Bacterial Plant Disease caused by Erwinia amylovora

1. Presented By: Ruqiya Sania
Roll. No: 177514
Dept. of Microbiology

2.  Fire blight is a contagious disease affecting
apple, pears and some other members of
family Rosacea
 It is caused by E.amylovora
 Under optimal conditions, it can destroy an
entire orchard in a single growing season and
is Gram- negative bacterium.

3.  In early 1800s, E. amylovora was used as a
first bacterium to indicated the plant disease
 Today it can currently be found in Canada,
USA, Africa and Egypt
 In 1950s it was first introduced into Northern
Europe
 During 1950s-1960s E. amylovora had
spread through much of Northern Europe

4.  In 1980s, it had been found in Eastern
Mediterranean
 In 1990s, it was discovered in Germany
 From the years 1995-1996 cases of fire
blight had begun to reported in countries
such as Hungry, Romania, Northern Italy and
Spain

5.  Honeybees and other insects, birds, rain and
wind can transmit the bacteria to susceptible
tissue
 Injured tissue is also highly susceptible to
infection
 Hail storm can infect the entire orchard in a
few minutes

6.  The bacterium enter the plant through open
stomata and produce a viscous exudate
 The pathogen spread through from the point
of infection via the plant’s vascular system.
 It typically enter into its host xylem and
cortical parenchyma

7.  Down pour or water sprinkling, bugs and
wings animals, other tainted plants and
unclean cultivated instruments
 Fly Delia platura has been observed visiting
fire blight wound to feed but was
unconfirmed as an effective vector
 Aerosols are also suspected in playing a role
in its transmission

8.  Symptoms on blossoms include water
soaking of floral receptacle, ovary and
peduncles
 A dull, grey-green appearance at 1-2 weeks
after petal fall & tissues become black in
colour
 A “ shepherd’s crook” can be seen when the
tip of the shoot wilts

9.  Pathogenicity depends on production of
siderophore desferrioxamine, metal
proteases, plasmids and histone like proteins
 Variations in the synthesis of EPS and
mechanism of type III secretion system and
its associated proteins
 Motility is another major virulence factor

10.  Select the resistant varieties
 Avoid heavy pruning
 Avoid planting close to wild plants
 Prune off infected branches
 Dip pruning shears into a 10% alcohol or
bleach solution between each cut to avoid
transmission
 Use of Streptomycel lydicus
 Use of Organocide® Plant Doctor

11. Causative agent Host Symptoms Additional
Features
Erwinia
amylovora
Apple & Pear Blossoms
appear, water
soaked and
shrivel. Spread
to leaves and
stems, causing
rapid die back
First plant
disease proved
to be caused by
a bacterium

12. Domain Bacteria
Phylum Proteobacteria
Class 𝛾 𝑃𝑟𝑜𝑡𝑒𝑜𝑏𝑎𝑐𝑡𝑒𝑟𝑖𝑎
Order Enterobacterales
Family Erwiniaceace
Genus Erwinia
Specie amylovora

13. (a)
(a) E. amylovora
on apples
(b)
(b)
E.amylovora
on pears