PIN-FORMED1 polarity in the plant shoot epidermis is insensitive to the polarity of neighboring cells

Valiya Kadavu, Abdul Kareem; Bhatia, Neha; Ohno, Carolyn; Heisler, Marcus G.

PIN-FORMED1 polarity in the plant shoot epidermis is insensitive to the polarity of neighboring cells

2022

Valiya Kadavu, Abdul Kareem | Bhatia, Neha | Ohno, Carolyn | Heisler, Marcus G.

At the Arabidopsis shoot apex, epidermal cells are planar-polarized along an axis marked by the asymmetric localization patterns of several proteins including PIN-FORMED1 (PIN1), which facilitates the directional efflux of the plant hormone auxin to pattern phyllotaxis. While PIN1 polarity is known to be regulated non -cell autonomously via the MONOPTEROS (MP) transcription factor, how this occurs has not been determined. Here, we use mosaic expression of the serine threonine kinase PINOID (PID) to test whether PIN1 polarizes according to the polarity of neighboring cells. Our findings reveal that PIN1 is insensitive to the po-larity of PIN1 in neighboring cells arguing against auxin flux or extracellular auxin concentrations acting as a polarity cue, in contrast to previous model proposals.

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