Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
1147 - Comparative biochemical analysis of enzyme
electrophoretic spectra from mycorrhizal roots
R.C. Maximilian 1* , E.M. Carasan 1 , A. Brezeanu 1 & A.
Rosu 2
1
Institute of Biology, Spl.Independentei 296, 79651, P.O.
Box 56-53, Bucharest, Rumenia. -
2
Faculty of
Biotehnology, University of Agricultural Sciences,
Str.Marasti 59, 71331, Bucharest, Rumenia. - E-mail:
cmaxi@ibiol.ro
Metabolic changes induced by mycorrhizal colonization
can be evaluated by modifications appear in enzyme
activities. We have investigated the potential use of
electrophoretic analysis for detection the specific isozyme
that presents differences in metabolic pathway in maize
colonized roots. Staining protocols for esterases, alkaline
phosphatases (ALP) and malate dehydrogenases (MDH)
provided the enzymes for the mycorrhizas. We found
differences between spectra of these enzymes at various
time of cultivation. We used a starter inoculum of Glomus
mossae (SI) and a current granular inoculum of Glomus sp
(CGI). For esterases, the electrophoretic spectrum revealed
5 bands for mycorrhizal roots comparative with 3 bands of
non-mycorrhizal roots using SI. After 42 days of
colonization on the gel appeared 2 electrophoretic bands.
For MDH the electrophoretic spectrum showed 6 bands at
12, 34 days and 2 bands at 42 days of symbiosis. We found
no differences between electrophoretic spectra of SI and
CGI. We used also various concentrations of inocula. The
electrophoresis spectra emphasized the following: 9 bands
for SI 5% and 10 bands for SI 10% comparative with 8
bands for control and 9 bands for both concentrations 5%
and 10% CGI for esterases. 8 electrophoretic bands using
5% and 10% concentrations of SI and CGI, and also 8
bands at control for detection isozymes of MDH. 3
electrophoretic bands of isozymes of ALP were revealed
comparative 2 bands for control.
1148 - Early molecular communication among plant
and fungus: detection of specifically expressed genes
during pre-symbiotic interaction
M. Menotta 1* , A. Amicucci 1 , A.M. Gioacchini 2 , D. Sisti 3 &
V. Stocchi 1
1 Istituto di Chimica Biologica Giorgio Fornaini, Università
degli Studi di Urbino, Via Saffi 2 I 61029 Urbino (PU),
Italy. - 2 Istituto di Ricerca Attività Motoria Università degli
Studi di Urbino, Via Sasso I 61029 Urbino (PU), Italy. -
3 Istituto e Orto Botanico Università degli Studi di Urbino,
Via Bramante 28 I 61029 Urbino (PU), Italy. - E-mail:
mmenotta@uniurb.it
Tuber borchii Vittad. is an ascomycetous fungus which
forms ectomycorrhizae on the roots of angiosperms and
gymnosperms. After the achievement of this symbiotic
association, the mycelium can form the hypogeous
fruitbody, commonly known as truffle. Ectomycorrhizae
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Book of Abstracts
formation is a highly regulated process that is accompanied
by molecular reorganization of both partners during
symbiosis. An analogous molecular mechanism also takes
place during the pre-symbiotic phase, when the partners
exchange molecular signals, in order to take their stand and
prepare both organisms for symbiosis instauration. We
studied this latter genetic reorganization in T. borchii
during the interaction with its symbiotic plant Tilia
americana. For this purpose we set up a culture system
where the mycelium interacts with the plant, but avoiding
physical contact between the two organisms. By
suppressive subtractive hybridization, we identified several
specifically expressed genes. All selected clones were
further analysed by Northern blot hybridization comparing
transcript levels of control RNA (mycelium grown alone)
and tester RNA (mycelium grown in presence of T.
americana), both obtained from a tested in vitro
ectomycorrhizae synthesis system. The same analysis was
conducted on RNA of T. borchii extracted at different stage
of its life cycle. Some differentially expressed genes are
involved in nuclear rearrangement, while some others seem
to be involved in extra cellular signal transduction.
1149 - Molecular karyotype of Thraustochytrium
striatum Schneider
J.I. Mitchell & J. Slatter *
School of Biological Sciences, University of Portsmouth,
King Henry Building, King Henry I Street, Portsmouth
PO1 2DY, England, U.K.
The thraustochytrids comprise a group of marine protists
that are important ecologically and commercially. Strains
of thraustochytrids can produce commercially significant
quantities of docosahexaenoic acid (DHA), a medically
important long chain polyunsaturated fatty acid.
Ecologically, thraustochytrids have been identified as
important degradative organisms, breaking-down naturally
occurring recalcitrant carbon-containing polymers, and an
important food source for picoplankton. Despite the rising
importance of thraustochytrids, little is known about their
life cycle or their molecular biology. This study presents
preliminary findings on the genome of Thraustochytrium
striatum Schneider, a member of the marine protistan
group the thraustochytrids. Pulsed field gel electrophoresis
studies identified 18 presumptive chromosomes from the
zoospores and thalli of T. striatum. The sizes of these
molecules varied from 0.4 to 2 Mbp and gave a genome
size of 18.77 Mbp. The chromosome locations of the
D15/n-3 desaturase gene, 18S rRNA genes and thymidine
kinase gene were determined. Results indicated that there
were at least four copies of the desaturase gene on separate
chromosomes; multiple copies of the 18S rRNA gene
present on all chromosomes and two copies of the
thymidine kinase gene. The unusual gene distribution and
unequal distribution of chromosome bands suggests that
these organisms might be processing their chromosomes.