Transcriptional profiling the 150 kb linear plasmid of Borrelia turicatae implicates an important role in vector colonization and establishing mammalian infection.. Borrelia turicatae 91E135

As vector-borne pathogens transit between the arthropod and vertebrate, adaptation is key for survival as each host varies and initiates unique defense mechanisms. An environmental signal that relapsing fever (RF) and Lyme causing spirochetes detect is the change of temperature between vector and mammal, yet incomplete genomes have hindered progress in understanding the genetic constituents expressed during tick colonization. We conducted a combined transcriptional and genomic sequence analysis to further assemble the ~150 kb linear plasmid (lp150) of Borrelia turicatae, a causative agent of RF borreliosis. Contiguous sequences (contigs), which were originally generated by Sanger sequencing, contained open reading frames (ORFs) identified to be up-regulated by the spirochetes when grown under tick-like conditions compared to the mammal. To aid in assembling the contigs, a PacBio RS I Single Molecule Real-Time DNA sequencing approach was used, given extended nucleotide reads over several thousand base pairs. A 36 kb locus was identified toward the 3‘ end of lp150, and expression of the ORFs was verified in the tick and mammal. We report the most complete version of lp150, and this study indicates that the plasmid likely facilitates vector colonization and establishing early mammalian infection Overall design: Borrelia turicatae at 35ºC vs. 25ºC vs. blood