Presentation on theme: "Basidiomycetes Characteristics: Septate mycelium"— Presentation transcript:
1 Basidiomycetes Characteristics: Septate mycelium Basidia and basidiosporesClamp connections. Not all Basidiomycetes produce these, but when a fungus does it will always be a basidiomycete.
2 Basidiomycetes 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
4 Basidiomycetes 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
6 Basidiomycetes 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
7 The 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.
9 Wheat stem rust, caused by Puccinia graminis tritici
10 Cedar apple rust, caused by Gymnosporangium juniperi-virginianum lacks the uredia stage = no repeating stage
11 The 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