Plasma membrane H+‐ATPases‐mediated cytosolic proton gradient regulates pollen tube growth

The polar growth of pollen tubes is essential for the delivery of sperm cells during fertilization in angiosperms. How this polar growth is regulated has been a long‐standing question. An in vitro pharmacological assay previously implicated proton flux in pollen tube growth, although genetic and cellular supporting evidence was lacking. Here, we report that protons form a gradient from the pollen tube tip to the shank region and this gradient is generated by three members of Arabidopsis H+‐ATPases (AHAs). Genetic analysis suggested that these AHAs are essential for pollen tube growth, thus providing new insight into the regulation of polar growth. Proton movement across cell membranes is critical for many developmental and physiological processes in all organisms. Here we report that plasma membrane H+−ATPases (AHAs) form a proton gradient in Arabidopsis thaliana pollen tubes that is essential for pollen tube growth.