Salgado-Salazar Catalina, Jones Leandro R, Restrepo Ángela, McEwen Juan G
Cell Biology and Immunogenetics Unit, Corporación Para Investigaciones Biológicas, Medellín, Colombia.
Instituto de Investigaciones Médicas, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia.
Cladistics. 2010 Dec;26(6):613-624. doi: 10.1111/j.1096-0031.2010.00307.x.
Paracoccidioides brasiliensis is the aetiological agent of paracoccidioidomycosis, the most important systemic mycosis in Latin America. In order to study the diversity of P. brasiliensis mitochondrial genes, to evaluate previous taxonomic proposals, and to explore the hypothesis that the previously described "divergent isolate" B30 (also called Pb01) could represent a new P. brasiliensis species, we undertook a molecular phylogenetic analysis based on five mitochondrial markers. Mitochondrial sequences of 59 P. brasiliensis isolates obtained from clinical and environmental samples, and the orthologous genes from outgroup species, are reported and analysed using parsimony and Bayesian methods. The combined data set comprised 2364 characters, of which 426 were informative. One of the studied strains presented a 376-nt insertion at the apocytochrome b (cob) gene. The corresponding sequence had a high similarity (79%) with an intron found in the Neurospora crassa cob gene. Interestingly, this intron is absent in the previously published sequence of the P. brasiliensis mitochondrial genome. Our trees were moderately congruent with the previous P. brasiliensis taxonomic proposals. Furthermore, we identified a new monophyletic group of strains within P. brasiliensis. Nevertheless, the phylogenetic species recognition (PSR) analyses described here suggested that these groups of strains could represent geographical variants rather than different Paracoccidioides cryptic species. In addition, and as previously proposed by other authors, these analyses supported the existence of a new specie of Paracoccidioides, which includes the previously described, divergent isolate B30/Pb01. This is the first report providing evidence, independent of nuclear markers, for the split of this important human pathogen into two species. We support the formal description of the B30/Pb01 as new specie. ©The Willi Hennig Society 2010.
巴西副球孢子菌是副球孢子菌病的病原体，该病是拉丁美洲最重要的系统性真菌病。为了研究巴西副球孢子菌线粒体基因的多样性，评估先前的分类学提议，并探讨先前描述的“分歧菌株”B30（也称为Pb01）可能代表一种新的巴西副球孢子菌物种这一假说，我们基于五个线粒体标记进行了分子系统发育分析。报告了从临床和环境样本中获得的59株巴西副球孢子菌分离株的线粒体序列，以及外类群物种的直系同源基因，并使用简约法和贝叶斯方法进行了分析。合并后的数据集包含2364个字符，其中426个具有信息性。所研究的菌株之一在脱辅基细胞色素b（cob）基因处有一个376 nt的插入。相应序列与粗糙脉孢菌cob基因中的一个内含子具有高度相似性（79%）。有趣的是，该内含子在先前发表的巴西副球孢子菌线粒体基因组序列中不存在。我们构建的树与先前的巴西副球孢子菌分类学提议适度一致。此外，我们在巴西副球孢子菌中鉴定出一个新的单系菌株群。然而，此处描述的系统发育物种识别（PSR）分析表明，这些菌株群可能代表地理变异，而非不同的副球孢子菌隐性物种。此外，正如其他作者先前所提议的，这些分析支持存在一种新的副球孢子菌物种，其中包括先前描述的分歧菌株B30/Pb01。这是第一份独立于核标记提供证据，证明这种重要的人类病原体分裂为两个物种的报告。我们支持将B30/Pb01正式描述为新物种。©Willi Hennig学会2010年。
