PAX-regulated self-organizing polarity drives procambial strand formation.

PAX protein establishes cell and tissue polarity in leaf vein formation independently of PIN auxin transporters.

• Why it matters: Understanding how vascular networks form in plants is crucial for insights into tissue patterning and plant development, yet the mechanisms behind procambial strand formation remain unclear.
• What they did: The study identified a novel role for the polar protein PAX in coordinating cell and tissue polarity during vein patterning, revealing an auxin-guided process that occurs before PIN transporter polarization.
• The result: This discovery refines models of vascular patterning, suggesting PAX's role in early polarity establishment enables more precise control of leaf venation and tissue organization.