TAXONOMY AND PATHOGENICITY OF PSEUDOMONAS
SYRINGAE ISOLATES FROM CHERRY (PRUNUS AVIUM)
J G Vicente1 and S J Roberts2
1
Warwick-HRI, The University of Warwick, Wellesbourne, Warwick, CV35 9EF, UK.
Plant Health Solutions, 20 Beauchamp Road, Warwick, CV34 5NU, UK.
2
Background
● Bacterial canker is one of the most important diseases of cherry (Prunus
avium L.) and a major limitaion for timber production from wild cherry.
● Most previous studies have been on sweet cherry, with Pseudomonas syringae pv. morsprunorum (Psm) considered the primay cause in the UK and
both P. syringae pv. syringae (Pss) and Psm in other other countries.
● More recently, Pss and/or intermediate forms between Psm and Pss were
also found in sweet and in wild cherry.
● Our aim was to identify the pathogens associated with bacterial canker in
wild cherry in England.
Methods
Pathogenicity
● 74 Pseudomonas syringae isolates from cherry (mostly from
England 1957-2000) plus 13 others.
● Characterised by: Physiological / biochemical tests (fluorescence, colour in NSB, GATTa,); Pathogenicity; Agglutination
and ELISA (three antisera); rep-PCR.
Tested on micropropagated lilac (Sensation) and two wild cherry clones (Charger and 1912) and rooted lilac cv. SensaLilac
Charger
1912
tion plants.
Control
● Differentiated
Pss and Psm
isolates .
● Demonstrated Pss
a range of aggressiveness
amongst Pss Psm r1
isolates.
+/–
+e
+
+/–
–
rep-PCR
Rep+Eric+Box
RepEricBoxAll
Rep
Eric
Box
100
+
95
–
+
+
+/–
85
–
+
+
+/–
90
10 w (4), s (5),
p (1)
7 w (1), s (2),
p (4)
8 w (2), s (6)
8 w (8)
+/–
+/–
+/–
80
––++
9/3 105D
+
+
70
w
8/3
+/–
75
N
Agglutinationd
65
Psm race 1
v
Col.
Path on Path on micropropagated
in G A T Tab No. Hostsc (no.) mature
Lilac Charger 1912 Spots
NSB
lilac
y + + – – 28 w (14), s (8),
+
+
+
+
–
cl (1), pl (2),
l (2), pr (1)
5 w (5)
(+)
+
+/–
+/–
–
7 w (7)
–
+
+/–
+/–
–
14 w (13), s (1)
–
–
–
–
–
60
Pss
Fluor.a
50
Group
55
Summary of physiological / biochemical, pathogencity and
agglutination test results.
Isolate Group
Host
Number
+/+
w
7928A
-/(+)
w
7962
-/-
w
7969
-/-
w
7970A
-/-
w
5828
-/(+)
w
7955C
-/(+)
w
7956
-/-
w
7959
Ps
-/-
w
7961
Ps
-/-
w
5837
Pss
+/+
s
7973A
Ps
-/-
w
7932A
Pss
-/(+)
w
7971A
Ps
-/-
w
7927A
Ps
-/-
w
7928C
Pss
+/+
w
5841
Pss
-/(+)
w
7919A
Pss
-/(+)
w
5265
Ps
-/-
w
7929A
Ps
-/-
w
7929D
Pss
(+)/+
w
7964
Pss
(+)/+
w
7965A
Pss
(+)/+
w
7963
Pss
-/(+)
w
7922A
Pss
(+)/+
w
5264
Pss
(+)/+
w
7921
Ps
-/-
w
7949
Pss
+/+
cl
SC073B
Pss
+/+
s
5355
Pss
+/+
w
7972
Pss
+/+
w
5277
Pss
+/+
s
5356A
Pss
+/+
w
5275
Pss
+/+
s
5262
Pss
+/+
w
5275
Pss
+/+
w
5275
Pss
+/+
s
5357
Pss
+/+
w
5275
Pss
+/+
w
7924
Pss
+/+
s
7926A
Pss
+/+
w
7929B
Pss
+/+
w
5267
Pss
+/+
w
5835
Pss
+/+
p
7872
Pss
+/+
s
7874
Pss
+/+
p
7873
Ps
-/-
s
2942
Pss
+/+
w
5272
Pss
+/+
w
8094A
Pss
+/+
w
8094C
Pss
+/+
w
8094B
Pss
+/+
s
7933
Pss
+/+
pr
5340
Conclusions
Pss
+/+
l
801
Pss
+/+
l
2070
my
5400
● Bacterial canker is present throughout southern England and can be caused by either Psm or Pss.
● The GATTa tests plus the colour of growth in NSB can
differentiate Psm races 1 and 2 from other P. syringae
isolates.
● Serological tests or rep-PCR can be used as alternatives to the classical tests to identify Psm, but cannot
replace pathogenicity for Pss.
Psm race 2
Intermediate
Others
v
B
–
–
–
–
+f
+
+/–
–
g
w +–––
–
–
+/–
+/–
+
+/– +/–
–
+
+
–
w or + + – –
–
–
+/–
+/–
+h
yw
N
w +–+–
2 myr, (1), ph
–
–
–
–
–
–
–
(+)
y ––––
(1)
a
Flourescence on King’s medium B: v - variable; N - non-fluorescent, B - blue fluorescent
b
Gelatinase, Aesculin hydrolysis, Tyrosinae, Tartrate untilisation
c
Hosts: w, wild cherry; s, sweet cherry; p, plum; cl, cherry laurel; l, lilac, pr, pear; my, myrobalan; ph,
peach.
d
Antiserum 8/3 prepared to Psm and 9/3 to Pss from wild cherry, 105D to Ps from pea.
e
Nine, f three, g six, and h four of these isolates produced leaf spots on plantlets of Charger and/or 1912.
Total genomic
DNA amplified
using REP,
ERIC and
BOX primers.
Pss
Pss
Ps
Ps
Ps
Pss
Pss
Ps
Other
Other
PLANT HEALTH SOLUTIONS
E: s.roberts@planthealth.co.uk
W: www.planthealth.co.uk
Acknowledgments
This work was funded by
●
●
●
●
ph
5402
Psm
race 2
w
5271
Ps
-/-
w
7920B
Psm
race 2
w
5845
Psm
race 2
s
5260
Psm
race 2
w
5831
Psm
race 2
s
5260
Psm
race 2
w
7967A
Psm
race 2
w
7968A
Psm
race 2
s
5260
Psm
race 2
w
5836
Psm
race 2
w
7958A
Psm
race 2
w
SC214
Psm
race 2
w
SC217
Psm
race 2
w
5268
Psm
race 2
s
5253
Psm
race 2
s
5261
Psm
race 2
s
5252
Psm
race 2
s
5260
Psm
race 2
s
5250
Psm
race 2
s
5255
Psm
race 1
p
5281
Psm
race 1
p
5299
Psm
race 1
p
2928
Psm
race 1
s
5244
Psm
race 1
w
5833
Psm
race 1
w
5269
Psm
race 1
p
5300
Psm
race 1
w
5270
Psm
race 1
p
797
Psm
race 1
s
798
Psm
race 1
s
2206
Psm
race 1
s
5239
Psm
race 1
s
5243
Psm
race 1
s
5259
Psm
race 1
s
5238
Psm
race 1
w
5270
Psm
race 1
w
5270
Psm
race 1
w
5266
Psm
race 1
w
5270
Psm race 1 uniform.
Psm race 2 uniform.
Psm races easily differentiated.
Pss highly variable.
Publications
Vicente, J.G. and Roberts, S.J. (2006) Discrimination of isolates of Pseudomonas syringae from sweet and wild
cherry using rep-PCR. European Journal of Plant Pathology (submitted).
Vicente, J.G., Alves, J.P., Russell, K. and Roberts, S.J. (2004) Identification and discrimination of Pseudomonas
syringae isolates from wild cherry in England. European Journal of Plant Pathology 110, 337-351.
Vicente, J.G. and Roberts, S.J. (2003) Screening wild cherry micropropagated plantlets for resistance to bacterial canker. In: Developments in Plant Pathology: Pseudomonas syringae pathovars and related pathogens ed.
Iacobellis, N.S. Dordrecht: Klewer Academic Publishers.
11th International Conference on Plant Pathogenic Bacteria, Edinburgh, 10-14 July 2006
11th International Conference on Plant Pathogenic Bacteria, Edinburgh, 10-14 July 2006
Taxonomy and pathogenicity of P.syringae isolates from cherry (Prunus avium)
J. G. Vicente1, and S. J. Roberts2
1
Warwick HRI, The University of Warwick, Wellesbourne, Warwick CV35 9EF, UK
2
Plant Health Solutions, 20 Beauchamp Road, Warwick CV34 5NU, UK
E-mail: s.roberts@planthealth.co.uk
Bacterial canker is one of the most important diseases of sweet and wild cherry (Prunus avium L.).
This disease can be caused by two pathovars of Pseudomonas syringae: pv. morsprunorum (Psm)
and pv. syringae (Pss). Seventy-four Pseudomonas syringae isolates from cherry and 13 isolates
from other hosts were characterised by physiological, biochemical, serological and pathogenicity
tests. Repetitive DNA polymerase chain reaction-based fingerprinting (rep-PCR) was also
investigated as a method to distinguish pathovars, races and isolates. Physiological and biochemical
tests discriminated Psm races 1 and 2 from other P. syringae isolates. Agglutination and indirectELISA tests with three different antisera showed that Psm race 1 and race 2 were very uniform and
indicated high variability amongst other P. syringae isolates. However, pathogenic Pss isolates could
not be distinguished from non-pathogenic isolates of P. syringae on the basis of physiological,
biochemical or serological tests. Pathogenicity tests on rooted lilac plants and on micropropagated
plantlets of lilac and two wild cherry clones differentiated Pss and Psm isolates and demonstrated a
range of aggressiveness amongst Pss isolates. The results of rep-PCR using three sets of primers
(REP, ERIC and BOX), indicated that the Pss isolates were highly variable, the two races of Psm can
be easily separated and the Psm isolates are generally very uniform within each race. Serological
tests or rep-PCR could be used as alternatives to the classical physiological and biochemical tests to
increase the speed of detection and discrimination of isolates, but pathogenicity tests are still
necessary to discriminate the pathogenic Pss isolates.