title: Glutamate receptor-like genes form Ca2+ channels in pollen tubes and are regulated by pistil D-serine.
abstract: Elevations in cytosolic free calcium concentration ([Ca(2+)](cyt)) constitute a fundamental signal transduction mechanism in eukaryotic cells, but the molecular identity of Ca(2+) channels initiating this signal in plants is still under debate. Here, we show by pharmacology and loss-of-function mutants that in tobacco and Arabidopsis, glutamate receptor-like channels (GLRs) facilitate Ca(2+) influx across the plasma membrane, modulate apical [Ca(2+)](cyt) gradient, and consequently affect pollen tube growth and morphogenesis. Additionally, wild-type pollen tubes grown in pistils of knock-out mutants for serine-racemase (SR1) displayed growth defects consistent with a decrease in GLR activity. Our findings reveal a novel plant signaling mechanism between male gametophyte and pistil tissue similar to amino acid-mediated communication commonly observed in animal nervous systems.
authors.affiliation: Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, P-2780-156 Oeiras, Portugal.
authors.forename: Erwan
authors.initials: E
authors.lastname: Michard
authors.forename: Pedro T
authors.initials: PT
authors.lastname: Lima
authors.forename: Filipe
authors.initials: F
authors.lastname: Borges
authors.forename: Ana Catarina
authors.initials: AC
authors.lastname: Silva
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Portes
authors.forename: João E
authors.initials: JE
authors.lastname: Carvalho
authors.forename: Matthew
authors.initials: M
authors.lastname: Gilliham
authors.forename: Lai-Hua
authors.initials: LH
authors.lastname: Liu
authors.forename: Gerhard
authors.initials: G
authors.lastname: Obermeyer
authors.forename: José A
authors.initials: JA
authors.lastname: Feijó
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D035264:Flowers / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D005998:Glycine / Q000494:pharmacology; D009024:Morphogenesis / Q000187:drug effects; D018408:Patch-Clamp Techniques; D030821:Plants, Genetically Modified; D053205:Pollen Tube / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D019998:Racemases and Epimerases / Q000235:genetics / Q000378:metabolism; D017470:Receptors, Glutamate / Q000235:genetics* / Q000378:metabolism; D012694:Serine / Q000378:metabolism* / Q000494:pharmacology; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D000099300:Serine Racemase
chemical_list: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D002118:Calcium; D015220:Calcium Channels; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D005998:Glycine; D019998:Racemases and Epimerases; D017470:Receptors, Glutamate; D012694:Serine; D000099300:Serine Racemase