Presentation on theme: "Basidiomycetes Characteristics: 1.Septate mycelium 2.Basidia and basidiospores 3.Clamp connections. Not all Basidiomycetes produce these, but when a fungus."— Presentation transcript:
Basidiomycetes Characteristics: 1.Septate mycelium 2.Basidia and basidiospores 3.Clamp connections. Not all Basidiomycetes produce these, but when a fungus does it will always be a basidiomycete.
Basidiomycetes Characteristics: 4.Two main groups, based on morphology of basidia. a.Basidia are septate and deeply lobed Order Uredinales – the rusts i.Produce all five spore stages – aeciospores, uredospores, teliospores, basidiospores and spermatia (aka pycniospores) ii.Important genera – Puccinia, Gymnosporangium Order Ustilaginales – the smuts i.Produce only basidiospores and teliospores ii.Important genera – Ustilago, Tilletia
Order UredinalesOrder Ustilaginales
Basidiomycetes Characteristics: 4.Two main groups, based on morphology of basidia. b.Basidia are unicellular, non-septate: wood decay fungi Order Aphyllophorales (aka Polyporales) – the bracket fungi i.Hymenium lines small pores on underside of sporophore ii.Important genera – Polyporus, Fomes Order Agaricales – the mushrooms i.Hymenium lines gills (lamellae) ii.Important genera – Armillaria, Agaricus
Basidiomycetes 5. Three types of hyphae a.Primary hyphae – develops from a germinating basidiospore. Nuclear status = n b.Secondary hypha – results from fusion of two primary hyphae. Yields a n+n cell that continues to grow as a n+n hyphae c.Tertiary hypha – exactly the same as secondary hypha. n+n However it has thick walls that enable production of fleshy and wood sporophores Primary hyphae Secondary hyphae Tertiary hyphae
The Rusts These 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 produced Alternative 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.
Wheat stem rust, caused by Puccinia graminis tritici
Cedar apple rust, caused by Gymnosporangium juniperi-virginianum lacks the uredia stage = no repeating stage
The Smuts Unique characteristics of smuts (vs. rusts) a.They are not obligate parasites. We can grow them in culture. b.They show a very high degree of selectivity. They attack not only certain host but certain tissues of the host. c.Have only tow spore types: basidiospores and teliospores. Example: corn smut, caused by Ustilago maydis
Review Wheat stem rust – all spore types Cedar apple rust – lacks ureida Coffee rust – no aecial stage Smuts – basidiospores + teliospores only