Book of Abstracts - Geyseco

P - Posters
fic responses and allows the establishment of relations between
some cell responses and environmental stress tolerance, i.e. osmotic
adjustment, proline accumulation or membrane transport
(Luttset al. JPP 149: 186-95, 1996; Kerkeb et al. PPlant 116: 37-
41, 2002; Yang et al. PC Rep 26: 229-35, 2007). We have further
developed this experimental system by the use of cell lines subjected
to dehydration stresses of different magnitude and selecting
those with high or low tolerance to compare their responses
to stress. Thus, we studied putative physiological and genomic
variations related to cryopreservation procedures (Moukadiri et
al. PPlant 105: 442-9, 1999), the pattern of endocytosis under
osmotic and saline stress (Bahaji et al. PCP 44: 1100-11, 2003),
and demonstrated the relationship between tolerance and ability
of ABA synthesis under stress (Perales et al. PPB 43: 786-92,
2005). More recently, we used transformed rice cell lines to study
the induction of a poliubiquitin promoter by dehydration stresses
(Perales et al JPP 165: 159-71, 2008) and, at present, we are investigating
the involvement of (plasmalemma and tonoplast) H +
pumps in NaCl tolerance mechanisms (Pons et al, MS in prep.).
Results from this investigation will be presented and discussed
in relation to previous research performed with this experimental
system.
P01-050: CHANGES IN FREE AND CONJUGATED ABS-
CISIC ACID (ABA AND ABAGE) CONCENTRATIONS IN
FIVE CULTIVARS OF HORDEUM VULGARE PLANTS
UNDER WATER STRESS CONDITIONS
Thameur, A. 1 - Ferchichi, A. 1 - López-Carbonell, M. 2
1
Institue Arid Zones, Medenine, Tunisie
2
University of Barcelona- Department of Plant Biology
Changes in endogenous abscisic acid (ABA) and its glucose ester
conjugate (ABAGE) as well as in proline content, water relations
and growth parameters in five barley genotypes (Ardhaoui,
Manel, Pakistan, Roho, Rihane) with different drought resistance
characteristics have been studied. The aim of this work was to
study the balance between free and conjugate ABA and how it
can affect the development of these plants grown under water
deficit conditions. Differences among the five genotypes lead to
changes in the pattern of growth and development. Water stress
led to a reduction in relative water content, as well as an increase
in proline and endogenous ABA and ABAGE concentrations in
all tested genotypes. The increase of proline ranged between
2-fold for var. Rihane and 1.3 fold for var. Manel. The lack of
water lead to increase in endogenous ABA concentrations between
5-fold for cv. Ardhaoui and 1.4-fold for var. Roho. Also
small increases in endogenous conjugated ABA in all genotypes,
except for cv. Ardhaoui, were observed. Nevertheless, the increases
in free ABA were more pronounced in tolerant cultivars
than in the less tolerant ones. Our results show that changes in
growth parameters were correlated with variations of endogenous
concentrations of ABA and ABAGE, and will contribute to
the knowledge of the involved mechanisms in drought adaptation
of Hordeum vulgare plants.
P01-051: LONG-TERM RESPONSES TO WATER STRESS
IN SELECTED CLONES OF EUCALYPTUS GLOBULUS L.
Granda, V. 1 * - de la Torre, C. 1 - Feito, I. 2 - Cuesta, C. 1 - Hernández,
B. 1 - Kidelman, A. 2 - Majada, J. 2 - Ordás, R.J. 1 - Rodriguez, A. 1
1
Departamento de Biología de Organismos y Sistemas, Área de
Fisiología Vegetal. Universidad de Oviedo
2
Área de Cultivos Hortofrutícolas y Forestales, Servicio Regional
de Investigación y Desarrollo Agroalimentario (SERIDA) ,
Asturias.
*Corresponding author, e-mail: biovgg@gmail.com
The response of juvenile forest crop plants to water stress is key
to the survival of forest populations. In this stage of development
plants are very sensitive to water stress; this in fact being the
major source of plant loss in commercial plantations. Therefore
early detection of tolerant genotypes/varieties using physiological
markers would be useful to avoid major loss during field establishment
of plantations.In order to understand the physiological
changes and adaptation occurring in juvenile plants of Eucalyptus
globulus L., selected clones were subjected to long-term stress
in controlled conditions. Half of the plants of every clone were
maintained at 90-100% of field water capacity, whereas the water
supply to the remainder was reduced; firstly to 40% of field capacity
(first sampling), and finally, until the death of the plant
(final sampling). Plants were monitored throughout the experiment
to detect changes in foliar area and growth. Hydrical, photosynthetic,
metabolic and other physiological measures were
also taken to compare the behavior of the different clones and
the establishment of physiological markers for water stress tolerant
clones.Acknowledgements. This work was supported by the
projects of Ministerio de Educación (AGL2006-13912-C02-01
and GEN2006-27791-C2-1E/VEG). V. Granda is funded by a
predoctoral grant by Ministerio de Educación y Ciencia (FPI
BES-2007-15663). The eucalyptus clones were provided by
ENCE group.
P01-052: TOMATO NHX ANTIPORTERS
Galvez, F.J. - Cagnac, O. - Abushamsiya, K. - Rodríguez Rosales,
M.P. - Venema, K.
EEZ-CSIC
Plant NHX antiporters can be subdivided in tonoplast Class I
proteins, with a suggested role in salt tolerance by Na + accumulation
in vacuoles, and Class II proteins. We previously determined
an endosomal localization of the Class II LeNHX2 protein
in plants and confirmed this expression pattern in yeast. We also
determined a predominantly K + /H + exchange reaction of the protein
in vitro. These data suggest that the salt tolerance phenotype
in over-expressing yeast does not rely strictly on vacuolar Na+
accumulation, which we confirmed in transgenic tomato.
We have identified several more tomato NHX isoforms. The
expression of the isoforms was induced more by salt stress in
salt tolerant tomato species as compared to salt-sensitive species,
confirming that NHX genes are determinants of salt tolerance. Of
these isoforms, Class I LeNHX4 shows a high expression level in
Fruit and Flower tissue, and could thus play an important role in
K + accumulation in these tissues, essential during flowering and
fruit development. Like LeNHX2, LeNHX4 confers salt, KCl
and Hygromycin resistance to yeast with a disruption in the yeast
ScNHX1 gene. The LeNHX4 protein has a tonoplast localization
in tomato plants, as is to be expected for a Class I NHX protein.
In yeast the majority of the fluorescence signal from GFP tagged
protein is found inside the vacuoles, and not in the membrane,
pointing to a degradation of the protein. This is also indicated
by SDS-PAGE electrophoresis, were the protein appeared as a
small band of the expected molecular weight and a large amount
of smaller molecular weight. As a consequence, we could so far
not determine the antiporter activity in vitro. New results regarding
function and functioning of the LeNHX4 protein will be
presented
P01-053: AGEING AND IRRADIANCE ENHANCE VITA-
MIN E CONTENT IN GREEN EDIBLE TISSUES FROM
CROP PLANTS
Garcia Plazaola, J.* - Lizarazo, K. - Fernández-Marín, B. - Becerril,
J.M.
Universidad del País Vasco
*Corresponding author, e-mail: joseignacio.garcia@ehu.es
Tocopherol (vitamin E) is an antioxidant essential in human nutrition.
Several approaches have aimed to enhance tocopherol
content in crops by the genetic modification of plants, a practice
that generates some social concern. As tocopherol accumulates
with leaf age in some wild plants and the antioxidant mechanisms
respond plastically to stress conditions, we hypothesize
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