This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 149/3/1424    most recent pp.108.132225v1 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 HighWire Citing Articles via CrossRef Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Genre, A. Articles by Bonfante, P. Search for Related Content PubMed PubMed Citation Articles by Genre, A. Articles by Bonfante, P. Agricola Articles by Genre, A. Articles by Bonfante, P.

PLANTS INTERACTING WITH OTHER ORGANISMS

Biotic and Abiotic Stimulation of Root Epidermal Cells Reveals Common and Specific Responses to Arbuscular Mycorrhizal Fungi^1,[W]

Dipartimento di Biologia Vegetale, Università di Torino and Istituto Protezione Piante-Consiglio Nazionale delle Ricerche, 10125 Torino, Italy

During arbuscular mycorrhizal (AM) colonization, a focal accumulation of organelles occurs in root epidermal cells, prior to fungal penetration, beneath adhering hyphopodia. This is followed by the appearance of the prepenetration apparatus (PPA), a transcellular column of cytoplasm connected to the nucleus and rich in cytoskeleton and secretory endomembranes. This apparatus appears to be responsible for the construction of an apoplastic compartment that confines the fungus within the cell lumen. To identify AM-specific elements within the PPA response, we challenged root cultures of Medicago truncatula, expressing a green fluorescent protein tag for the endoplasmic reticulum, with an AM symbiont, a necrotrophic pathogen, a hemibiotrophic pathogen, a noncompatible endomycorrhizal fungus, or abiotic physical stimuli. Parallel experiments were made on a M. truncatula nonsymbiotic mutant (doesn't make infections, dmi3-1). The results have highlighted a correlation between physical stimulation of the cell surface and nuclear repositioning. Cytoplasmic aggregation was only induced by contact with compatible fungi, whereas PPA appearance was specifically triggered by the AM fungus. The dmi3-1 mutant did not develop cytoplasmic aggregation or PPA and underwent cell death upon physical stimulation. The up-regulation of an expansin-like gene, already identified as an early marker of AM fungal contact, was triggered in wild-type roots by all the fungi tested. Such observations identify responses that are specific to mycorrhizal interactions and extend the role of the DMI3 protein, a calcium/calmodulin-dependent kinase, from symbiotic to pathogenic interactions.

The author responsible for the 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: Paola Bonfante (p.bonfante{at}ipp.cnr.it).

^[W] The online version of this article contains Web-only data.

www.plantphysiol.org/cgi/doi/10.1104/pp.108.132225

^* Corresponding author; e-mail p.bonfante{at}ipp.cnr.it.

Received November 6, 2008; accepted January 12, 2009; published January 16, 2009.

This article has been cited by other articles:

				G. E. D. Oldroyd, M. J. Harrison, and U. Paszkowski Reprogramming Plant Cells for Endosymbiosis Science, May 8, 2009; 324(5928): 753 - 754. [Abstract] [Full Text] [PDF]