organisation - the Instituto Gulbenkian de Ciência

PLANT
MOLECULAR BIOLOGY
Paula Duque Principal Investigator
PhD in Physiology and Biochemistry, Universidade de Lisboa, 1998
Postdoctoral Fellow, The Rockefeller University, New York, USA
Postdoctoral Associate, The Rockefeller University, New York, USA
Adjunct Assistant Professor, Queens College, City University of New York, USA
Principal Investigator at the IGC since 2006
The Plant Molecular Biology group uses Arabidopsis thaliana as a model system
to investigate how plants perceive and respond to environmental signals and
endogenous developmental cues at the molecular level. In particular, we focus
on the role of pre-mRNA splicing in the regulation of gene expression. The versatility
of this mode of regulation suggests that it is likely to play an important
contribution in ensuring the developmental plasticity and stress tolerance that
are essential for plant survival. Another major line of work in the lab is examining
the role of Major Facilitator Superfamily membrane transporters in plant
tolerance to abiotic stresses.
THE FUNCTIONAL SIGNIFICANCE OF ALTERNATIVE SPLICING IN ARABIDOPSIS
Alternative splicing is a key post-transcriptional mechanism for expanding proteomic
diversity and regulating gene expression in higher eukaryotes, with its
prevalence in many genomes pointing to crucial roles in biological processes.
In plants, stress-associated genes are particularly prone to alternative splicing,
which is also markedly affected by a wide variety of abiotic stresses.
In support of a functional role for alternative splicing in plant stress responses,
SR proteins, which are widely recognised as the major modulators of alternative
splicing, are stress-regulated at the transcriptional, post-transciptional and
translational levels in plants, indicating that these splicing factors may act as
central coordinators of responses to environmental changes. This project aims
at investigating the potential in vivo stress roles of plant-specific SR proteins.
GROUP MEMBERS
Estelle Remy (Post-doc)
Raquel Carvalho (PhD Student)
Sofia Carvalho (PhD Student)
Rita Batista (Trainee, left in August)
Carolina Feijão (Trainee, started in December)
COLLABORATORS
Ji He (The Samuel Roberts Noble Foundation, USA)
John Brown (The James Hutton Institute, UK)
Anthony Kinney (Dupont, USA)
Elena Baena-González (IGC, Portugal)
Isabel Sá-Correia (Instituto Superior Técnico, Portugal)
FUNDING
Fundação para a Ciência e a Tecnologia (FCT), Portugal
PUBLIC ENGAGEMENT IN SCIENCE
Public Talk, Centro Ciência Viva de Bragança, Portugal, June
Functional analysis of two Arabidopsis SR genes has revealed roles in the regulation
of sugar signalling and osmotic/salt stress responses during the early
stages of plant development, via modulation of the abscisic acid (ABA) stress
signalling pathway. The identification of endogenous targets of these splicing
factors is uncovering the first mechanistic links between SR protein function
and plant stress tolerance. We have started preparing two manuscripts reporting
these findings.
ROLE OF PLANT MAJOR FACILITATOR SUPERFAMILY TRANSPORTERS
IN ABIOTIC STRESS TOLERANCE
One way by which a living cell can achieve multiple drug resistance (MDR) is
by actively extruding toxic compounds via membrane pumps that catalyse
the efflux of a broad range of chemically distinct substrates. In Saccharomyces
cerevisiae, TPO1, a plasma membrane MDR transporter belonging to the
Major Facilitator Superfamily (MFS), determines the resistance to one of the
most widely used herbicides worldwide, 2,4-dichlorophenoxyacetic acid (2,4-D)
and to other xenobiotic compounds, presumably via active direct extrusion
from the yeast cell. Based on the role played by this MFS transporter in yeast
adaptation to toxic compounds, and in view of the substantial conservation of
molecular pathways among eukaryotic organisms, we are collaborating with the
Instituto de Biotecnologia e Bioengenharia at Instituto Superior Técnico with
the main goal of evaluating the role played by Arabidopsis thaliana MFS transporters
in 2,4-D resistance in particular and MDR in general.
The Arabidopsis sr45-1 mutant is hypersensitive to glucose during early seedling
development.
Using reverse genetics, we have found that three Arabidopsis MFS genes encoding
transporters sharing homology with the yeast TPO1 positively regulate
different aspects of abiotic stress response in plants, such as drought tolerance
(Remy et al., submitted) phosphate uptake during phosphorus starvation (Remy
et al., submitted) and resistance to elevated zinc levels in the soil (Remy et al.,
in prep.).
The ZIF2 MFS transporter conferring zinc resistance is specifically expressed in the
cortex and endodermis of the Arabidopsis root.
IGC ANNUAL REPORT ‘11
RESEARCH GROUPS
36