Detail structure of Puccnia and Fusarium.

1. Department of M.sc Microbiology
Bangalore university
Structure and reproduction of Puccinia and
Fusarium by
Vivek kumar

2. Puccinia
Introduction
 Puccinia is a fungus
 It is included in the class – basidiomycetes and in the
family- pucciniacea.
 The name puccinia was given after the name T.
puccinia, who was an Italian botanist.

3. Classification
Division- Eumycota
Class- basidiomycetes
Order- uredinales
Family- pucciniacea
Genus- puccinia

4.  Puccinia is a very large genus with about 1800 species.
In India, the genus is represented by more than 147
species.
 Common Indian species are-
Puccinia graminis- black rust or stem rust
Puccinia recondita- brown rust or leaf rust
Puccinia striiformis- yellow rust or stripe rust
 Puccinia species causes rust diseases in cereal crops
like wheat, barley, oats, and maize.

5. Black rust or stem rust
Brown or leaf
rust

6.  The best known species of puccinia is puccinia
graminis.
 It is an internal obligate parasite.
 Puccinia graminis is a heteroecious fungus.
 It requires two host to finish its life cycle –
The wheat plant (Triticum aestivum)
Barberry plant (berberis vulgaris)

7. Two hosts of puccinia

8. Structure
 In puccinia, the plant body is called mycelium.
 There are two types of mycelia namely- dikaryotic and
monokaryotic mycelia.
 The dikaryotic mycelium occurs in the primary host
i.e. wheat plant and monokaryotic mycelium occurs in
the alternate host i.e. barberry plant.
 The mycelia contains tubular filaments called hyphae.

9. Monokaryotic and Dikaryotic mycelium

10.  The hyphae are intercellular, septate and branched.
the mycelium takes nourishment from the host cells
with the help of branched haustoria.
 Each cell of the dikaryotic mycelium has a dikaryon
(binucleate) and that of monokaryotic mycelium has a
single nucleus.
 The cell consist of cell wall, plasma-membrane and
protoplasm. The cell wall is made up of fungal
cellulose, chitin.
 The cytoplasm of the cell contains vacuoles, glycogen
bodies and oil droplets.

11. Reproduction
 Puccinia is a fungus which causes rust disease in
wheat. It reproduces by sporulation and completes its
life cycle in two host.
 The life cycle of puccinia graminis is macrocyclic
because it produces several types of spores –
Uredospore
Teleutospore
Basidiospore
Pycnidiospores or spermogonium
aecidiospore

12. Types of spores in Puccinia
graminis

13. Uredospore stage
 This stage is found in the primary host.
 Uredospores are stalked, unicellular, rounded,
binucleated spore produced during early summer.
 The uredospore are produced by the aecidiospores,
which are produced on the alternate host.
 During early summer aecidiospore infect wheat plants
and produce dikaryotic mycelium.

14. Uredospore stage

15.  The mycelium produces a number of reddish brown
pustules or streaks on the upper surface of the leaf.
 Each pustule is called uredosorus, consisting of
number of uredospores.
 The epidermis of host plant bursts and uredospores
are liberated out, carried by wind and attacks fresh
wheat plants.
 The uredospore enters through stoma and produce
dikaryotic mycelium, which produces uredospores
within 6-10 days so are called repeating spore.

16. Teleutospore
 This stage is found in wheat plant.
 During late summer, the dikaryotic mycelium of
puccinia which gives rise to uredospore now gives rise
to teleutospores.
 In the beginning of winter they are produce
enormously, so they are called winter spores.
 The teleutospores are produced in teleutosorus.

17. Teleutospore stage

18.  They produce black streaks in leaf sheaths and stem.
 Teleutospores are composed of two cells- bicelled,
stalked and binucleate.
 The teleutospore are liberated out by the breaking of
epidermis and they do not attack the wheat plant.
 The two nuclei in a cell of teleutospore fuses to form
diploid nucleus. they remain dormant in the soil till
the beginning of the spring season.

20. Basidiospore
 The stage is found on the alternate host.
 In spring, the teleutospore produces one germ tube
from each cell. the germ tube is known as
promycelium or epibasidium.
 The diploid nucleus in a cell of the teleutospore moves
into the promycelium and divide meiotically to form
four haploid nuclei, two are of(+) strain and two are
of(-) strain

21. Basidiospore stage

22.  The promycelium becomes four-celled each cell
contains a haploid nucleus.
 From each cell of the promycelium arises a sterigma. at
the tip of the sterigma a basidiospore is formed.
 Each cell of the teleutospore produces four
basidiospores, two are of (+) strain and two are of(-)
strain.
 The basidiospores are uninucleate and unicellular and
can germinate only on the leaves of alternate host.

23. Pycnidiospore
 This stage is found on the barberry plant.
 The basidiospore germinates on the leaves of berberry
plant and produce monokaryotic mycelium below the
upper epidermis of the leaf.
 They produce flask shaped structures called the
pycnidium or spermogonium .the pycnidium opens on
the outer surface of the leaf by a minute pore called
ostiole.

24.  The ostiole is guarded by a tuft of sterile hairs called,
periphyses.
 At the lower portion of the pycnidium there is one
uninucleate hyphae called spermatophores. The tip of
the spermatophores produce pycnidiospores or
spermatia.
 The pycnidiospore are of either (+) or (-) strain. from
the pycnidia arise certain long hyphae called the
receptive hyphae or flexuous hyphae.

25.  The flexuous hyphae and pycnidiospores of a
pycnidium belongs to one strain because they are
formed by the germination of single basidiospore.
 The pycnidiospore or spermatia are liberated and
dispersed by wind. The pycnidiospore of one strain is
transferred to flexuous hyphae of the opposite strain
by insects.
 At the point of contact of spermatium with the
flexuous hypha the walls are dissolved. then is
transferred from spermatium to flexuous hypha. the
two nuclei of opposite strain remains together forming
a dikaryon. This process is known as spermatization or
dikaryotization.

27. Aecidiospore
 This stage is formed on the barberry plant.
 The binecleate cell formed as a result of
spermatization , divides and forms the dikaryotic
mycelium of puccinia.
 The mycelium accumulates and produces aecidosorus
or aecidial cup on the lower surface of the barberry
leaf.
 the aecidial cup is surrounded by sterile hyphae called
peridium.

28.  From the middle of the cup, the dikaryotic mycelium
forms a number of erect hyphae called sporophore.
 Each sporophore produces a number of binucleated
spore called the aecidiospore in chain. In between the
aecidiospores small, sterile intercalary cells are present
called disjunctor cells.
 The aecidiospore are liberated out by the breaking of
epidermis of host plant. the aecidiospore germinate on
wheat plant, produces dikaryotic mycelium. this
mycelium again produce uredospore, in wheat plant
within 10-12 days.

29. Aecidiospore stage

30.  The life history of puccinia graminis shows
polymorphism. It shows different stages in the life
cycle namely-
1) Parasitic life on wheat plant producing uredospore
and teleutospore.
2) Saprophytic life in the soil producing basidiospores.
3) Parasitic life on the berberry plant producing
pycnidiospore and aecidiospore.

31. Control measures of rust disease
 Affected plant should be removed and burnt to avoid
further infection.
 The alternate host, should be eradicated in the hills
and plains.
 Several fungicides like nickel-sulphate, sulphadiazine,
napthaquinones, zinc-sulphate, etc are used to prevent
rust infection.
 Rust resistant varieties can be cultivated .some
varieties are- N.P.797, N.P.798, N.P.799.

32. Life cycle of puccinia graminis

33. Fusarium

34. Fusarium
 Many are saprophytic and mild facultative parasites
 Some of the parasitic species are soil inhabitants and
can live as soil saprophytes but some are soil invaders.
 The parasitic form species cause rot of stores fruits,
vegetables and other commodities, and are
responsible for dry rot of potato tubers and soft rot of
rhizomes of ginger.

35. Mycelium
 The mycelium is extensive.
 The hyphae is septate and branched.
 They are both intercellular and intracellular.
 When the mycelium is young they are colorless and
dark colored when reaches to maturity.
 The dark mycelium produces thick bands which plug
the vascular tissue and produce toxic sclerotions. the
toxins are carried up in the xylem vessels, as a result
plant wilts and dies.

36. Mycelium

37. Reproduction
ASEXUAL REPRODUCTION-
It takes place by the formation of three kinds of spores-
Microconidia
Macroconidia
Chlamydospores (sclerotia are also formed)

39. Microconidia
 These are very small conidia produced from the tips of
simple or branched conidiophores.
 The conidiophores are distinguishable from the
vegetative hyphae .the microconidia vary in form from
round shape to oval
 They are held in small masses.
 At times they are elongated and crescent shaped.

40. Microconidia and
macroconidia

41. Macroconidia
 They are large multicellular, usually 2-4 celled conidia.
 They are elongated, crescent shaped and sickle
shaped.
 They are produced at the tips of simple and branched
conidiophores which are assembled to form a
sporodochium type of frutification.
 The microconidia and macroconidia are produced in
vast.
 On falling on a suitable substratum they germinate
and initiate new infections.

44. Chlamydospores
 They are rounded, oval shaped thick walled cells
formed in the hyphae.
 They may be formed singly or in chains of two or more.
 They are separated from the parent hyphae after
maturing and function as resting spores.
 Under suitable conditions they germinate by germ
tube.

45. Sclerotia
 They are mycelial resting bodies, thick walled hyphae.
 They functions as storage organs and also serves as
means of vegetative propagation.
 The are short lived.
 They germinate under suitable conditions, and
infections take place by the root tip region and
through wound

46. Fusarium oxysporum
 The disease is found all over the world, wherever the crop
of cotton is grown.
 It is believed that this disease has started from Mexico or
Central America.
 This disease has been reported from many other countries
such as Africa, France, Russia, Italy West Indies etc.
 In India the disease has been recorded from several states
especially Maharashtra, Madhya Pradesh Gujarat and other
parts of central India.
 The disease is restricted to black cotton soils, which are
heavy clay with an alkaline reaction, but in the light
alkaline and loamy soil it is unknown.

47. Classification
Division- eumycota
Subdivision- deutromycotina
Class- hyphomycetes
Order- Moniliales
Family- tuberculariaceae
Genus- Fusarium

48. Symptoms
 The fungus attacks the host when the plants are 1-3
week old.
 The disease becomes manifest when the plants are of
5-6 week old, at which time the leaves become yellow
and wither, until finally the entire plant dries up. The
plants soon wilt and die.
 In young affected plant the basal part become black
whereas in mature plants partial discoloration takes
place.

49. symptoms

50. Pathogen
 The wilt of cotton is caused by Fusarium oxysporum.
 The fungus is found both inter and intracellularly in
the host tissue.
 The mycelium of fungus plugs the xylem vessels.
Hyphae run through the vessels and permeate the
stem and the complete root system.

51.  The plugging of vessels, interferes the flow of water
and wilting of vessels is resulted.
 The fungus secretes toxic substances, which also cause
the wilting of the plant.
 Mycelium is hyaline and produces microconidia and
macroconidia, chlamydospores are formed only in
culture media.
 The macroconidia are 1-5 septate, hyaline, thin walled.

52. Nature and recurrence of disease
 This is a soil-borne as well as seed-borne disease.
 This fungus is a facultative parasite and can remain
viable in the soil for a long time.
 The fungus enters the root when the plants are 1-3
week old.
 The fungus multiplies and moves to xylem vessels, and
vessels are being plugged by abundance of mycelium.
 The soil borne fungal hyphae and chlamydospores play
the major role in perpetuation of disease.

53. Predisposing factors
 The soil temperature ranging from 20-30degree
Celsius favour the disease incidence.
 Hot and dry periods followed by rains also favour the
disease.
 Nitrogenous fertilizers increase the incidence.
 The disease is restricted to black cotton soils which are
heavy clay with an alkaline reaction.

54. Life cycle

55. Control measures
 Resistant varieties - The use of resistant varieties is the
only appropriate method of controlling this disease.
 Phytosanitation

56. Reference
 C.J.ALEXOPOULOS, C.W.MIMS, M.BLACKWELL. 4th
EDITION. INTRODUCTORY MYCOLOGY. PAGE
NUMBER- BASIDIOMYCETES-598-638,
DEUTEROMYCETES-244-245.
 A.RAGLAND, V.KUMARESAN. FIRST EDITION. 2002.
FUNGI AND PLANT PATHOLOGY. PAGE NUMBER-
RUST DISEASE- 131-153, WILT DISEASE- 296-299.

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