© Benaki Phytopathological Institute
Hellenic Plant Protection Journal - Special Issue
14
ent mutants. Furthermore, the expression of
the defence related genes
PR1
,
PR2
,
PR3
,
PR4
,
PR5
and
PDF1.2
. was examined using qPCR.
It was revealed that the genes
PR1
,
PR2
and
PR5
were overexpressed in
etr1-1
plants com-
pared to Col-0 plants, indicating their role in
plant defence mechanisms.
Investigation of the role of
VdSteA
G protein coupled pheromone receptor
in the virulence and biology of the vascular wilt pathogen
Verticillium
dahliae
Ι.Α. S
TRINGLIS
1,2
, I. K
ALAITZOGLOU
1
, Ε.J. P
APLOMATAS
1
and D.Ι. T
SITSIGIANNIS
1
1
Agricultural University of Athens, Department of Crop Science, Laboratory of Plant
Pathology, 75 Iera Odos Str., GR-118 55 Athens, Greece.
2
Current Address: Utrecht
University, Department of Biology, Plant Microbe Interactions, Padualaan 8, 3584
CH, Utrecht, The Netherlands
V. dahliae
is a soil-borne fungus causing wilt
diseases in several hosts. The particular bi-
ology of this fungus complicates its treat-
ment through conventional methods. Thus,
the study of genes implicated in the inter-
actions of
V. dahliae
with its hosts is neces-
sary to unravel the pathogenicity or viru-
lence mechanisms and to discover putative
novel methods to control the disease. G Pro-
tein Coupled Receptors (GPCRs) represent
the largest family of transmembrane recep-
tors consisting of seven transmembrane do-
mains. GPCRs are critical factors in regulat-
ing the morphogenesis, defence, mating,
infection and virulence in various organ-
isms. Protein sequences of characterized
GPCRs of the well-studied fungi
Aspergil-
lus nidulans
and
Magnaporthe grisea
were
used for alignment comparison with the ge-
nome of
V. dahliae
in order to detect poten-
tial GPCRs. Seven different groups of GPCRs
emerged from the phylogenetic analysis,
varying in sensing different environmental
signals.
Agrobacterium
mediated disruption
of a pheromone GPCR (named as
VdSteA
) in
two wild type races, 70V and 25V of
V. dahli-
ae
was performed in order to study the role
of this receptor in virulence and morpholo-
gy. 70V and 25V
ΔVdSteA
mutants displayed
a reduction in virulence in eggplant and to-
mato plants and 70V
ΔVdSteA
mutants exhib-
ited increased microsclerotia formation and
conidiation when compared to their corre-
sponding wild types. Both
ΔVdSteA
mutants
exhibited higher conidial germination rates
compared to wild types.
Study of the role of the secondary metabolite regulatory gene
VdLaeA
in the
virulence and biology of the phytopathogenic fungus
Verticillium dahliae
Α.Μ. G
IANNAKOPOULOU
1,2
, Α.Α. G
KATZOUNI
1
and D.Ι. Τ
SITSIGIANNIS
1
1
Agricultural University of Athens, Department of Crop Science, Laboratory of
Phytopathology, 75 Iera Odos Str., GR-118 55 Athens, Greece.
2
Current Address: John
Innes Centre, The Sainsbury Laboratory, Norwich, UK
interactions. For this purpose, the respons-
es of
Arabidopsis thaliana
mutant plants im-
paired in known pathogen response path-
ways were used to explore the components
of defence against
Fusarium oxysporum
f.sp.
raphani
. It was observed that
etr1-1
plants
were the most resistant among the differ-
Fungal secondary metabolites are com-
pounds with high degree of specialization
that fulfil various roles in toxin production,
sporulation processes and the biosynthe-
sis of substances of special biotechnological
and pharmaceutical interest. Previous stud-
ies have shown that the phytopathogenic
fungus
V. dahliae
produces phytotoxins and
other molecules that induce the process of
programmed cell death or other forms of
