Zygomycota

 

Links to other web pages:

http://www.botany.hawaii.edu/botany/201/zygomy.htm

http://www.pacificcoast.net/~mycolog/chap3b.htm

http://muse.bio.cornell.edu/~fungi/findex.html

 

Features;

Zygospores

Zygosporangia

aplanospores;

chitin in cell wall

coenocytic hyphae

coenozygote

absence of gametes

homothallic or heterothallic

simple bipolar compatibility

 

Trichomycetes: obligately associated with living arthropods and grow in gut; attach to chitin of hindgut via a holdfast; otherwise poorly known.

Zygomycetes:

 

Mucorales

No forceful spores discharge; saprobes or weak parasites; aplanospores; germination easy (simple sugar fungi), dissemination easy; rapid growth; growth easily slowed due to staling by carbon dioxide

variation in sporangia gives concept to morphological phylogeny (Rhizopus- sporangium only, also has columella, apophysis, and sporangiophore); Thamnidium- sporangium and sporangiolum; Choanephora (sporangiola with several spores), Cunninghamella (sporangiolum with one spore), Syncephalastrum (with merosporangium on end of vesicle), Piptocephalis (with merosporangia on end of dichotomously branched sporangiophore), Kickxella (merosporangia on sporocladium).

 

Classification:

 

Mucoraceae (Mucor- heterothallis) ( Zygorhynchus- homothallic): saprobes; columellate; no apophysis, sporangiola, or merosporangia.

Dicranophoraceae; facultative parasites on insects or on mushrooms (Spinellus not dichotomous; Syzgites dichotomous); columella, apophysis but not sporangiola

Mortierellaceae: Mortierella; saprobes, arachnoid hyphae; non-columellate, non-apophysate sporangia; no sporangiola

Pilobolaceae: trophocysts and forceful sporangia discharge; saprobles; columellae with large subsporangial vescile, non-apophysate; no sporangiola

Thamnidiaceae: saprobes; no columella nor apophsis; multispored or unispored sporangiola

Choanephoraceae: saprobes, sporangia have one or more longitudinal sutures; sporangia and sporangiola

Syncephalstraceae: saprobes; branched sporangiophores bearing apical vesicles covered with merosporangia

Cunninghamellaceae; contains Cunninghamella; saprobes; coenocyctic sporangiophores terminating in vesicles bearing pedicellate unispored sporangiola (at times considered to be conidia

Phycomycetaceae: contains Phycomyces; saprobes; huge sporangium containing large number of spores; sporangiophore is constricted; sporangium is columellate

Absidiaceae; Absidia (pyriform), Rhizopus (globose); saprobes; apophysate, columellate sporangia; often with rhizoids and stolons

Gilbertellaceae-sporangiophore directly from substrate, dark columellate, non-apophysate sporangia; no sporangiola nor merosporangia.

Mycotyphaceae; cylindrical, fertile vesicles with dimorphic, unispored sporangiola (often considered conidia) attached by denticles

Entomophthorales: forceful sporangia (conidium) discharge; hyphae typically septate; Obligate parasites of insects.

Life cycle of Entomophthora synchronized to biological clock; infects fly and uses spores to spread throughout fly body, at time fly ready to die, it climbs to top of grass or on windows, dies; hyphae produce rhizoidal branches adhering fly body to substrate; if encounter new host will form hyphae; if not, it will form a sticky secondary conidium; either germinates to produce hyphae or microsopores (function) to spread fungus (see handout Fig. 10-5; 12-1).

Life cycle of Massospora cicadina that infects 20 year locus (see handout Fig. 12-12).

Basidiobolus occurs in dung of reptiles, amphibians, fish, and bats; gets into beetles that the lizards and frogs eat.

Zoopagales: no forceful discharge of sporangia; parasites of protozoans, small animals, or other fungi

asexual propagules calles sporangiospores but most workers refer to them as conidia. Lethal lollipops. Capillary spore (blastospore produced at time of abundant water) and haptor (sticky end) of Stylopage anomala; spore adheres to mites that ride along on dung beetles for their own dispersal. Parasitizes amoebae in dung.

Piptocehaplidaceae: biotrophic, haustorial, multispored merosporangia; ornamented zygosporangium; mycocparasites (mainly Mucorales)

Dimargaritales: produce two-spored, merosporangia; regularly septate hyphae; thin-walled zygosporangia; haustorial mycoparasites of Mucorales.

Kickxellales: single-spored merosporangia produced from pseudophialides; pseudophialides produced on a sporocladium

Glomales: endomycorrhizal formers; no sporocarp; produces azygospore and chlamydospores.

Endogonales: endomycorrhizal formers; sporocarp.containing zygospores.

 

Life Cycle of Rhizopus: see book Figure 5-12; pg. 140; handout as well.

Production of prohormones and hormones that function in formation of zygophore and attraction of hyphae (see handouts)

Pilobolus: discussion of forceful sporangium discharge.