Saccharomycotina

Saccharomycotina is a subdivision (subphylum) of the division (phylum) Ascomycota in the Kingdom Fungi. It comprises most of the ascomycete yeasts. The members of Saccharomycotina reproduce by budding and they do not produce ascocarps (fruiting bodies). The subdivision includes a single class: Saccharomycetes, which again contains a single order: Saccharomycetales. Notable members of Saccharomycotina are the baker's yeast Saccharomyces cerevisiae and the genus Candida that includes several human pathogens. The name comes from the Greek word σάκχαρον (sákkharon), meaning 'sugar' and μύκης (mukēs) meaning 'fungus'. Historical records from ancient Egypt and China describe the processes of brewing and baking from 10,000 to 8,000 years ago, and the production of fermented beverages and foods seems to have paralleled the beginning of agriculture. In the 1850s, Louis Pasteur demonstrated that yeasts are responsible for the fermentation of grape juice to wine. Saccharomycotina include some of the economically most important fungi known. Members include species of industrial and agricultural importance (e.g. brewing, baking, fermentation of food products, production of citric acid, production of recombinant proteins, biofuel production, biological pest control of crops). Other species cause economic losses worldwide (plant pathogens, contaminants of foods and beverages). Yet others are animal and human pathogens. Saccharomycete yeasts usually grow as single cells. Their cellular morphology is fairly simple, although their growth form is highly adapted. Asci are naked and ascospores can have several forms. No species produce ascocarps (fruiting bodies). Saccharomycete genomes are often smaller than those of filamentous fungi. Some species (e.g. Metschnikowia species) tend to form chains of budding cells that are termed pseudohyphae. Yet other species are able to produce true septate hyphae. Such species (e.g. Candida albicans) are termed dimorphic, which means they can propagate both as budding yeasts and as filamentous hyphae.