title: The PAM1 gene of petunia, required for intracellular accommodation and morphogenesis of arbuscular mycorrhizal fungi, encodes a homologue of VAPYRIN.
abstract: Most terrestrial plants engage into arbuscular mycorrhizal (AM) symbiosis with fungi of the phylum Glomeromycota. The initial recognition of the fungal symbiont results in the activation of a symbiosis signalling pathway that is shared with the root nodule symbiosis (common SYM pathway). The subsequent intracellular accommodation of the fungus, and the elaboration of its characteristic feeding structures, the arbuscules, depends on a genetic programme in the plant that has recently been shown to involve the VAPYRIN gene in Medicaco truncatula. We have previously identified a mutant in Petunia hybrida, penetration and arbuscule morphogenesis 1 (pam1), that is defective in the intracellular stages of AM development. Here, we report on the cloning of PAM1, which encodes a VAPYRIN homologue. PAM1 protein localizes to the cytosol and the nucleus, with a prominent affinity to mobile spherical structures that are associated with the tonoplast, and are therefore referred to as tonospheres. In mycorrhizal roots, tonospheres were observed in the vicinity of intracellular hyphae, where they may play an essential role in the accommodation and morphogenesis of the fungal endosymbiont.
authors.affiliation: Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland.
authors.forename: Nadja
authors.initials: N
authors.lastname: Feddermann
authors.forename: Rajasekhara Reddy Duvvuru
authors.initials: RR
authors.lastname: Muni
authors.forename: Tatyana
authors.initials: T
authors.lastname: Zeier
authors.forename: Jeroen
authors.initials: J
authors.lastname: Stuurman
authors.forename: Flavia
authors.initials: F
authors.lastname: Ercolin
authors.forename: Martine
authors.initials: M
authors.lastname: Schorderet
authors.forename: Didier
authors.initials: D
authors.lastname: Reinhardt
mesh_terms: D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D038821:Mycorrhizae / Q000502:physiology*; D032306:Petunia / Q000235:genetics* / Q000382:microbiology*; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000382:microbiology; D017433:Protein Structure, Secondary; D029701:Saccharomyces cerevisiae Proteins; D013559:Symbiosis
chemical_list: C438144:ASI1 protein, S cerevisiae; D018744:DNA, Plant; D008565:Membrane Proteins; D028061:Phosphate Transport Proteins; D010940:Plant Proteins; D029701:Saccharomyces cerevisiae Proteins