Book of Abstracts - Geyseco

P - Posters
Betaine aldehyde dehydrogenase catalyzes the last step in the
synthesis of glycine betaine, a compatible solute accumulated by
many plants under various abiotic stresses. Although rice (Oryza
sativa L.) produces little glycine betaine, it was reported that rice
has two BADH genes (OsBADH1 and OsBADH2). To characterize
BADH enzyme of rice, we investigated the enzymatic properties
of recombinant OsBADH1 and OsBADH2 proteins. The
affinity of OsBADH2 for betaine aldehyde (Km of 231 μM)
was similar to that found in the BADH of other glycine betaineaccumulating
plants BADHs. However OsBADH1 showed an
extremely low affinity for betaine aldehyde with apparent Km
of 2590 μM. OsBADH1 and OsBADH2 catalyzed the oxidation
of ω-aminoaldehydes such as 4-aminobutyraldehyde,
3-aminopropionaldehyde, 4-N-trimethylaminobutyraldehyde,
and 3-N-trimethylaminopropionaldehyde. We also found
that both OsBADH proteins catalyzed the oxidation of acetaldehyde,
but OsBADH1 showed a higher V max
value for acetaldehyde
than OsBADH2 did. The accumulation of OsBADH1 and
OsBADH2 mRNA was decreased by submergence treatment and
recovered by re-aeration. Analysis of the subcellular localization
of OsBADH1 protein using green fluorescent protein indicated
that OsBADH1 was localized in peroxisomes. These results suggest
that OsBADHs show dehydrogenase activity for a range
of aldehydes, and that OsBADH1 has a possible physiological
function in the oxidation of acetaldehyde in rice plant peroxisomes.
P01-019: CHANGES IN THE SALICYLIC ACID PA-
THWAY IN WHEAT DURING LEAF RUST INFECTION
Szalai, G.* - Vida, G. - Janda, T.
Agricultural Research Institute of the Hungarian Academy of
Sciences
*Corresponding author, e-mail: szalaig@mail.mgki.hu
Salicylic acid (SA) has been known as a signal molecule in the
induction of defence mechanisms in plants for a long time. Exogenous
SA treatment may also induce the expression of pathogenesis
related proteins and has been shown to establish systemic
acquired resistance (SAR). Although SA is not considered to be
the signal translocated from the infection site, its accumulation
in distant tissues is essential for the induction of SAR. The aim
of the present work was to investigate the SA pathway and the
antioxidant response during leaf rust (Puccinia triticina) infection
in wheat plants. Near isogenic lines containing various leaf
rust resictance genes were used in the experiments. Plants were
grown under field and greenhouse conditions. The activity of
the antioxidant enzymes (glutathione-S-transferase, ascorbate
peroxidase, guaiacol peroxidase and catalase) increased after
infection. The level of ortho-hydroxy-cinnamic acid decreased
while the SA level increased in infected plants during the filed
experiments. Further experiments were made in greenhouse to
check the SA contents of various leaf levels after infection.
P01-020: LIGHT-DEPENDENT REGULATORY MECHA-
NISMS DURING COLD HARDENING IN WHEAT
Janda, T. 1 * - Majláth, I. 1 - Szalai, G. 1 - Soós, V. 1 - Sebestyén, E.
1
- Balázs, E. 1 - Vanková, R. 2 - Dobrev, P. 2 - Tari, I. 3 - Tandori, J. 1
1
Agricultural Research Institute of the Hungarian Academy of
Sciences
2
Institute of Experimental Botany of the Czech Academy of Sciences
3
University of Szeged
*Corresponding author, e-mail: jandat@mail.mgki.hu
Frost tolerance is the result of a wide range of physical and biochemical
processes that allow functioning at low temperatures.
Earlier results showed that frost hardening at low temperature
under low light conditions is much less effective than under normal
light conditions, and several processes, including the lipid,
polyamine, or salicylic acid metabolism and antioxidant activity,
may contribute to the light-induced freezing tolerance. The aim
of the present work was to discover what other changes in the
regulatory processes were responsible for the light-enhanced
freezing tolerance of wheat plants. Young winter and spring
wheat varieties were cold hardened under medium or low light
conditions. Microarray and RT-PCR analyses show that the light
intensity during the hardening period significantly affected the
expression of several genes, which may have role in the development
of frost hardiness of wheat plants. In order to get more
information about the regulatory processes during cold hardening
period, the changes in the levels of plant hormones were
also detected. While the abscisic acid level was lower in the 12-d
cold hardened plants than in the controls in both genotypes, independently
on the light intensity, changes in the plant growth
regulator cytokinins, signal transducer NO, ethylene precursor
ACC, and proline levels showed a strong light and variety dependencies.
Results suggest that temperature and light regulate the
development of frost hardiness in a complex way.
P01-021: A TRUNCATED FORM OF A Β-ADAPTIN CON-
FERS WEAK ACID RESISTANCE IN ARABIDOPSIS
Niñoles, R. 1 * - Alejandro, S. 2 - Fernández, J.A 3 - García-Sánchez,
M.J. 3 - Serrano, R. 1
1
IBMCP
2
Institute of Plant Biology University of Zurich
3
Universidad de Málaga
*Corresponding author, e-mail: renioro@ibmcp.upv.es
The homeostasis of intracellular pH is a fundamental activity of
living cells. In order to identify new components of the Arabidopsis
pH regulation system, an activation-tagged mutant seed
collection was screened using acetic acid as a selection agent.
The dominant mutant wat1-1D (Weak Acid Tolerant) is more resistant
to the acid stress generated by weak acids such as acetic,
propionic and sorbic acid, and this tolerance correlates with its
T-DNA insertion. Wat1-1D also shows lithium sensitivity and
ABA resistance during the germination stage. Measurements of
intracellular pH show that during acid stress mutant plants maintain
a higher cytosolic pH than the wild type, although their acetate
uptake is normal. The plasma membrane (PM) H+ATPase
activity and the PM potential are similar in the wild type and
the mutant in normal conditions. However, under acid stress the
wild type undergoes a higher PM hiperpolarization. The T-DNA
insertion of wat1-1D interrupts the At3g55480 gene, an adaptin
family protein, and causes an induction of the adjacent gene
At3g55470. Surprisingly it is the expression of a truncated form
of the adaptin and not the overexpression of At3g55470 what
causes the observed phenotypes, as transgenic plants expressing
the truncated adaptin or the antisense gene have similar phenotypes
to those of the wat1-1D mutant. In adition, a SAIL T-DNA
insertion mutant in At3g55480 also shows the same phenotypes.
Our working hypothesis is that under acid stress this mutant introduces
the excess of protons into the vacuole.
P01-022: THE ROLE OF PROLINE AND ITS METABO-
LISM ENZYMES IN CUCUMBER CELL CULTURES DU-
RING ACCLIMATION TO SALINITY
Naliwajski, M.* - Sklodowska, M.
Department of Plant Physiology and Biochemistry, University of
Lodz, Poland,
*Corresponding author, e-mail: nalmar@biol.uni.lodz.pl
Proline is one of the most widely distributed osmolytes and
acts as a reservoir of nitrogen and carbon source for post stress
growth, a stabilizer of the membranes and as a sink of energy to
regulate redox potential. The aim of this study was to investigate
the role of the activities of pyrroline-5-carboxylate: synthetase
(P5CS), reductase (P5CR), proline dehydrogenase (PDH) and
proline level in salinity adaptation in cell cultures. All biochemical
analyses were carried out in two cucumber cell cultures:
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