Sequence variation in ROP9 gene among Toxoplasma gondii strains from different hosts and geographical locations

Jia Chen, Su Fang Fang, Zhong Yuan Li, Dong Hui Zhou, Guo Hua Liu, Xing Quan Zhu

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Toxoplasma gondii infects a wide range of animals and humans causing toxoplasmosis. T. gondii rhoptry protein 9 (TgROP9) is expressed only in tachyzoite stage that might be involved in the early stages of invasion and this soluble protein is constituted with putative B-cell epitope but also can trigger a T cell response and exclusively react with CD4 + T cell clone. In this study, researchers examined sequence variation in ROP9 gene among seven T. gondii strains from different hosts and geographical localities by PCR amplification, sequence analysis and phylogenetic reconstruction using Maximum Parsimony (MP). The results showed that the entire genome sequence of the TgROP9 gene was 4555bp in length and no size variation was detected among all the strains. In addition, there were 26 (0-0.7%) variable nucleotide positions among all isolates with 9 variations of these being in the coding region and the other 11 were distributed among the 4 introns. Phylogenetic analyses revealed that the TgROP9 sequences were not a suitable genetic marker to differentiate T. gondii strains of different genotypes from different hosts and geographical locations. This study determined the TgROP9 genomic sequences of seven T. gondii strains and demonstrated the existence of low sequence variation in TgROP9 gene, suggesting that T. gondii ROP9 may represent a good vaccine candidate against toxoplamosis.

Original languageEnglish
Pages (from-to)4288-4291
Number of pages4
JournalJournal of Animal and Veterinary Advances
Issue number22
StatePublished - 2012
Externally publishedYes


  • Phylogenetic analysis
  • Rhoptry protein 9 (ROP9)
  • Sequence variation
  • Toxoplasma gondii toxoplasmosis


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