OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 149/4/1824    most recent pp.108.132092v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Speth, E. B. Articles by He, S. Y. Search for Related Content PubMed PubMed Citation Articles by Speth, E. B. Articles by He, S. Y. Agricola Articles by Speth, E. B. Articles by He, S. Y. Related Collections Membrane Trafficking

PLANTS INTERACTING WITH OTHER ORGANISMS

Subcellular Localization and Functional Analysis of the Arabidopsis GTPase RabE^1,[W],[OA]

Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824

Membrane trafficking plays a fundamental role in eukaryotic cell biology. Of the numerous known or predicted protein components of the plant cell trafficking system, only a relatively small subset have been characterized with respect to their biological roles in plant growth, development, and response to stresses. In this study, we investigated the subcellular localization and function of an Arabidopsis (Arabidopsis thaliana) small GTPase belonging to the RabE family. RabE proteins are phylogenetically related to well-characterized regulators of polarized vesicle transport from the Golgi apparatus to the plasma membrane in animal and yeast cells. The RabE family of GTPases has also been proposed to be a putative host target of AvrPto, an effector protein produced by the plant pathogen Pseudomonas syringae, based on yeast two-hybrid analysis. We generated transgenic Arabidopsis plants that constitutively expressed one of the five RabE proteins (RabE1d) fused to green fluorescent protein (GFP). GFP-RabE1d and endogenous RabE proteins were found to be associated with the Golgi apparatus and the plasma membrane in Arabidopsis leaf cells. RabE down-regulation, due to cosuppression in transgenic plants, resulted in drastically altered leaf morphology and reduced plant size, providing experimental evidence for an important role of RabE GTPases in regulating plant growth. RabE down-regulation did not affect plant susceptibility to pathogenic P. syringae bacteria; conversely, expression of the constitutively active RabE1d-Q74L enhanced plant defenses, conferring resistance to P. syringae infection.

² Present address: Center for Research in College Science Teaching and Learning, Michigan State University, East Lansing, MI 48824.

³ Present address: Department of Medicine, Virginia Commonwealth University and McGuire Veterans Affairs Medical Center, Richmond, VA 23284.

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: Sheng Yang He (hes{at}msu.edu).

^[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.108.132092

^* Corresponding author; e-mail hes{at}msu.edu.

Received November 13, 2008; accepted February 15, 2009; published February 20, 2009.