Patterning

Stomatal development is regulated by multiple intrinsic developmental and environmental signals. Here, the authors show that spatially patterned hydrogen peroxide activates the energy sensor SnRK1 to stabilize the SPCH transcription factor and optimize stomatal development in Arabidopsis.

This study shows that Dof transcription factors in the phloem precursors not only induce formation of phloem, but also cause secretion of CLE peptides, which in turn inhibit phloem formation in neighbourhing cells by post-transcriptionally decreasing Dofs.

Division tracking of mesophyll cells shows that initial division plane orientations alternate creating cell walls at right angles, and intercellular spaces. Disruption of this pattern halts initiation of multi-cell junctions and intercellular spaces.

A xylan-rich nanodomain at pit boundaries of xylem vessels maintains distinct wall patterns by anchoring cellulosic nanofibrils at the pit borders. These nanocompartments are produced by the xylan synthase IRREGULAR XYLEM (IRX)10 and its homologues.

The establishment of leaf adaxial–abaxial polarity happens early at the shoot apical meristem. Using quantitative live imaging of auxin and dorsiventral polarity markers, the authors trace the origin of polarity to before primordium emergence, to an overlay of high auxin onto a meristem periphery prepattern.