title: A plant plasma membrane Ca2+ pump is required for normal pollen tube growth and fertilization.
abstract: Ca(2+) signals are thought to play important roles in plant growth and development, including key aspects of pollen tube growth and fertilization. The dynamics of a Ca(2+) signal are largely controlled by influx (through channels) and efflux (through pumps and antiporters). The Arabidopsis genome encodes 14 Ca(2+) pumps, 10 of which belong to a family of autoinhibited Ca(2+) ATPases (ACA) that are predicted to be activated by Ca(2+)/calmodulin. Here, we show that isoform ACA9 is expressed primarily in pollen and localized to the plasma membrane. Three independent T-DNA [portion of the Ti (tumor-inducing) plasmid that is transferred to plant cells] gene disruptions of ACA9 were found to result in partial male sterility. Complementation was observed by using a ACA9-yellow fluorescence protein (YFP) fusion that displayed plasma membrane localization. Mutant aca9 pollen displayed a reduced growth potential and a high frequency of aborted fertilization, resulting in a >80% reduction in seed set. These findings identify a plasma membrane Ca(2+) transporter as a key regulator of pollen development and fertilization in flowering plants.
authors.affiliation: Department of Plant Biology, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Schiøtt
authors.forename: Shawn M
authors.initials: SM
authors.lastname: Romanowsky
authors.forename: Lone
authors.initials: L
authors.lastname: Baekgaard
authors.forename: Mia Kyed
authors.initials: MK
authors.lastname: Jakobsen
authors.forename: Michael G
authors.initials: MG
authors.lastname: Palmgren
authors.forename: Jeffrey F
authors.initials: JF
authors.lastname: Harper
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000235:genetics* / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology*; D005306:Fertilization; D018745:Genome, Plant; D010957:Plasmids; D011058:Pollen / Q000201:enzymology / Q000254:growth & development* / Q000502:physiology
chemical_list: D000252:Calcium-Transporting ATPases