© Benaki Phytopathological Institute
Abstracts - 16th Hellenic Phytopathological Congress
31
P.F. S
ARRIS
1
*, E.A. T
RANTAS
1
, D.A. B
ALTRUS
3
, C.T. B
ULL
4
, W.P. W
ECHTER
5
, S. Y
AN
6
, C.D. J
ONES
7
,
J.L. D
ANGL
7,8
, N.J. P
ANOPOULOS
2,9
, F.N. V
ERVERIDIS
1
, B.A. V
INATZER
6
and D.E. G
OUMAS
1
1
Department of Plant Sciences, School of Agricultural Technology, Technological
Educational Institute of Crete, Greece.
2
Department of Biology, University of
Crete, Heraklion, Greece.
3
School of Plant Sciences, The University of Arizona,
Tucson, Arizona, USA.
4
United States Department of Agriculture, Agricultural
Research Service, Salinas, CA, USA.
5
United States Department of Agriculture–
Agricultural Research Service, Charleston, South Carolina, USA.
6
Department of
Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, Virginia,
USA.
7
Department of Biology, University of North Carolina at Chapel Hill, Chapel
Hill, North Carolina, USA.
8
Howard Hughes Medical Institute.
9
Professor Emeritus,
University Crete, Heraklion, Greece and University of California, Berkeley, CA, USA.
*Present Address: The Sainsbury Laboratory, John Innes Centre, Norwich Research
Park, Norwich NR4 7UH, UK
nage
pv.
maculicola
ES4326 as identical to
Pcal
ES4326, the model pathogen
P. syringae
pv.
tomato
DC3000 of
Arabidopsis thaliana
and
tomato, and
P. syringae
pv.
syringae
B728a
bean pathogen. All
Pcal
strains harbour two
genomic islands containing genetic elements
for type VI secretion systems (T6SSs). Surpris-
ingly, one of the
Pcal
T6SS is phylogenetical-
ly closer to
P. aeruginosa
T6SS-I than the
P. sy-
ringae
T6SSs. All
Pcal
strains also harbour a
hrp/hrc
gene cluster coding for a type III se-
cretion apparatus (T3SS), which in regard to
structure and DNA sequence is most similar
to
Psy
B728a, although
Pst
DC3000 is the clos-
er relative, suggesting horizontal gene trans-
fer of the
hrp/hrc
cluster between the strains’
ancestors. Although the overall genetic con-
tent of each of the four
Pcal
genomes appears
to be highly similar, the repertoire of the type
III effector proteins (T3EPs) was found to be
significantly divergent between the exam-
ined strains, reinforcing previous molecular
data suggesting the existence of two distinct
lineages within this pathovar of
Pseudomonas
cannabina
.
Comparative genomic study of closely re-
lated
pathogens
with different host range
provides insights into mechanisms of host-
pathogen interaction, differential virulence
factors, and pathogen evolution. Moreover,
sequencing of various strains of the same
pathogen can reveal additional information
concerning pathogen diversity and the mo-
lecular basis of virulence differences between
strains. In the current study we present draft
genome sequences and a comparative ge-
nomics analysis of four strains of
Pseudomo-
nas cannabina
pv.
alisalensis
(
Pcal
), one of the
causative agents of bacterial blight of cruci-
fers, isolated from geographically distant ar-
eas of Greece and the USA. Since
Pcal
causes
disease in a wide range of plant species and
can infect both monocots and dicots, includ-
ing the model plants
Arabidopsis thaliana
and
tomato, draft genome sequences of four
Pcal
strains were obtained to develop hypothe-
ses regarding the molecular basis of virulence
and host range determinants of this patho-
gen. Genomes were also compared to the ge-
nome of the recently reclassified strain
P. syri-
Study of the resistance of tomato hybrid CLX3731 transgenic plants
overexpressing the
gmgstu4
gene after infection with the bacterium
P.
syringae
pv.
tomato
Ν. Τ
ZIOUTZIOU
1
, P. M
ADESIS
2
and I. Ν
IANIOU
-Ο
BEIDAT
1
1
Laboratory of Genetics and Plant Breeding, School of Agriculture, A.U.TH. , GR-541
24 Thessaloniki, Greece.
2
Institute of Agrobiotechnology, C.E.R.TH., 6
th
km Charilaou-
Thermis Road, GR-570 01 Thermi, Thessaloniki, Greece
