10.1371/journal.pone.0101996 Allison L. Creason Allison L. Creason Olivier M. Vandeputte Olivier M. Vandeputte Elizabeth A. Savory Elizabeth A. Savory Edward W. Davis II Edward W. Davis II Melodie L. Putnam Melodie L. Putnam Erdong Hu Erdong Hu David Swader-Hines David Swader-Hines Adeline Mol Adeline Mol Marie Baucher Marie Baucher Els Prinsen Els Prinsen Magdalena Zdanowska Magdalena Zdanowska Scott A. Givan Scott A. Givan Mondher El Jaziri Mondher El Jaziri Joyce E. Loper Joyce E. Loper Taifo Mahmud Taifo Mahmud Jeff H. Chang Jeff H. Chang Analysis of Genome Sequences from Plant Pathogenic <i>Rhodococcus</i> Reveals Genetic Novelties in Virulence Loci Public Library of Science 2014 microbiology Microbial evolution Bacterial evolution Microbial genomics bacterial genomics Plant microbiology Plant science Plant pathology Plant pathogens Plant bacterial pathogens genome sequences pathogenic reveals novelties virulence loci 2014-07-10 02:58:18 Dataset https://plos.figshare.com/articles/dataset/Analysis_of_Genome_Sequences_from_Plant_Pathogenic_Rhodococcus_Reveals_Genetic_Novelties_in_Virulence_Loci/1099270 <div><p>Members of Gram-positive Actinobacteria cause economically important diseases to plants. Within the <i>Rhodococcus</i> genus, some members can cause growth deformities and persist as pathogens on a wide range of host plants. The current model predicts that phytopathogenic isolates require a cluster of three loci present on a linear plasmid, with the <i>fas</i> operon central to virulence. The Fas proteins synthesize, modify, and activate a mixture of growth regulating cytokinins, which cause a hormonal imbalance in plants, resulting in abnormal growth. We sequenced and compared the genomes of 20 isolates of <i>Rhodococcus</i> to gain insights into the mechanisms and evolution of virulence in these bacteria. Horizontal gene transfer was identified as critical but limited in the scale of virulence evolution, as few loci are conserved and exclusive to phytopathogenic isolates. Although the <i>fas</i> operon is present in most phytopathogenic isolates, it is absent from phytopathogenic isolate A21d2. Instead, this isolate has a horizontally acquired gene chimera that encodes a novel fusion protein with isopentyltransferase and phosphoribohydrolase domains, predicted to be capable of catalyzing and activating cytokinins, respectively. Cytokinin profiling of the archetypal D188 isolate revealed only one activate cytokinin type that was specifically synthesized in a <i>fas</i>-dependent manner. These results suggest that only the isopentenyladenine cytokinin type is synthesized and necessary for <i>Rhodococcus</i> phytopathogenicity, which is not consistent with the extant model stating that a mixture of cytokinins is necessary for <i>Rhodococcus</i> to cause leafy gall symptoms. In all, data indicate that only four horizontally acquired functions are sufficient to confer the trait of phytopathogenicity to members of the genetically diverse clade of <i>Rhodococcus</i>.</p></div>