Dothideomycetes

Overview

Scanning electron micrograph of apple scab, a disease caused by a member of Dothideomycetes.

Dothideomycetes is the largest and most diverse class of ascomycete fungi within the phylum Ascomycota. This class includes a wide variety of fungi that are primarily characterized by their production of ascospores in a structure known as an ascoma. Dothideomycetes are known for their ecological diversity, with species found in a range of habitats including terrestrial, aquatic, and symbiotic environments.

Morphology

Dothideomycetes exhibit a wide range of morphological forms. The fruiting bodies, or ascomata, can be perithecial, pseudothecial, or apothecial. The asci are typically bitunicate, meaning they have a double wall, which is a distinguishing feature of this class. The ascospores are often darkly pigmented, which is thought to provide protection against ultraviolet radiation.

Ecology

Members of Dothideomycetes play significant roles in various ecosystems. They can be saprotrophic, breaking down organic matter, or pathogenic, causing diseases in plants and animals. Some species form lichens, while others are involved in endophytic relationships with plants. A notable example of a plant pathogen in this class is the fungus responsible for apple scab, a disease that affects apple trees and is of economic importance in agriculture.

Economic Importance

Close-up of apple scab lesions on a leaf.

Dothideomycetes include several species that are important in agriculture and industry. Plant pathogens such as those causing apple scab and black spot on roses can lead to significant crop losses. Conversely, some species are beneficial, being used in the production of enzymes and bioactive compounds for pharmaceuticals.

Taxonomy

The class Dothideomycetes is divided into several orders, including Capnodiales, Pleosporales, and Dothideales. Each order contains a variety of families and genera, reflecting the diversity within the class. The taxonomy of Dothideomycetes is complex and subject to ongoing research and revision as new molecular data become available.

Related pages

• Ascomycota
• Fungal morphology
• Plant pathology
• Lichen