classification of fungi are fungi? fungi (fungus, mushroom) are achlorophyllus, chemoorganotrophic...

FUNGIFUNGI

Dr. Dr. LeenaLeena S. S. BarhateBarhate

Department of MicrobiologyDepartment of Microbiology

M.J.CollegeM.J.College,,

JalgaonJalgaon..

Fungi In The Scheme Of LifeFungi In The Scheme Of Life

PlantaeFungi

Monera

Animalia

..

.

.

... ..

... .. ..

....

....

Protista

Kingdom

Kingdom

Photosynthetic

Nutrient

uptake by

absorption

Nutrient uptake

by ingestion

Whittaker’s Five –

Kingdom Concept

MycologyMycology

Gr. Gr. MykesMykes = mushroom or fungus= mushroom or fungus

LogusLogus = discourse= discourse

AlexopoulousAlexopoulous and and MimsmMimsm, the Italian , the Italian

botanist Pier ‘ Antonia botanist Pier ‘ Antonia MicheliMicheli called called

founder of mycologyfounder of mycology

What are fungi?What are fungi?

Fungi (fungus, Mushroom) are Fungi (fungus, Mushroom) are

achlorophyllusachlorophyllus, chemoorganotrophic, chemoorganotrophic

heterotrophic (Saprophytic, parasitic, heterotrophic (Saprophytic, parasitic,

symbiotic or symbiotic or hyperparasitichyperparasitic), eukaryotic and ), eukaryotic and

sporespore--bearing organisms bearing organisms

surrounded by a well defined cell wall made surrounded by a well defined cell wall made

up of chitin with or without fungal cellulose, up of chitin with or without fungal cellulose,

along with many other complex organic along with many other complex organic

molecules.molecules.

Distribution and HabitatDistribution and Habitat

The fungi are cosmopolitan in distribution The fungi are cosmopolitan in distribution

Diverse habitatDiverse habitat

Majority Majority –– terrestrialterrestrial

Few Few –– aquaticaquatic

Most are saprophyticMost are saprophytic

ParasiticallyParasitically

FungiFungi--3. large diverse group3. large diverse group

rustsrusts aquatic fungiaquatic fungi mushroomsmushrooms

Yeast Characteristics

solitary, unicellular

reproduction via budding

rounded shape

moist & mucoid colonies

Mould Characteristics

filamentous hyphae

hyphal formation

tips may be rounded

(conidia/spores)

Figure 1. Typical Yeast

Figure 2. Typical mould

Dimorphic fungiDimorphic fungi

Exist in two formsExist in two forms

Mostly pathogenicMostly pathogenic

Have unicellular and Have unicellular and yeastlikeyeastlike form in host form in host

but but saprophyticallysaprophytically in soil or laboratoryin soil or laboratory

mediummedium

Opposite dimorphic phenomenon occurs in Opposite dimorphic phenomenon occurs in

some plant pathogens. (some plant pathogens. (TaphrinaTaphrina or in or in

Smuts)Smuts)

Fungal CharacteristicsFungal Characteristics EukaryoticEukaryotic

MulticellularMulticellular

HeterotrophicHeterotrophic

Absorb nutrients Absorb nutrients -- may be saprobes (absorb may be saprobes (absorb from dead material), parasites, or mutualistic from dead material), parasites, or mutualistic symbionts (with algae make lichen).symbionts (with algae make lichen).

Secrete powerful hydrolytic enzymesSecrete powerful hydrolytic enzymes

Cell walls contain chitin, an amino sugar Cell walls contain chitin, an amino sugar polysaccharide also found in arthropod polysaccharide also found in arthropod exoskeletonsexoskeletons

Lack flagellaLack flagella

Vegetative body consists of Vegetative body consists of

mycelia mycelia made up of networks of made up of networks of

hyphaehyphae

Hyphae Hyphae -- Long treads of cells Long treads of cells

designed to maximize surface area designed to maximize surface area

and also transport nutrientsand also transport nutrients

FungusFungus--like like protistsprotists::

––Lack this body structureLack this body structure

––Lack cell walls of chitinLack cell walls of chitin

The Body Plan of FungiThe Body Plan of Fungi

HyphaeHyphae Hyphae are designed to increase the surface Hyphae are designed to increase the surface

area of fungi and thus facilitate absorptionarea of fungi and thus facilitate absorption

May grow fast, up to 1 km per day, as they May grow fast, up to 1 km per day, as they

spread throughout a food sourcespread throughout a food source

Modifications of hyphae into Modifications of hyphae into specialisedspecialised

structuresstructures RhizoidsRhizoids

–– RhizopusRhizopus

AppresoriaAppresoria

–– Produced by parasites Produced by parasites

–– EgEg. Rusts and powdery mildews. Rusts and powdery mildews

HaustoriaHaustoria ((HausterHauster = drinker)= drinker)

HyphalHyphal traps traps egeg. . DactylellaDactylella, , ArthrobotryaArthrobotrya

PlectenchymaPlectenchyma

–– ProsenchymaProsenchyma

–– pseudoparenchymapseudoparenchyma

HaustoriaHaustoria -- Specialized structures budding Specialized structures budding

off hyphae of parasitic fungi which penetrate off hyphae of parasitic fungi which penetrate

host cells to absorb nutrientshost cells to absorb nutrients

Some fungiSome fungi

–– Have hyphae divided into cells by septa, with Have hyphae divided into cells by septa, with

pores allowing cellpores allowing cell--toto--cell movement of cell movement of

materialsmaterials

Coenocytic fungiCoenocytic fungi

–– Lack septaLack septaNuclei

Cell wall

Septu

m

Pore

(a) Septate hypha (b) Coenocytic hypha

Cell wall

Nuclei

Type of Septum

in fungi

Type of septa in fungiType of septa in fungi

SieveSieve-- like septum:like septum:

–– Uniform distributed pores throughout the area of Uniform distributed pores throughout the area of

septumseptum

–– EgEg GeotrichumGeotrichum

Simple pore septum:Simple pore septum:

–– Found in Found in ascomyceteascomycete fungi.fungi.

–– Single, simple central pore.Single, simple central pore.

DoliporeDolipore septum:septum:

–– Cell wall abutting the pore expandsCell wall abutting the pore expands

–– Central pore is plugged by the membrane of ER Central pore is plugged by the membrane of ER

called called parenthosomeparenthosome

–– Found in Found in basidiomycetousbasidiomycetous fungifungi

Bordered pit typeBordered pit type--septum:septum:

–– Pore is surrounded by an over arching Pore is surrounded by an over arching

bifurcation of the bifurcation of the septalseptal margin.margin.

–– Look like a bordered pit of a tracheid of Look like a bordered pit of a tracheid of pinuspinus

–– Found in Found in mucoralesmucorales and and trichomycetestrichomycetes..

• reproduction mainly by spores (both sexual and asexual)

• spores somewhat resistant to harsh environmental conditions

• spore germination mainly upon exposure to water

• sexual spore (perfect stage)terms vary

• asexual spores = conidia, formed on conidiophores

• Asexual- (imperfect stage)

• spores formed by mitosis

• some fungi exhibit only asexual reproduction (imperfect fungi)

Nutrition and Growth Nutrition and Growth

requirementsrequirements

Devoid of chlorophyllDevoid of chlorophyll

HeterotrophicHeterotrophic

Type based on nutrientType based on nutrient

Obligated saprophytes Obligated saprophytes egeg. . AgaricusAgaricus

Facultative saprophytes or parasites Facultative saprophytes or parasites egeg. .

AlternariaAlternaria , , PythiumPythium

Obligate parasites Obligate parasites egeg. . AlbugoAlbugo, , PucciniaPuccinia

SymbiontsSymbionts (Lichens and (Lichens and mycorrhizaemycorrhizae))