Download Reactive oxygen species (ROS) and defence response in

Reactive oxygen species (ROS) and defence
response in plants
Group leader: Miguel Angel Torres
Study of function of the Reactive Oxygen Species (ROS) produced
by the NADPH oxidase in response to pathogens and other
responses to the environment in Arabidopsis.
The goal is to decipher, using functional genomics tools, the
functions of the plant NADPH oxidase gene family. Different
members of the rboh (respiratory burst oxidase homologues)
family, components of the
plant NADPH oxidase,
control production of ROS
during defense and other
responses.
We
are
performing this research in
Arabidopsis,
model
organism for studies in
plants,
where
many
genomic tools are available.
We intend to further the
identification of the factors
that
regulate
Atrboh
function, as well as putative
Production of ROS and cell death in response to different pathogens.
targets or mediators of
Detection of H2O2 by diaminobenzidine stain (top) and cell death
monitored by trypan blue stain (bottom) in Arabidopsis leaves infected
ROS-dependent signaling.
with different pathogens.
Relevant results
My research work during 2004-2006 has been carried out at the
University of North Carolina, at Jeff Dangl’s laboratory,. There,
we pioneered studies in the field of production of reactive oxygen
species in plants, particularly in the plant-pathogen interactions,
and we made important contribution to dissect the NADPH oxidase
function in plants, that I intend to continue now with my own
group.
Our previous work provided genetic evidence that the plant
NADPH oxidase is responsible for the apoplastic ROS produced
following pathogen recognition (Torres et al., 2002). This finding
solved a mystery set into motion by Doke’s work nearly 20 years
ago. Additional studies confirmed and generalized our findings
(see Torres and Dangl, 2005). We also attributed clear
developmental and cell biological functions to several members of
the Atrboh gene family. We have collaborated with experts
studying those processes to further dissect the function of ROS in
stomata closure and root hair development. (Kwak et al., 2003).
(Foreman et al., 2003). Interestingly, both works indicate that
NADPH oxidase-derived ROS can control processes by regulating
the activation of Ca2+ channels.
During this latest period, we furthered these
studies and demonstrated that pathogen-induced,
NADPH
oxidase-derived
ROS
regulate
differentially pathogen induced cell death
depending on the interaction. Whereas Rbohderived ROS are positive regulators of the HR
induced by an avirulent bacteria, they are
negative regulators of the cell death after an
The Arabidopsis NAPDH oxidase AtrbohD is
avirulent oomycete (Torres et al., 2002). In
responsible for the production of most ROS
addition Rboh-derived ROS are negative
in response to pathogens. DAB stain of 4
regulators of the unrestricted cell death that
weeks old leaves from different genotypes.
surrounds the initial HR in the lesion mimic
mutant lsd1 (Torres et al., 2005). These data demonstrated that
ROS derived from Atrboh-containing NADPH oxidases are not
cellular killers, but rather function as signaling molecules to
protect cells from cell death. Interestingly, whereas NADPH
oxidase-derived ROS and SA were proposed to act synergistically
driving the HR, both signals antagonize in the regulation of cell
death expansion at the margins of the HR lesions in lsd1. This
underscores how ROS can mediate different functions in different
cellular compartments and spatial context, and in relation to other
regulatory signals.
Recent Publications
Torres, M. A., et al. (2006) Plant Physiol 141, 373-378
Torres, M. A., et al. (2005) Nat Genet 37, 1130-1134
Torres, M. A., and Dangl, J. L. (2005) Curr Opin Plant Biol 8,
397-.