Book of Abstracts - Geyseco

P - Posters
Many plants accumulate triacylglycerols (TAG) in their seeds
and fruits as lipid reserves. In our laboratory we are studying the
sunflower (Helianthus annuus L.), whose oil has especial value
for the food industry. However, the distribution of fatty acids in
its different TAG species does not have the required best technological
features.
In the present work we isolated, cloned and sequenced cDNAs
coding for two isoforms of LPAAT (HaLPAAT1 y HaLPAAT2)
as well as three isoforms of DAGAT (HaDAGAT1A, HaDA-
GAT1B y HaDAGAT2), enzymes involved in final steps of TAG
biosynthesis.
The expression levels of these genes in vegetative tissues and
seeds were examined by Q‐PCR. All the studied acyltransferases
are expressed ubiquitously, with differences in expression levels.
The levels in vegetative tissues appear to be constant for each
enzyme, with higher values for HaDAGAT2, however, that trend
is broken in developing seeds by the appearance of peaks of expression
at 12-15 days after flowering. This particular expression
pattern is according to the oil accumulation period in seeds from
the third week after flowering, suggesting a possible transcriptional
regulation of these acyltransferases during the seed development,
which HaDAGAT2 seems to have an important role due to
his highest expression levels.
P13-010: AN OVERVIEW OF THE CARBON METABO-
LISM ACTORS THAT CONDITION THE SURVIVAL OF
THE PARASITIC PLANT: PHELIPANCHE RAMOSA
Péron, T. 1 * - Pouvreau, J.B. 1 - Draie, R. 2 - Véronési, C. 1 - Thoiron,
S. 1 - Delavault, P. 1 - Simier, P. 1
1
Laboratoire de Biologie et Pathologie Végétales (LBPV), IFR
149 Qualité et Santé du Végétal (QUASAV)
2
Faculty of Agronomy, Tishreen University, Lattakia, Syria
*Corresponding author, e-mail: thomas.peron@etu.univ-nantes.fr
Some broomrapes are harmful parasitic plants. They attach to the
roots of the host plant establish vascular connections and then
grow at the expense of the host plant’s resources. The absence
of chlorophyll in broomrape explains that it needs host-derived
sucrose for growth. As a consequence, sucrose utilization is essential
to entertain the sink strength and the development of the
parasite. Nonetheless information on this topic remains poor. Our
work shows at cellular and molecular levels the relative implication
and the possible cross-talk between the key components
of sucrose metabolism, including: invertase, sucrose synthase
and sucrose transporters. The analyses were carried out on both
broomrapes growing rapidly on a susceptible host genotype and
broomrapes growing slowly on a tolerant host genotype. The data
give some insights on the sink strength regulation in parasite and
on the mechanisms of host tolerance which induce deregulation
in broomrape growth.
P13-011: ANTIOXIDANT COMPOUNDS IN GREEN AND
RED VARIETIES OF LETTUCE (LACTUCA SATIVA L.)
Baslam, M.* - Morales, F. - Goicoechea, N.
University of Navarra
*Corresponding author, e-mail: bmarouane@alumni.unav.es
Lettuce is a major crop within the European Union and exhibits
healthy properties due to its large supply of antioxidant compounds,
mainly vitamin C, carotenoids and polyphenols. The
beneficial effect of lettuce on both lipid metabolism and tissue
oxidation could improve protection against cardiovascular diseases.
Our objective was to study the levels of some antioxidants
–carotenoids, phenolics, vitamin C and anthocyanines- and their
distribution between the outer and the inner leaves of three varieties
of lettuce consumed as salads – the green varieties Cogollos
de Tudela and Batavia and the red variety Maravilla - Results
showed that antioxidant compounds differed between the three
lettuce varieties and, except for the higher amount of anthocyanins
in the red variety, no relationship was found between the
type and/or the amount of every antioxidant and the classification
of each variety as “green” or “red”. While the highest levels
of carotenoids were detected in Cogollos de Tudela, the greatest
amounts of soluble phenolics and vitamin C were measured in
Batavia and Maravilla. In addition, within each variety the content
of antioxidant compounds differed between the internal and
the external leaves. The inner leaves had greater levels of anthocyanines,
vitamin C and soluble phenolics than the outer leaves
in Cogollos de Tudela, Batavia and Maravilla, respectively. In
contrast, the highest contents of carotenoids and anthocyanins
in Batavia and Maravilla were detected in the external leaves.
The distribution of antioxidant compounds between the outer and
inner leaves of each variety should be taken into account when
consumed in the diet or when used as food crop for the called
”Fourth Range” of vegetables.
P13-012: SUBCELLULAR COMPARTMENTATION OF
PRIMARY METABOLISM IN ARABIDOPSIS THALIANA
LEAVES – FOLLOWING THE ROUTE OF NEWLY
FIXED CARBON
Vosloh, D.* - Arrivault, S. - Feil, R. - Szecowka, M. - Fernie, A.
- Lunn, J. - Stitt, M.
Max-Planck-Institute of Molecular Plant Physiology
*Corresponding author, e-mail: vosloh@mpimp-golm.mpg.de
Metabolism in plant cells is highly compartmented, with many
pathways involving reactions in more than one compartment. For
example, during photosynthesis in leaf mesophyll cells, carbon
fixation and starch synthesis take place in the chloroplast, whereas
sucrose is synthesized in the cytosol. Therefore, knowledge
of compartmentation is essential for a proper understanding of
how plant metabolism is regulated. Classical fractionation methods
such as sucrose density gradient centrifugation can be used
for enzyme localization, but the separation of organelles by these
methods is generally too slow compared to the very short turnover
times of pathway intermediates to provide useful information
about the distribution of metabolites. To circumvent this problem
we fractionate the cells under non-aqueous conditions, whereby
the metabolic state is frozen at the time of harvest and held in
stasis throughout the fractionation procedure. After analysing the
distribution of marker enzymes, metabolites are measured using
liquid or gas chromatography linked to tandem or single mass
spectrometry, respectively. The combination of non-aqueous
fractionation and sensitive mass spectrometry techniques (LC-
MS/MS, GC-MS) allows us to determine the intracellular distribution
of most photosynthetic intermediates and products. We
also use LC-MS/MS and GC-MS to follow the labelling patterns
of intermediates after pulse labelling with 13CO2. By combining
all these data we can calculate the size and turnover times of the
chloroplastic and cytosolic metabolite pools and determine the
fluxes through the main photosynthetic pathways, providing an
unprecedented level of understanding of photosynthetic carbon
metabolism in leaves.
P13-013: VACUOLAR MONOSACCHARIDE IS CRITI-
CAL FOR PLANT DEVELOPMENT AND SUGAR SEN-
SING.
Neuhaus, E.*
Technische Universität Kaiserslautern
*Corresponding author, e-mail: neuhaus@rhrk.uni-kl.de
The vacuole represents the largest plant organelle and can occupy
more than 90 % cell volume. We identified several solute carriers
in the vacuolar membrane, e.g. a first malate carrier (Emmerlich
et al. 2003) and a first glucose transporter (TMT; Wormit et al.
2006). Arabidopsis knock out mutants lacking all three TMT proteins
show difficulties to accumulate monosaccharides upon cold
stress. Interestingly, TMT overexpressor lines exhibit increased
vacuolar monosaccharide levels and show substantially altered
sugar signaling. These mutants also show altered growth pattern
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