Fungi structure Reproduction Classification, Life cycles Bot coaching material dr dnr

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Dr. D. Nagaraju, Assistant Professor of Botany, Government City College (A), Hyderabad
Fungi – General Characters, Structure,Reproduction,
Classification, Life cycles….
‘Fungus’ (pl., fungi) is a taxonomic term,
2nd
largest group after Insects (1st
)
Mycology is the study of fungi
– Myco- = fungi , Mykes= Moulds/ Mushrooms
– -ology = the study of
Mycosis - a disease caused by a fungus
Mycotoxins - toxins of fungal origin
Mycology originally arose as a branch of botany because fungi were once believed to
be “achlorophyllic” plants.
Fungi are the eukaryotic, achlorophyllous, and unicellular or multicellular organisms,
which may reproduce by asexual and sexual spores.
P. A. Micheli (1679- 1737) (Italy)Father of Mycology.
Nova plantarum genera was published in 1729.
Father of Modern Mycology (world) & Father of Plant Pathology (Phytopathology)
-Heinrich Anton de Bary (Germany)(1831-1888)
Father of Indian mycology-Edwin John Butler & Father of Plant pathology in India
The body of the fungus is called as 'thallus'
Fungi - molds and yeasts
Molds - exhibit filamentous type of growth ; Yeasts - pasty or mucoid form of fungal growth
Eukarpic fungi =filamentous fungi
Holocarpic fungi= single cell organisms-Yeast, Chytridium, Elphidium
Hypha (hyphae -plural) - fundamental tube-like structural units of fungi.
Mycelium (Mycelia) - The hyphal mass or network of hyphae constituting the body
(thallus) of the fungus is called as mycelium.
a. Septate - divided by cross walls
b. Aseptate - lacking cross walls
Coenocytic - a cell or an aseptate hypha containing numerous nuclei.

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Simple porus septa : Ascomycetes
Dolipore septa : a barrel-shaped or cylindrical structure surrounding the pore (Peranthozome).
(L. dolium = a large jar or cask i . e., barrel). Basidiomycetes
Unique cell wall components – Chitin, • Glucans, Mannan, cellulose(Omycetes)
Cellulose predominates in the cell wall of mastigomycotina (lower fungi) while in higher fungi
chitin is present.
Cell wall of fungi lacks: –Peptidoglycan, Glycerol & ribitolteichoicacid, ipopolysaccharide
Lactophenol Cotton Blue (LPCB) - very popular for quick evaluation of fungal structures; will
stain the chitin in cell walls of fungi.
dimorphic fungi may be able to appear as yeasts or molds- Histoplasma capsulatum, the
pathogen that causes histoplasmosis cause Lungs infection
Homokaryotic mycelium: The mycelium contains genetically identical nuclei.
Heterokaryotic mycelium: The mycelium contains nuclei of different genetic constituents.
Multinucleate: The fungal cell contains more than 2 nuclei.
Microsporidia are unicellular fungi that are obligate intracellular parasites. They lack
mitochondria, peroxisomes, and centrioles

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Plants - photosynthetic, cellulosic cell walls
Animals - digestive systems, wall-less cells
Fungi - absorptive nutrition, chitinous walls
Algae Fungi
Mostly aquatic Mostly terrestrial
Chlorophyll present Chlorophyll absent
Autotrophic nutrition Heterotropic nutrition
except Blue-Green Algae)
Majority are eukaryotic All fungi are eukaryotic
Cell wall composed of cellulose Cell wall composed of chitin
Cells usually uni-nucleate Cells usually bi-nucleate or multinucleate
Reserve food material is starch Reserve food material is glycogen
Parasitic members are very
Uncommon Parasitic members of very common
Dikaryotic phase is completely
Absent Distinct dikaryotic phase is present
Clamp connection and crozier Present
formation are completely absent
in algae
Para-sexual cycle absent Present
Oomycetes True Fungi
Diploid Haploid or dikaryotic
Dikaryotic Phase Absent Present in higher groups
Cell wall Cellulose Chitin
Sexual spores Multinucleate Uni-nucleate conidia
sporangia
Motile asexual
Spores Present Very uncommon, (present only in Chytrids)
Oospores Present Absent
Major energy
Reserve Mycolaminarin Glycogen
Mitochondria With tubular cristae With flattened cristae
Flagella Heterokont, of two types,
one whiplash, another ciliated Flagella usually absent, If present,

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only whiplash type
Hyphal modifications in fungi are:
(Gr. plekein = to weave + encyma = infusion i.e., a woven tissue).
There are two types of plectenchyma viz., prosenchyma and pseudoparenchyma
.
(1). Prosenchyma formed by the loosely packed tissue like organization of fungi-
Plectenchyma or Proso-plectenchyma
(2). Pseudoparenchyma-hyphae are closely intertwined and forms a tissue
like structure in cross section =Para-plectenchyma
(3). Rhizomorphs (Mycelial cords) (Gr. rhiza=root + morphe = shape) thick strands or root like
aggregation of somatic hyphae in some fungi . honey agaric Armillariella mellea (=Armillaria
mellea).
(4). Sclerotium ((pl. sclerotia; Gr. skeleros = hard) compact globose structure formed by the
aggregation of hyphae in some fungi- resting stage of some fungi- accumulate food materials and
helps in vegetative reproduction eg. Claviceps
(5). Appressorium(p1. appressorium; L. apprimere = to press against))= terminal simple or lobed
swollen structure of germ tubes on infecting hyphae
(6). Haustorium (pl. Haustoria)= the intracellular absorbing structures of obligate parasites- knob
like, elongated, finger like or branched in parasitic fungi
(7). Stroma=(pl. stromata; Gr. stroma = mattress) Compact, flat cushion like
pseudoparenchymatous structures
(8). Snares (hyphal traps)= Snares are trap like structures produced by predaceous fungi to
capture small animals such nematodes and protozons.
A rhizoid (Gr. rhiza = root + oeides = like) is a short, root-like filamentous outgrowth of the
thallus, Eg: Chytridiomycetes, Oomycetes and Zygomycetes.

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Nutrition
Saprophytes= fungi obtain nutrition from dead organic matter 1.Ectophytic 2. Endophytic
Eg: Mucor,Rhizopus,Penicillium and Aspergillus
(2). Parasites= fungi take food from other living plants or animals
Obligate parasites: these fungi can live only as parasite on a living host Puccinia
Facultative parasites: these fungi usually follow saprophytic mode of nutrition
Under certain conditions, they parasitize suitable host plants Eg: Fusarium and Pythium
Endoparasite & Ectoparasite
Facultative saprophytes: They are parasites, but they can also survive on dead
organic matter in the absence of living host Eg: Taphrina
(3). Symbionts= fungi grow on or with other living organism but both of them are mutually
benefited eg: Lichens and mycorrhiza
Lichens are the symbiotic association between algae and fungi
Mycorrhizae are the symbiotic association between fungi and roots of some higher
Plants, helps in the absorption of nutrients by the host plant.

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(4). Predacious fungi= animal capturing fungi (predators) Eg:Arthrobotrys, Dactylella,
Dactylaria, Beauveria bassiana can be used as a biocontrol agent to control Colorado potato
beetle , Nematophthora gynophila and Verticillium chlamydosporium
Trichoderma lignorum, Rhizoctonia solani, Gliocladium roseum is used to control
white mould, Sclerotinia diseases, Metarhizium anisopliae as biocontrol
agents to control Rhinoceros beetle and Black rice bug.
Vegetative reproduction in fungi occurs by:
(1). Fragmentation- Rhizopus and Aspergillus
(2). Fission- Yeast
(3). Bud fission
(4). Budding
(5). Gemmae
(6). Sclerotia= are pseudo-parencymatous mycelial aggregations
(7). Rhizomorphs= root like mycelial aggregations found in some fungi
Asexual Reproduction:
Spores may be unicellular (Aspergillus, Penicillium)
or Multicellular (Alternaria, Cercospora)
(1). Zoospores= (Gr. Zoon = animal + spora = seed, spore)
flagella (sing. flagellum, L.flagellum=whip) whiplash and
tinsel types. Phythium, Phytopthora- Chytridiomycetes,
HypoChytridiomycetes, Oomycetes
(2). Aplanospores= non-motile spores, produced in
sporangia (endospores)
(3). Conidiospores= Conidia produced in single or in chain on
special type of hyphae called conidiophores in ascomycotina,
Basidiomycotina and Deuteromycotina.
(4). Chlamydospores= thick walled resting spores, store
food materials (Eg. Fusarium, Mucor racemosus, Saprolegnia, Ustilago)
(5). Pycnidiospores= very small spores produced in special structures
Called Pycnidia- fungi imperfectii (Deuteromycetes) and many lichens
(6).Oidia=Hyphae breaks up to small pieces each develops into single
called oidia Eg. Coprinus).
Sexual Reproduction
monoecious (bisexual) or dioecious (unisexual)
Moneoecious species produce two sex organs (male and female) in the same thallus,
thus they are called homothallic
Dioecious forms produces sex organs in separate thalli, hence called heterothallic
Self-fertile = homothallic. Mating types = heterothallic.

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Heterothallism was first used by an American geneticist A.F. Blakeslee in 1904. He called “fungi
with different mating types are called heterothallic” Eg: Saccharomyces cerevisiae, Aspergillus
fumigatus, Aspergillus flavus, Penicillium marneffei and Neurospora crassa.
Eukarpic fungi =filamentous fungi, Holocarpic fungi= Yeast, Elphidium
Plasmogamy: fusion of cytoplasm- fusion of protoplasts of two compatible gametes or sex cells
or hyphae, (Phycomycetes) karyogamy occurs immediately after plasmogamy, fungi
(Ascomycetes and Basidiomycetes) karyogamy is much delayed. dikaryotization
(B). Karyogamy: fusion of nuclei- Fusion of two nuclei to form a diploid nucleus
(C). Meiosis: reduction division to produce meiospores
haplobiontic (Gr. haplos = single + bios = life). e.g. Oomycetes
diplobiontic (Gr. diplos = double + bios = life). e.g. Allomyces
Sexual Reproduction:
(1). Planogametic copulation= fusion of two naked motile gametes (planogametes)- Isogamy,
Anisogamy, Oogamy
(2). Gametangial contact= male and female gametangia come in close contact with help of
fertilization tube, gametangia never fuse or lose,Eg: Albugo, Aspergillus, Pythium
(3). Gametangial copulatin= entire content of two compatible gametangia fuse each other
(4). Spermatization= minute spore like spermatia and specialized (receptive) hyphae acting as
male and female structures
(5). Somatogamy= Two vegetative cells or vegetative hyphae take over the sexual function and
fuse together Basidiomycota-Eg. Morchella, Peziza, Agaricus
Important sexual spores in fungi are
(1). Zygospores= formed by the fusion of male and female structures during sexual
Reproduction- Dipliod (Rhizopus)
(2). Ascospores= Ascospores are produced in specialized sac like structure called ascus, Hapliod,
single ascus contain eight ascospores tip is recurved to form a crozier (Shepherd's crook).
(3). Basidiospores= Basidiospores are produced on specialized structure called basidium,
haploid, single basidium produce four basidiospores.
‘holobasidia’ aseptate, Uredinales and Ustilaginales,
segmented basidia, Segmented basidia are sometimes termed phragmobasidia (or heterobasidia).
Sporangiophores in Oomycetes of Mastigomycotina and Zygomycotina.
conidiophores (as in Ascomycotina and Deuteromycotina)

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Fungi, which produce morphologically distinguishable male and female sex organs in
each thallus, are called hermaphroditic (Gr. hermes = the messenger of the Gods, symbol of the
male sex + aphrodite = the Goddess of love, symbol of female sex) or monoecious or bisexual
(Gr. monos = single, one + oikos = dwelling, home). A single thallus of a monoecious fungi can
reproduce sexually by itself if it is self-compatible. In a fungus when the female and male organs
are produced on two different thalli it is said to be dioecious or unisexual (Gr. dis = twice, two
+oikos = home; i.e.; the sexes separated into two different individuals).
The male gamete is known as antherozoid or sperm and the female as an egg or oosphere.
Heterokaryosis
The phenomenon of existence of different kinds of nuclei in the same individual is known
as heterokaryosis. (Gr. heteros = other+ karyon=nut, nucleus). Eg. Ascomycetes,
Basidiomycetes and Fungi Imperfecti (Davis, 1966).
Some fungi (Deuteromycetes) do not go through a sexual cycle but derive many of the
benefits of sexuality through parasexuality (Gr. para =beside+sex ).
Pontecorvo and Roper from the University of Glasgow in Aspergillus nidulans, the
imperfect stage of Emericella nidulans first discovered parasexuality in 1952. Since then it has
been reported in number of fungi in Ascomycotina, Cochliobolus sativus, (imperfect state:
Bipolaris sorokiniana (syn . Helminthosporium sativum) Leptosphaeria maculans etc.),
Basidiomycotina Puccinia graminis
Self-fertile = homothallic. Mating types = heterothallic. A F Blakeslee in 1904
Clamp connection is a mechanism found in Basidiomycetes. It is a bridge-like hyphal
connection characteristic of the secondary mycelium in many Basidiomycetes.
Asexual fructification:

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Synnema or Coremium (pl. coremia) Consists of a group of conidiophores often united at
the base and part way up the top. Deuteromycotina (Arthrobotryum sp (Fig), Penicillium
claviforme, Doratomyces stemonitis, Ceratocystis ulmi.
Sporodochium(pl. sporodochia) is a fruiting body in which conidiophores arise from a central
cushion-like aggregation of hyphae. Superficial, cushion-shaped asexual fruiting body consisting
of a cluster of conidiophores e.g. Epicoccum, Nectria
Pycnidium is a globose or flask-shaped body, which is lined on the inside with
conidiophores. The opening or mouth of pycnidium is called ostiole (L. ostiolum = little
door). The wall of pycnidium is called peridium (pl. peridia; G. peridion=small leather
pouch)e.g. Septoria ,Phoma, Ascochyta,Leptosphaeria.
Acervulus (pl. acervuli) is a fruiting structure commonly found in the order
Melanconiales (Deuteromycotina). It is typically a flat or saucer-shaped mass of aggregated
hyphae bearing short conidiophores in a compact layer. setae (sing. seta; L. seta = bristle) e.g.
Colletotrichum.
Sorus Sorus (pl. sori; Gr. Soros = heap) is a little heap of sporangia or spores.
Sexual pructification
Pycnium or spermagonium (pl. pycnia; Gr.pycnos = concentrated) is a fruit body, ‘periphyses’
(sing. periphysis; Gr. peri = around + physis = a being, a growth). spermatiophores (Gr.
spermation = little seed+ phoreus=bearer) Pycnospore is a non-motile, uninucleate, unicellular
spore-like male structure
Aecium (pl. Aecia: Gr. aikia = injury) Aecium is a shallow or deep cup-shaped structure
produced in a leaf and located in the lower portion and break through the lower epidermis.
Ascocarp (Gr. askos = sac+ karpos =fruit) is a fruiting body that contains asci and
ascospores. They are in various forms like spherical, flask-shaped, cup-and saucer shaped and
pod-shaped.
Cleistothecium: (pl. cleistothecia; Gr. kleistos = closed + theke = case).Asci are produced in
completely closed ascocarp.

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Perithecium: (pl. perithecia, Gr. peri = around + theke = a case) is a flask -shaped ascocarp with
a wall of its own. It is more or less closed ascocarp;
Apothecium: (pl. Apothecia; Gr. apotheke=store house) is an open ascocarp.Ascocarp produce
asci in open. cup fungi (Pyronema, Ascobolus, Peziza, Morchella etc) in Pezizales and
Sclerotinia, Trichoscyphella etc.)
Ascostroma or Pseudothecium: Stromatic ascocarp, which bears asci directly in locules
within the stroma. Pseudothecium or ascostroma (pl. ascostromata; Gr. askos = sac + stroma =
mattress, cushion) like perithecium is a flask-shaped ascocarp provided with an ostiole
through which the asci are discharged.
Basidiocarp (Gr. basidion=small base + karps = fruit) is a fruiting body, which bears
basidia and basidiospores.
Hymenium is composed of basidia and large sterile structures called cystidia (sing. cystidium;
Gr. Kystis =bladder + -idion = dimin. Suffix).
Ainswoth 1973 Classification of Fungi
Kingdom Fungi - true fungi
– Kingdom Straminipila - “water molds” Chromists are a broadly diverse of protists containing
stramenopiles (also spelled straminiples), but not true fungi
heterokonts, referring to two types of flagella found in this group
– Smooth (whiplash) flagellum
– “Tinsillated” (or tinsel) flagellum

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Contains stiff lateral hairs (mastigonemes)
Comprised of three fungal-like phyla
• Hyphochytridiomycota -Motile spores (zoospore) possess a single, anterior tinsel flagellum
[distinguishes the hyphochytrids from the chytrids]
Oomycota-Glucan and cellulose-like cell walls (not chitin), Zoospores have two flagella - a
forward directed tinsel type and a backward directed whiplash type.
Potato blight (Phytophthora infestans)
– Sudden oak death (Phytophthora ramorum)
– “Decline” diseases (Pythium spp.)
– Downy mildews (Peronospora spp.)
– Water molds/fish pathogens (Saprolegnia spp.)
• Labyrinthulomycota-Commonly referred to as “net slime molds” Characterized by a network of
branch, anastomosing (fusing), wall-less filaments held together by a secreted polysaccharide
sheath, Produce biflagellated zoospores, Anteriorly directed tinsel type, Posteriorly directed
whiplash type, Most members are marine parasites
Mycetozoa/ Myxomycota - “slime molds” as “net slime molds” lack cell wall Characterized by
a network of branch, anastomosing (fusing), wall-less filaments held together by a secreted
polysaccharide sheath,eg. Plasmodium amoeboid movement, or pseudoplasmodium
(EuMycota)
Chytridiomycota/ Mastigomycota (motile zoospores) Only true fungi that produce motile,
flagellated zoospores, zoosporic fungi, many are solely aquatic cell wall with chitin and
glucan
Zygomycota (zygospores) a thick-walled spore in Phycomycetes, chitin, chitosan, and
polyglucuronic acid, The zygospore represents the teleomorphic phase (sexual; perfect form) of
this phylum, homothallic or Heterothalic thallus present.
Glomeromycota (typically asexual) These fungi were originally placed within the Phlyum
Zygomycota, Donot produce Zygospores, Live as obligate, mutualisitic symbionts
in >90% of all higher plants - known at arbusular mycorrhizas (AM; endomycorrrhiza)
Ascomycota ( Sac fungi)(ascospores) two layered cell wall, spore formed in a sac-like cell
known as an ascus, Often eight (8) spores formed. a simple septum with a central pore
surrounded by Woronin bodies, Fruiting Bodies Ascocarps are
Flasked shaped – perithecium -- Neurospora , Cup-shaped – apothecium=Peziza,
Closed structure – cleistothecium-Eurotium, Embedded structure – pseudothecium
The fertile layer of a fruiting body is called the hymenium: Peziza, yeasts, molds, mildews and pencillium
Cup fungi, morels, truffles, yeasts, and mildew
Basidiomycota (Club fungi)(basidiospores) multilayered cell wall, dolipore septum , clamp
connection, specialized club-shaped structure, called a basidium. mushrooms and toadstools,
dikaryotic life cycle phase, primary secondary tertiary mycelium (Button stage) formed

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Eg: Mushrooms Toadstools, Bracket & Shelf fungi, Puffballs, Stinkhorns, Rusts and smuts
mushrooms, toadstools, bracketfungi, bird's nest fungi, stinkhorns, earthstars, pufJballs, coral
fungi, jelly fungi, smuts and rusts
Deuteromycota (Fungi Imperfecti)
Fungi Imperfecti - truly an artificial classification scheme based solely on conidial structures
– Hyphomycetes - conidia borne on conidiophores
– Coelomycetes - conidia borne on an acervulus or within a pycnidium
– Agonomycetes - “Mycelia Sterilia” - no conidia; sometimes sclerotia
thrush, ringworm, and athletesfoot
Due to the absence of a teleomorph (Perfect stage/ Sexual reproduction stage), these fungi are
often given a provisional name termed a “form” genus/species
If the teleomorph is discovered, the fungus renamed and added to special group
teleomorph/anamorph dichotomy of names:
Anamorph - Aspergillus nidulans -Teleomorph - Emerciella nidulans - forms a cleistothecium;
Penicillium vermiculatus- Talaromyces vermiculatus
Holomorph: the whole fungus, including all anamorphs and the teleomorph.
Pseudohyphae - a chain of elongated budding cells that have failed to detach (not true hyphae)
Candida
AFTOL=Assembling the Fungal Tree of Life – Phylogenetic Classification of Fungi Based on
molecular phylogenetic analyses

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Aspergillus, Penicillium, Paecilomyces, Trichoderma, Fusarium
Alternaria, Curvularia, Cladosporium, Rhizopus, Mucor, Candida
A. Candida attacks family Brassicaceae (Cruciferae)

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Mucor Life cycle
Puccinia Life Cycle
Heteroecious (requiring two hosts; wheat and barbery for the completion of life
Cycle, Wheat plant is called as Primary host and barberry is the secondary host or alternate host.
macrocyclic and polymorphic rust. karyogamy occurs and the teliospores become diploid
promycelium. The teliospore is the site of karyogamy and meiosis. phragmobasidium . Each cell

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produces a single haploid basidiospore germinate Pycnia/Spermatia to aecidiospores.
Yeast Life cycle

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Penicillium Life cycle

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Cercospora – Mycosphaerella berkeleyii , Mycosphaerella arachidicola causeTikka Disease of
Ground nut

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Ref: Google, and Standard Books of Fungi
******************
By
Dr. D. Nagaraju
Assistant Professor of Botany
Govt. City College (A), Hyderabad

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