Unexpected conservation and global transmission of agrobacterial virulence plasmids

Abstract

The accelerated evolution and spread of pathogens are threats to host species. Agrobacteria require an oncogenic Ti or Ri plasmid to transfer genes into plants and cause disease. We developed a strategy to characterize virulence plasmids and applied it to analyze hundreds of strains collected between 1927 and 2017, on six continents and from more than 50 host species. In consideration of prior evidence for prolific recombination, it was surprising that oncogenic plasmids are descended from a few conserved lineages. Characterization of a hierarchy of features that promote or constrain plasticity allowed inference of the evolutionary history across the plasmid lineages. We uncovered epidemiological patterns that highlight the importance of plasmid transmission in pathogen diversification as well as in long-term persistence and the global spread of disease.

Emergence and rising of ceftazidime-avibactam resistant KPC-producing Pseudomonas aeruginosa in China: a molecular epidemiology study

“…Orthologs were found by Orthofinder v.2.4.0 [27]. Gene synteny was visualized by Cytoscape v.3.8.0 [28], according to a published script [29], with minute modification.…”

Phylogeographic Approaches to Characterize the Emergence of Plant Pathogens

“…The era of population genomics based on HTS offers new opportunities for tracking the movement of many different genes or loci simultaneously, revealing which genes or loci have shared histories and which have discordant geographic histories. Especially relevant here are genomic islands or loci that impact disease phenotypes such as pathogenicity, virulence and resistance, which tend to be acquired through lateral transfers of genetic information either by recombination or HGT (Soanes and Richards 2014;Weisberg et al 2020). The ability to identify and track the movement of these loci holds the promise of being able to identify the potential source of novel genetic variation driving disease phenotypes, which could then be targeted for greater surveillance or control.…”

“…At the same time, we live in an exciting era where whole genome sequencing will soon allow for the joint inference of the demographic history of plant pathogens in conjunction with a rigorous analysis of genomic regions that are subject to selection, recombination, and/or horizontal transfer (Davis et al 2018;Kelleher et al 2019;Weisberg et al 2020). We believe that for plant pathogens in particular, our ability to sequence whole genomes of pathogen populations on a large scale will provide new insights into both the deep origins and recent movement of pathogens while providing the ability to identify particular loci or regions that have driven their emergence and spatial expansion.…”

Dual Adhesive Unipolar Polysaccharides Synthesized by Overlapping Biosynthetic Pathways inAgrobacterium tumefaciens

“…A. tumefaciens C58, the type strain we use in this study, is in Genomospecies 8 (G8, also given the species designation A. fabrum). There is now a wealth of genomic data for comparison across the agrobacteria and among the wider Rhizobiaceae that allows great insights into the genetic conservation and ecological context among these bacteria (Weisberg et al, 2020).…”