initials: SV
authors.lastname: Kerckhove
authors.affiliation: Scientia Terrae vzw, B-2860 Sint-Katelijne-Waver, Belgium.
authors.forename: Anneleen
authors.initials: A
authors.lastname: Paeleman
authors.affiliation: Centre of Microbial and Plant Genetics, MS, KU Leuven, B-3001 Leuven, Belgium.
authors.forename: René
authors.initials: R
authors.lastname: De Mot
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (MS), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Rediers
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (MS), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium bart.lievens@kuleuven.be.
authors.forename: Bart
authors.initials: B
authors.lastname: Lievens
mesh_terms: D060054:Agrobacterium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D018556:Crops, Agricultural / Q000382:microbiology*; D019662:Cucurbitaceae / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D014644:Genetic Variation; D018551:Solanum lycopersicum / Q000382:microbiology*; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology*; D010957:Plasmids / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D011938:Rec A Recombinases
keywords: Cucurbitaceae; Solanaceae; genomospecies; hairy roots; phenotypic and phylogenetic diversity