SNAP30 forms a SNARE complex with VAMP726 and SYP131 and mediates vesicle secretion at the plasma membrane of the Arabidopsis pollen tube tip

SNAREs are important proteins that mediate the fusion of vesicles with target membranes in eukaryotic cells. The fusion of secretory vesicles with the plasma membrane is the basis of pollen tube tip growth. However, the role of Qbc SNARE SNAP30 in Arabidopsis pollen tubes has not yet been reported, and the intact SNARE complex that regulates exocytosis at the pollen tube tip has yet to be determined. Our study revealed that the deletion of SNAP30 inhibited the tip growth of Arabidopsis pollen tubes. Fluorescence recovery after photobleaching (FRAP) experiments indicated that SNAP30 plays an important role in exocytosis at the Arabidopsis pollen tube tip. Confocal microscopy revealed that SNAP30 and SYP131 or VAMP726 colocalize to the plasma membrane at the tips of Arabidopsis pollen tubes. Furthermore, we found that SNAP30 can interact with the Qa-SNARE SYP131 and R-SNARE VAMP726. In addition, SNAP30 can form a SNARE complex with VAMP726 and SYP131. These results suggest that SNAP30 forms a SNARE complex with VAMP726 and SYP131 to mediate vesicle secretion at the plasma membrane of Arabidopsis pollen tube tip. These results also indicate that the molecular mechanism of vesicle secretion may be evolutionarily conserved between animal nerve cells and plant pollen tubes.