A plant plasma membrane Ca2+ pump is required for normal pollen tube growth and fertilization.
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.
Schiøtt
Morten
M
Department of Plant Biology, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark.
Romanowsky
Shawn M
SM
Baekgaard
Lone
L
Jakobsen
Mia Kyed
MK
Palmgren
Michael G
MG
Harper
Jeffrey F
JF
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
D000252:Calcium-Transporting ATPases