Plant Physiol. Bio-Rad Microplate Reader
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on January 9, 2008; 10.1104/pp.107.113969

OPEN ACCESS ARTICLE
This Article
Free via Open Access: OA
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrowOA All Versions of this Article:
146/3/1267    most recent
pp.107.113969v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Depuydt, S.
Right arrow Articles by Vereecke, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Depuydt, S.
Right arrow Articles by Vereecke, D.
Agricola
Right arrow Articles by Depuydt, S.
Right arrow Articles by Vereecke, D.

Received November 26, 2007
Accepted January 3, 2008

Modulation of the hormone setting by Rhodococcus fascians results in ectopic KNOX activation in Arabidopsis thaliana

Stephen Depuydt , Karel Dolezal , Mieke Van Lijsebettens , Thomas Moritz , Marcelle Holsters *, and Danny Vereecke

Department of Plant Systems Biology, Flanders Institute for Biotechnology, 9052 Gent, Belgium; Department of Molecular Genetics, Ghent University, 9052 Gent, Belgium; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-90183 Umea, Sweden; and Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, 783 71 Olomouc, Czech Republic

* Corresponding author; email: marcelle.holsters{at}psb.ugent.be.

The biotrophic actinomycete Rhodococcus fascians has a profound impact on plant development and a common aspect of the symptomatology is the deformation of infected leaves. In Arabidopsis thaliana, the serrated leaf margins formed upon infection resemble the leaf phenotype of transgenic plants with ectopic expression of KNOTTED-like homeobox (KNOX) genes. Through transcript profiling, we demonstrate that class-I KNOX genes are transcribed in symptomatic leaves. Functional analysis revealed that BP/KNAT1 and mainly STM were essential for the observed leaf dissection. However, these results also positioned the KNOX genes downstream in the signaling cascade triggered by R. fascians infection. The much faster activation of ARABIDOPSIS RESPONSE REGULATOR5 and the establishment of homeostatic and feedback mechanisms to control cytokinin levels support the overrepresentation of this hormone in infected plants due to the secretion by the pathogen, thereby placing the cytokinin response high up in the cascade. Hormone measurements show a net decrease of tested cytokinins, indicating that secretion by the bacterium and degradation by the plant are in balance, or, as suggested by the strong reaction of 35S:CKX plants, that other (unknown) cytokinins are at play. At early time points of the interaction, activation of gibberellin 2-oxidase presumably installs a local hormonal setting favorable for meristematic activity that provokes leaf serrations. The results are discussed in the context of symptom development, evasion of plant defense, and the establishment of a specific niche by R. fascians.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2008 by the American Society of Plant Biologists