Fungi The Ascomycota Ascomycota is sister to Basidiomycota

Fungi The Ascomycota

Ascomycota is sister to Basidiomycota in a subkingdom called dikarya. This kingdom, Fungi, is sister group to the Animalia. The ascogenous fungi all have a similar life cycle with a brief dikaryotic phase After cells or hyphae fuse, the dikaryotic cells insure the distribution of each nucleus type by the formation of a hook, called a crosier

Types of Ascocarps

The Yeasts • Fungi that have been secondarily reduced to a unicellular form • 2 major types: • Schizosaccharomyces type • Saccharomyces type Schizosaccharomyces, these divide by the production of cross walls Scaccharomyces, these divide by budding

Ascomycota with Pseudothecia • Pseudothecia are asci produced without any part of the mycelium making a structure to support them • Taphrina, causative agent of leaf curl (e. g. Peach leaf Curl) Photomicrograph of Taphrina deformans, showing the production of scattered asci on the surface of a peach leaf

Ascomycota with cleistothecia • Many Ascomycota produce cleistothecia, structures that do not have an opening • Common structure in molds such as Penicillium • Dispersal through asexual spores called conidiospores Cleistothecium of Penicillium, common blue mold Conidia of Penicillium.

Ascomycota with Perithecia • Perithecium is similar to a cleistothecium, but the structure has an opening. • Claviceps purpurea, which parasitizes rye grains and causes ergot, produces cleistothecia from infected rye Life cycle of Claviceps purpurea Detail of an ergotized grain of rye

Ascomycota with Apothecia • Apothecia are large specialized structures on which occur exposed asci. • At the base of the apothecium, specialized gametangia allow the mixing of nuclei from compatible mycelia. From them emerge dikaryotic filaments that culminate in the formation of asci Life history of Peziza Asci on the surface of the Peziza cup