| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
|
First published online January 12, 2007; 10.1104/pp.106.090985 Plant Physiology 143:825-837 (2007) © 2007 American Society of Plant Biologists OPEN ACCESS ARTICLE
The Lipopolysaccharide of Sinorhizobium meliloti Suppresses Defense-Associated Gene Expression in Cell Cultures of the Host Plant Medicago truncatula1,[W],[OA]Proteom und Metabolomforschung, Fakultät für Biologie (V.T., K.N.) and Institut für Genomforschung, Center for Biotechnology (H.K.), Universität Bielefeld, D–33501 Bielefeld, Germany; and Max-Planck-Institut für Molekulare Pflanzenphysiologie, Wissenschaftspark Golm, Potsdam, Germany (B.U., O.T., M.S.)
In the establishment of symbiosis between Medicago truncatula and the nitrogen-fixing bacterium Sinorhizobium meliloti, the lipopolysaccharide (LPS) of the microsymbiont plays an important role as a signal molecule. It has been shown in cell cultures that the LPS is able to suppress an elicitor-induced oxidative burst. To investigate the effect of S. meliloti LPS on defense-associated gene expression, a microarray experiment was performed. For evaluation of the M. truncatula microarray datasets, the software tool MapMan, which was initially developed for the visualization of Arabidopsis (Arabidopsis thaliana) datasets, was adapted by assigning Medicago genes to the ontology originally created for Arabidopsis. This allowed functional visualization of gene expression of M. truncatula suspension-cultured cells treated with invertase as an elicitor. A gene expression pattern characteristic of a defense response was observed. Concomitant treatment of M. truncatula suspension-cultured cells with invertase and S. meliloti LPS leads to a lower level of induction of defense-associated genes compared to induction rates in cells treated with invertase alone. This suppression of defense-associated transcriptional rearrangement affects genes induced as well as repressed by elicitation and acts on transcripts connected to virtually all kinds of cellular processes. This indicates that LPS of the symbiont not only suppresses fast defense responses as the oxidative burst, but also exerts long-term influences, including transcriptional adjustment to pathogen attack. These data indicate a role for LPS during infection of the plant by its symbiotic partner.
1 This work was supported by the German Research Council "Bioinformatics and genome research," by the European Community's Human Potential Programme (under contract HPRN–CT–2002–00251), and by the German Ministry for Education and Research (grant nos. GABI 313112 and 313110). The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Karsten Niehaus (karsten.niehaus{at}genetik.uni-bielefeld.de). [W] The online version of this article contains Web-only data. [OA] Open Access articles can be viewed online without a subscription. www.plantphysiol.org/cgi/doi/10.1104/pp.106.090985 * Corresponding author; e-mail karsten.niehaus{at}genetik.uni-bielefeld.de; fax 49–521–106–5626. Received October 6, 2006; accepted November 28, 2006; published January 12, 2007. This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|
