L 23. Rust-1.ppt

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1. Symptoms and life cycle of
PucciniaUromycesand Hemileia

2. Order: Pucciniales(Rust fungi)
•Obligate parasites infect wide host range (identified by its sign, sori)
•Mycelium is simple, septate, branched, initially uninucleateand
later binucleate. Clamp connection is absent or rare.
•Binucleateuredosporesrepresent the asexual spore (conidia).
Produced successively by the dikaryoticmycelium until the
environment is conducive, hence called as repeating spores
•Basidiomataare absent

3. •Produce distinct sex organs (spermagonia/ pycnia) and the
plasmogamyoccurs through spermatization
•Teleutosporesare binucleateonly at the end of dikaryoticphase.
As the karyogamyand meiosis occurs only during
germination, they are referred as sexual spores.
They are thick walled, germinate to form septate
promycelium(=basidium) and bear four basidiospores.

4. •Teliosporesare formed in a soruscalled teliumand may be sessile
(Melampsora) or borne on pedicels (Puccinia, Uromyces) or
in chains (Cronartium).
•Teleutosporesmay be single celled (Uromyces, Melampsora) or
two celled (Puccinia) or multicelled(Phragmidium) with a
range of surface ornamentations. They mostly undergo
dormancy (Pucciniagraministritici) and hence called as
resting spores.
In some species, they germinate immediately without
dormancy (Pucciniaxanthii, Pucciniahoriana) and are
called leptospores.

5. Rusts are small raised reddish pustules on the leaves or leaf
sheaths, stem, usually of a rusty colour. The pustules may be either
compact or break through the host epidermis to become dusty.
E.g. Black rust stem rust of wheat -Pucciniagraministritici
Rust of groundnut -P. arachidis
Rust of sunflower -P. helianthi
Rust of pearlmillet-P. substriatavar. penicilliariae(P. penniseti)
Blackgram/ greengramrust -Uromycesphaseoli-typica
Bean rust -Uromycesappendiculatus
Coffee rust -Hemileiavastatrix
Linseed or Flax rust -Melampsoralini

6. Five stages of rust fungi
Stage 0: Spermagonia(Pycnia) with spermatia(pycniospores)
and receptive hyphae.
Stage I : Aecia with aeciospores
Stage II: Urediawith uredospores
Stage III: Teliawith teleutospores
Stage IV: Basidiawith basidiospores

8. (a) PycniosporesStage (0): Produced in a flask-shaped structure
called as pycnium. Periphysesand flexuous hyphae(receptive
hyphae) are present in pycnia. Pycniaare formed in the host after it
is infected by the basidiospores. Pycniosporesare uninucleateof
either + or –type, single celled and behave as spermatia.
(b) Aeciospores Stage (I): Single celled, dikaryoticspores produced
in chains in cup-like structures known as aecia.Spores are yellow
to orange in colourwith a hyaline characteristically verrucosewall.

10. (c) UredosporesStage (II): Single celled, binucleate, pedicellate
spores borne in urediaor uredinia. Uredosporesare brown, oval
and echinulate. They behave as conidia and repeat several cycles
in a season and are also called as repeating spores.

11. (d) TeliosporesStage (III): Binucleate, pedicellateor sessile spores
producedina soruscalled teliain host tissue. They may be single
celled, bicelledor more than 2-celled with dark brown walls. They
produce basidiumand basidiosporesupon germination.

12. (e) BasidiosporesStage (IV):Haploid, unicellular spores borne
on sterigma. These spores arise from cylindrical to club-shaped 2
to 4 celled basidia.

13. Rust fungi that complete their life cycle in one host are termed as
autoecious(and the condition is called autoecism) and those
requiring two hosts for the completion of their life cycle are called as
heteroecious(and the condition is called heteroecium).
a. Autoeciousrust:Five spore stages are formed on a single host.
e.g., Sunflower rust -Pucciniahelianthi
Bean rust -Uromycesappendiculatus
Sunflower rust Bean rust
Flax rust

14. b. Heteroeciousrust:Two different hosts (viz., primary host and
alternate hosts) are required for completion of its life cycle.
Primary host is the plant where the teliosporesare produced.
Alternate host is a plant, which is required to complete life cycle
without which the pathogen cannot survive.
Urediaand telia-primary host.
Pycniaand aecia -alternate hosts.
e.g., Wheat stem rust -Pucciniagraminisvar. tritici.
Wheat is the primary host and barberry is the alternate host.

15. Macrocyclicrust or Long cycled rust: Five spore stages are
produced in the life cycle of fungi.
a. Autoeciousrust: Five spore stages are formed on a single host.
e.g., Sunflower rust -Pucciniahelianthi
Bean rust -Uromycesappendiculatus
Flax rust -Melampsoralini
b. Heteroeciousrust: Two different hosts (viz., primary host and
alternate hosts) are required for completion of its life cycle.
Wheat stem rust -Pucciniagraminisvar. tritici
(wheat –primary host; Barberry, Mahonia–alternate host)
Leaf rust of wheat –Pucciniarecondita
(wheat –primary host; Thalictrum, Isopyrum–alternate host)
Bajrarust -Pucciniasubstriatavar. penicillariae
(Bajra–primary host; Brinjal–alternate host)

16. Demicyclicrust
Uredialstage is absent. It produces only pycnia(sometime missing),
aecia and teliain host plant
e.g. Cedar apple rust -Gymnosporangiumjuniperivirginianae
(heteroeciousrust)
Rubusorange rust –Gymnoconiapikiana(autoeciousrust)
Cedar apple rust

17. Microcyclicrust or Short cycled rust
Complete its life cycle in a single host (autoeciousrust).
Teliosporeis the only binucleatespore produced in their life cycle.
Fungi which lack pycniosporesand aeciospores are microcyclicrust
e.g., Jasmine rust–Uromyceshobsonii
Hollyhock rust -Pucciniamalvacearum
Chrysanthemum rust -Pucciniahoriana
Jasmine rust Chrysanthemum rust

18. Black or stem rust of wheat -Pucciniagraministritici
Systematic position
Domain : Eukarya
Kingdom : Fungi
Phylum : Basidiomycota
Sub phylum : Pucciniomycotina
Class : Pucciniomycetes
Order : Pucciniales
Family : Pucciniaceae
Genus : Puccinia
Species : P. graministritici

19. Pathogen
Heteroeciousrust
Primary host-wheat; Alternate host-barberry (Berberisvulgaris)
Alternate host
Stage 0 -Pycniaand pycniospores
Stage I -Aecia and aeciospores
Main host
Stage II -Urediaand uredospores
Stage III -Teliaand teleutospores
Plant debris
Stage IV -Basidiaand basidiospores

20. Symptoms
Reddish brown pustules (raised blisters) are produced mostly on the
stem and also on leaves. Later they merge and form linear lesions.
Late in the season linear, black teliaare formed in the same
uredosorior on a separate place; severe infection causes drying of
leaves.
Uredosori Teleutosori

21. Barberry pycnialstage
Aecialcup -Barberry

22. Pathogen
Pycnium Flask shaped, ostiolate(spermagonium)
PycniosporeSpherical, thin-walled, hyaline, unicellular, uninucleate
Aecium Cup like and thick walled
AeciosporeUnicellular, yellow, hexagonal, thick walled,
binucleate, echinulated.
Uredium/ Uredosori
UredosporeOval, single celled, binucleate, golden brown, thick
walled, echinulated, pedicillate(repeating spores)
Telium/ Teleutosori
TeleutosporeTwo celled, dark brown, thick walled apex with
pointed at the tip with slight constriction at the
septum (resting spore), Young teleutosporesare
binucleateat maturity it has a single diploid nucleus
Basidiumor promycelium–Long thin walled, hyaline and 4 celled
BasidiosporeUnicellular, round and uninucleate

24. Rust of pearlmillet-Pucciniasubstriatavar. penicillariae(P. penniseti)
Symptoms: Appears on lower and older leaves as typical erumpent
pustules containing a reddish, brown powder (uredospores). As the
leaves senesce dark brown teliosporesare produced. Heteroecious
rust. Primary host is pearlmilletand the alternate host is brinjal

25. Rust –Pucciniahelianthi
(Autoeciousrust)

26. Rustofblackgram/greengram-Uromycesphaseoli-typica
(syn.U.appendiculatus)
Systematic position
Domain : Eukarya
Kingdom : Fungi
Phylum : Basidiomycota
Sub phylum : Pucciniomycotina
Class : Pucciniomycetes
Order : Pucciniales
Family : Pucciniaceae
Genus : Uromyces
Species : U. phaseoli-typica

27. Symptoms
Appears first on leaves as small, round or oval, cinnamombrown,
powdery pustules and coalesce. These pustules occur rarely on both
the surfaces but more frequently on lower surface.

28. Pathogen
Autoeciousmacrocyclicrust.
Uredosporesare globose, single celled, echinulated,
pedicellate, golden brown with two equatorial germ pores.
Teliosporesare single celled, smooth walled, globose, chestnut
brown, pedicellateand with hyaline papilla.
Pycniosporesare hyaline and spherical
Aeciosporesare hyaline and elliptical with minute verrucose
markings
Pea rust caused by Uromycesfabaeand Uromycespisi
Bean rust caused by Uromycesappendiculatus

29. Uredosporesof
Uromyces
Teleutosporesof
Uromyces

30. Rust pycnia, aecia and
urediniapustules on beans
(left to right)

31. Leafrustofcoffee–Hemileiavastatrix
Systematic position
Domain : Eukarya
Kingdom : Fungi
Phylum : Basidiomycota
Sub phylum : Pucciniomycotina
Class : Pucciniomycetes
Order : Pucciniales
Family : Incertaecedis
Genus : Hemileia
Species : H. vastatrix

32. Symptoms
Infectionisrestricted to leaves but rarely seen on tender shoots
and berries
Pustules appear as small yellowish spots, 1-2 mm in dia. Later
they become orange colouredand increased in size.
On upper surface, the colouris often brownish.
The infected leaves are defoliated which affects the yield.

33. Life cycle
The uredosporesare orange segment like with convex surface
ornamented with spines or warts. The fungus occasionally
produces teliosporeswhich are turnip shaped and germinate to
produce basidiumand basidiospores. They do not infect coffee or
any other host. No alternate host has been reported.
Uredospores Teleutospores

36. Thank you