The biological variability among Neospora caninum isolates has been widely shown, however, the molecular basis that determines this diversity has not been thoroughly elucidated to date. The latest studies have focused on a limited number of isolates. Therefore, the goal of the present study was to compare the proteome of a larger number of N. caninum isolates with different origins and virulence. Label-free LC–MS/MS was used to investigate the tachyzoite proteomic differences among Nc-Bahia, Nc-Spain4H and Nc-Spain7, representing high virulence isolates and Nc-Ger6, Nc-Spain2H and Nc-Spain1H, representing low virulence isolates. Pairwise comparisons between all isolates and between high virulence and low virulence groups identified a subset of proteins with higher abundance in high virulence isolates. These proteins were involved in energy and redox metabolism, and DNA/RNA processing, which might determine the faster growth rates and parasite survival of the high virulence isolates. Highlighted proteins included a predicted member of the rhoptry kinase family ROP20 specific for N. caninum, Bradyzoite pseudokinase 1 and several dense granule proteins. DNA polymerase, which was more abundant in all high virulence isolates in all comparisons, might also be implicated in virulence. These results reveal insights into possible mechanisms involved in specific phenotypic traits and virulence in N. caninum, and the relevance of these candidate proteins for N. caninum virulence deserves further investigation.

犬新孢子虫分离株之间的生物学变异性已被广泛显示，但是，至今仍未完全阐明决定这种多样性的分子基础。最新的研究集中在数量有限的分离株上。因此，本研究的目的是比较大量犬新孢子虫的蛋白质组。具有不同来源和毒力的分离株。无标记LC-MS / MS用于研究代表高毒力分离株的Nc-Bahia，Nc-Spain4H和Nc-Spain7之间的速殖子蛋白质组学差异以及代表低毒力分离物的Nc-Ger6，Nc-Spain2H和Nc-Spain1H之间的速殖子蛋白质组学差异。所有分离株之间以及高毒力和低毒力组之间的成对比较确定了高毒力分离物中具有较高丰度的蛋白质子集。这些蛋白质参与能量和氧化还原代谢以及DNA / RNA加工，这可能决定了高毒力分离株的较快生长速率和寄生虫存活。突出显示的蛋白质包括特异于犬新孢子虫的rhoptry激酶家族ROP20的预测成员，缓殖子假激酶1和几种致密颗粒蛋白。在所有比较中，所有高毒力分离物中的DNA聚合酶含量都较高，也可能与毒力有关。这些结果揭示了对与犬新孢子虫特定表型性状和毒力有关的可能机制的见解，这些候选蛋白与犬新孢子虫毒力的相关性值得进一步研究。