Arbuscular Mycorrhizal Fungi Elicit a Novel Intracellular Apparatus in Medicago truncatula Root Epidermal Cells before Infection[W]
Year: 2005
Type: article
Abstract: The penetration of arbuscular mycorrhizal (AM) fungi through the outermost root tissues of the host plant is a critical step in root colonization, ultimately leading to the establishment of this ecologically important endosymbiotic association. To evaluate the role played by the host plant during AM infection, we have studied in vivo cellular dynamics within Medicago truncatula root epidermal cells using green fluorescent protein labeling of both the plant cytoskeleton and the endoplasmic reticulum. Targeting roots with Gigaspora hyphae has revealed that, before infection, the epidermal cell assembles a transient intracellular structure with a novel cytoskeletal organization. Real-time monitoring suggests that this structure, designated the prepenetration apparatus (PPA), plays a central role in the elaboration of the apoplastic interface compartment through which the fungus grows when it penetrates the cell lumen. The importance of the PPA is underlined by the fact that M. truncatula dmi (for doesn't make infections) mutants fail to assemble this structure. Furthermore, PPA formation in the epidermis can be correlated with DMI-dependent transcriptional activation of the Medicago early nodulin gene ENOD11. These findings demonstrate how the host plant prepares and organizes AM infection of the root, and both the plant-fungal signaling mechanisms involved and the mechanistic parallels with Rhizobium infection in legume root hairs are discussed.
Source: The Plant Cell
Institutions: Institute for Sustainable Plant Protection, University of Turin, Centre National de la Recherche Scientifique, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Laboratoire des Interactions Plantes Microbes Environnement, Institut National de la Recherche Agronomique
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2132178124