Fungi Midterm 1

Opisthokonta are characterized by

posterior flagella, unites fungi with animals

Archaeplastida

plants, humans closer to fungi than we are to plants, hard to fight fungal disease since we are so similar

Fungi considered to be plants for a long time is wrong because

no chlorophyll, do not obtain food from water and CO2

Taxonomy

nomenclature of organisms, classification falls under here

Systematics

determination of evolutionary relationships among organisms

Nucleotide

nitrogenous base pair + sugar backbone + phosphate

DNA sequence

sequence of nucleotides, mtDNA (mitochondrial), nDNA (nuclear)

Genome

mtDA + nDNA

Saccharomyces cerevisiae example genome

baker/brewer’s yeast, 12.1 Mb (nDNA), or 85.9 kb (mtDNA)

Most fungal genomes are

between 10^7 and 10^8 Mb

Anomorph

asexual phase, imperfect stage

Telemorph

sexual phase, perfect stage

Holomorph

anomorph + telemorph

Central Dogman

transcription = DNA to mRNA, translation = mRNA to functional molecule

Imperfect fungus form old taxonomy

Penicillium species

Dilemma of one fungus two names (Trichoderma virens v Hypocrea virens)

one organism assigned two different scientific names, confusion, database redundancy

Trichoderma virens

asexual mitotic phase, green powdery mold used as biological control agent for plant pathogens

Hypocrea virens

sexual meiotic phase, fruiting bodies found on decaying wood

Ribosomal Gene Cluster

encodes 3 regions of ribosomal RNA (18S SSU, 58S & 28S LSU, internal transcribed spacers)

58S and 28S LSU

encodes RNA for large subunit

18S SSU

encodes RNA for small subunit

18S SSU, 58S & 28S LSU

more conserved by fungi and useful for phylogenetics

internal transcribed spacers

encodes nonfunctional RNA, less conserved, bar code DNA for identification of fungi (taxonomy/classification)

Tandem repeats

ITS sequence copies separated by non-transcribed spaces, increase gene counts for genetic work

PCR primers

short, single-stranded DNA/RNA initiate DNA synthesis

ITS1 & ITS4 primers

DNA primers to amplify ITS region

ITS1-F and ITS4-B

Basidiomycota specific ITS primers

Culture-dependent ID using ITS barcode

amplify ITS, sequence ITS and use it to search databases

culture-independent ID

same as dependent, extract all DNA & use high-throughput sequencing (HTS)

Operational Taxonomic Unit (OTU)

assigned grouping at any level of hierarchy, exact DNA sequencing

Environmental Molecular Operational Taxonomic Unit (eMOTU)

same as OTU, will not trace to any known culturable species

many lower fungi have

flagellated zoospores

Lower Fungi includes

opisthosporidia, blastocladiamycota, chytidiomyceta, zoopagomycota, mucoromycota

Opisthosporidia characterized by

microsporidia, xenoma: large, conspicuous spore-bearing structure

Opisthosporidia habitat

soil, freshwater and marine

Opisthosporidia characteristics

1300 described species all parasitic, many lack mitochondria, no glycolysis or ATP production

Blastocladiamycota habitat and characteristics

aerobic, freshwater and mud, soil

Blastocladiamycota morphologies

Nuclear cap (diagnostic feature)

Blastocladiamycota nuclear cap

membrane-bound assemblage of ribosomes surrounding nucleolus

Chytidiomyceta - Neocallimastigomycota

anaerobic, about 20 species, herbivore gut fungi

Chytidiomyceta - Neocallimastigomycota morphologies

Uni- and Polyflagellate: 10+ flagella in some cases, Lack mitochondria: degenerated to hydrogenosome

Without mitochondria, Neocallimastigomycota

co-opt cellular respiration of hosts, steal sugar factories

Chytidiomyceta - Chytridiomycota

about 1250 species, aerobic, freshwater, brackish, salt water, soil

Chytidiomyceta - Chytridiomycota morphologies

Thallus, Rhizoids, Zoosporangium (thallus modified to produce spores), Zoospore, discharge tube*

Zoospore

flagellated, motile spore

Rhizoids

hair-like structures used to root/anchor thallus to substrate

Thallus

multinucleate, spheroidal bodies

Discharge tube

thallus opening with a lid (operculate) or without a lid (inoperculate)

Mucoromycota

aerobic (many anaerobic), largely terrestrial, coprophilic (simple sugar sources), very few aquatic

Mucoromycota morphologies

Coenocytic, sporangiophore, sporangia, sporangiospore, zygospore, zygophore, zygosporangium*, aerial hyphae

Zygosporangium

fused gametangia, swollen containing zygospores

Zygophore

branched aerial appendages that fuse

Sporangia

bulbous tips of sporangiophore that contain sporangiospores

Sporangiophore

stalked aerial appendage that develops sporophore

Coenocytic

hyphae lacking septa, fluffy aerial hyphae

vesicles

large nutrient storage cells inside root cells

Mucoromycota (Glomeromycotina) Intraradical mycelium

nutrient exchange

Mucoromycota (Glomeromycotina) Extraradical mycelium

nutrient acquisition and transport

Mucoromycota (Glomeromycotina) characteristics

large spores (up to 800 micrometers), obligate symbionts, non-septate IRM and ERM hyphae, arbuscules diagnostic feature, <200 species, 90% all land plants form mycorrhizae

Mycrotrophic

obligate symbiont with fungi to grow

Slime molds

fungi adjacent, protists, found in forays

Water molds

oomycetes, protist, fungi adjacent, many plant pathogens

Higher fungi includes

ascomycota and basidiomycota

Ascomycota

largest phylum in fungi, more than 33,000 species named

Ascomycota general characteristics

anamorph and teleomorph phases

Ascomycota sexual phase (dikaryotic) - heterokaryotic phase

ascospores born inside Asci: sac (8 ascospores per ascus)

Characteristics of ascomycota anamorphic phase

homokaryotic, haploid, heterothallic, conidia

Ascomycota septal pore

central pore in hyphae that allows flow between cells

Homokaryotic

containing nuclei of a single origin, derived from single spores

heterothallic

different, compatible mating types

Homothallic

having no mating types

Conidia

asexual spores borne on stalks of conidiophores, diagnostic feature

Conidiophores

produces asexual, non-motile spores (conidia)

Ascomycota plasmogamy

fusion of hyphae, to merge cytoplasm and share nuclei, can be undergone by homothallic and heterothallic species

Characteritics of ascomycota teleomorphic phase

heterokaryotic, dikaryotic, diploid, ascoma, karyogamy, crozier

Ascoma

fruiting body formation with asci containing ascospores, diagnostic feature

Karyogamy

fusion of nuclei during dikaryotic phase

Crozier hook

tip growth that enables nuclei isolation during ascospore development

8 ascospores per ascus

produced by initial replication, meiosis I, meiosis II, and mitosis

Ascomycota – Subphylum Pezizomycotina

90% of ascomycota

Woronin bodies

type of microbody (mobile organelle)

Woronin body plug

densification of proteins that plug septal pore when hyphael cell on one side bursts

Cup-shaped apothecia spore dispersal

open during release

flask shaped perithecia spore dispersal

spores release through neck

spherical cleistothecia spore dispersal

outer layer disintegrates

droplet-like fissitunicate asci spore disperal

forced ejection

Lichen

symbiosis between filamentous fungi and algae or cyanobacteria

Mycobiont

fungal partner

Photobiont

algal or cyanobacterial partner

Cortex

outer layer of woven hyphae

Medulla

Inner layer of loose hyphae

Rhizines

specialized hypha anchors

Budding yeasts

mother cells use buds formed along cell walls to accept daughter cells

Fission yeasts

cells use mitosis and division in the middle via septal wall formation to form two new cells

Basidiomycota

2nd largest group, 30,000 species

Basidiomycota characteristics

anomorph and teleomorph phases

Basidiospores

sexual phase borne on basidia with 4 per basidium

basidia

club shaped reproductive structure bearing basidiospores

dolipore septa

barrel shaped swelling around central pore

clamp connections

grow hyphal cells, keeps fungi dikaryotic