75 Integrating Membrane Transport with Male Gametophyte ... - TAIR

293 A Role for a Flavin-Containing Monooxygenase in Resistance against Microbial Pathogens
in Arabidopsis
Martina Koch 1 , Sonja Vorwerk 2 , Clarissa Masur 1 , Gholamreza Sharifi-Sirchi 1 , Nicoletta Olivieri 1 , Nikolaus Schlaich 1
1
RWTH Aachen University, Institut Bio III (Pflanzenphysiologie), Aachen, Germany, 2 Carnegie Institution of
Washington, Department of Plant Biology, Stanford, CA, USA
Using activation-tagging in the Arabidopsis Col-0 rps2-101C background we identified a mutant (SRS1-D) that
showed virtually no symptoms after inoculation with virulent Pseudomonas syringae pv. tomato DC3000 bacteria. The
dominant, gain-of-function phenotype of the SRS1-D mutant is due to over-expression of a class 3 flavin-containing
monooxygenase (FMO). We recapitulated the SRS1-D mutant phenotype in independent transgenic Col-0 lines overexpressing
the FMO cDNA under control of the 35S CaMV promoter. The increased basal resistance observed in the
SRS1-D mutant was also effective against the taxonomically unrelated downy mildew-causing pathogen Hyaloperonospora
parasitica. By investigating the progeny from crosses of SRS1-D mutant with the NahG transgenic line we showed that the
enhanced basal resistance phenotype was dependent on the accumulation of salicylic acid. SRS1-D plants showed wildtype
resistant reactions after inoculation with avirulent bacteria, indicating that the R-gene-mediated defence physiology
was not compromised by FMO over-expression. Transcripts of the class 3 FMO gene accumulated within 6 hours after
inoculation of wt Col-0 plants with avirulent Pst+avrRpt2 cells. Moreover, a T-DNA insertion into the SRS1 gene results
in enhanced susceptibility to virulent Pseudomonas and Hyaloperonospora parasitica, suggesting that expression of the
FMO gene is a hitherto undescribed component of the plant's resistance repertoire. We discuss the possibility that the
FMO may participate in the detoxification of virulence factors produced by pathogens.
294 Transcriptomic analysis of potyvirus-infected plants: Comparative study between
Arabidopsis thaliana and tomato
Xao Yan Feng 1 , Maud Rivard 1 , Johann Petit 2 , Ludivine Taconnat 3 , Christophe Rothan 2 , Jean-Pierre Renou 3 , Valerie
Schurdi-Levraud 1, 4 , Olivier Le Gall 1 , Carole Caranta 5 , Frederic Revers 1
1
UMR GDPP, INRA Bordeaux-Universite Bordeaux 2, BP81, 33883 Villenave d'Ornon cedex, France, 2 UMR
PBV, INRA Bordeaux-Universite Bordeaux 1 et 2, Villenave d'Ornon, France, 3 URGV, INRA Evry, France ,
4
AGRO Montpellier, France, 5 UGAFL, INRA, Montfavet, France
With the aim to identify and compare host genes of two species differentially regulated in the presence of an infecting
virus, Arabidopsis thaliana Landsberg erecta (Ler) accession and tomato cv. Microtom were challenged with Tobacco
etch potyvirus (TEV) which is able to infect both species. Microarrays slides from Cornell University for tomato and
from the CATMA project for Arabidopsis were respectively hybridized with total RNA extracted from TEV infected
and mock inoculated microtom plants or Ler plants 7 days post inoculation. The patterns of the differentially expressed
genes were evaluated in inoculated and systemic leaves.
More than 1500 genes were found to be deregulated in TEV infected Arabidopsis and about 650 in tomato. In both
species a ten-fold difference in deregulated genes were found between inoculated leaves and systemic leaves. Few
commun homologous genes have been found to be differentially expressed in both species.