Department of Botany, Brandon University, Brandon, Manitoba, R7A 6A9 Canada.
Mycologia. 2004 Jul-Aug;96(4):812-21. doi: 10.1080/15572536.2005.11832928.
Phylogenies inferred from the analysis of DNA sequence data have shown that the Onygenales contains clades that do not correspond with previously described families. One lineage identified in recent molecular phylogenetic studies includes the dimorphic pathogens belonging to the genera Ajellomyces, Emmonsia and Paracoccidioides. To evaluate the degree of support for this lineage and determine whether it includes additional taxa, we examined relationships among the members of this clade and selected saprobic onygenalean taxa based on maximum-parsimony analyses of partial nuclear large RNA subunit (LSU) and internal transcribed spacer (ITS) sequences. A clade distinct from the Onygenaceae was found to encompass Ajellomyces (including the anamorph genera Blastomyces, Emmonsia and Histoplasma) and Paracoccidioides brasiliensis. The members of this lineage are saprobic and pathogenic vertebrate-associated taxa distinguished by their globose ascomata with coiled appendages, muricate globose or oblate ascospores, and lack of keratinolytic activity. Anamorphs are solitary aleurioconidia or irregular alternate arthroconidia. Based on molecular data and on morphological and physiological similarities among these taxa, we propose the new family, Ajellomycetaceae.
从 DNA 序列数据分析推断的系统发育表明，Onygenales 包含与先前描述的科不对应的类群。在最近的分子系统发育研究中确定的一个谱系包括属于 Ajellomyces、Emmonsia 和 Paracoccidioides 属的二态病原体。为了评估该谱系的支持程度并确定它是否包含其他分类群，我们研究了这个类群成员之间的关系，并根据核大亚基 RNA 亚单位 (LSU) 和内部转录间隔区 (ITS) 序列的最大简约分析选择了腐生性 Onygenales 分类群。发现一个与 Onygenaceae 不同的谱系包含了 Ajellomyces（包括其无性型属 Blastomyces、Emmonsia 和 Histoplasma）和 Paracoccidioides brasiliensis。这个谱系的成员是腐生的、与脊椎动物相关的病原体，其特征是具有卷曲附属物的球形子囊壳、具粒状的球形或扁球形子囊孢子，以及缺乏角蛋白分解活性。无性型是单个的粉孢子或不规则交替的节孢子。基于分子数据以及这些分类群之间的形态和生理相似性，我们提出了新的科，Ajellomycetaceae。
