Dothideomycetes

Dothideomycetes is a class within the fungal phylum Ascomycota. It is one of the largest and most diverse classes, containing thousands of described species across many genera and families. Members are found in a wide range of habitats, but most are associated with plants, functioning as pathogens, endophytes, or saprobes.

A defining feature is the production of asci inside pseudothecia, a type of sexual fruiting body that is typically embedded in plant tissue or a superficial stroma. The asci are usually bitunicate, meaning they have two functional walls. When mature, the outer wall dehisces and the inner wall expands to release ascospores into the surrounding environment.

Sexual reproduction is often accompanied by extensive asexual morphs (anamorphs) in many lineages. These asexual states can belong to various genera such as Alternaria, Cladosporium, Cercospora, and Botryosphaeria, although many species are known only from their sexual state.

Ecology and economic importance: Dothideomycetes include numerous plant pathogens causing leaf spots, cankers, fruit diseases, and other disorders, as well as many leaf endophytes and saprobes. They are widespread on land and can be important drivers of agricultural disease, biodiversity, and ecosystem function. Some species produce secondary metabolites with pharmaceutical or agricultural relevance.

Systematics: The class is highly diverse and divided into multiple orders, with Pleosporales being the largest, followed by Capnodiales, Dothideales, Botryosphaeriales, and Mycosphaerellales. Molecular phylogenetics has clarified relationships within the group and led to revisions of genera and families.