As sessile organisms that cannot evade adverse environmental conditions, plants have evolved various adaptive strategies to cope with environmental stresses. One of the most successful adaptations is the formation of symbiotic associations with beneficial microbes. In these mutualistic interactions the partners exchange essential nutrients and improve their resistance to biotic and abiotic stresses. In arbuscular mycorrhiza (AM) and in root nodule symbiosis (RNS), AM fungi and rhizobia, respectively, penetrate roots and accommodate within the cells of the plant host. In these endosymbiotic associations, both partners keep their plasma membranes intact and use them to control the bidirectional exchange of signaling molecules and nutrients. Intracellular accommodation requires the exchange of symbiotic signals and the reprogramming of both interacting partners. This involves fundamental changes at the level of gene expression and of the cytoskeleton, as well as of organelles such as plastids, endoplasmic reticulum (ER), and the central vacuole. Symbiotic cells are highly compartmentalized and have a complex membrane system specialized for the diverse functions in molecular communication and nutrient exchange. Here, we discuss the roles of the different cellular membrane systems and their symbiosis-related proteins in AM and RNS, and we review recent progress in the analysis of membrane proteins involved in endosymbiosis.
Keywords: symbiosis, arbuscule, mycorrhiza, LysM receptor, SYMRK, VAPYRIN, root nodules, rhizobium
Citation: Bapaume L and Reinhardt D (2012) How membranes shape plant symbioses: signaling and transport in nodulation and arbuscular mycorrhiza. Front. Plant Sci. 3:223. doi: 10.3389/fpls.2012.00223
Received: 03 July 2012; Accepted: 14 September 2012;
Published online: 05 October 2012.
Edited by:Markus Geisler, University of Fribourg, Switzerland
Copyright © 2012 Bapaume and Reinhardt. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Didier Reinhardt, Department of Biology, University of Fribourg, Rte Albert Gockel 3, CH-1700 Fribourg, Switzerland. e-mail: firstname.lastname@example.org