Glycolysis regulates pollen tube polarity via Rho GTPase signaling

<div><p>As a universal energy generation pathway utilizing carbon metabolism, glycolysis plays an important housekeeping role in all organisms. Pollen tubes expand rapidly via a mechanism of polarized growth, known as tip growth, to deliver sperm for fertilization. Here, we report a novel and surprising role of glycolysis in the regulation of growth polarity in <i>Arabidopsis</i> pollen tubes via impingement of Rho GTPase-dependent signaling. We identified a <i>cytosolic phosphoglycerate kinase</i> (<i>pgkc-1</i>) mutant with accelerated pollen germination and compromised pollen tube growth polarity. <i>pgkc-1</i> mutation greatly diminished apical exocytic vesicular distribution of REN1 RopGAP (Rop GTPase activating protein), leading to ROP1 hyper-activation at the apical plasma membrane. Consequently, <i>pgkc-1</i> pollen tubes contained higher amounts of exocytic vesicles and actin microfilaments in the apical region, and showed reduced sensitivity to Brefeldin A and Latrunculin B, respectively. While inhibition of mitochondrial respiration could not explain the <i>pgkc-1</i> phenotype, the glycolytic activity is indeed required for PGKc function in pollen tubes. Moreover, the <i>pgkc-1</i> pollen tube phenotype was mimicked by the inhibition of another glycolytic enzyme. These findings highlight an unconventional regulatory function for a housekeeping metabolic pathway in the spatial control of a fundamental cellular process.</p>