3 - Chytrids

Major clades in the chytrid group

Blastocladiomycota, Monoblepharidiomycota, Chytridiomycota, Neocallimastigomycota, Sanchytriomycota, Olpidiomycota

Lipid globule

refracts light

Chytrid Morphology

zoospore, zoosporangium, thallus, rhizoids, operculum

Zoospore

flagellated spore, lacking ergosterol

Thallus

main “body” of chytrid

holocarpic

entire thallus converted into a sporangium

eucarpic

portions of thallus converted into sporangia; development of rhizoids or vegetative thallus

monocentric

one sporangium

polycentric

multiple sporangia

endobiotic

sporangium produced inside of host cell

epibiotic

sporangium produced outside of host cell

Zoosporangia

chitinous cell wall, cytoplasm cleaved into individual zoospores

papillae

site of zoospore discharge (plural)

operculum

lid-like cap on zoosporangium

plasmogamy

fusion of hyphae/thallus to exchange nuclei

Karyogamy

fusion of two nuclei to become diploid

chytridiomycota life cycle

Ecological Significance

aquatic habitats, saprobes, ruminant symbionts, pathogens

Blastocladiomycota characters

aquatic and soil zoosporic fungi with alternation of haploid gametothallic and diploid sporothallic generations, also produces mating pheromones

Blastocladiomycota life cycle

Allomyces

mainly aquatic, saprotrophic

Coleomomyces

mosquito parasite, alternation of generation with two hosts

Monoblepharidiomycota characters

freshwater saprobes, oogamous sexual reproduction, have hyphae

Monoblepharis life cycle

Chytridiomycota characters

motile cells with one flagellum, coenocytic thallus, conversion of zygote into resting spore/sporangium, cell walls composed of chitin

chytridiales

water and soil inhabiting parasites, cellulose saprobe

cladochytriales

saprobes

rhizophydiales

parasites of algae, other chitrids, aquatic invertebrates

synchytriales

plant parasite

synchytrium endobioticum

black wart disease of potato tubers

Neocallimastigomycota characteristics

obligate anaerobe, live in rumen of herbivores, no true mitochondria

Sanchytriomycota characteristics

freshwater algae parasite, monocentric epibiotic thallus, amoeboid zoospores

Olpidiomycota characteristics

obligate endoparasites