Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme III: PATHOGENS AND NUISANCES, FOOD AND MEDICINE Posters
909 - Ochratoxin producing Aspergillus species in
organic raisins and sultanas
M. Torp 1* , P. Kruse 1 , P.-E. Clasen 1 & F.J. Cabañes 2
1 National Veterinary Institute, Department of Food and
Feed hygiene, Ullevålsvn. 68, P.O.Box 8156 Dep., N-0033
Oslo, Norway. - 2 Universitas Autònoma de Barcelona,
Departament de Sanitat i d'Anatomia Animals, Grup de
Micologia, Bellaterra E-08193, Spain. - E-mail:
mona.torp@vetinst.no
On behalf of the Norwegian National Food Control
Authority, a study on potential mycotoxin producing fungi
in organically grown raisins and sultanas was conducted.
The 61 tested samples were bought in stores in Oslo during
spring and summer 2001. The dried fruits were cut in
halves and plated out on Dichloran Glycerol agar and
incubated at 25 °C for seven days. Potential mycotoxin
producers were isolated from all the 15 samples of
sultanas, while 44 samples (95%) of raisins were affected.
Fungi belonging to the Aspergillus niger aggregate were
the most dominant, infesting all samples of sultanas and
95% of the raisins, while Aspergillus carbonarius was
isolated from 93% of the sultanas and 2% of the raisins.
The high recovery of these fungi in raisins and sultanas is
of concern, since they have been reported as producers of
the highly toxic Ochratoxin A (OTA). In this study, 18
strains were analysed by HPLC for OTA production in
pure culture on Yeast Extract Sucrose agar. Nine out of 12
tested strains of A. carbonarius and four out of six tested
strains of the A. niger aggregate produced OTA. The ITS-
5.8S rDNA RFLP patterns of the OTA-producing isolates
in the A. niger aggregate were also determined. All four
isolates were classified as type N [Accensi et al. 1999],
corresponding to the RFLP group 'A. niger'. The results
indicate that OTA analyses of organically grown raisins
and sultanas would be of interest to the consumers.
910 - A monitoring system for green fluorescence
protein gene-transformed Fusarium oxysporum in
melon seedlings
H. Toyoda * , T. Nonomura & Y. Matsuda
Laboratory of Plant Pathology and Biotechnology, Faculty
of Agriculture, Kinki University, 3327-204 Nakamachi,
Nara 631-8505, Japan. - E-mail:
toyoda@nara.kindai.ac.jp
Using melon seedlings at the cotyledon stage and
genetically marked fungi, a system for monitoring
pathogenic and nonpathogenic Fusarium oxysporum was
devised in the present study. Protoplasts were prepared
from three formae speciales (melonis, radicis-lycopersici
and fragariae) of F. oxysporum and transformed with a
synthetic gene for green fluorescence protein.
Transformants were primarily isolated in the presence of
hygromycin B and then screened by the emission of bright
green fluorescence. Roots of melon seedlings were
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Book of Abstracts
inoculated with fluorescing microconidia of these fungi,
and fungal infection behavior was traced. Using
fluorescence microscopy, we directly observed not only the
fungus at the root surface, but also the mycelia elongating
in the trachea of roots. Both pathogenic and nonpathogenic
fungi germinated and hyphae elongated superficially on the
surface of root. Only pathogenic fungi caused root necrosis
at the inoculation site. Hyphae grew within the stem to
induce constriction or cracking of lower hypocotyls, then
causing wilting of the seedlings. Infection behavior of
genetically marked pathogenic and nonpathogenic F.
oxysporum could be successfully monitored after
inoculation of cotyledons of seedlings.
911 - Biological control of bluestain in logs using an
albino bluestain fungus
A. Uzunovic * & A. Byrne
Forintek Canada Corp., 2365 East Mall, Vancouver, B.C.,
Canada. - E-mail: adnan@van.forintek.ca
Bluestain causes significant economic losses to the
Canadian forest industry. We examined the feasibility of
using an albino bluestain strain (Cartapip TM , now renamed
Sylvanex TM ) of Ophiostoma pilferum to control bluestain in
lodgepole pine logs. Cartapip and four challenge bluestain
fungi were sprayed alone, and in sequence, on two types of
wounds artificially produced on pine billets. When
inoculated alone, Cartapip colonized fresh lodgepole pine
and did not cause stain. The challenge fungi alone caused
significant stain. However, when the challenge fungi were
applied 2 or 10 days after Cartapip, the stain was negligible
in most cases and Cartapip outcompeted the fungi. Field
work using commercial size logs was done in 2000 and
2001 in Alberta, Canada. Cartapip suspension was sprayed
on logs and the bluestain development quantified and
compared with logs sprayed only with water. Statistical
analysis of the data after 12-13 weeks of storage showed
that Cartapip significantly reduced the amount of bluestain.
After 6 weeks of summer storage in 2001, Cartapip-treated
logs remained almost spotless compared to the
considerable stain found on non-treated logs. After 13
weeks of storage there was some stain development in
Cartapip-treated logs but the amount was significantly less
than in non-treated logs. The product, and the concept of
using albino isolates to control stain, therefore have
potential for industrial use.
912 - Expression of fruit body color in Pleurotus spp.
hybrids derived from pairings of compatible
neohaplonts
G. Valencia del Toro 1* & H. Leal Lara 2
1 Department of Chemistry, UPIBI, IPN; Research Division,
FESI, UNAM;, ENEP Iztacala, Av de los Barriois S/N,
54090 Los Reyes Iztacala, Tlalnepantla, Estado de México,
Mexico. - 2 Department of Food Science and Biotechnology,
Faculty of Chemistry, National University of Mexico