Ascomycota fungi kingdom jssjks bbjs kjbb.ppt

this file include description about fungi ascomycota

1. Phylum -Ascomycota
Kingdom -Fungi

2. •Phylum : Acomycota
•Its members are commonly known as the sac fungi this
name comes from forming sexual spore (ascospore).
They are the largest phylum of Fungi, with over 64,000
species. Among the Ascomycota are some famous fungi:
Saccharomyces cerevisiae,(baker yeast) the yeast of
commerce and foundation of the baking and brewing
industries, Penicillium chrysogenum, producer of
penicillin, Morchella esculentum, the edible morel, and
Neurospora crassa, using as a model in genetic
studies. There are also some in famous Ascomycota, a
few of the worst being: Aspergillus flavus, producer of
aflatoxin, the fungal contaminant of nuts and stored grain
that is both a toxin and known natural carcinogen,
Candida albicans, cause of thrush, diaper rash and
vaginitis and some species cause powdery mildew on
plants like -Erysiphae sp. is caused powdery mildew on
grasses and cucumberaceae plants
•.

3. •Characteristics of Ascomycota
•1-Somatic phase :Most have either
unicellular like yeast or filamentous
growth forms Hyphae have perforated
septa.
•2-Almost all ascomycetes are terrestrial or
parasitic.However, a few have adapted to
marine or freshwater environments.
•3-The cell walls of the hyphae are variably
composed of chitinand β-glucans, just as
in Basidiomycota.

4. •5-Includes yeast, cup fungi, truffles,
powdery mildew, & morels(true
mushrooms).

5. •6-Sexual reproduction by forming ascospores produce
inside sacs are called asci(singular :ascus) ,Most asci
are cylindrical, or globose each ascus has 8 ascospores
.
•7-Most produce multicellular fruiting body –the
ascocarp in which the asci and ascospores are formed .
Asci usually develop on an inner surface of the ascocarp
, a layer called the hymenium or hymenial layer .
•Ascocarp –specialized hyphae formed by parent fungi
during sexual reproduction
•8-Characterisitics of asci and ascocarp important in
classification
•9-Asexual reproduction –production of conidia bearing
on conidiophores or budding .
•10-Many of the Deuteromycetes (imperfect fungi group )
thought to be asexual or anamorphs of Ascomycota.
•11-Previous hypotheses that the Ascomycota evolved
from red algae (similarities in
• morphology of sexual structures) and Mucorales

7. •Life cycle of Ascomycota

8. •In asexual reproduction, spores are
formed as the result of mitosis(nuclear
division in which the number of
chromosomes in the daughter nuclei is the
same as it was in the parent nucleus). The
resulting mitospores(aso called conidia)
are released in large numbers, and allow
the ascomycete to disperse over a wide
area.

9. •Sexual reproduction involves the formation
of an ascus(plural; asci) by the fusion of
two hyphae of different mating types. The
ascus is shaped like a bag, and acts like a
bag in that it contains the spores. These
spores are called ascosporesand are
formed by the fusion of two nuclei
(karyogamy) to form a diploidnucleus.
This diploid nucleus divides by meiosis
(nuclear division with reduction in the
number of chromosomes) to give four
spores, which then divide by mitosisto
give eight haploid ascospores.

10. •These ascospores have thick cell walls,
and have the ability to persist in the
environment for a long time.The structure
of the ascus varies within the group except
yeasts tend to have single asci (naked
asci) not forming ascocarp , others have
their asci formed within a fruiting body
called an ascocarp. These occur in
several different forms:

11. Ascogenous hyphae
•After plasmogamy, two hyphal systems
begin to grow
–Sterile haploid hyphae envelope
the ascogonium to form the
multicellular ascoma (fruiting body)
–Dikaryotic ascogenous hyphae
grow from ascogonium –will give
rise to the asci
•Tips of ascogenous hyphae form
croziers (hooks) before developing into
an ascus

12. Developing ascoma
•Ascoma contains two
types of hyphae
•Ascogenous hyphae
–dikaryotic, form asci
through crozier
formation
•Sterile hyphae –
haploid, form bulk of
ascoma

13. Crozier and ascus formation
•During ascus formation, karyogamy occurs to
form diploid nucleus followed by meiosis to
form 4 haploid nuclei
Mitosis

14. Ascus formation
•Most asci are cylindrical,
but may be globose
•8 ascospores/ascus is a
common number but this
may vary
•In most, ascogenous
hyphae continue to
proliferate, forming more
croziers and more asci

15. Types of asci
•Great deal of variation in
asci and ascospores
•Three basic types of asci
•Prototunicate asci –thin,
delicate wall that
deliqueses to release
ascospores

16. Types of asci
•Unitunicate asci –
ascus wall layers
adhere closely to one
another, ascospores
released through a
pore, a slit or an
operculum (hinged
cap)
•Operculate asci
•Inoperculate asci

17. Types of asci
•Bitunicate asci –
two wall layers that
separate with the
inner wall
expanding,
ascospores
released through a
pore

18. BITUNICATEASCI
•have a double wall
–OUTER wall: thin, inextensible
–INNER wall: thick, elastic inner wall
•At maturity the thin outer wall splits, and
the thick inner wall absorbs water and
expands upward, carrying the
ascospores with it
•design allows the ascus to stretch up
into the neck of the ascoma to expel its
spores

19. •In most, the ascogenous hyphae are
produced only in the ascoma (pl.
ascomata
•Ascomata consist of two types of hyphae –
dikaryotic ascogenous hyphae that form
the asci and haploid sterile hyphae that
form the bulk of the ascoma
•Four major types of ascomata

20. Cleistothecium
•The cleistothecium
remain closed until
broken by internal
forces, the asci are
produced randomly
within the ascoma
Fruiting bodies -ascomata

21. Perithecium
•Begins as a closed
structure but
produces a pore at
maturity through
which the ascospores
can escape
•Asci produced in a
definite layer -
hymenium

22. Apothecium
•Ascoma is open when
asci mature, asci are
produced in an
hymenium

23. Ascostroma
•Asci are produced
in a cavity (locule)
within a mass of
sterile tissue =
stroma
•No ascoma wall as
stroma did not
originate from
ascogonium

24. Class:
ascomycetes
sub class:
Protoascomysetes
*the asciare nacked
not enclosed in
ascocarp.
Order:
endomycetales
Family:Saccharomy
cetaceae
ex:Candidaalbicans
Order:taphrinales
family:Taphrinacea
e
ex: Taphrina
deformans
Subclass:
Euascomysetes
*ascior ascus
enclosed in an
ascocarp.
Plectomycetes
*asciare
enclosed in a
cleistothecium
Pyrenomycetes
*ascienclosed in
aperithecium
Discomycetes
*asciare
enclosed in
apothecium

25. •Use of ascocarps in the classification
of fungi belonging to the Ascomycota:
1. Hemiascomycetes (includes yeasts)
•In this case the asci are NOT ENCLOSED
in an asocarp.
•Asci are naked

26. •Pyrenomycetes
•Fungi belonging to this group form
PERITHECIA.
•Perithecia are spherical or flask-shaped
ascocarps.
•They open via a neck-like OSTIOLE with a
terminal pore through which the ascospores are
liberated.
•The asci are arranged in an orderly layer at the
base of the cavity.

27. •4. Loculoascomycetes
•Fungi belonging to this group form
ASCOSTROMATA (or PSEUDOTHECIA).
•Ascostromata resemble perithecia but in the
former there is no wall surrounding the central
region of the ascocarp -only a cavity within the
mass of hyphal tissue (STROMA) in which the
asci are located. Ascocarp with asci formed in
cavity (locule) within stromatic tissue

28. •5. Discomycetes
•Fungi belonging to this group form APOTHECIA.
•An apothecium is an OPEN-or CUP-SHAPED
ascocarp.
•The asci are arranged on the exposed surface
(HYMENIUM).

29. •Plectomycetes
•Fungi belonging to this group form
CLEISTOTHECIA.
•These are round, completely closed ascocarps,
possessing no natural opening.
•The asciare arranged irregularly within them.
•When mature the cleistothecia burst open to
release their asci and ascospores.
•Asci are prototunicate, globose to pear
shaped
•

30. Cleistothecial Ascomycota
•Include species that grow as saprotrophs on
keratin (protein in hair, nails)
•Contains the teleomorphs of human pathogens
–Dermatophytes –cause superficial skin infections
such as atheletes foot
–Anamorphs are Trichophytonand Microsporium
•Also contains fungi that cause deep or systemic
infections of humans
–Ajellomyces, the teleomorph of Histoplasma
capsulatumwhich causes histoplasmosis
–Blastomyceswhich causes blastomycosis

31. •Subclass: Euascomycetes
•Class Plectomycetes
Order: Asergillales Order: Erysiphales
(Asci are scattered) family: Erysiphaceae
Family: Aspergillaceae
Ex: Aspergillus
Penicillium
(asci are arranged)

32. Aspergillus
•Produce characteristic
conidiophore
•Conidia produced by
phialides –flask shaped
conidiogenous cells
•Have a characterisitic
foot cell

33. Aspergillus
•*Aspergillus is a widely distrisbuted genus, most are
saprophytes on dead organic materials(fruits,jams ,leather,
wood,……..) on orange, aspergillus form blue mould.
•On otherhand some species are parasites.
•*A.flavus,A.fumigtusand A.nigercause diseases to human and
animals known asperilloses also they may cause disease for
human ear called otomycosis.
•A.flavus produce mycotoxins.
•A. fumigatus give fumes which may contaminate the
enviroment and cause respiratory tract infections of human.
•A.niger is very important for industry it produce about (18-
19)enzymes including: cellulases xylanases amaylases
pectinases inulinases phylase.

34. vegetative structure:
•The vegetative structure of Aspergillus is
branched and septated mycelia which may:
Substarte mycelium:
Responsible for fixation and nutrient up take.
Aerial mycelium:
Appeare above and carrying reproductive
organs.

35. Asexual reproduction:
•It takes place by means of conidia ,which are
formed in chains externally on conidiophores.
1.When asexual reproduction takes place a certain cell of the
hyphae become larger and thick walled(foot cell).
2.From each foot cell a vertical, non-septated conidiophore
arise each conidiophore ends with a vesicle.
3.A large number of nuclei and cytoplasm migrate into the
vesicle.
4. From each vesicle a tubular outgrowths are
produced(sterigmata).
(sterigmata may be used in identification of Aspergillus).
5. From the tips of sterigmata a chain of conidia are formed.

36. Penicillium
•Pencicillium is a saprophytic fungus known as(blue or
green mould),it live on several organic
substrates(fruits, vegetables,bread,……………….).
•Vegetative mycelium is branched and septated.
•Some species such as P. chrysogenum produce the
antibiotic pencillin(break bonds between
peptidoglycan in the cell wall of G+ve bacteria).
•Conidiophores are spetated and branched.

37. Penicillium
•Asexual
conidiophore –not
swollen at tip, no
foot cell
•Phialides arranged
in a brushlike
manner

38. Order: Erysiphales
Family: Erysiphaceae
•members of this family are :
•Obligate parasites,causepowdery mildew disease.
•Produce their asciarranged on hymeniallayer inside a
cleistothecium.
•Depending on: The aggregation of conidia on conidiophores.
Number of asciinside the cleistothecium.
Type of appendages.

39. *the order Erysiphales is classified as follow
Family:Erysiphales
Subfamily:phyllactinae sub family:Erysipheae
*conidia
Are solitary
Phyllactinea leivellula
Conidia more one contain more than one
ascus appendages are normal myceloid
Ascus ,appendages with
Bulbous base and pointed tips

40. •sub family:Erysipheae
Erysiphe uncinulla
More than One ascus. More than one ascus
Normal appendges curved appendeges
Sphaerotheca
have one ascus
normal appendages

41. Asexual reproduction
•Hyphae produce
chains of conidia
during growing
season (spring and
summer) on
surface of plant
leaf –giving the
powdery, white
appearance

42. Sexual reproduction
•Late in growing season, as plants begin to
senesce, ascomata are produced –thought to
overwinter as ascomata
•Ascomata are closed, have characteristic
appendages extending from them
•Asci are globose to ovoid, generally one to a few
asci/ascoma

43. Ascoma
•Appendages

44. Subclass:Euascomycetes
Series:pyrenomycetes
Perithecial Ascomycota
•Ascoma is a perithecium
•Has an opening through which
ascospores leave the ascoma =
ostiole
•Asci produced in a layer =
hymenium
•Asci are unitunicate and
inoperculate
•Asci typically have a pore or slit at
the thickened tip

45. Perithecia
•Typically flask shaped
structures
•Pore with opening =
ostiole
•Perithecial wall
composed of
pseudoparenchyma
tissue
•Centrum is the central
part where asci develop

46. Perithecia
•Perithecial wall composed of fungal tissue
called pseudoparenchyma –thin cell walls,
looks like plant parenchyma tissue
•Centrum –the asci and sterile structures that
fill the cavity within the perithecial wall
•Sterile structures:
–Paraphyses –basally produced in hymenium
–Pseudoparaphyses –originate from top of the
perithecium, grow into hymenium
–Periphyses –extending into the ostiole

47. Perithecium
Ostiole
Wall
Stroma
Paraphysis
Periphysis
Ascus
Ascospore

48. Perithecia
•Perithecia may be
produced individually or
they may be produced
within a mass of tissue =
stroma (always produce a
separate perithecial wall)

49. Stroma (stromata)
•Compact tissue that forms
a flat plate or a mass
•Hyphae may be inflated,
intertwined, have lost
identity to form a tissue that
looks like parenchyma
tissue of plants –called
pseudoparenchyma
•May be hard and woody or
soft and fleshy

50. Perithecial Ascomycota
•Saprotrophic fungi on dung, wood, in soil
& decaying leaves
•Includes Neurospora–important in study
of genetics
•Asci are club shaped to cylindrical, most
produce 8 ascospores
•Asci may breakdown and release
ascospores or persist & forcibly discharge
ascospores

51. Chaetomium
•Common saprotrophs in
soil and dung, highly
cellulolytic
•Perithecia have distinctive
filaments (straight or
spiral )extending from
upper part of perithecium
•Asci are club shaped and
wall deliqueses leaving
ascospores embedded in
jelly like substance that
oozes out of the ostiole

52. Chaetomium
•Ascospores
are lemon
shaped

53. Neurospora crassa
•Red (pink) bread mold –grows on dough in
bakeries, forms lots of conidia, bad
contaminant
•Widely used in genetic studies, one gene –
one enzyme concept developed in
Neurospora
•Mostspecies are heterothallic –two mating
types –A & a

54. Ascospore discharge
•In many Ascomycota, asci develop high
turgor pressure and actively discharge
ascospores individually or as a group from
ascus
•In some, particularly coprophilous forms,
the asci or ascomata may be phototrophic
so that ascospores are discharged toward
the light

55. Ascospore discharge
•In Sordaria, Neurosporaand other members of
this group, asci stretch through ostiole and
actively discharge ascospores

56. Xylaria
•Produce dark colored, brittle solitary
perithecia or perithecia may be produced
in a stroma
•Stromata are hard and woody, generally
dark colored
•In development of centrum, paraphyses
grow from base and sides to expand the
perithecium that allows the asci space –
paraphyses may persist or disappear

57. Xylaria
•Forms a dark colored,
woody stroma, ca 10
cm long and 1-2 cm in
diam
•Extends up from
ground, grows on
wood
•Commonly called
“dead man’ s fingers”

58. Nectria
•Produce brightly
colored stromata that
are generally soft and
fleshy with embedded
perithecia
•Includes both plant
and fungal parasites

59. Claviceps purpurea
•Ascospores produced in spring –infect the
ovaries of rye flowers
•Hyphae grow and replace ovary tissue,
forming a hyphal mat that produces small
conidiophores and conidia, secretes a
nectar like substance that attracts insects
for dispersal to other plants
•Mycelial mat differentiates –becomes
hardened and forms pseudoparenchyma –
eventually becoming a sclerotium

60. Claviceps purpurea
•Sclerotium –firm
mass of fungal
tissue, resistant to
environmental
extremes, can
remain dormant
•Falls to ground &
overwinters as a
sclerotium

61. Claviceps purpurea
•In spring, sclerotia
germinate to produce
stalked stromata
within which
perithecia are
produced

62. Claviceps
life cycle

63. Ergotism
•If sclerotia are harvested with grain and ground
into flour, they contain a number of alkaloids that
are poisonous to humans and animals –cause
ergotism
•Latest epidemic in 1951 in France resulted in
several deaths and many sick and crippled
people –also called St. Anthony’s fire
•Symptoms –vomiting, intense cold or hot
sensations, lesions on hands and feet, diarrhea,
convulsions, gangrenous condition in limbs that
may lead to loss, causes constriction of arteries
and contraction of smooth muscle

64. Ergotism
•In 1951, some people
suffered from
hallucinations
•Concluded that these
were similar to LSD
(lysergic acid
diethylamide)
•LSD not produced by
Claviceps, but thought
that other fungi converted
some of the alkaloids
produced to LSD

65. Ergotism
•Ergotism thought to have caused symptoms
that lead to the Salem witch trials
•Ergot alkaloids in the proper dose have
been used in medicine
–Stimulate labor –sclerotia carried by midwives
–Treatment of migraines
•Alkaloids only produced by sclerotium, not
by mycelium –until recently had to infect
fields of rye to obtain sclerotia, recent
methods have produced alkaloids in culture

66. Cordyceps
•Parasite of insects
and fungi forms
stromata from host

67. Quorn
•Fusarium venenatum is used to produce the
mycoprotein that is used as a substitute for meat
called Quorn

68. •This fungi produce asci in an open ascocarp(apothecium).
•The apothecium is cup shaped so these fungi may known as
cup fungi.
•The asci are arranged on a hymenial layer.
order:Pezizales
Family:Pezizaceae
Peziza sclerotinia morchella
Cup fungi cause rot of onion sponge mushroom
Saprophytes on animal
dungs. saprophytes grow on
And decaying wood cluster in soil rich in
Form large apothecium. Organic substances
Subclass:Euascomycetes
Series:Discomycetes

69. Apothecial Ascomycota
•Unitunicate asci
•Operculate & inoperculate
asci
•Asci present in a
hymenium
•Ascoma is open &
hymenium exposed when
asci mature

70. Apothecia
•Range in size from
microscopic to morels
•Many called cup fungi
since apothecium
forms a cup, others
may be flat, disk
shaped or stalked
•Truffles produce a
modified apothecium

71. Apothecia
•Most are produced above ground = epigean
•Some are produced below ground = hypogean
•Asci are typically club shaped or cylindrical
•Most actively discharge ascospores distances
from 2-30 cm
•Simultaneous discharge of many asci causes
wind currents that may carry ascospores
farther –puffing
•Puffing caused by changes in humidity,
wind,etc

72. Apothecia in Pezizales
•Cup-shaped
apothecia
–Stalked
–Sessile

73. Morels and relatives
•Morchella
•Modified apothecia

74. Morels
•False morels -Verpa

75. False morels
•Gyromitra
•Helvella

76. Truffles
•Truffles produce
hypogeous ascomata
•Ascomata are highly
modified
•Hymenium has great
deal of infolding
•Ascospores not
forcibly ejected

77. Truffles
•Ascomata broken
open by animals or by
weathering
•Some species emit
strong odor so that
small animals, insects
can detect them
underground, dig up
and eat them,
dispersing spores
•Geopora, Tuber

78. Truffles
•Ascomata of Tuber
thought to be the best
fungi to consume
•Are mycorrhizal with
certain trees (oaks,
hazelnuts)
•Use trained pigs and
dogs to find them

79. Subclass:Euascomyctes
Series:Loculoascomycetes
•This group of fungi are form their asci in ascostroma .
•The ascus has two walls so it called bitunicate ascus
•The inner called endotunica extensible and thin
•The outer called exotunica inextensible and thick

80. Pseudothecial Ascomycota
•Ascoma produced by
these fungi is an
ascostroma –asci are
produced in cavities
(locules) in a stroma,
no separate wall
around ascoma, only
stroma
•In some, superficially
look like perithecia

81. Asci
•Most produce
bitunicate asci
•Two layers that
separate when
mature

82. Hemiascomycetes–yeasts
Subclass:protoascomycetes.
Order: Endomycetales.
Family: Saccharomycetaceae.
Saccharomyces cervisae.
•Vegetative structure and economic importance:
yeasts are unicellular organisms, oval or spherical shaped,
live in colonies with white or yellow, and they are dimorphic.
Dimorphism:
Is the ability of an organism to grow either
unicellular or filamentous according to surrounding condition.
Ex:
Yeast at 37
0
c grow as unicellular.
at 24
0
c grow as mycelia
•Saccharomyceshas averyimportant role in industries such as
fermentation beakingproduction of vitamins and alchols.

83. Reproduction:
1.budding:
• At favorable conditions (food is abundant) the nucleus of
the yeast cell divides mitotically and a bud is formed from the
wall of mother cell.
•Then one nucleus passes into this bud with a part of the
cytoplasm then this bud separated from the mother cell to give
daughter cell.
•Some times the bud itself may give another bud and the bud
do not detached from the mother cells resulting in the
fromation of
•Achain of bud called pseudomycelium.

84. •fission:
Parent cell elongates and its nucleus divides to produce
two daughter nuclei , then a wall is formed in the middle of the
cell from two new cell.

85. sexual reproduction
•It takes place when food is exhausted ,it occurs by conjugation
between two vegetative cells the process is called hologamy
,this result in the formation of diploid zygot cell which function
directly as an ascus and produce ascospores.
•1-Haplopiontic life cycle. 2-diplobiontic life cycle.
3-haplodiplobiontic life cycle.
•Candid albicansis ahuman pathogen live in mouth, vagina and
cause in young candidomycosis which may treared by
amphotrosin c.

86. Sexual
reproduction
•Haploid-diploid life
cycle as in
Saccharomyces
cerevisiae(baker’s
and brewer’s yeast)

87. Taphrinomycotina
•Third subdivision
•Pathogens of
plants
•Cause peach leaf
curl, witches
broom, shriveled
pocket of plum
and others

88. Taphrinales
•Produce dikaryotic
hyphae in the host tissue
that give rise to naked
asci (no ascoma)
•Asci split across the top to
release ascospores (not
typical of other
Ascomycota)

89. ANAMORPH
CLASSIFICATIO
N BASED ON:•Mitospores or conidia
•Diverse Structures Bearing the Conidia
–Conidiogenous cells
–Conidiophores
–Conidiomata
•The ways in which they develop
(conidiogenesis)
•Either Coelomycetes (covered
conidiomata) or Hyphomycetes (exposed
conidiomata/molds)

90. TYPES OF
CONIDIOPHORES
/ CONIDIOMATA

91. TYPES OF SPORE
DEVELOPMENT
•blastic conidiogenesis
–the young conidium is
recognizable before it is
cut off by a cross‐wall
(BUDDING)
•thallic conidiogenesis
–cross‐wall is laid down
before differentiation of
the conidium begins

92. TYPES OF SPOREDEVELOPMENT
•schizolytic dehiscence
the halves of a double
septum split apart by the
breakdown of a kind of
middle lamella
•rhexolytic dehiscence
the outer wall of a cell
beneath or between
conidia breaks down