Ammonia: a candidate for nitrogen transfer at the mycorrhizal interface.

In mycorrhizal associations, the fungal partner assists its plant host with nitrogen and phosphorus uptake while obtaining photosynthetically fixed carbon. Recent studies in mycorrhiza have highlighted the potential for direct transfer of ammonia from fungal to plant cells. This presents a new perspective on nitrogen transfer at the mycorrhizal interface, which is discussed here in light of recent progress made in characterizing a large array of membrane proteins that could fulfil the function of transporting ammonia.

[1]  P. Lammers,et al.  The uptake, metabolism, transport and transfer of nitrogen in an arbuscular mycorrhizal symbiosis. , 2005, The New phytologist.

[2]  N. von Wirén,et al.  Tonoplast Intrinsic Proteins AtTIP2;1 and AtTIP2;3 Facilitate NH3 Transport into the Vacuole1 , 2005, Plant Physiology.

[3]  B. André,et al.  Molecular characterization, function and regulation of ammonium transporters (Amt) and ammonium‐metabolizing enzymes (GS, NADP‐GDH) in the ectomycorrhizal fungus Hebeloma cylindrosporum , 2003, Molecular microbiology.

[4]  Robert M. Stroud,et al.  Mechanism of Ammonia Transport by Amt/MEP/Rh: Structure of AmtB at 1.35 Å , 2004, Science.

[5]  U. Nehls,et al.  Biochemical and molecular aspects of C/N interaction in ectomycorrhizal plants: an update , 1999, Plant and Soil.

[6]  A. Gessler,et al.  The high-affinity poplar ammonium importer PttAMT1.2 and its role in ectomycorrhizal symbiosis. , 2005, The New phytologist.

[7]  W. Burgstaller Transport of small lons and molecules through the plasma membrane of filamentous fungi. , 1997, Critical reviews in microbiology.

[8]  Sally E Smith and David J Read Mycorrhizal Symbiosis 2nd ed , 1997 .

[9]  D. Blaudez,et al.  Structure and function of the ectomycorrhizal association between Paxillus involutus and Betula pendula II. Metabolic changes during mycorrhiza formation , 1998 .

[10]  Sandra Tenreiro,et al.  Saccharomyces cerevisiae Aqr1 Is an Internal-Membrane Transporter Involved in Excretion of Amino Acids , 2004, Eukaryotic Cell.

[11]  Y. Shachar-Hill,et al.  Could the urea cycle be translocating nitrogen in the arbuscular mycorrhizal symbiosis? , 2001, The New phytologist.

[12]  Martin Guttenberger,et al.  Arbuscules of vesicular-arbuscular mycorrhizal fungi inhabit an acidic compartment within plant roots , 2000, Planta.

[13]  S. Tyerman,et al.  Voltage-Dependent Cation Channels Permeable to NH4 +, K+, and Ca2+ in the Symbiosome Membrane of the Model Legume Lotus japonicus 1 , 2002, Plant Physiology.

[14]  W. Frommer,et al.  The molecular physiology of ammonium uptake and retrieval. , 2000, Current opinion in plant biology.

[15]  N. Guaragnella,et al.  ATO3 Encoding a Putative Outward Ammonium Transporter Is an RTG-independent Retrograde Responsive Gene Regulated by GCN4 and the Ssy1-Ptr3-Ssy5 Amino Acid Sensor System* , 2003, Journal of Biological Chemistry.

[16]  S. Hohmann,et al.  Aquaporins in yeasts and filamentous fungi , 2005, Biology of the cell.

[17]  M. Chalot,et al.  Physiology of organic nitrogen acquisition by ectomycorrhizal fungi and ectomycorrhizas. , 1998, FEMS microbiology reviews.

[18]  Peter J. Lammers,et al.  Nitrogen transfer in the arbuscular mycorrhizal symbiosis , 2005, Nature.

[19]  U. Hartwig,et al.  Mycorrhizas improve nitrogen nutrition of Trifolium repens after 8 yr of selection under elevated atmospheric CO2 partial pressure. , 2005, The New phytologist.

[20]  A. Le Quéré,et al.  Spatial patterns of gene expression in the extramatrical mycelium and mycorrhizal root tips formed by the ectomycorrhizal fungus Paxillus involutus in association with birch (Betula pendula) seedlings in soil microcosms. , 2005, The New phytologist.

[21]  Frantisek Baluska,et al.  Polar transport of auxin: carrier-mediated flux across the plasma membrane or neurotransmitter-like secretion? , 2003, Trends in cell biology.