WE WILL LEARN
General characteristics of fungi
Structure of fungi
Economic Importance
Pathogenicity
Brief intro of some fungi
THE CHARACTERISTICS OF FUNGI
Fungi are NOT plants
Nonphotosynthetic
Eukaryotes
Nonmotile
Most are saprobes(live on dead organisms)
6
THE CHARACTERISTICS OF FUNGI
Absorptive heterotrophs(digest food first & then absorb it into their bodies
Release digestive enzymes to break down organic material or their host
Store food energy as glycogen
7
BREAD MOLD
THE CHARACTERISTICS OF FUNGI
Important decomposers& recyclers of nutrients in the environment
Most are multicellular, except unicellular yeast
Lack true roots, stems or leaves
8
MULTICELLULAR MUSHROOM
UNICELLULAR YEAST
THE CHARACTERISTICS OF FUNGI
Cell walls are made of chitin (complex polysaccharide)
Body is called the Thallus
Grow as microscopic tubes or filaments called hyphae
10
THE CHARACTERISTICS OF FUNGI
Some fungi are internal or external parasites
A few fungi act like predators & capture prey like roundworms
11
Predaceous Fungi feeding on
a Nematode(roundworm)
THE CHARACTERISTICS OF FUNGI
Produce both sexual and asexual spores
Classified by their sexual reproductive structures
13
Spores come in various shapes
THE CHARACTERISTICS OF FUNGI
Grow best in warm, moist environments
Mycology is the study of fungi
Mycologists study fungi
A fungicide is a chemical used to kill fungi
14
Fungicide kills leaf fungus
THE CHARACTERISTICS OF FUNGI
Fungi include puffballs, yeasts, mushrooms, toadstools, rusts, smuts, ringworm, and molds
The antibiotic penicillin is made by the Penicillium mold
15
Penicillium mold
Puffball
HYPHAE
18
Tubular shape
ONE continuous cell
Filled with cytoplasm & nuclei
Multinucleate
Hard cell wall of chitin also in insect exoskeletons
HYPHAE
Stolons –horizontal hyphae that connect groups of hyphae to each other
Rhizoids – rootlike parts of hyphae that anchor the fungus
19
STOLON
RHIZOIDS
HYPHAE
Cross-walls called SEPTA may form compartments
Septa have pores for movement of cytoplasm
Form network called mycelia that run through the thallus(body)
20
ABSORPTIVE HETEROTROPH
Fungi get carbon from organic sources Tips of Hyphae release enzymes Enzymatic breakdown of substrate Products diffuse back into hyphae
Digested material is then used by the hypha
Nucleus “directs” the digestiveprocess
MODIFICATIONS OF HYPHAE
Fungi may be classified based on cell division (with or without cytokinesis)
Aseptate or coenocytic (without septa)
Septate (with septa)
22
NO CROSS WALLS CROSS
WALLS
MODIFICATIONS OF HYPHAE
23
HAUSTORIA – parasitic hyphae on plants & animals
Septate Hyphae Coenocytic Hyphae
HYPHAL GROWTH
Hyphae grow from their tipsMycelium is an extensive, feeding web of hyphae
Mycelia are the ecologically active bodies of fungi
24
This wall is rigid Only the tip wall is plastic and stretches
REPRODUCTION
Most fungi reproduce Asexually and Sexually by spores
ASEXUAL reproduction is most common method & produces genetically identical organisms
Fungi reproduce SEXUALLY when conditions are poor & nutrients scarce
26
SPORES
Spores are an adaptation to life on land
Ensure that the species will disperse to new locations
Each spore contains a reproductive cell that forms a new organism
NonmotileDispersed by wind
27
HYPHAL GROWTH FROM SPORE
28
Mycelia have a huge surface area More surface area aids digestion & absorption of food
mycelium
Germinating spore
SEXUAL REPRODUCTION
Used when environmental conditions are poor (lack of nutrients, space, moisture…)
No male or female fungi
Some fungi show dimorphism
May grow as MYCELIA or a YEAST –LIKE state (Filament at 25oC & Round at 37oC)
31Dimorphic Fungi
SEXUAL REPRODUCTION
Haploid 1n hyphae from 2 mating types (+ and -) FUSE (Fertilization)
Forms a hyphae with 2 nuclei that becomes a ZYGOTE
The zygote divides to make a SPORE
32
+ -
SPORE FORMS
THREE TYPES OF ASEXUAL REPRODUCTION
Fragmentation – part of the mycelium becomes separated & begins a life of its own
Budding – a small cell forms & gets pinched off as it grows to full sizeUsed by yeasts
Asexual spores – production of spores by a single mycelium
34
REPRODUCE BY SPORES
Spores may be Formed:Directly on hyphaeInside sporangiaOn Fruiting bodies
Amanita fruiting bodyPilobolus sporangia
Penicilliumhyphae
ASEXUAL REPRODUCTION
Fruiting Bodies are modified hyphae that make asexual spores
An upright stalk called the Sporangiosphore supports the spore case or Sporangium
36
MAJOR GROUPS OF FUNGI
Within the past few years, several groups have been re-classified into the protists
Two of these groups are the slime molds and water molds
Classification by Nutrition
SaprobesDecomposersMolds, mushrooms, etc.
ParasitesHarm hostRusts and smuts (attack plants)
MutualistsBoth benefitLichensMycorrhizas
39
MAJOR GROUPS OF FUNGI
Basidiomycota – Club Fungi
Zygomycota – Bread Molds
Chytridiomycota – Chytrids
AM Fungi - Mycorrhizas
Ascomycota – Sac Fungi
Lichens – Symbiosis (algae & Fungi)
HUMAN-FUNGUS INTERACTIONS
Beneficial Effects of Fungi Decomposition - nutrient and carbon recycling. Biosynthetic factories. Can be used to produce
drugs, antibiotics, alcohol, acids, food (e.g., fermented products, mushrooms).
Model organisms for biochemical and genetic studies.
Production of vitamin Hormone production Edible fungi Production of insecticides
FUNGI FORM BENEFICIAL PARTNERSHIPS (SYMBIOSIS) WITH OTHER ORGANISMS SUCH AS TREES AND FLOWERING PLANTS:
Lichen – symbiotic relationship between algae
and fungi
Algae
hyphae
HUMAN-FUNGUS INTERACTIONS
Harmful Effects of FungiDestruction of food, lumber, paper, and cloth. Plant diseases. Animal diseases human diseases, including allergies.Toxins produced by poisonous mushrooms and
within food (e.g., grain, cheese, etc.).
PUCCINIA
Systematic Position
Division : Mycota (Basidiomycota)
Subdivision: Eumycota
Class: Basidiomycetes
Order: Uredinales
Family: pucciniacea
HABIT AND HABITAT
Puccinia are generally known as rust fungi.
700 species
They are parasites on plants(wheat, coffee, beans etc).
It is an internal obligate parasite.
They are generally heteroecious, i.erequiring two hosts to complete life cycle.
MORPHOLOGICAL FEATURES
Delicate septate mycellia
. It is intercellular
sending out haustoria in the host cells
penetrating the host cell causes hypertrophy, distortion and malformation
The mycelium is monokaryotic on secondary host and dikaryotic on primary host
REPRODUCTION
life cycle on two different hosts. The diplophase (2n) stage is a parasite on wheat
while
the haplophase (1n) stage on an alternate host which is Barberry vulgaris.
We’ll take example of Puccin graminisia
LIFE CYCLE
Its life cycle spreads over five stages, which are
a.Uredinial stage:-
b.Telial stage:-
c.Basidial stage:-
d.Spermogonial stage or pycnidialstage:-
e.Aecial or Aecidial stage:-
A.UREDINIAL STAGE:-
first or rust stage. appear on culms, The pustule is called a Uredinium, which on maturity bursts and releases uredospores.
Each uredospore is a binucleate Lying together -red-rust like appearance readily germinate on wheat plant
Wheat rust ( Puccinia ) Uredospores are small, roughly circular, thick-walled reddish spores found within ruptured rust...
B.TELIAL STAGE:-
dark brown or black pustules
occur in the form of streaks called telia
Containing teliospores or teleutospores(dark brown )
diploid nucleus
C.BASIDIAL STAGE:-
, nuclear fusion a row of four haploid nucleus. This four celled structure is called a
promycelium or epibasidium Tube formation…-basidiospore Formation of spores each spore is either of + or – strain Basidiospore detach… now ready to infect
D.SPERMOGONIAL STAGE OR PYCNIDIAL STAGE:-
basidiospores germinate . to attack barberry leaves
mycelia spreads ( huastoria)
barberry protoplasm ( their only food )
Monokaryotic mycellium (+ or – strain )
Afterfour days 2 structure formed
1.Pycnia or spermogonia on upper surface
2.Aedia or cluster cups on ventral surface
E.AECIAL OR AECIDIAL STAGE:-
Aecia, aecidia or cluster cups are produced as little yellow cups on ventral surface of barberry leaf.
AECIAL OR AECIDIAL STAGE
Spermatization Formation of aecidiospores. These are binucleate and brightly yellow
coloured and they germinate on wheat blown by wind having six germ pores Entering in host through stomata Life cycle continues
ECONOMIC IMPORTANCE:-
Puccinina graminis tritici causes black or stem rust,
P. recondita causes brown or orange leaf rust
P.coronata brown rust of wheat
P. sorghi causes leaf rust of corn
SYSTEMATIC POSITION
Division Mycota
Sub division Eumycota
Class Basidiomycetes
Order Ustilagonales
Family Ustilaginaceae
HABIT AND HABITAT:
400 species
internal parasites of plants
Causing diseases called smuts because of black coloured spores.
VEGETATIVE STRUCTURE:
mycelium may be primary or secondary. Primary mycelium is uninucleate and is called
monokaryotic mycelium. Secondary mycelium is septate, dikaryotic and
spreads throughout interior of the host plant Firstly intracellular and later on becomes
intercellular. Mycelluim sending huastoria into the host infection appearance in flowering stage (loose
smut ) , dark brown powder, ( easily blown by wind ) And host destroyed
REPRODUCTION:
Chlamydospore formation mycellium accumulation Division and redivision Hyphae swelling brandspores, smut spores or
chlamydospores, formation ( the black spores )
beaded appearance to the hyphae. This rusty mass or group of black spores
is called the smut
CHLAMYDOSPORE rounded or oval in shape covered by a two layered wall outer thick layer called exospore an inner delicate and smoothn layer called
endosperm. after dispersal fall on soil and lead a
saprophytic life basisiospore or a sporidium formation Germination .after germination basidiospores are
capable of infecting
ECONOMIC IMPORTANCE:
2.it causes about 1% damage in the planes and around 10-20% in foot hills and humid places of Pakistan.
3. Covered smut of barley is caused by U.hordei and U.nuda.