15th International Conference on Arabidopsis Research - TAIR

T05-031
Arabidopsis, a model plant to study the molecular
bases of biological control
Feng Dong Xin(1), Olivier Jocelyne(1), Deslandes Laurent(1), Hu Jian(1), Trigalet
Danièle(1), Trigalet André(1), Marco Yves(1)
1-Laboratoire des Interactions plantes-Microorganismes, CNS/INRA, Chemin de Borde Rouge,
BP27, Castanet-Tolosan 31326, France
Bacterial wilt caused by the phytopathogenic bacterium, Ralstonia solanacearum
is one of the most important plant diseases world-wide. Methods to
control the disease are limited. Biological control, based upon the preinoculation
of potato or tomato by an hrp- strain followed by the inoculation
of a virulent strain leads to a significant reduction of wilt symptoms under
controlled conditions. Molecular mechanisms are however poorly understood.
We have shown that Arabidopsis can be used as a model plant to study these
mechanisms. Our results indicate that the increased resistance of hrp- -protected
plants is not caused by physical competition between the virulent and
avirulent strains and that living bacteria are required to obtain full protection.
Several lines of evidence that will be presented suggest that the protection
caused by the preinoculation with an hrp- mutant is related neither to systemic
acquired resistance, nor to induced systemic resistance. The understanding
of mechanisms controlling hrp--induced protection may render possible
a rational development of biological control for agriculture.
T05 Interaction with the Environment 2 (Biotic)
T05-032
Sulfate-based performance of Arabidopsis thaliana in
response to fungal infection
Cordula Kruse(1), Ricarda Jost(2), Rüdiger Hell(1)
1-Heidelberg Institute of Plant Science, University of Heidelberg, 69120 Heidelberg, Germany
2-Research School of Biological Sciences, Australian National University, Canberra AC T 2601
The link of sulfur metabolism with resistance towards biotic and abiotic stress
factors has first been observed in agricultural sciences. An optimal support of
crop plants like rape with sulfate leads to an increase of resistance especially
towards compatible fungi. This form of resistance is a quantitative effect due
to nutritional conditions which is clearly separated from the gene-for-gene
model, systemic acquired or induced resistance by rhizospheric bacteria.
Here we analysed the effects of variable sulfate supply in an accurately
defined modell pathosystem of A. thaliana and A. brassicicola on the
molecular level. To quantificate the proliferation of the fungus, measurement
of S-metabolites and multiparallel gene analysis were performed during the
infection process. Cellular signal mechanisms that mediate between mineral
sulfur support and activation of defense reactions will be identified by using
mutants that are affected in pathogen-relevant signal transduction pathways
and transgenic lines of Arabidopsis with modified steps of sulfur metabolism.
The phenomenon of sulfate-triggered defense is an important new approach
in phytopathology which has to be analysed with regard to known resistance
genes and expression of marker genes for use in basic science and agrobiotechnology.
15 th <strong>International</strong> <strong>Conference</strong> on Arabidopsis Research 2004 · Berlin