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Mycology (菌学)






Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

[fungi, mycorrhiza, saprophytic plant, fungal taxonomy, lichens, references]

myco = fungus (Greek) + logy = logic (Greek)
Formerly, mycology is one of the subjects in botany.

taxonomy
genetics
medicine, pharmacy and pathology
agriculture
ecology

Animals and fungi are sister groups while plants constitute an independent evolutionary lineage.

About 100,000 named species and perhaps more than 200,000 unnamed species

  • Nutrition: heterotrophic (photosynthesis lacking) and absorptive (ingestion rare). No photosynthetic ability (heterotrophic nutrition)
  • Mode of life: saprophytic, parasitic, or symbiotic
  • Thallus: on or in the substratum and plasmodial amoeboid or pseudoplasmodial; or in the substratum and unicellular or filamentous (mycelial), the last, septate or nonseptate; typically nonmotile (with protoplasmic flow through the mycelium) but motile states (e.g., zoospores) may occur.
索引
  • Cell wall: well-defined, typically chitinished (cellulose in Oomycetes).
  • Nuclear status: eukaryotic, multinucleate, the mycelium being homo or heterokaryotic, haploid, dikaryotic, or diploid, the last being usually of limited duration.
Reproduction (繁殖): sexuality → asexual or sexual and homo-or heterothallic
Sporocarps (胞子嚢果): micro-or macroscopicc and showing limited tissue differentiation
Habitat (生息地): ubiquitous as saprobes, symbionts, parasites, or hyperparasites
Distribution (分布): cosmopolitan

Fungus (pl. fungi)

Life cycle

life cycle
 Fig. Fungal life cycles. Ech circle represents a life cycle and should be read clockwise; M, meiosis; single line, haploid phase; double line, dikaryotic phase; solid line, diploid phase. The three principal life cycles are as follows; 1, asexual; 2, haploid (common in Ascomycotina); 3, haploid dikaryotic (many Ascomycotina have a brief dikaryotic phase but a long dikaryotic phase is typical of Basidiomycotina); 4, haploid-diploid (unusual in fungi but occurs in some Chytridiomycotina); 5, diploid (characteristic of the Straminipila, only very rarely in Eumycota). (Burnett 1975)
zygomycete
Zygomycete		 ascomycete
Ascomycete		 basidiomycete
Basidiomycete

Reproduction (生殖)

conidium

Perfect and imperfect states

Conidium (pl. conidia, 分生子)
Blastic: holoblastic, enteroblastic
Thallic: holothallic, holoarthric, enteroarthric

Morphology (形態)

Fruiting body (子実体)

0) Growth mode
6) Skirt (鍔)
Skirt
(Left to right) pendant, flaring, sheathing, double, clbwebby, ring zone 		ring Fairy ring, fairy circle, elf circle or pixie ring (菌輪): occurring ring or arc of mushrooms

tethered type: mycorrhizal fungi living in symbiosis with trees
free type: not connected with other organisms → saprotrophic

Food

  • High protein (20-30% of dry mass) containing essential amino acids
  • chitinous walls as a source of dietary fiber
  • containing B-group vitamins
  • low in fat
  • virtually free of cholesterol

Morels1 Morels2
[1] Edible and choice Morchella spp. (morels) [2] Do not eat Gyromitra esculenta (left) and Verpa boheica (right). Morels are common in Alaska soon after wildfires (森林火災). (Morchella f<g Gr植物名morchelから。ノボリリョウ科)

Yeast (酵母)

Classification ((Lodder & Kreger-van Riji 1952)
Yeast groupu (family)SubfamilyRepresentative genera
Ascosporogenous yeast 有子嚢胞子酵母
(Endomycetaceae)		 Schizosaccharomycetoideae
Saccharomycetoideae
Nematosporoideae		 Schizosaccharomyces, Endomycopsis
Saccharomyces, Pichia, Debaryomyces, Hansenula, Nadsonia
Nematospora, Lipomyces
Sporobolomycetous yeast スポロボロミセス酵母
(Sporobolomycetaceae)		Sporobolomyces, Bullera
Asporogenous yeast 無胞子酵母
(Cryptococcaceae)		Cryptococcoideae
Trichosporodideae
Rhodotoruloideae		Cryptococcus, Torulopsis, Candida, Trigonopsis
Trichosporon
Rhodotorula

Ecology (生態)

Succession of fungi (遷移)

Primary and secondary sere
Coprophilous fungi (糞生菌)

[mycorrhiza helper bacteria]

Mycorrhiza (菌根菌)

A symbiotic or pathogenic relationship between fungi and the vascular plant roots

Fungus kingdom: Basidiomycetes, Ascomycetes and Zygomycetes

Plants give carbohydrates produced by photothynthesis to fungi

Reward:
increase root surface area
increase ability to capture water, N and P
increase tolerance to adverse soil conditions
provide protection against pathogenic fungi and nematodes
modify composition of rhizosphere

Fungi give nutritents for photothynthesis, in particular, N and P, to plants

Endomycorrhiza

→ the hyphae penetrating the plant cell wall and invaginate the cell membrane

Arbuscular mycorrhiza (AM, formerly VAM)
colonize most plants
most are nonhost-specific

Glomeromycota

Ericoid mycorrhiza
Arbutoid mycorrhiza
Orchid mycorrhiza
Monotropoid mycorrhiza

Ectomycorrhiza, ECM

→ the hyphae not penetrating plant cells within the root

limited to trees and shrubs
most are host-specific
Ectendomycorrhiza → in case that the hyphae of ectomycorrhiza penetrate the plant cells

Akasaka, Tsuyuzaki & Hase 2007
Annual growth of invasive Larix kaempferi seedlings with reference to microhabitat and ectomycorrhiza1 colonization on a volcano
Titus JH & Tsuyuzaki S. 2002
Arbuscular mycorrhizal distribution in relation to microsites on recent volcanic substrates of Mt. Koma, Hokkaido, Japan 		Type Fig. 1. Five types of mycorrhizae observed on Mount Koma in 2000. A: arbuscular mycorrhizae detected from the roots of Elaeanus pungens Thunb., B: ectomycorrhizae from the roots of Salix bakko Kimura., C: ericoid mycorrhizae from the roots of Ledum palustre L. var. diversipilosum Nakai, D: orchid mycorrhizae from Spiranthes sinensis (Pers.) Ames, and E: arbutoid mycorrhizae from Pyrola incarnata Fisch. M: mantle, H: hyphae, C: hyphal coil, V: vesicules, and A: arbuscules. OH: outer hyphae. IHC: Intracellular-hyphae-complex. No monotropoid mycorrhizae were observed in the present study. Each scale bar indicates 50 mm. (Tsuyuzaki et al. 2005)
Isotope analysis
Sporocarps of mycorrhizal fungi (Hobbie et al. 2001):

3.5 ‰↓ δ13C
5.7 ‰↑ δ15N
→ δ13C should be interpreted cautiously (Hobbie et al. 2002)

Assumptions on N availability and isotopes (Hobbie & Colpaert 2003)

mycorrhizal fungi have higher δ15N
mycorrhizal plants have lower δ15N
ectomycorrhial plants have lower δ15N at low N availability
δ15N of nonmycorrhizal plants does not change with N availability

Saprophytic plant (腐生植物)

= myco-heterotrophy
symbiotic relationship between plants and fungi, in which the plant gets all or part of its food from parasitism on fungi rather than from photosynthesis
Habitats → forests (with many exceptions)
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