Presentation on theme: "Basidiomycetes Characteristics: Septate mycelium"— Presentation transcript:
1Basidiomycetes Characteristics: Septate mycelium Basidia and basidiosporesClamp connections. Not all Basidiomycetes produce these, but when a fungus does it will always be a basidiomycete.
2Basidiomycetes Characteristics: Two main groups, based on morphology of basidia.Basidia are septate and deeply lobedOrder Uredinales – the rustsProduce all five spore stages – aeciospores, uredospores, teliospores, basidiospores and spermatia (aka pycniospores)Important genera – Puccinia, GymnosporangiumOrder Ustilaginales – the smutsProduce only basidiospores and teliosporesImportant genera – Ustilago, Tilletia
4Basidiomycetes Characteristics: Two main groups, based on morphology of basidia.Basidia are unicellular, non-septate: wood decay fungiOrder Aphyllophorales (aka Polyporales) – the bracket fungiHymenium lines small pores on underside of sporophoreImportant genera – Polyporus, FomesOrder Agaricales – the mushroomsHymenium lines gills (lamellae)Important genera – Armillaria, Agaricus
6Basidiomycetes 5. Three types of hyphae Primary hyphae – develops from a germinating basidiospore. Nuclear status = nSecondary hypha – results from fusion of two primary hyphae. Yields a n+n cell that continues to grow as a n+n hyphaeTertiary hypha – exactly the same as secondary hypha. n+n However it has thick walls that enable production of fleshy and wood sporophoresPrimary hyphaePrimary hyphaeSecondary hyphaeTertiary hyphae
7The RustsThese are obligate parasites. Generally these require two host to complete their lifecycle.Primary hosts – the host on which basidia and basidiospores are produced.Alternate host – the other host in the life cycle on which spermagonia and aecia are producedAlternative host – the host that a pathogen can infect in place of the primary or alternate hosts.Heteroecious – organisms with a primary and alternate host.Autoecious – organisms that have only a single (primary) host.Macrocyclic rust – long cycle rust. Produce all 5 spore types.Demicyclic rust – medium cycle rust. Omits uredia.Microcyclic rust – short cycle rusts. Produces basidiospores, teliospores and spermatia.
9Wheat stem rust, caused by Puccinia graminis tritici
10Cedar apple rust, caused by Gymnosporangium juniperi-virginianum lacks the uredia stage = no repeating stage
11The Smuts Unique characteristics of smuts (vs. rusts) They are not obligate parasites. We can grow them in culture.They show a very high degree of selectivity. They attack not only certain host but certain tissues of the host.Have only tow spore types: basidiospores and teliospores.Example: corn smut, caused by Ustilago maydis