The ‘species complex’ issue in clinically relevant fungi: A case study in Scedosporium apiospermum

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• 作者：Min Chen^a ; ^b ; ^c ; Jingsi Zeng^d ; ^{wuhanzjs@aliyun.com" class="auth_mail" title="E-mail the corresponding author} ; G. Sybren De Hoog^a ; ^b ; ^c ; ^e ; ^f ; ^g ; ^h ; Benjamin Stielow^b ; A.H.G. Gerrits Van Den Ende^b ; Wanqing Liao^a ; Michaela Lacknerⁱ ; ^{Michaela.Lackner@i-med.ac.at" class="auth_mail" title="E-mail the corresponding author}
• 关键词：ITS rDNA ; Populations ; Primary barcode ; Secondary barcode
• 刊名：Fungal Biology
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：120
• 期：2
• 页码：137-146
• 全文大小：2161 K

文摘

The genus Scedosporium currently comprises six species, Scedosporium apiospermum, Scedosporium boydii, Pseudallescheria angusta, Scedosporium minutisporum, Scedosporium dehoogii, and Scedosporium aurantiacum, most of which can be distinguished with the primary fungal DNA barcode, the ITS1/2 region of the rDNA gene cluster. In the present study, four additional genetic loci were explored from a phylogenetic point of view enabling a barcoding approach based on K2P pairwise distances to resolve the taxa Scedosporium. We included partial γ-actin (ACT), β-tubulin (BT2), elongation factor 1α (TEF1), and the small ribosomal protein 60S L10 (L1) (RP60S). Phylogenetic inference of each marker individually showed that four out of six species within Scedosporium can be distinguished unambiguously, while strains of S. apiospermum, S. boydii, and P. angusta showed occasional recombination, and accordingly, no genealogical concordance between markers was obtainable. We defined S. apiospermum, S. boydii, and P. angusta as the ‘S. apiospermum species complex’ since observed differences were not consistent between lineages, and no clinical differences are known between entities within the complex. While BT2 revealed the best performance among the genetic loci tested at the lineage level, barcoding of the ITS region is sufficient for distinction of all entities in Scedosporium at the species or ‘complex’ level.