Book of Abstracts - Geyseco

P17
Plant Microbe
Interaction
P17-001: INFLUENCE OF MYCORRHIZAL FUNGI ON
GROWTH, CHLOROPHYLL CONTENT AND K AND MG
UPTAKE IN MAIZE UNDER DIFFERENT CONCENTRA-
TIONS OF POTASSIUM AND MAGNESIUM
Khanpour Ardestani, N.* - Reyhaneh, H. - Hassan Z.M.
Tarbiat Modares University
*Corresponding author, e-mail: n.khanpour@modares.ac.ir
Mycorrhizal fungi have a positive effect on growth and nutrition
of host plant. In this research Influence of Vesicular-Arbuscular
Mycorrhiza) VAM) on Growth, chlorophyll Content and K and
Mg Uptake in Maize in pot culture were studied.This experiment
was performed using natural soil containing spores of Glomus
spp. Mycorrhizal spores were exposed to 4 concentrations of K
solution, i. e. 240 (soil K content), 360 and 480 mg/L and 3 concentrations
of Mg, i.e. 4.8 (soil Mg content), 7.2 and 9.6 meq/L
concurrently. Plants were watered every 4 days for 16 days with
50 ml distilled water. A pot with sterilized soil was used as negative
control. For study of mycorrhizal colonization, very thin
longitudinal sections of plant roots (>1mm in diam.) were prepared
manually and were stained with lactophenol-cottonblue.
Mycorrhizal percentage was determined by the grid-line intersect
method. Sampling from root and shoot of maize had done. The
results have shown that mycorrhizal plant significantly had higher
dry and fresh weight and chlorophyll content than non-mycorrhizal
control plants (p £ 0.05). The concentrations 7.2 meq/L
of Magnesium and 360 mg/L of Potassium concurrently with 7.2
meq/L of Mg had better effect on morphological characters (Dry
and fresh weight of root and shoot). Mycorrhizal colonization
increased Mg uptake but decreased K uptake.
Keywords: Magnesium and Potassium uptake, Growth, maize,
Vesicular- Arbuscular Mycorrhiza ( VAM )
P17-002: CHARACTERIZATION OF AN ALTERNARIA
ALTERNATA EXTRACELLULAR LACCASE INVOLVED
IN THE PATHOGENESIS OF CITRUS FRUIT
Del Río, J.* - Díaz, L. - Ortuño, A. - Pérez-Gilabert, M.
Universidad de Murcia
*Corresponding author, e-mail: jadelrio@um.es
Fungi of the genus Alternaria are respondible for substantial preharvest
losses in Citrus. The susceptibility to Alternaria alternata
depends on the Citrus species (1, 2). In this communication, an
extracellular laccase from A. alternata, apparently involved in
the infection process in several Citrus species, is described for
the first time. The enzyme was isolated from the culture medium
of this fungus and characterized using ABTS as substrate. It exhibits
a pH optimum of 3.5 and a Km of 1.9 mM. The effect
of temperature was also studied. The enzyme is active between
15 and 45ºC, the optimum temperature being around 35ºC. The
thermostability of the enzyme at its optimum temperature is very
low and 50% of the activity is lost in 35 min. Different inhibitor
agents were also studied, with L-cysteine and caffeic acid
found to be the most effective. Study of the substrate specificity
of this enzyme reveals that Citrus flavonoids are substrates of
A.alternata laccase. These results suggest that the enzyme could
P - Posters
be involved in the degradation of flavonoids, observed in fruits
infected with A. alternata. On the other hand, an increase of laccase
activity was observed in the presence of Citrus fruit extracts.
The possibility of considering laccase as a target to control the
infection by Alternaria is also discussed.
(1)Peever et al. (2000). Phytopathology.90, 407-414.
(2) Ortuño et al. (2008). Physiological and Molecular Plant Pathology.
72, 162-166.
Acknowledgments: This work was funded by the Projects
AGR/11621/08 of the Consejería de Agricultura, Agua y Medio
Ambiente de la Región de Murcia, Spain, and 08676/PI/08 of the
Consejería de Educación, Ciencia e Investigación de la Región
de Murcia-Fundación Séneca, Spain.
P17-003: HOMOLOGY-DRIVEN PROTEOMICS RE-
VEALS THE PROTEOME COMPLEXITY OF RESTING
SPORES OF THE CLUBROOT PATHOGEN PLASMO-
DIOPHORA
Ludwig-Müller, J. 1 * - Knaust, A. 2 - Shevchenko, A. 2
1
Technische Universität Dresden
2
MPI-CBG, Dresden
*Corresponding author, e-mail: Jutta.Ludwig-Mueller@tu-dresden.de
The clubroot disease is one of the most damaging diseases of
the Brassicaceae, which is caused by the protist Plasmodiophora
brassica. The study of the pathogen is hampered due to its obligate
biotrophic nature and the organism does not belong unequivocally
into a systematic group, even within the protists. P. brassicae
forms a group with three other plasmodiophorids whose genomes
are uncharacterized. Sequence databases contain 50 proteins and
96 ESTs of P. brassicae having low homology to other organisms.
We employed a proteomics approach to characterize several stages
of the life cycle of the pathogen outside and inside the host
plant Arabidopsis thaliana. Protein extracts of the pathogen were
separated on 1D SDS PAGE and the entire lane was cut into 9
slices that were separately digested with trypsin and analyzed
by LC-MS/MS. Proteins were identified by MASCOT searches,
while unmathed spectra were interpreted de novo and candidate
sequences submitted to homology-based identifications by MS
BLAST. We demonstrated that resting spores are not dormant,
but contain many proteins, of which 20 proteins were identified
with 120 unique peptides matched: 2 hits were P. brassicae
ORFs, 2 hits were the known P. brassicae proteins polyubiquitins
1 and 2, as well as 16 cross-species hits to proteins from other
pathogens and fungi. Among these were house-keeping proteins
as well as proteins for which a function in the life cycle can be
predicted. In conclusion, we were able to extract protein material
from resting spores and identify a number of proteins with no
genome of the pathogen available. Homology driven proteomics
altogether matched more peptides, validated cross-species MAS-
COT hits and provided new protein identifications.
P17-004: THE STUDY OF BIOCHEMICAL FEATURES OF
PATHOGEN-DEPENDENT ENZYMES (CA2+ - ATPASE)
UNDER INFECTION OF POTATO WITH FUSARIUM SO-
LANI
Manadilova, A.* - Tuleeva, G.T. - Duzgenbekova, B.
Institute of Molecular Biology and Biochemistry
*Corresponding author, e-mail: man_Alija@mail.ru
The important part of the defensive response at infection is the
activation of pathogene-dependent enzymes, including ATPase.
The plasma membrane fractions,have been isolated from the potato
suspension cells (Tamasha, Santa) different in their resistance
to the Fusarium Solani. Main structure-functional parameters
of Ca2+ ATPase of potato under normal and infected conditions
were studied; the optimums for ion concentration of Ca2+, pH
incubation medium and kinetic characteristics were determined.
The influence of Fusarium Solani metabolites over the activity of
enzyme was studied. After the infection by the fungus cultural fil-
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