Chytridiomycota, zygomycota pdf

Classification of zycomycota and chytridiomycota and their general characters will give us an idea about fungi that comes under and idea and variations about different categories of fungi

1. Chytridiomycota
Chytridionmeans –Little pot
N.H. SHANKAR REDDY
2
nd
Ph.D. Plant Pathology
Annamalai University

3. General characters
•Thechiefcharacteristicfeatureofthisclassistheproduction
ofuniflagellatereproductivecells(zoosporesand
planogametes).
•Thesingleflagellumisofawhiplashtypeandisinserted
posteriorly.Thezoosporewithaposteriorlyinsertedflagellum
iscalledopisthocont.
•Theflagellumisattachedtotheblepharoplastwithinthecell.
•Majorityofthemembersoccurinwater.

4. •Thehyphearecoenocytic.Chitinisthechiefconstituentof
thecellofhyphalwall.
•Theasexualreproductiveorgansarethesporangia,eachof
whichproducesnumeroustiny,uninucelateanduniflagellate
opisthocontzoospores.
•Theliberatedzoosporesswimforatime.Latereachretracts
itsflagellumandundergoesencystment.Afterashortperiod
ofrest,theencystedsporegerminates.Thesexual
reproductionmaybeisogamousoranisogamous.Insomeitis
typicallyoogamous(Monoblepharidales).

5. Order –Chytridiales
(Synchytridiumendobioticum)
Life cycle of Synchytridiumendobioticum(Potato wart disease)
Symptoms –Cells enlarged due to hypertrophy and form warty
outgrowth.
Phylum –Chytridiomycota
Class –Chytridiomycetes
Order –Chytridiales
Family –Synchtriaceae
Genus –Synchytrium
Species -endobioticum

6. Potato wart symptoms

8. Asexual reproduction
•Largenumberofuniflagellate
zoosporesarereleasedfromthe
infectionportion.
•After2hrsofswimmingtheyreach
potatotubers
•Theflagellumshredsandenters
intohostandforamoeboidshape.
•Theamoeboidzoosporeincrease
size and form prosorus
(zoosporangium)
•Afterrepeatedmitoticdivisionsand
form32nuclei
•Theprosorusdividedinto4-9
divisionsandproduce200-300
nuclei
•Eachnucleidevelopintodevelop
intoauniflagellatezoosporewhich
swimsandattachestothehost
Sexual reproduction
•The water released zoospores
functions s gamates.
•Karyogamyand plasmgamytakes
place and a biflagellate zygote
formed
•Hypertrophy and hyperplasia takes
place
•The diploid zygote enlarges an
develop into resting sporangium
•This resting sporangium undergoes
reduction division and form
uninucleatedaughter protoplatseach
of which converted into a haploid
zoospores.
•The haploid zoospores are liberated
by the rupturing of the infected host
and the host life cycle is repeated

10. Zygomycota
General characters
•OtherwisecalledasYolkfungi
•CellwalliscomposedofChitosanchitin
•Producerhizoids(anchoringorgan)andstolon(attachmentorgan)
•Thesporangiaissupportedbysporangiophorewherethesporangiosporesare
packedinsidethesporangium
•Zygomycotafungicanreproducebymeansofbothsexualandasexual
reproduction
•Asexualreproductionbymeansofaplanospores(non-motile)orsporangiaor
conidiaandsexualreproductionbymeansofgametangialcopulation
•Asexualspores–sporangiospore,chlamdospore,oidia
•Sexualspores–zygospores(exampleofdiploidsexualspore,itisathickwalled
restingspore)
•Classifiedas3ordersMucorales(pinmoulds),Entomophthoralesand
Zoopagales
•Eg–Rhizopus,MucorandPilobolus

12. •Order –Mucorales(Pin moulds)
•Order –Endogonales(Pea truffles)

13. Difference Rhizopusand Mucor
Particulars Rhizopus Mucor
Other names Commonlycalledasbread
mould
Commonlycalledaspin
mould
Mycelium
Myceliumisdifferentiated
intothreekindsofhyphae
viz.,stolonsandrhizoids
andsporangiophores
Myceliumconsistsofonly
onekindofhyphaeandis
notdifferentiatedinto
Stolonsandrhizoids.
Hyphae and
holdfast
Absorptivehyphae or
holdfastsarepresent
Holdfastareabsentand
arenotspecializedwell
Sporangiophores
Sporangiophores are
developedintoclusters
(groups)abovethenodes
andariseonlyfromthe
junctionofrhizoidsand
stolons.
Sporangiophores may
developsfromanypoint
Spore
dissemination
Sporesareeasilyblown
awaybywind,thusa
commoncontaminatofair
Sporesarenoteasily
disseminatedandremains
attachedtothecolumella.
Collumella Columellainmostspecies
becomemoreorlessdome
orumbrellashapedafter
dehiscenceofsporangium
Columelladoesnotchange
shapeafterdehiscenceof
sporangium
Examples RhizopusstoloniferMucormucedo

14. Zygospore
(sexual
spore of
Zygoycota)