title: High-affinity ammonium transporters and nitrogen sensing in mycorrhizas.
abstract: Most terrestrial plants live in mutualistic symbiosis with root-infecting mycorrhizal fungi. This association requires a molecular dialogue between the two partners. However, the nature of the chemical signals that induce hyphal differentiation are not well characterized and the mechanisms for signal reception are still unknown. In addition to its role in ammonium scavenging, the Mep2 protein from Saccharomyces cerevisiae has been proposed to act as an ammonium sensor that is essential for pseudohyphal differentiation in response to ammonium limitation. We propose that the high-affinity ammonium transporters from mycorrhizal fungi act in a similar manner to sense the environment and induce, via as-yet-unidentified signal transduction cascades, the switch in the mode of fungal growth observed during the formation of mycorrhiza.
authors.affiliation: Université Henri Poincaré, Nancy I, UMR INRA/UHP 1136 Interactions Arbres/Micro-organismes, BP 239, 54506, Vandoeuvre-les-Nancy, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Javelle
authors.forename: Bruno
authors.initials: B
authors.lastname: André
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Marini
authors.forename: Michel
authors.initials: M
authors.lastname: Chalot
mesh_terms: D005075:Biological Evolution; D005656:Fungal Proteins / Q000378:metabolism*; D005658:Fungi / Q000145:classification / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008954:Models, Biological; D038821:Mycorrhizae / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D010802:Phylogeny; D010944:Plants / Q000382:microbiology; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D015398:Signal Transduction; D012988:Soil Microbiology; D013559:Symbiosis
chemical_list: D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D000644:Quaternary Ammonium Compounds; D009584:Nitrogen