The document discusses the phylum Basidiomycotina and provides details about three major classes: Uredinomycetes, Ustomycetes, and Basidiomycetes. It focuses on characteristics of rust fungi (order Uredinales) and smut fungi (order Ustilaginales), including that rusts require two hosts to complete their lifecycle and are obligate parasites, while smuts are facultative saprophytes. Specific examples of the rust fungus Puccinia graminis and the smut genus Ustilago are also outlined.

1. Basidiomycotina
Mushrooms, bracket fungi, puffballs,
rusts and smuts

2. Basidiomycota
• Large phylum – 16,000 spp
of higher fungi
• All produce a basidium –
club shaped structure (site
of karyogamy & meiosis)
that produces haploid
basidiospores

3. Basidiomycota
• Three classes
• Basidiomycetes – produce a basidia,
(multicellular fruiting body), includes the
mushrooms, brackets, puffballs, jelly fungi,
stinkhorns
• Uredinomycetes – no basidia, teliospore
produces basidia, obligate plant parasites, the
rusts
• Ustomycetes – no basidia, teliospore produces
basidia, facultative plant parasites, the smuts

4. Basidia
• Basidia divided into two types depending on whether
they are septate
• Septate basidia – phragmobasidia
– Septa can be transverse or longitudinal
• Aseptate basidia - holobasidia

5. TYPES
HOLOBASIDIA
PHRAGOMOBASIDIA

6. OTHER EXAMPLES OF HOLOBASIDIA AND
PHRAGMOBASIDIA

7. Hyphae
• Hyphae are regularly
septate
• Specialized type of pore
can occur – dolipore
septum with
parenthosome
• Allows cytoplasmic
movement but prevents
nuclear migration from
one compartment to the
next

8. Basidiomycetes
5. Three types of hyphae
a. Primary hyphae – develops from a germinating
basidiospore. Nuclear status = n
b. Secondary hypha – results from fusion of two primary
hyphae. Yields a n+n cell that continues to grow as a n+n
hyphae
c. Tertiary hypha – exactly the same as secondary hypha. n+n
However it has thick walls that enable production of fleshy
and wood sporophores
Primary hyphae Primary hyphae
Secondary hyphae
Tertiary hyphae

9. • Most Basidiomycetes are heterothallic
• Haploid basidiospores germinate to produce
haploid mycelium = primary mycelium
• In some species, the primary mycelium contains
one nucleus in each compartment called
monokaryon
Dikaryon

10. Dikaryon
• Plasmogamy occurs shortly after basidiospore
germination
• Plasmogamy occurs between two compatible
hyphae
• Plasmogamy initiates dikaryotic phase or the
secondary mycelium (dikaryon)
• After plasmogamy, nuclei migrate into
monokaryotic cells to establish dikaryotic
condition

11. Basidiospore germinate
Primary hyphae
Secondary hyphae
Dikariotic hypae
Basidiospore germinate
Dikaryon

12. • As mycelium grows, nuclei divide conjugately
to maintain dikaryotic condition in cells
• Dolipore septum prevents nuclear migration
so that each compartment contains two
nuclei, pore is 0.1-0.2 μm in diameter
• Under certain conditions (e.g. after
plasmogamy), dolipore septum breaks down
to allow nuclear migration
Clamp connections

13. • Secondary mycelium is
the major vegetative
phase of Basidiomycota
• Many Basidiomycetes
also form clamp
connections (formation
is reminiscent of crozier
formation in
Ascomycota)
Clamp connections

14. Clamp connections
• Branch that grows back

15. Clamp connections
• Thought to be a mechanism to maintain
dikaryotic condition
• Only found in dikaryotic hyphae, but not all
dikaryotic hyphae form them

16. • Development of basidium and basibiospores

17. Dikaryon
• Favorable environmental conditions stimulate
formation of basidium
karyogamy
meiosis

18. Basidium
sterigmata
basidiospores

19. Discharge of basidiospore
• Basidia with
sterigmata can actively
discharge
basidiospores
• Basidiospores are
positioned at a 45
angle
• 5-10 seconds before
discharge a droplet
forms of water bubble

20. Hymenium, Basidia,and Basidiospores

21. Basidium
• Basidia are produced in hymenia – fertile regions in
the basidioma (will discuss position in different
basidiomata)

22. Basidia
• Spore is discharged less than a mm, then drops
straight down
• Hymenia must be vertical with respect of gravity

23. Basidium
• Basidiospores fall out of basidium, into
turbulent air current and are carried away

24. Basidium
• Sterigma (pl. –mata) –
projections from basidium to
basidiospores
• Basidia may or may not
produce sterigmata

25. Basidium
• Composed entirely of dikaryotic hyphae
• Basidioma is generally divided into 3 zones
– Hymenium – layer of basidia with basidiospores
– Subhymenium – distinct area that gives rise to
hymenium
– Trama – comprises the bulk of the basidium,
separates hymenia

26. Class - Basidiomycetes
• Produce macroscopic basidia
• Most produce holobasidia, phragmobasidia
produced by some jelly fungi
• Large and diverse class
• In life cycle, dikaryotic mycelium becomes the
major vegetative mycelium

27. Agaricales
• Large order - ~5000 spp
• Hymenium lines surfaces of tubes or gills in
fleshy basidiomata
• Includes the mushrooms and boletes
• Primarily saprotrophs in soil, litter or wood
• Many are biotrophic – form mycorrhizal
associations with trees
• Economically important as cultivated
mushrooms and mycorrhizae (used in forestry)

28. Systematic position:
Kingdom: Mycetae
Division: Eumycota
Subdivision: Basidiomycotina
Class: Hymenomycetes
Sub-class: Holobasidiomycetedae
Order: Agaricales
Family: Agaricaceae
Genus: Agaricus
Species : A. bisporus, A campestris
Genus: Agaricus

29. Fig: Perennial nature of Agaricus:

30. Agaricales
• Basidiomata arise
from extensive
perennial mycelia
• Overall structure of
basidia

31. Fig: Agaricus campestris anatomy of the pileus

32. Gills
• Increased surface area for greater number of
basidia

33. Basidioma development
• Hemiangiocarpic development – button is
surrounded by a layer of tissue, the universal veil
(forms the volva and scales) , also contains a partial
veil (forms the annulus and cortina)

34. Basidioma development
• Pseudoangiocarpic development – button has only a
partial veil (forms annulus and cortina)

35. Gymnocarpic development

36. Phylum Basidiomycotina: Three major classes
• Class Uredinoiomycetes
– Order Uredinales - The Rusts
• Class Ustomycetes
– Order Ustilaginales - The Smuts
–
• Class Basidiomycetes
– Order Agaricales – the gilled mushrooms - caps, oyster
mushrooms, etc.

37. Uredinomycetes
Order Uredinales – the rusts
i. Produce all five spore stages – aeciospores, uredospores,
teliospores, basidiospores and spermatia (aka
pycniospores)
ii. Important genera – Puccinia, Gymnosporangium
Ustomycetes
Order Ustilaginales – the smuts
i. Produce only basidiospores and teliospores
ii. Important genera – Ustilago, Tilletia

38. RUST AND SMUT FUNGI
– Uredinales (rusts)
– Ustilaginales (smuts)

39. Order Uredinales Order Ustilaginales

40. The Rusts
These are obligate parasites. Generally these require two host to
complete their lifecycle.
Primary hosts – the host on which basidia and basidiospores are
produced.
Alternate host – the other host in the life cycle on which spermagonia
and aecia are produced
Alternative host – the host that a pathogen can infect in place of the
primary or alternate hosts.
Heteroecious – organisms with a primary and alternate host.
Autoecious – organisms that have only a single (primary) host.
Macrocyclic rust – long cycle rust. Produce all 5 spore types.
Demicyclic rust – medium cycle rust. Omits uredia.
Microcyclic rust – short cycle rusts. Produces basidiospores, teliospores
and spermatia.

41. • The genus includes about 3000 species of these 147 has been
reported from India.
• It causes a rust disease - black stem rust of Wheat.
•Puccinia graminis is an obligate parasite.
•It is a heteroecious parasite.
•It completes its life cycle on wheat and on barberry.
•Wheat is a primary host.
•Barberry is a secondary or alternate host.
Puccinia

42. The Rusts
• Stem Rust of Wheat caused by Puccinia
graminis
–Reduces yield and quality of grain; fungus
causes lesions or pustules on wheat stems.
–Management - remove alternate host (i.e.,
barberry); use resistant cultivars of wheat

43. Systematic position:
Kingdom: Mycetae
Division: Eumycota
Subdivision: Basidiomycotina
Class: Teliomycetes/ Uredinoiomycetes
Order: Uredinales
Family: Pucciniaceae
Genus: Puccinia
Species : P. graminis-tritici, P. graminis-hordei, P. graminis-
avenae, P. graminis-secale.
Genus: PUCCINIA

44. •Puccinia graminis forma specialis tritici
•The fungus causing black stem rust of
wheat
•Macrocyclic, heteroecious rusts (those
producing all five spore forms and moving
between two different hosts)

45. Spore-producing stages:
0 =Pycnial/Spermogonial stage:
spermatia/pycniospore (n)
I =Aecial/Aecidial stage:
aeciospore/aecidiospore (n+n)
II =Uredial/Uredinial stage:
uredospore/urediniospore (n+n)
III =Telial stage:
teliospore/telutospore (n+n>2n)
IV=Basidial stage:
basidispore (n)
Stages 0 and I on barberry bushes
(Berberis vulgaris: dicot)
Stages II and III on various grasses
(monocot)
Stage IV on soil
Contd…

46. Puccnia Infected Plant Parts

47. • Acediospores from berberry bushes fall on wheat stem
or leaf, germinates to form dikaryotic, filamentous, well
developed, branched, intercellular mycelium
• The hyphae of the dikaryotic mycelium - aggregate near
the surface of the infected organ to form a hyphal mass
known as Uredia.
• The tips of hyphae swell to form binucleate oval
uredospore in a group known as uredinium or
uredosorus.
Uredial Stage Stage II

48. Uredosori on different parts of wheat

49. • They exert pressure on the epidermis, cause
rupture and rusty coloured uredospores are
seen
• Each uredospore contains a pair of nuclei (n +
n) cominig from dikaryotic hypha.
• To obtain nutrition haplophase develop
haustoria.

50. Mycelium

51. Puccinia Uredosorus in Wheat

52. Uredospore are stalked, unicellular oval, binucleate
structures, rusty red in colour.

53. Telial Stage:
• Late in growing season, uredospores are
metamorphosed into telutospores in the
same Uredosori.
• Uredosori is known as Telutosori.
• Telutospores are dark brown or black in
colour.
Stage III

54. Stage III: Telia bearing teliospores
(n+n>2n)

55. Puccinia Teluto
sorus
Telutospores

56. Telutospores dark
brown or black in
colour. stalked, two
celled, spindle shaped.
The wall is thick, black
and smooth.

57. Puccinia teluto
spores
•Each cell has two nuclei (one plus strain
and the other of minus strain).
•final stage on primary host
•Telutospore matures, the nuclei in each
cell fuse to form a diploid nucleus
(Kayogamy) (2N).

58. Germination of Telutospore
• On Soil/ wheat straw
• Favourable condition- Proper
Temperature, Moisture
• Germination of Teluto spore-
germination tube - Epibasidium

59. Germination of Teliospore
Germination tube

60. Germinated Teluto spore and formation of
Basidium & Basidio spores
Epibasidium
Basidio spore
(+) Or (-)Sterigmata
Hypobasidium Basidium

61. Stages of Puccinia on
Barberry leaf
• Pycnial stage: On upper epidermis
with +ve and – ve basidiospores
(Sexual reproduction) (Plasmogamy)
• Aecidiospore stage: On lower
epidermis, Binucleate Aecidiospore

62. Basidiospores which are of + and -
mating types, land on a young leaf of
barberry in spring, and initiate
localized monokaryotic infections. The
hyphae are intercellular, but they send
haustoria into host cells to absorb
food

63. Basidiospores
(+ and -)
Basidiospores
germinate on upper
epidermis of
Barberry leaf and
produce
Pycniosporangium

64. Puccinia Pycnium on Upper epidermis

65. Infection of Puccinia on Barberry
leaf Lower and Upper sides

66. Each Pycniosporangium forms Pycniospore which ooze
out in a sweet-smelling nectar. A tuft of receptive hyphae
also grows out from the neck of the Pycniosporangium.
Insects are attracted by the nectar, and transfer
spermatia of each mating type to receptive hyphae of
the other type. This process, analogous to pollination,
initiates the dikaryophase
The dikaryotization spreads to the lower surface of the
barberry leaf, where the fungus has already produced
the primordia of cup-like aecia (stage I). Aeciospores
cannot infect barberry.

67. Receptive hyphae and Spermatia
Spermatia Receptive hyphae

68. Develop-ment of Aecidiosporangium

69. Stage I: Aecia bearing
aeciospores (n+n)

70. •Puccinia- Aecio sporangium on lower
epidermis aeciospores infect primary host.
Aeciospores produced on alternate host
(e.g.,Barberry) infect primary host (e.g.,
grasses)

71. • Aeciospores-
round, yellowish
red, Unicellular,
binucleate, thick
walled, 6 germ
pores.
• Germinate on
wheat plant.
Aeciospores
Aecial cup

72. Puccinia- Polymorphic
fungi
• Polymorphism: Various types of
spores produced during life cycle
according to hosts life cycle and
climatic condition.
• Known as Polymorphism.
• Fungi shows polymorphism known
as Polymorphic fungi.

74. Puccinia Life Cycle

75. Puccinia
Life Cycle

76. Genus-Ustilago
Systematic position
Sub-Division: Basidiomycotina
Class: Teliomycetes
Order: Ustilaginale
Family: Ustilaginaceae
Genus: Ustilago

77. • Order- Ustilaginales (smut fungi)
• Basibiospores are sessile and produced directly
on promycelium.
• Basibiospores are passively discharged.
• Facultative saprophyte.
• Teliospore (one celled) most intercalary.

78. • Some species of smut fungi with
their hosts:
U. tritici ------loose smut of wheat
U. hardei ----- cover smut of barley
U. nuda ------lose smut of barley
U. scitaminea ----smut of sugarcane

79. Smut
• Obligate parasites
(cereals)
• Replace kernels with
spore masses
• 2 spores: teliospores and
basidiospores (sporidia)

80. Ustilago maydis
corn smut (Agrios 583-584)
 Overwinters as
teliospores in debris
 Basidiospores
produced in spring
 Infect all tissues
 Must fuse to form
dikaryon to grow

81. Ustilago maydis
Teliospore Release

82. Loose Smut of Barley
Ustilago nuda
Agrios 584-588

83. Loose smut of cereals

84. Uredinales (rusts) Ustilaginales (smuts)
1. Teliospores terminal. 1. Teliospores intercalary.
2. Basidiospores 4, discharged from sterigmata. 2. Basidiospores variable in number, not on
sterigmata, not discharged.
3. Spermagonia produce dikaryotic stage. 3. No spermagonia; dikaryotic stage. stage
arises from fusion of any two compatible cells.
4. Clamp connections absent. 4. Clamp connections common.
5. Many species require two hosts for complete
life cycle.
5. Never requires two hosts.
6. Most species unculturable on artificial media. 6. Most species readily culturable.
7. Infections usually localized. 7. Infections usually systemic.
8. Teliospores in telial sori, usually on stems or
leaves.
8. Teliospores replace host organs, usually
ovaries and anthers.
9. Attack ferns, gymnosperms, or angiosperms. 9. Attack only angiosperms.
Comparison of Rust & Smut Fungi