© Benaki Phytopathological Institute
Hellenic Plant Protection Journal - Special Issue
66
may contribute to fungal growth inhibition
in soil. In this respect it will be of great inter-
est to investigate the behavior of these bac-
teria under greenhouse conditions and to
characterize the bacterial genes involved in
fungal growth inhibition.
Selection of non-toxigenic strains of
Aspergillus flavus
from pistachio and
cottonseed as biological control agents for aflatoxin management
K. V
ICHOU
, G. V
ARDOUNIOTIS
and D.I. T
SITSIGIANNIS
Laboratory of Plant Pathology, Department of Crop Science, Agricultural University
of Athens, 75 Iera Odos Str., GR-118 55 Athens, Greece
The presence of mycotoxins in agricultural
products is considered as one of the most
serious food safety concerns worldwide.
One of the most carcinogenic mycotoxins is
aflatoxin produced by the fungi
Aspergillus
flavus
and
A. parasiticus.
Aflatoxin has been
detected at high concentrations in Greece,
including in pistachio. A promising and ef-
fective strategy to reduce aflatoxin levels is
the application in the field of endemic non-
toxigenic
Aspergillus
spp. strains. This tech-
nique is based on the gradual substitution
and exclusion of
A. flavus
and
A. parasiti-
cus
toxigenic strains by the non-toxigenic
strains due to competition. The goal of this
study was to create a collection of greek en-
demic non-toxigenic
Aspergillus
spp. strains.
Initially, soil samples were collected from
different experimental fields in the Fthioti-
da region and transferred to the laborato-
ry. The isolation of several strains of
Asper-
gillus section Flavi
was performed by plating
soil-water suspensions on plates of selec-
tive medium. Furthermore, several strains of
Aspergillus
section
Flavi
were isolated from
pistachio during harvest from experimental
fields of Aegina, as well as frompistachio ker-
nels from several other sources in the mar-
ket. Using thin layer chromatography (TLC)
the collection of isolates was evaluated for
their ability to produce aflatoxins in order
to discover non-aflatoxigenic strains that
could be used in biological control experi-
ments. Finally,
in vitro
competition assays
were carried out using two wild toxigen-
ic and 12 non-toxigenic strains, in order to
study the potential for the reduction of the
aflatoxigenic capacity of toxigenic strains by
non-toxigenic strains. Most non-toxigenic
strains reduced the aflatoxigenic activity of
wild type strains, and some strains prevent-
ed aflatoxin production completely.
Evaluation of rhizobacterial activity against soil-borne plant pathogenic
fungi
in vitro
A. M
ALAFOURIS
AND
L.A. L
AGOPODI
Plant Pathology Laboratory, School of Agriculture, Aristotle University of
Thessaloniki, GR-541 24 Thessaloniki, Greece
Eight (8) rhizobacterial strains, known for
their
in vitro
and
in planta
activity against
the plant pathogenic fungus
Fusarium ox-
ysporum
f. sp.
radicis-lycopersici
(Forl), and 3
new strains, were tested
in vitro
for the for-
mation of an inhibition zone in the myceli-
al growth of 4 soil-borne plant pathogenic
fungi. Specifically, the strains
Bacillus cere-
us
S76 and S79,
Serratia marcescens
PiHa5-
II, S47 and S52,
Serratia rubidea
S55 and S49,
Pseudomonas chlororaphis
ToZa7, and the
new strains ΤοΖa9-12, ΤοΖa1-5-10, ΤοΖa4-8 of
yet unknown genetic identity, were tested
against
Verticillium dahliae, Sclerotium rolfsii,
and
Rhizoctonia solani
, with the latter three
also being tested against Forl. In addition,
S76, PiHa5-II, ToZa7, ToZa9-12 and ToZa4-8
were tested
in vitro
against Forl and
S. rolf-
sii
for the presence of volatile compounds
that inhibit mycelial growth. The most im-
