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Identification of horizontal gene transfer and recombination of PsaA gene in streptococcus mitis group
Author(s) -
Zhang Qiao,
Ma Qianli,
Su Dan,
Li Qi,
Yao Wei,
Wang Changzheng
Publication year - 2010
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2010.00216.x
Subject(s) - streptococcus mitis , biology , streptococcus pneumoniae , housekeeping gene , gene , horizontal gene transfer , microbiology and biotechnology , streptococcus , genetics , pneumolysin , bacterial adhesin , streptococcus oralis , phylogenetic tree , virulence , bacteria , gene expression
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.