Yeast chromosomes have also been modified to serve as vectors for transporting human DNA fragments for use in gene mapping . Sac fungi are also important in decomposing and recycling organic matter. Some ascomycetes are parasites responsible for Dutch Elm disease and Chestnut blight. Other sac fungi are used in commercial baking and brewing, wine making, and in the production of antibiotics. Some sholars speculate that an outbreak of wild ergot may have been responsible for the hallucinations associated with the Great Awakening in 17th century America.
Sexual reproduction involves the formation of basidiospores on club-shaped cells known as basidia .
Image from W.H. Freeman and Sinauer Associates, used by permission. Club fungi are important as commercial crops. They also cause many diseases that result in loss or reduction of grain yields. Amanita phalloides is the most poisionous of all mushrooms. Fungi provide nutrients from the substrate, the phototroph provides food.