© Benaki Phytopathological Institute
Abstracts - 16th Hellenic Phytopathological Congress
65
D.F. A
NTONOPOULOS
1,2
, M. G
EORGIADOU
3
, S.P. A
GORITSIS
1
, S. G
IANNIOTIS
3
and D.I. T
SITSIGIANNIS
1
1
Laboratory of Plant Pathology, Agricultural University of Athens, 75 Iera Odos Str.,
GR-118 55, Athens, Greece.
2
Laboratory of Crop Protection, School of Agricultural
Technology, ΤΕΙ of Kalamata, Antikalamos, GR-241 00 Kalamata, Greece.
3
Laboratory of Food Process Engineering, Agricultural University of Athens, 75 Iera
Odos Str., GR-118 55, Athens, Greece
One of the most significant threats for food quality and safety are the mycotoxins, partic-
ularly toxic and carcinogenic low molecu-
lar weight metabolites produced by certain
fungal species. Aflatoxins produced by the
fungi
Aspergillus flavus
and
A. parasiticus
are
highly carcinogenic mycotoxinsthat several
times have been detected at high concentra-
tions levels in pistachio nuts in Greece. The
aim of this study was to evaluate a collec-
tion of 20 yeast isolates and 4 non-toxigenic
strains of
A. flavus
, isolated from experimen-
tal pistachio orchards located at Fthiotida
County for the management of
A. flavus
and
aflatoxins. The yeast isolates MR7 (
Candida
sp.) and FR6 (
Aureobasidium pullulans
) were
selected as the most effective against the
aflatoxigenic pathogen
A. flavus
, strain Δ1.3
ΑF2 because they led to a 40-50% reduction
of
Aspergillus
growth and to a significant re-
duction in conidiogenesis by approximate-
ly 1000 times, in comparison to the control.
These 2 yeast strains were further tested on
shelled pistachio nuts cultivar “Eginis” for
their role in aflatoxin production (assessed
by High Performance Liquid Chromatogra-
phy-HPLC) and led to a significant decrease
by 89% (FR6) and 85% (MR7), respectively,
in comparison to the control. Evaluation of
the non-toxigenic
A. flavus
strains as biolog-
ical control agents of the disease and myco-
toxin in pistachio orchards, AF38, AF51 and
AF57 reduced significantly the production
of the aflatoxins (assessed by HPLC) AFΒ1, Β2
and G1 of the Δ1.3 AF2 strain by 41%, 48%
and 69%, respectively, whereas AF45 strain
did not show any effect in comparison to
the control. The results of this study contrib-
ute to the development of environmentally
friendly methods of biological management
of mycotoxins in pistachio nuts.
Τhe swarming motility of biocontrol antagonistic Pseudomonas strains
possibly inhibits the growth of phytopathogenic fungi
A. V
ENIERAKI
1
, K. P
APAMELETIOU
1
, A. P
APADOPOULOU
1
, M. D
IMOU
1
, P. A
NTONIOU
2
and P.
K
ATINAKIS
1
1
Laboratory of General and Agricultural Microbiology, Department of Agricultural
Biotechnology,
2
Laboratory of Plant Pathology, Department of Crop Science,
Agricultural University of Athens, 75 Iera Odos Str., GR-118 55 Athens, Greece
More than 30 antagonistic culturable bacte-
rial strains were isolated from solarized, to-
mato rhizosphere soil in greenhouses and
characterized for their potential to inhib-
it the growth of plant pathogenic fungi. In
i
n vitro
experiments they showed remark-
ably antagonistic activity against
Fusarium
oxysporum, Phytophthora
sp. and
Rhizoc-
tonia solani.
The antagonistic isolates were
first characterized using classical microbio-
logical methods and further assessed using
16S rRNA analysis. Most were found to be-
long to the
Pseudomonas
group (
P. fluores-
cens, P. poae, P. lurida, P. synxantha. P. moorei
etc). Strains were tested for their swarming
motility capacity under different environ-
mental conditions. Two strains, designat-
ed as P3 and P23,
Pseudomonas lurida
and
Pseudomonas azotoformans
, respectively,
showed hyper-swarming motility and inhib-
ited the growth of phytopathogenic fungi.
The results suggest that swarming activity
