In silico and phylogenetic analyses of partial BbRAP-1, BbCP2, BbSBP-4 and BbβTUB gene sequences of Babesia bovis isolates from cattle in South Africa

Abstract

BackgroundBovine babesiosis is one of the most economically important tick-borne diseases threatening the livestock industry globally including South Africa. This disease is induced by members of Babesia bovis species. Antigenic variations among geographical strains of B. bovis, and these heterogeneities are cited as the mechanism by which parasites evade from host immune system and they hamper the successful development of a single vaccine that could confer absolute protection. Given the economic importance of livestock industry in South Africa, the extent of genetic diversity among field isolates of B. bovis merits extensive investigation.In this study, we genetically characterized partial genes of B. bovis and studied the phylogenetic relationship among B. bovis isolates of South African origin. The genes, which were PCR-amplified from bovine samples collected from different locations across South Africa, coded for rhoptry-associated protein 1 (BbRAP-1), cysteine peptidase 2 (BbCP2), spherical body protein 4 (BbSBP-4) and β-tubulin (BbβTUB). Phylogenies were inferred from newly determined sequences using the neighbour-joining approach.ResultsNested PCR assays with gene-specific primers indicated that, of the 54 bovine samples tested, 59.3% (32/54; 95% CI = 46.0–71.3%), 27.8% (15/54; 95% CI = 17.6–40.9%), 37.0% (20/54; 95% CI = 25.4–50.4%) and 29.6% (16/54; 95% CI = 19.1–42.8%) possessed BbRAP-1, BbCP2, BbSBP-4 and BbβTUB fragments, respectively. Sequencing of PCR-generated fragments revealed that nucleotide sequences of each of the four genes were highly conserved among the B. bovis isolates examined. Phylogenetic analyses of BbCP2, BbSBP-4 and BbβTUB sequences indicated a close phylogenetic relatedness among South African-derived sequences and those of global B. bovis strains.ConclusionThe data reported in this study indicated that there is a high conservation among the genes of B. bovis isolates from cattle in South Africa. These findings give an indication that immunologically important proteins encoded by these genes could potentially be considered for exploitation as viable candidates for inclusion in recombinant subunit vaccines.

Use of molecular markers can help to understand the genetic diversity of Babesia bovis

“…We constructed phylogenetic trees using the genes sbp-2 (spherical body protein 2), sbp-4 (spherical body protein 4), trap (thrombospondin-related anonymous protein), msa-1 (merozoite surface antigen 1), msa-2b (merozoite surface antigen 2b), msa-2c (merozoite surface antigen 2c) and Bv80 (or Bb-1, merozoite protein) and also ITS region (internal transcribed spacer). These genes/regions were selected based in previous diversity analysis from published data available on database (Bing-Zang et al, 2016;Brown et al, 1996;Molad et al, 2015;Flores et al, 2012;Niu et al, 2015;Ramos et al, 2012;Tattiyapong et al, 2016;Mazuz et al, 2012;Sivakumar et al, 2013;Molad et al, 2014;Yokoyama et al, 2015;Combrink et al, 2014;Hilpertshauser et al, 2007;Mtshali & Mtshali, 2017;Matos et al, 2017;Rittipornlertrak et al, 2017;Gallego-Lopez et al, 2018). The genes 18S rRNA, acs-1 (acyl-CoA synthetase 1), ama-1 (apical membrane antigen 1), β-tub (tubulin beta chain), cp-2 (cysteine peptidase 2), p0 (ribosomal phosphoprotein) and rap-1a (rhoptry associated protein 1a) were previously selected but after some analysis they were excluded (Table 1S -Supplementary material).…”

“…The genome of B. bovis was described in 2007 (Brayton et al, 2007) and since then some studies have been carried out to characterize genetic diversity. Some genes (sbp-2 (spherical body protein 2), sbp-4 (spherical body protein 4), trap (thrombospondin-related anonymous protein), msa-1 (merozoite surface antigen 1), msa-2b (merozoite surface antigen 2b), msa-2c (merozoite surface antigen 2c), Bv80 (or Bb-1, merozoite protein), 18S rRNA, acs-1 (acyl-CoA synthetase 1), ama-1 (apical membrane antigen 1), β-tub (tubulin beta chain), cp-2 (cysteine peptidase 2), p0 (ribosomal phosphoprotein) and rap-1a (rhoptry associated protein 1a) and also ITS region (internal transcribed spacer (Brown et al, 1996;Hilpertshauser et al, 2007;Mazuz et al, 2012;Ramos et al, 2012;Sivakumar et al, 2013;Combrink et al, 2014;Molad et al, 2014;Molad et al, 2015;Niu et al, 2015;Yokoyama et al, 2015;Tattiyapong et al, 2016;Matos et al, 2017;Mtshali & Mtshali, 2017;Rittipornlertrak et al, 2017;Gallego-Lopez et al, 2018)) pointed for the production of highly immunogenic proteins have been targets of these studies. However, it remains not elucidated which gene or which of these genes would be a good marker for genotyping studies regarding attenuation or virulent phenotypes.…”

Current Status and Challenges Associated with Tick-Borne Pathogens and Diseases: Where Do We Stand?

“…Various TBPs, including Anaplasma spp., Babesia spp., Ehrlichia spp., Rickettsia spp., and Theileria spp., were documented as significant pathogens in domestic ruminants, particularly cattle [25][26][27][28][29][30]. The review also examined the prevalence of TBPs in different tick species.…”