Main characteristics

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Division Chytridiomycota
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Main characteristics
u Somatic stage Coenocytic hyphae with globular,
ovoid or well-develop mycelium Mostly haploid,
but some species are diploid Cell wall are
mainly chitin and glucan Centriole u
Reproduction Asexual reproduction by production
of single posterior whiplash zoospore in
sporangium Sexual reproduction by formation of
resting sexual spore by mean of planogametic
copulation
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Life cycle of Chytridiomycota
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Sexual reproduction in Chytrids 1.
Planogametic copulation a) Conjugation of
isogamous planogamete b) Conjugation of
heterogamus planogamete c) Fertilization
of non-motile female gamete (egg) by
a motile male gamete (antherozoid) 2.
Gametangial copulation 3. Somatogamy
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Sporangium and zoospore development
www.mycolog.com/chapter2b.htm
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Chytrid zoospore
www.mycolog.com/chapter2b.htm
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Classification
Order Chytridales Order Spizellomycetales Order
Neocallimasticales Order Blastocladicales Order
Monoblepharidales
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Order Chytridiales
u Zoospore character have central core
of ribosome enclosed by two membrane,
have a single lipid droplet and
rumposome present
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u Water- or soil- inhibiting saprophytic fungi
and some are parasite on algae, water
mold and animal eggs u For example genus
Synchytrium, Rhizophydium and
Chytriomyces
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Synchytrium spp.
u Holocarpic, endobiotic, parasitic fungi of
flowering plant u S. endobioticum is parasite
causing black wart disease on potato
characterized by enlargement of surface cell
(hypertrophy) and increase numbers of cell
(hyperplasia)
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Life cycle of synchytium endobioticum
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S. taraxaci mature sporangium (A) and empty
sporangium
A
B
www-biol.paisley.ac.uk/.../Fungi/
Synchytrium_taraxaci.html
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Black wart disease caused by S. endobioticum
www.redepapa.org/verruga.html
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Rhizophydium spp.
u Eucarpic form that exhibit endogenous
development u Saprophytic or parasitic species
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Eucarpic thallus of Rhyzophydium
www.mycolog.com/chapter2b.htm
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Rhizophydium sp. parasite on Spirogyra sp.
protist.i.hosei.ac.jp/.../Eumycota/
Rhyzophydium/sp_23c.html
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Chytriomyces spp.
u Eucarpic chytrid u Common genus can be found in
water and soil sample
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Life cycle of Chytriomyces hyalinus
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Order Spizellomycetales
u Previously had been included in Chytridiales u
Zoospore character ribosome are
dispersed, several lipid droplet occurs in
anterior end of zoospore and rumposome absent.
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u Sexual reproduction is unknown in this order u
Water- or soil- inhibiting saprophytic fungi and
some are parasite on plants and
fungi u For example Rozella spp. and Olpidium
spp.
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Rozella spp.
u Obligate endoparasite of aquatic fungi
(Oomycota and Chytridiomycota) u R. allomycis is
parasite of Allomyces.
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Olpidium
spp. u Holocarpic endobiotic plant parasite of
algae, mosses and pollen u O.brassicae is a
vector for a number of plant virus u O. brassicae
is parasite of cabbage
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Order Neocallimasticales
u Once included in Spizellomycetales u Anaerobic
chytrids that inhibite within rumen and cecum of
herbivorous animals u Zoospore character
have aggregated ribosome, but lack
rumposome and mitochondria u Uniflagellate or
polyflagellate (ca 10) zoospores u For example
genus Neocallimastix
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Neocallimastix spp.
u Inhabitat in rumen and cecum of mamalian
herbivorous u Anaerobic chytrid u Polyflagellate
zoospores u Complete life cycle is unclear
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Neocallimastrix sp.
www.towson.edu/wubah/rumenfungi/
Anaerobic20zoosporic...
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Order Blastocladicales
u Zoospore character common feature as other
order and having nuclear cap, which is a
cluster of ribosome surrounded by a
membrane u With resting sporangia surrounded by a
thick outer dark-brown wall u Water or soil
inhabitants u For example genus Allomyces,
Coelomomyces and Blastocladiella
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Allomyces spp.
u Filamentous polycentric eucarpic
chytrid u Saprophytic on soil and water
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Thick-walled resting spore of Allomyces sp.
www.ucmp.berkeley.edu/ fungi/allomyces.jpg
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Male and female gametangia of Allomyces arbuscular
micol.fcien.edu.uy/atlas/ ChytrOomycetes.html
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Coelomomyces spp.
u Obligate parasite of mosquitoes and chironomids
inhabited by the body cavity or coelom u
Host specific ---gt biological control agents u C.
psorophorae is heteroecious, e.g. require two
completely different hosts, mosquito and
copepod.
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Life cycle of Coelomomyces psorophorae
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Sporangium of Coelomomyces sp.
www.rmc.edu/facstaffpages/wmartin/
public_html/research.html
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Order Monoblepharidales
u Small order with small number of species u
Zoospore character with cluster ribosome around
centrally positioned nucleus, numerous
lipid droplet and numerous mitochondria at
posterior end u Saprobes on twig or fruit
submerging in fresh water u For example genus
Monoblepharis
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Monoblepharis polymorpha
u Well developed branch hyphae. u
Protoplasm is highly vacuolated, so
that is appears foamy . u Gametangial
copulation occurs with in oogonium.