Basidiomycotina 2 Chromistan Fungi Eumycotan Fungi 1 Chytridiomycota

Basidiomycotina (2) • Chromistan Fungi • Eumycotan Fungi. 1. Chytridiomycota 2. Zygomycota 3. Dikaryomycota phyla sub-phyla • Ascomycotina • Basidiomycotina

Basidiomycotina - main features (cf. Ascomycetes) – sexual spores (basidiospores) outside basidium – complex septal pores – extended dikaryophase (most hyphae) – multi-layered cell walls – clamp connections – molecular differences from ascomycetes anamorphs occur but are less important

Basidiomycotina A. Basidia not subdivided) Holobasidiomycetes (Mushrooms) Hymenomycetes - forcible discharge of spores Gasteromycetes - not forcible B. Basidia subdivided. Phragmobasidiomycetes - jelly fungi (gelatinous fruit bodies) Teliomycetes - rust and smut pathogens - no fruit bodies

Not all mushrooms have gills. The ‘Boletes’ have pores instead.

Some important Gasteromycetes • Sclerodermatales - earthballs – spores borne in large masses (gleba) often covered with thin skin • Lycoperdales - puffballs, earthstars • Nidulariales - birds-nest fungi • Phallales - stinkhorns foul smell attracts flies - disperse spores

Sclerodermatales Pisolithus tinctorius, an important ectomycorrhizal fungus. gleba

Puffballs - can be several feet in diameter Gleba masses of spores inside

Gleba divided up into several peridioles (‘eggs’)- splashed out of cup by rain - attaches at new site and forms basidia Nidulariales - Birds’ nest fungi

Spore dispersal in Birds Nest Fungi (Cyathus)

Phallales stinkhorns Phallus sp. Mutinus sp.

Basidiomycotina Phragmobasidiomycetes • Basidia are subdivided • Jelly like fruit bodies, sometimes blobs, sometimes ‘ear-shaped’ • some are mycoparasites, none of economic importance

Photo - Dr. Greg Thorn Phragmobasidiomycetes - Jelly Fungi

Basidiomycotina Teliomycetes - Rusts and Smuts • Basidia are subdivided - 4 cells • No fruit bodies - instead basidia formed on overwintering diploid spores (teliospores) • simple septal pores • Many important pathogens of crops and other plants

Teliomycetes - Rusts and Smuts • Uredinales - Rust fungi – obligate pathogens with complex cycles - often alternate hosts for anamorph/teleomorph – localized infection – special sex organs (spermatogonia/receptive hyphae) • Ustilaginales - smut and bunt fungi – facultative pathogens - no alternate hosts - have yeast like anamorph – systemic but often form spores just in flowers – no spermatogonia - any two cells can fuse

Uredinales - Rust fungi Some rusts such as Black Stem rust (Puccinia graminis) have: 1. 5 different spore types (macrocyclic) 2. alternate hosts (heteroecious) cycles between Wheat & Barberry. 3. sub-species & physiologic races which specialize on different grass sp. and varieties. Others have fewer types of spore (microcyclic) and/or only one host (autoecious)

Puccinia graminis black stem rust.

3 Spermagonia forming innumerable tiny haploid spermatia which ooze out in a sweet-smelling nectar. Insects are attracted by the nectar, and walk or fly from one spermagonium to another, transferring spermatia of each mating type to receptive hyphae of the other type. This process initiates the dikaryophase. The dikaryotization spreads to the lower surface of the barberry leaf and produces cup-like structures called aecia - two are shown in this section. Aeciospores (n + n)

The flower-like aecia burst through the host epidermis, and liberate dikaryotic aeciospores - but these spores can't infect the barberry - they must infect a wheat plant where they soon form uredinia (n+n) Uredinia of Puccinia sp. growing on Ribes. Red pustules give rust fungi their name.

The uredinia on wheat produce first masses of urediniospores (n+n) which rapidly spread the infection in wheat - producing more uredinia Later thick walled overwintering teliospores (2 n) are produced spores which germinate to give basidiospores (n) which infect barberry to begin cycle again.

In rusts the teliospore replaces the fruit body - germinates to produce a compartmented basidium which then produces the 4 basidiospores (often forcibly discharged)

Some other important rusts Teliomycetes - Uredinales - telial horns of Gymnosporangium on juniper (Juniperus). Aecial stage of Cronartium fusiforme - blister rust on Pinus (left). Uredinia and teliospores on Currant (right) Hemilaea vastatrix - coffee rust - wiped out coffee in Ceylon - hence now grow tea

Ustilaginales - Smut + bunt fungi • Form masses of dark diploid thick-walled spores (teliospores) in flowers or fruit, leaves or stems • Teliospores produce 3 -4 celled basidium which buds off basidiospores (not forcibly expelled) - which bud off more sporidia • Can grow saprobically as yeast-like haploid sporidia; fuse in/on host - grow systemically as dikaryotic hyphae. • Several important pathogenic species e. g corn smut (Ustilago maydis); loose smut of barley(Ustilago nuda), bunt of wheat (Tilletia caries) and onion smut (Urocystis cepulae)

Ustilago maydis - corn smut. spores often replace entire cob

Ustilago violacea - anther smut. Systemic infection but forms spores only in anthers (replaces pollen) causes sex change in plant Loose smut, a disease of barley caused by Ustilago nuda. Spores replace grains

Sporidia of U. violacea Fimbriae - very long protein-RNA fibrils on surface of cells (only 7 nm wide)

Tilletia (Stinking Smut)

Follow-up to lecture • Chap 5, text, Web and CD. • know main features of Basidiomycetes and how to distinguish from other groups. • Important economic species • key life cycles • typical mushroom, rust, smut life cycles • review terms • teliospore, sporidia, 5 spore types of rusts, heteroecious, autoecious, macrocyclic, microcyclic.