dikaryomycota persistent dikaryon: cells with two haploid nuclei regularly septate hyphae
TRANSCRIPT
Dikaryomycota
• Persistent dikaryon: cells with two haploid nuclei
• Regularly septate hyphae
Dikaryomycota – two haploid nuclei
Haploidy nuclear condition, referring to number of chromosome copies per cell in G1
G1 G2S M
Dikaryomycota – two haploid nuclei
Nuclei: Haploid Dikaryotic Diploid
plasmogamy karyogamy
?
Dikaryons in fungi
• Only one cell – Zygomycetes
• Limited dikaryon – Ascomycetes
• Persistent dikaryon – Basidiomycetes
monokaryon
dikaryon
Maintaining the dikaryon state
• Conjugate mitosis – coordinated nuclear division
• Typically at
“clamp connections” that have specialized septa
Simple septum vs Dolipore septum
Dikaryomycete classes based on sexual sporulation
• Ascomycetes in sacs
• Basidiomycetes on stalks
Ascomycete life cycleAsexual cycle: haploid spores (n)+/– mating typesseptate hyphae (n)
Ascomycete life cycle, Raven 15-14
Asexual cycle: haploid spores (n)+/– mating typesseptate hyphae (n)
ascogonium trichogyne
antheridium
plasmogamy
Mating structures:
Trichogyne growth
Nuclear migration
Ascogonia and antheridia
An
As
T
Ascus development
crozier
karyogamy2n
meiosis I
meiosis II
mitosis(sp dep)
germination
Ascus formation
Crozier = hook
penultimate cell karyogamy
Meiosis andmitosis in developing ascus
Ascus development
meiosis I meiosis II mitosiskaryogamy
Ascomata: four types
PezizaMorchella
NeurosporaMagnaporthe
EmericellaErysiphe
Cochliobolus
Note ascus shape: elongate vs spherical
Elongate asci: 2 types
unitunicate bitunicateoperculum
pore
Cleistothecial asci
Asci and ascospores
Peziza
Eurotium
Otidea
Ascoma development
dikaryoticascogenous hyphae (n+n)
SterileHyphae (n)
croziersAscogonium
Ascogonium
apothecium
perithecium
Ascomycete fruiting bodies: ascomata
Mycosphaerella pseudothecia
Erysiphe graminis
HeterobasidiaHolobasidiaSynchronous spore formation Asynchronous spore formation
septa
sterigma
basidiospore
Nuclei migrate through the sterigma/spore junction
Mushroom life cycle 15-19
Basidiomata initiation is triggered by environmental conditions, including moisture
Dikaryotic hyphae
Mushroom development
Hymenium – fertile layer
Mushroom hymenium on: _____, _____, _____
Lactarius indigo
Gilled mushroomsAgaricales
Pores are lined with basidia
Fomes fomentarius
Hydnum repandum
Auriscalpium vulgare
Deuteromycetes – life without sex
Deuteromycetes – life without sex
• Advantages– speed (of reproduction, ~1 day)
– flexibility (can maintain a well-adapted genome)
– can maintain (lethal?) mutations in haploid nuclei, since hyphae are multinucleate