Week 1 - FUNGAL REPRODUCTION Flashcards
Fungi reproduce primarily through the formation of_____, which can either be produced sexually or asexually.
Sexual reproduction involves the fusion of two compatible mating types to form a zygote, followed by_____ to produce haploid spores.
In asexual reproduction, spores are formed through_____, leading to the production of genetically identical offspring.
spores
meiosis
mitosis
FUNGAL REPRODUCTION
Different names:
•_________ (teleomorph)
•_________ (anamorph)
• Since January 1, 2013, use of teleomorph (sexual name) and anamorph (asexual name) has been prohibited.
Ajellomyces capsulatum
Histoplasma capsulatum
Sexual Reproduction in Fungi
Sexual reproduction in fungi is a complex process that involves three main phases, where opposite gametes (reproductive cells) mate to form a______, and then undergo further processes to produce______.
zygote
sexual spores
3 phases of sexual reproduction:
Plasmogamy
Karyogamy
Meiosis
– fusion of opposite but compatible mating types
Plasmogamy
– fusion of 2 nuclei to form a diploid nucleus
Karyogamy
By_______, diploid nucleus gives rise to haploid spores
meiosis
Important SEXUAL SPORES in Fungi (3)
Zygospore
Ascospore
Basidiospore
Enclosed in a thick wall
Nucleic fusion of morphologically similar cells
Zygospore
Rhizopus, Mucor
Zygospore
Produced in ascus (sac-like); 2-8 spores/ascus
Nucleic fusion of morphologically dissimilar cells
Ascospore
Histoplasma capsulatum
Ascospore
formed externally on a base pedestal called basidium
Basidiospore
Mushroom
Basidiospore
• Fusion of two compatible mating types
• diploid spores enclosed in a thick wall
• Thick-walled resting spores in some fungi
ZYGOSPORES
• endospores; produced in ascus (thin-
walled sac) containing 2-8 haploid
ascospores
• Nucleic fusion of morphologically
dissimilar cells
ASCOSPORES
• Exospores formed externally on a base pedestal called Basidium (typically contains 4 basidiospores)
• Sexual fusion of compatible nuclei
followed by meiosis
BASIDIOSPORE
Examples: Teleomorphs of Cryptococcus: genera - Filobasidium and Filobasidiella
BASIDIOSPORE
Asexual Reproduction Process
In asexual reproduction, fungi create______ that can germinate into new individuals. These spores are often produced in specialized structures like______, which play a crucial role in spore formation. Once these spores are formed, they are dispersed to new locations, where they can germinate and grow into new fungal colonies.
asexual spores
fruiting bodies
SPORE GERMINATION
_______: Principal structure - asexual spores
Fruiting body
• Asexual spores are dispersed through various mechanisms, such as wind, water, or by animals, depending on the fungal species.
• This is essential for the spread of fungi and colonization of new environments.
Spore Dispersal
Important ASEXUAL SPORES in Fungi
Arthospore
Blastospore
Chlamydospore
Conidiospore
Sporangiospore
•Vegetative;
formed by fragmentation of septate hypha into single slightly thickened cells
Arthrospore or arthroconidia
•Vegetative;
consist of a bud coming off a parent cell
Blastospore
•Vegetative;
thick-walled spores formed along the
periphery or tip of the hyphae
Chlamydospore
•Aerial;
microconidia (unicellular) and macroconidia (multicellular)
Produced in a chain at the end of conidiophore
Conidiospore
• spores within a sac (sporangium)
• Attached to a specialized hyphae
(sporangiophore)
Sporangiospore
Arthrospore or arthroconidia (3)
Coccidioides
Trichosporon
Geotrichum
Blastospore (2)
Candida
Cryptococcus
Chlamydospore (2)
Candida albicans
C. dubliniensis
Conidiospore (3)
Aspergillus
Penicillium
Trichophyton
Sporangiospore
Rhizopus
Mucor
________reproduction is a unique form of genetic exchange that occurs without meiosis
Parasexual
Parasexual reproduction involves the following key steps:
•: A heterokaryon is a structure that contains two different haploid nuclei within the same thallus (fungal body).
•: The fusion of these two haploid nuclei leads to genetic recombination through mitotic mechanisms, rather than meiosis.
• Occurrence in____: Parasexual reproduction is mostly observed in the class Deuteromycetes (imperfect fungi), where sexual reproduction is not observed.
Heterokaryon Formation
Genetic Exchange
Imperfect Fungi
(thallus w/ 2 haploid nuclei of 2
different genotypes)
heterokaryon
(imperfect fungi)
Deuteromycetes
