Molecular mechanisms of pollen aperture formation in Arabidopsis and rice

Pollen apertures are specialized regions on the pollen surface that receive little to no exine deposition, forming distinct structures important for pollen function. Aperture number, shape, and positions vary widely across species, resulting in diverse, species-specific patterns that make apertures fascinating from both cell-biological and evolutionary perspectives. Aperture formation requires developing pollen to establish polarity and define specific regions of the plasma membrane as aperture domains. In the decade or so since the discovery of the first aperture factor, INP1, pollen apertures have become a powerful model for investigating how cells form distinct plasma membrane domains. Recent studies in Arabidopsis and rice, two species with contrasting aperture patterns, have identified key molecular players that regulate aperture domain specification and development. In this review, we summarize these advances and discuss directions for future studies into the molecular mechanisms controlling aperture formation.