Basidiomycetes AN INTRODUCTION TO FUNGI, ALGAE AND PLANTS: THEIR MORPHOLOGY, CLASSIFICATION AND EVOLUTION THIRD EDITION JOHN C. SEMPLE AsterGraphics, Waterloo ISBN 0-9736087-0-6   © J.C. Semple, 2004

Dikaryomycota – two haploid nuclei Dominant stage of many species  haploid Mating: plasmogamy  karyogamy Between these stages the cell is dikaryotic Dikaryotic hyphae contain two types of haploid nuclei Plasmogamy is separate from karyogamy

Two groups of Basidiomycetes Holobasidiomycetes Heterobasidiomycetes

AN INTRODUCTION TO FUNGI, ALGAE AND PLANTS: THEIR MORPHOLOGY, CLASSIFICATION AND EVOLUTION THIRD EDITION JOHN C. SEMPLE AsterGraphics, Waterloo ISBN 0-9736087-0-6   © J.C. Semple, 2004

Holobasidiomycete characteristics Basidium lacking septa Synchronous spore maturation Mushrooms many are mycorrhizal with trees some saprobes, some pathogens Bracket fungi – saprobic on trees Puffballs Sterigma (pl. sterigmata)

Heterobasidiomycete characteristics Basidia having septa Asynchronous spore maturation Rusts and smuts – obligate plant pathogens Sterigma (pl. sterigmata) septa

Holobasidiomycetes – mushroom life cycle Dikaryotic hyphae Basidiomata initiation is triggered by environmental conditions, including moisture Hymenium – fertile layer

Basidium development in the hymenium karyogamy meiosis 2 meiosis 1 nuclear migration

Nuclei are extremely flexible: they migrate through the sterigma / spore junction basidiospore sterigma

The hymenium can be on ... Gills Pores Teeth

Gilled mushrooms Agaricales Lactarius indigo

Gills are covered with basidia Coprinus cinereus

Holobasidiomycetes – Polyporales Pore shape is important in identification Fomes fomentarius

Pores are lined with basidia

Tooth mushrooms – Hydnales Teeth are covered with basidia Hydnum repandum

Auriscalpium vulgare

Getting spores out of tight places Gills and pores can be tightly packed / tiny, and shielded from breezes

Cystidia keep gills properly spaced

Getting spores out of tight places Buller’s drop is a launching mechanism

Hilar appendage on ballistic basidiospores

The importance of being vertical Basidiomata can reorient their growth so gills/pores are perpendicular

Some mushroom caps seem poorly designed for air dispersal of spores Coprinus comatus Common in Saskatchewan, especially in autumn on/near tree stumps

Autolysis can modify cap shape Inky cap – water dispersal

Partial veil Universal veil

How mushroom caps get spots and scales

Water-dispersed spores: puffballs Lycoperdon gemmatum

Water-dispersed spores: birds’ nests Splash cup Funicular thread

Heterobasidiomycetes have septate basidia

Heterobasidiomycetes – obligate plant pathogens – rusts and smuts Puccinia graminis f. sp. tritici Aecial stage, on barberry Ustilago maydis on corn

Wheat stem rust Puccinia graminis f. sp. tritici Five spore stages Pycnia, aecia, uredia, telia, basidia Two hosts Barberry – sporidia/pycnia, aecia Wheat – uredia, telia, basidia Uredial stage is most damaging to crops

Wheat stem rust uredia Rust-coloured urediospores

Nutrient extraction by haustoria

Overwintering as teliospores meiosis karyogamy

Some rust fungi require two hosts! Heteroecious  “other houses” “Microcyclic” rusts have reduced numbers of spore types

Sexual recombination in wheat stem rust

... house-eating HolobasidiomyceteS Poria incrassata Serpula lacrymans DRY ROTS

Fungi imperfecti (Deuteromycetes) Next time Fungi imperfecti (Deuteromycetes) or Life without sex (really)