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A plant plasma membrane Ca 2+ pump is required for normal pollen tube growth and fertilization

2004; National Academy of Sciences; Volume: 101; Issue: 25 Linguagem: Inglês

10.1073/pnas.0401542101

1091-6490

Morten Schiøtt, Shawn M. Romanowsky, Lone Bækgaard, Mia Kyed Jakobsen, Michael Palmgren, Jeffrey F. Harper,

Photosynthetic Processes and Mechanisms

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.