Rnase p rna gene marker based Taxonomy of Leptospira spp and Development of diagnostics forLeptospirosis

Abstract

Leptospirosis is a spirochetal bacterial zoonotic disease caused by the genus Leptospira. Leptospirosis causes life-threatening clinical symptoms and communicates its greatest burden on several endemic regions in India. The strains of Leptospira genus have been initially classified based on serology. Currently, both serology-based classification and genotypic classification coexist but certain anomalies like grouping of pathogenic and non-pathogenic strains under same species prevail. In our present study, RNase P RNA (RPR) gene present as single copy gene in chromosome I of Leptospira spp. have been used to investigate putative taxonomic inconsistencies present in the leptospiral strains. RPR gene sequences were also examined to understand the strain-specific structural differences present in leptospiral RPRs. Sequence variations present in the RPR gene impacted on the configuration of loops, stems and bulges found in the RPR highlighting species and strain specific structural motifs. In vitro transcribed leptospiral RPR ribozymes were demonstrated to process precursor tRNA into mature tRNA similar to other bacterial RPRs showed in studies elsewhere. A novel phylogeny-based classification was constructed based on the sequence variations of RPR gene and resulting secondary structural differentiation among the various leptospiral strains. RPR sequences used for the construction of phylogenetic tree exemplified the segregation of strains into their respective lineages. We have identified the taxonomic positions of several unknown strains of leptospires, most notably L. borgpetersenii was bifurcated into A and B groups while performing RPR gene-based phylogeny newline