title: Identification of an Arabidopsis plasma membrane-located ATP transporter important for anther development.
abstract: ATP acts as an extracellular signal molecule in plants. However, the nature of the mechanisms that export this compound into the apoplast are under debate. We identified the protein PM-ANT1 as a candidate transporter able to mediate ATP export. PM-ANT1 joins the mitochondrial carrier family, lacks an N-terminal amino acid extension required for organelle localization, and locates to the plasma membrane. Recombinant PM-ANT1 transports ATP, and the gene is substantially expressed in mature pollen grains. Artificial microRNA (amiRNA) mutants show reduced silique length and less seeds per silique but increased seed weight associated with unchanged pollen viability. Anthers from amiRNA mutants exhibited a normal early development, but stomium breakage is inhibited, leading to impaired anther dehiscence. This results in reduced self-pollination and thus decreased fertilization efficiency. amiRNA pollen grains showed increased intracellular ATP levels but decreased extracellular ATP levels. The latter effects are in line with transport properties of recombinant PM-ANT1, supporting in planta that functional PM-ANT1 resides in the plasma membrane and concur with the PM-ANT1 expression pattern. We assume that PM-ANT1 contributes to ATP export during pollen maturation. ATP export may serve as an extracellular signal required for anther dehiscence and is a novel factor critical for pollination and autogamy.
authors.affiliation: Plant Physiology, Technical University of Kaiserslautern, Kaiserslautern, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Rieder
authors.forename: H Ekkehard
authors.initials: HE
authors.lastname: Neuhaus
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs; D008969:Molecular Sequence Data; D009154:Mutation; D030821:Plants, Genetically Modified; D011058:Pollen / Q000235:genetics / Q000254:growth & development; D018749:RNA, Plant / Q000235:genetics; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D026901:Membrane Transport Proteins; D035683:MicroRNAs; D018749:RNA, Plant; D011993:Recombinant Fusion Proteins; C577261:solute carrier family 25 protein, Arabidopsis; D000255:Adenosine Triphosphate