15th International Conference on Arabidopsis Research - TAIR

T05-057
ARF-GTPases in plant pathogen interactions
Ulrike Unte(1, 2), Joachim Uhrig(1), Paul Schulze-Lefert(1), Volker Lipka(2)
1-Max-Planck-Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne,
Germany
2-ZMBP, Forschungsgruppe Pflanzenbiochemie, Auf der Morgenstelle 5, 72076 Tübingen,
Germany
Cell polarization induced by developmental stimuli is mechanistically based
on cytoskeleton rearrangements, targeted vesicle transport and secretion.
The same processes have recently also been demonstrated to be crucial
for plant defence against fungal intruders (Schmelzer, 2002; Collins et al.,
2003). Small GTPases of the ADP RYBOSYLATION FACTOR (ARF) family
are believed to be involved in vesicle coatomer formation, cargo loading,
transport and uncoating in many organisms, including plants. The Arabidopsis
genome harbours 19 ARF or ARF-like genes that have not been systematically
characterized so far. In this project we aim to assess the role of ARF
controlled vesicle traffic in plant pathogen interactions. To do so, a collection
of arf T-DNA insertion lines will be analyzed for aberrant pathogen interaction
phenotypes. In addition, transgenic Arabidopsis lines expressing ARF-GFP
fusion proteins were generated that allow tracing pathogen induced vesicle
dynamics in planta.
Schmelzer (2002) Trends in Plant Science 7(9): 411-415
Collins et al. (2003) Nature 425: 973-97
15 th <strong>International</strong> <strong>Conference</strong> on Arabidopsis Research 2004 · Berlin
T05-058
Identifying pathogen-induced changes in the plant
defense signaling network
Thierry Genoud(1), John Pufky(2), Patrick Bozo(1), Patrick Hurban(2), Jean-Pierre
Métraux(1)
1-University of Fribourg, Department of Biology, Unit Plant Biology, rte Gockel 3, 1700 Fribourg
2-Paradigm Genetics, Inc., 108 Alexander Drive, Bldg. 1A, P.O. Box 14528, Research Triangle
Park, NC 27709-4528
Three compounds play a central role in the transduction of signals generated
during pathogen attack: salicylic acid (SA), ethylene (ET), and jasmonic
acid (JA). We performed a global analysis of gene expression in Arabidopsis
submitted to exogenous treatment with SA, ET, and JA, as well as their combinations
(SA+JA, SA+ET, JA+ET, SA+JA+ET). Genes have been grouped
in regulons according to their expression profile. The resulting classes were
used to build a Boolean model of the signaling network activated by the
three hormones. The model has been inferred as minimal digital circuit and
is represented in the form of a single network for computer simulation. Data
mining was conducted to find transcription factors that undergo changes in
expression during interactions with virulent but not with avirulent pathogens.
A thorough analysis of these data reveals that some virulent bacteria manipulate
the expression of genes controlling morphological traits and/or genes
involved in salt and drought resistance. A new molecular strategy has been
implemented to counteract the modifications of the signaling/genetic network
induced by such pathogens.
T05 Interaction with the Environment 2 (Biotic)