© Benaki Phytopathological Institute
Abstracts - 16th Hellenic Phytopathological Congress
11
Race classification and host range pathoge-
nicity determination of 32
Verticillium dahl-
iae
isolates, originating from 19 plant spe-
cies from 8 different botanical families, were
carried out. The physiological races of iso-
lates were identified using the two differ-
ential tomato cultivars Belladona (suscepti-
ble to both races 1 and 2 of
V. dahliae
) and
Ace 55VF (resistant to race 1, susceptible to
race 2 of
V. dahliae
). Among these isolates,
14 were characterized as race 2 (43.8 %), 12
race 1 (37.5 %) and 6 nonpathogenic (18.7
%) on tomato. The host range pathogenici-
ty of isolates was determined using four dif-
ferential hosts (eggplant, turnip, tomato (
Ve
-
) and sweet pepper). Among the isolates, 5
were pathogenic to both eggplant and tur-
nip (15.6 %), 21 to eggplant, turnip and to-
mato (65.6 %), 5 to eggplant, turnip, tomato
and sweet pepper (15.6 %) and 1 was patho-
genic to eggplant, turnip and sweet pepper
(3.2 %). The pathogenicity of isolates on the
aforementioned five hosts was investigat-
ed on the basis of external symptoms and
by calculating the relative areas under dis-
ease progress curves (relative AUDPC). Re-
sults showed that eggplant was the most
susceptible, followed by turnip and toma-
to cv. Belladona, while sweet pepper and to-
mato cv. Ace 55VF were less susceptible to
the isolates used. The pathogenicity of iso-
lates varied from highly to mildly virulent
on eggplant and turnip whilst on Belladona,
Ace 55VF and sweet pepper it varied from
highly virulent to nonpathogenic. Belladona
exhibited a similar level of susceptibility to
race 1 and 2 of
V. dahliae
, but was more sus-
ceptible than Ace 55VF to race 2. Interest-
ingly, the isolates originating from eggplant
were clearly more virulent than those orig-
inating from tomato and black nightshade
on all solanaceous plants tested.
Phytopathological characterization, morphology, genetics and molecular
differentiation combined in an integrated population study of
Verticillium
dahliae
I.A. P
APAIOANNOU
1
, E.K. L
IGOXIGAKIS
2
, D.J. V
AKALOUNAKIS
2
, E.A. M
ARKAKIS
3
and M.A. T
YPAS
1
1
Department of Genetics and Biotechnology, Faculty of Biology, National and
Kapodistrian University of Athens, Panepistimiopolis, GR-157 01 Athens, Greece.
2
Laboratory of Plant Pathology, Plant Protection Institute, National Agricultural
Research Foundation, GR-710 03 Heraklion, Crete, Greece.
3
Laboratory of Plant
Pathology, School of Agricultural Technology, Technological Educational Institute of
Crete, GR-710 04 Heraklion, Crete, Greece
Understanding the genetic diversity of
V.
dahliae
populations and an early recording
of their pathogenic profile are essential for
disease management. An extended
V. dahli-
ae
populationmainly originating fromCrete,
Greece, was characterized in terms of patho-
genicity/virulence, morphology/physiology,
vegetative compatibility and mating type.
Tomato race 2 has supplanted race 1 and
was more virulent on a susceptible toma-
to cultivar than race 1. Pathotypes of all iso-
lates were determined using four differential
hosts (tomato, eggplant, sweet pepper and
turnip). All isolates from Crete fell into VCG
subgroups 2A, 2B and 4B, while a remark-
ably high incidence of bridging isolates was
recorded. The tomato-sweet pepper patho-
type was morphologically distinct from the
others, while conidial length and pigment
intensity were discriminatory parameters
among VCGs 2A, 2B and 4B. The PCR-based
molecular marker Tr1/Tr2 was reliable in race
prediction among tomato-pathogenic iso-
lates, except for members of VCG 4B, while
the application of markers Tm5/Tm7 and 35-
1/35-2 was highly successful in distinguish-
ing tomato pathotypes. E10 marker was re-
lated to VCG 2B. A SNP in the ITS2 region,
and two novel molecular markers, M1 and
M2, proved useful for the fast and accurate
determination of major VCGs 2A, 2B and 4B,
and can be used for high-throughput popu-
