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Advisor(s)
Abstract(s)
Borrelia burgdorferi sensu lato comprises a species complex of tick-transmitted bacteria that includes the agents of
human Lyme borreliosis. Borrelia turdi is a genospecies of this complex that exists in cryptic transmission cycles
mainly between ornithophilic tick vectors and their avian hosts. The species has been originally discovered in
avian transmission cycles in Asia but has increasingly been found in Europe. Next generation sequencing was
used to sequence the genome of B. turdi isolates obtained from ticks feeding on birds in Portugal to better
understand the evolution and phylogenetic relationship of this avian and ornithophilic tick-associated genospecies.
Here we use draft genomes of these B. turdi isolates for comparative analysis and to determine the
taxonomic position within the B. burgdorferi s.l. species complex. The main chromosomes showed a maximum
similarity of 93% to other Borrelia species whilst most plasmids had lower similarities. All three isolates had nine
or 10 plasmids and, interestingly, one plasmid with a novel partitioning protein; this plasmid was termed lp30.
Phylogenetic analysis of multilocus sequence typing housekeeping genes and 113 single copy orthologous genes
revealed that the isolates clustered according to their classification as B. turdi. In phylogenies generated from
these 113 genes the isolates cluster together with other Eurasian genospecies and form a sister clade to the avian
associated B. garinii and the rodent associated B. bavariensis. These findings show that Borrelia species maintained
in cryptic ecological cycles need to be included to fully understand the complex ecology and evolutionary
history of this bacterial species complex.
Description
Keywords
Bird Borrelia burgdorferi sensu lato Borrelia turdi Host Association Illumina SPAdes Genome Assembly Infecções Sistémicas e Zoonoses
Pedagogical Context
Citation
Mol Phylogenet Evol. 2019 Feb;131:93-98. doi: 10.1016/j.ympev.2018.10.044. Epub 2018 Nov 10
Publisher
Elsevier/ Academic Press
