Book of Abstracts - Geyseco

P - Posters
Villalta, I.* - Pardo, J. M. - Quintero, F.J.
Instituto de Recursos Naturales y Agrobiología de Sevilla
*Corresponding author e-mail: ivillalta@irnase.csic.es
The Na+/H+ antiporter SOS1 is the most important regulator of
Na+ homeostasis in Arabidopsis thaliana by controlling net Na+
uptake and translocation from roots to shoots. SOS1 activity is
regulated through phosphorylation by the protein kinase complex
SOS2-SOS3. SOS2 is a Ser-Thr protein kinase belonging to the
SNF1-related kinase (SnRK) family (also known as SnRK3.11
and CIPK24). SOS3 is a myristoylated Ca2+ sensor belonging
to the family of calcineurin B-like (CBL) protein. Recently the
PYR/PYL (Pyrabactin resistance/Pyrabactin resistance-like protein)
family of abcisic acid receptors have been shown to interact
with the type 2C protein phosphatases (PP2C) in an ABA
dependent manner. ABA-bound PYR/PYLs are inhibitors of the
PP2Cs activity. PP2Cs counteract ABA signalling by interacting,
dephosphorylating and inhibiting the SnRK2 kinases, which are
positive regulators of the pathway. Initial studies of interactions
between SOS1, SOS2 and several PP2Cs (PP2CA, PP2CB,
ABI1, ABI2, HAB1 and HAB2) indicate that SOS2 interacts
with PP2CA and ABI1, suggesting a regulatory role of PP2Cs
in the activity of SOS2 and, in turn, the Na+ transporter SOS1.
Since PP2Cs also interact with the SnRK3 member CIPK23,
which regulates K+ uptake through channel AKT1, the PP2C
family constitute a common link for the coordinate regulation of
ion transport processes mediated by SnRK3 and ABA signalling
by the SnRK2 kinases in the salt stress response.
P07-027: THELLUNGIELLA SALSUGINEA SHOWS HIG-
HER SALT TOLERANCE THAN ARABIDOPSIS THA-
LIANA AT THE CELLULAR LEVEL
Nosov, A. 1 * - Taranov, V. 1 - Baranova, E. 1 - Shugaev, A. 1 - deBoer,
A. 2 - Babakov, A. 1
1
Russian Academy of Agricultural Sciences
2
Faculty of Earth and Life Science Vrije Universiteit, Amsterdam,
The Netherlands
*Corresponding author e-mail: alex_n@ippras.ru
Thellungiella salsuginea (Ts) is a close relative of Arabidopsis.
thaliana (At) and displays high tolerance to harsh environments
including extreme salinity. It is commonly accepted that restriction
of Na+ influx into roots of Ts is an important mechanism
of salt tolerance in this plant. Ts leaves accumulate proline under
salinity, what means that leaf cells respond to elevated Na+
around the roots. This raises the question whether Ts tolerates salt
stress at the cellular level? Stable cell-suspension cultures from
calli generated from mature leaves of Ts ecotype Yakutsk and At
ecotype Columbia plants were established. Both cell suspensions
were grown in SH medium with equal inoculums and growth
conditions. Growth indices of At and Ts cell cultures were reduced
by 50% at 75 mM and 200 mM of NaCl, respectively. After
two-week-long salinity (100 mM) the respiration (KCN sensitive)
and TTC reduction were doubled in Ts cells, and the reverse
situation was measured in At cells. Moreover, two-fold higher
Na+ and proline concentrations were measured in Ts as compared
to At cells, along with the detection of increased vacuolar
volume and energized mitochondria structure in Ts cells. Thus,
Ts can adapt to and tolerate salinity at the whole plant and the
cellular level as well.
P07-028: METALLOTHIONEIN PARTICIPATION IN CO-
PPER AND ZINC DETOXIFICATION IN PLANTS
Volkov, K.* - VlV Kuznetsov - Ivanova, E.M. - Grinin, A.L. - Kholodova,
V.P.
IPP RAS
*Corresponding author e-mail: volkov_ks@mail.ru
Metallothionein (MT) participation in Cu and Zn excess detoxification
was investigated in Mesembryanthemum crystallinum,
Brassica napus and B. juncea. Expression of genes McMT2,
McМТ2a, BnМТ2, BjMT2 was evaluated with RT-PCR technique
using 18S RNA as the control. The prolonged action of
HM excess (7-10 days) increased MT mRNA levels compare to
control in leaves of all plants studied. Maximal values - 3-fold
higher than in the control variant - were obtained in leaves of
M.crystallinum plants under 50 M CuSO4, ZnSO4 (500 M) increased
gene McМТ2 expression not more than 1,5 times. Detailed
dynamic of HM effect to gene activation was followed for
rape plants. Significant activation of BnМТ2 was registered in
24 hours of HM action, later the effect was enhanced and maintained
to the level exceeding 5-times the control variant during
5-7 days then mRNA content dropped almost to the control level.
In distinction to BnМТ2, activation of BjMT2В expression
started later but retained longed in leaves of rape plants. It was
determined that sum mRNA content of the two genes investigated
correlated much stronger to the rates of Cu accumulation
than to its total content in leaves. It may witness that the role of
MT in HM detoxification is limited to HM active center blockage
until they were in cytoplasm, in the zone of an active metabolism.
After HM sequestration for prolonged storage in vacuole or apoplast,
phytochelatins seems to serve as HM chelators. The conclusion
was supported by increased activation by Cu and Zn of
PCS, gene encoding phytochelatinsynthase during the later stage
of B. napus adaptation to HM excess. The work was partially
supported by the RFBR and by the Presidium of RAS program
(Cell and Molecular Biology).
P07-029: SCREENING FOR DROUGHT RESISTANCE IN
AN OAT GERMOPLASM COLLECTION.
Sanchez-Martín, J.* - Rubiales,D. - Prats, E.
Susteinable Agriculture Institute
*Corresponding author e-mail: javiersanchez84@ias.csic.es
Drought is the main abiotic stress on cereal yield. To date cereal
breeding has mainly based on empirical selection for yield
per se. However this is far from being optimal, since yield is
characterized by a low heritability and a high genotype x environment
interaction. The sought of new sources of resistance,
as well as dissecting the complex resistance traits into different
components, highly heritable, easy to measure and repeatable is
crucial to improve breeding for drought resistance To this aim,
an oat germplasm collection consisting on 141 accessions of A.
sativa and A. byzantina together with 32 oat cultivars (A. sativa)
was screened for drought tolerance. A visual scale of symptoms
able to discriminate among genotypes was set up in seedlings,
under controlled conditions and along a treatment of progressive
drought. According to this evaluation, 11 genotypes were
classified as highly resistant. In these ones together with three
susceptible controls several physiological traits associated with
resistance were assessed to determine which parameters better
reflected the resistance observed. Relative water content (RWC)
and cell membrane stability (CMS) was measured at 0, 6, 9, 12,
15 and 18 days after withdrawing the water. CMS at a similar
and low RWC reflected better the plant symptoms that RWC
alone. In addition, we determined daily the stomatal response to
drought stress. Unlike resistant genotypes, the susceptible ones
were not able to maintain the circadian rhythm from the sixth day
following drought and kept conductance at levels similar to the
dark period. In several genotypes, this stomatal closure lead to
photo inhibition and oxidative damage such as lipid peroxidation
that later correlated with burned and rolled tip leaves
P07-030: CHARACTERIZATION OF P RESPONSIVE GE-
NES IN RELATION TO ROOT HAIR GROWTH
Bremer, M.*
Leibniz Universität Hannover
*Corresponding author e-mail: melanie-bremer@web.de
web.de Enhanced P efficiency hab been attributed to the forma-
P