Book of Abstracts - Geyseco

03 - S - Selected Abstracts for Oral Presentations
cules and transcriptional factors (TFs). In order to identify TFs
and gene networks involved in AR development in Populus trichocarpa,
we have carried out a series of genome-wide transcript
profilings during the development of AR.
Aintegumenta–like TFs (PtANTs) are dramatically upregulated
during primordium formation and root emergence, suggesting
a role for this TFs in AR formation. The differential expression
of PtANTs has been validated by qPCR. Poplar transgenic lines
over-expressing PtANT1 showed an increased capacity in AR
formation compared to the wild-type confirming the importance
of ANT TFs in AR development. The function of this gene in the
root formation will be discussed.
This research project is funded by the European project ENER-
GYPOPLAR, the Région Lorraine Research Council (Project
FORBOIS), and the French National Space Agency (CNES).
S07-001: COLD SHOCK DOMAIN PROTEIN GENES IN
THE EXTREMOPHYTE THELLUNGIELLA SALSUGI-
NEA: IDENTIFICATION AND DIFFERENTIAL EXPRES-
SION
Taranov, V. * - Berdnikova, M. - Nosov, A. - Galkin, A. - Babakov, A.
All-Russia Research Institute of Agricultural Biotechnology,
Russian Academy of Agricultural Sciences
*Corresponding author e-mail: v.taranov1@gmail.com
Four genes encoding cold shock domain (CSD) proteins have
been identified in salt cress [Thellungiella salsuginea (halophila),
an extremophyte currently recognized as a promising model
for studying stress tolerance]. The deduced proteins prove
highly homologous to those of Arabidopsis thaliana (up to 95%
identity) and are accordingly enumerated TsCSDP1--TsCSDP4;
after the N-proximal conserved CSD, they have respectively 6,
2, 7, and 2 zinc finger motifs evenly spaced by Gly-rich stretches.
Much lower similarity (~45%) is observed in the regions
upstream of TATA-box promoters of TsCSDP1 vs. AtCSP1, with
numerous distinctions in the sets of identifiable cis-regulatory
elements. Plasmid expression of TsCSDP1 (like AtCSP1/3) rescues
a coldsensitive csp-lacking mutant of E. coli, confirming
that the protein is functional. In leaves of salt cress plants under
normal conditions, the mRNA levels for the four TsCSDPs relate
as 10:27:1:31. Chilling to 4°C markedly alters the gene expression;
the 4-day dynamics are different for all four genes and
quite dissimilar from those reported for their Arabidopsis homologues
under comparable conditions. Thus, the much greater cold
hardiness of Thellungiella vs. Arabidopsis cannot be explained
by structural distinctions of its CSDPs, but rather may be due
to expedient regulation of their expression at low temperature.
S07-002: TRANSCRIPTOME ANALYSIS OF A M. TRUN-
CATULA SALT-ADAPTED GENOTYPE REVEALED AN
APETALA2- DEPENDENT PATHWAY ASSOCIATED TO
ROOT GROWTH UNDER SALT STRESS
Zahaf, O.¹* - Blanchet S.² - de Zélicourt, A.¹ - Alunni, B. - de
Lorenzo, L.4 - Imbeaud, S.5 - Ichanté, J.L.5 - Diet, A.¹ - Plet, J.¹ -
Badri, M.6 - Delacroix, H.4 - Frugier, F.¹ - Crespi, M.¹
¹ISV CNRS
²CEA
³IBP
4
Departamento de Microbiología y Parasitología, Universidad de
Sevilla
5
DNA MicroArray Platform and Centre de Génétique Moléculaire,
CNRS
6
Laboratoire des Interactions Légumineuses-Microorganismes
*Corresponding author e-mail: ons.zahaf@isv.cnrs-gif.fr
Evolutionary diversity can be driven by the interaction of plants
with different environments. Global molecular bases involved
in these ecological adaptations can be explored using genomic
tools. Legumes due to their capacity to establish symbiotic associations
are able to grow in nitrogen poor soils and are major
crops worldwide. As soil salinity is a major stress in legumes, we
compared the root transcriptomes of two M. truncatula genotypes
having contrasting responses to salt stress. The genotype TN1.11,
isolated from salty Tunisian soils, shows increased root growth
and symbiotic nodulation under salt stress when compared to the
reference model legume M. truncatula Jemalong A17. Genomic
analysis revealed specific gene clusters differentially regulated
by salt in the TN1.11 genotype. Among those, functional clustering
of regulatory pathways pointed to a link with auxin and,
accordingly, TN1.11 and A17 roots show a differential response
to this phytohormone. In addition, several transcription factors
(TFs) were differentially regulated between the two genotypes
and 6 TF genes were over-expressed in roots of the Jemalong
A17 genotype. Overexpression of an APETALA2-type transcription
factor, regulated by auxin and ABA, conferred a significant
increase in root growth under salt stress conditions. Hence, an
APETALA-2 pathway may play a critical role in the adaptation of
M. truncatula to saline soil environments.
S07-003: THE ARABIDOPSIS VACUOLAR ANION
TRANSPORTER, ATCLCC, IS INVOLVED IN THE RE-
GULATION OF STOMATAL MOVEMENTS AND SALT
TOLERANCE
Leonhardt, N.¹* - Kroniewicz, L.¹ - Jossier, M. - Dalmas, F.¹ - Le
thiec, D. - Barbier-Brygoo, H.² - Ephritikhine, G.² - Filleur, S. ²
¹CEA Cadarache-IBEB-LEMS
²CNRS
³INRA
*Corresponding author e-mail: nathalie.leonhardt@cea.fr
In plants, the main function of chloride transport is the net salt
accumulation responsible for the high cell turgor, involving the
creation and maintenance of a large vacuolar volume. In recent
years, various plant chloride channels and transporters have
been identified to be involved in specific function such as plant
nutrition, stomatal movement, and metal tolerance. In addition,
plant chloride channels play a predominant role in signal perception
and transduction since a large number of signals such
as pathogen-derived elicitor or hormones induce membrane depolarization
by stimulating anion efflux. In this study, we report
for the first time evidence that a member of the CLC family in
Arabidopsis thaliana, AtCLCc, plays an important role in stomatal
movements and salt tolerance. The AtCLCc protein is localized
to the tonoplast and AtCLCc is highly expressed in guard
cell and up-regulated by ABA and salt treatment in the whole
plant. Four T-DNA mutants in AtCLCc of two ecotypes (WS and
Col-0) are impaired in light-induced stomatal opening and ABAinduced
stomatal closing. These alterations are associated to
modifications in chloride content in guard cells. Concomitantly,
the clcc mutants exhibit a hypersensitive phenotype to salt stress
compared to wild-type. Our recent data on the role of AtCLCc in
salt tolerance and stomatal movement will be presented and the
importance of the chloride in these processes will be discussed.
S07-004: ROLE OF SOS1 IN POTASSIUM NUTRITION
Tello, C.* - de Luca, A. - Leidi, E.O. - Pardo, J.M.- Quintero, F.J.
Instituto de Recursos Naturales y Agrobiología de Sevilla
*Corresponding author e-mail: ctello@irnase.csic.es
Potassium nutrition is vital for plants, since this cation plays a
major role in plant growth, stomatal movements, enzyme activation
and osmoregulation. SOS1, a plasma membrane Na + /H +
antiporter which determines sodium homeostasis in saline conditions,
was first described as an essential locus for potassium
acquisition, as sos1 plants are unable to grow under low potassium
conditions. However, biochemical and transport assays in
SOS1 showed this protein is highly specific for Na + and doesn’t
transport K + or other monovalent cations. The role of SOS1 in
potassium uptake has been thus thought to be indirect, by preventing
inhibition of potassium channels, such as AKT1, by sodium.
This hypothesis was tested in our study by growing sos1 and akt1
S