Manipulation of the PtWOX11-PagKNAT2/6b Module Bidirectionally Regulates Petiole Traits in Populus.

Bidirectional regulation of petiole length and angle in poplar is controlled by a transcriptional module involving PtWOX11 and PagKNAT2/6b.

• Why it matters: Understanding how petiole traits are coordinated is crucial for optimizing canopy architecture and light interception in woody plants, yet the molecular mechanisms remain largely unknown.
• What they did: The study used yeast one-hybrid, electrophoretic mobility shift assays, chromatin affinity purification, and transient expression assays to show that PtWOX11 binds and activates the PagKNAT2/6b promoter, with transcriptomic and qPCR analyses revealing its role in maintaining meristematic gene expression and suppressing differentiation genes.
• The result: Overexpression of PtWOX11 results in compact petioles with upright leaf angles, while its repression causes hyperelongated petioles with reduced leaf angles, suggesting a strategy for modifying canopy architecture in bioenergy poplar.