7 Blastocladiomycota

Abstract

The Blastocladiomycota (blastoclads) are a phylum of zoosporic fungi that include diverse taxa such as the model water mold Allomyces. The 14 genera of blastoclads form a monophyletic group that is phylogenetically distinct from other Fungi and unique in having an alternation of haploid and diploid generations. Blastoclads can be distinguished from other zoosporic true fungi (e.g., Chytridiomycota) on the basis of the ultrastructure of their uniflagellated zoospores. These ultrastructural characters are also taxonomically informative at the generic level. The precise placement of Blastocladiomycota in the fungal tree of life is uncertain but has a large bearing on the evolution of several traits, such as an intact nuclear envelope during mitosis and heterothallism with mating types. Environmental DNA studies suggest that blastoclads may be enriched in suboxic or anaerobic environments, and although some species are known to be obligate fermenters, none is known to be obligately anaerobic.