Identification of horizontal gene transfer and recombination of PsaA gene in streptococcus mitis group.

Abstract

Pneumococcal surface adhesin A (psaA) gene is universally confirmed as one of the Streptococcus pneumoniae adhesion genes, but it is disputed whether the psaA gene is a Streptococcus pneumoniae species-specific gene. In the present study, the presence of the psaA gene in 34 streptococcus mitis group isolates was identified by the PCR approach and a comparison of sequencing PCR products (Streptococcus pneumoniae R6 as the control strain). Also, the evolutionary scenarios of these psaA genes in these streptococcus mitis group isolates were analyzed by a phylogenetic tree based on the housekeeping genes (sodA and rnpB) and psaA genes. As a result, a high degree of conservation of open reading frame sequences in all six Streptococcus pneumoniae strains (100% similarity) and in the other species of the streptococcus mitis group (92.6-100% similarity) was revealed. Further genetics research based on housekeeping genes and psaA gene phylogenies showed that the psaA gene was of vertical inheritance only in Streptococcus pneumoniae; however, high-frequency horizontal psaA gene transfer and recombination occurred in the other species of the streptococcus mitis group. These findings confirmed that the psaA gene was not a Streptococcus pneumoniae species-specific gene, and high-frequency HGT and recombination events may explain the presence of the psaA gene in the other species of the streptococcus mitis group.

DOI: 10.1111/j.1348-0421.2010.00216.x

Cite this paper

@article{Zhang2010IdentificationOH, title={Identification of horizontal gene transfer and recombination of PsaA gene in streptococcus mitis group.}, author={Qiao Zhang and Qianli Ma and Dan Su and Qi Li and Wei Yao and Changzheng Wang}, journal={Microbiology and immunology}, year={2010}, volume={54 6}, pages={313-9} }