ARF19 Condensation in the Arabidopsis Stomatal Lineage.

The phytohormone auxin regulates nearly every aspect of plant development. Transcriptional responses to auxin are driven by the activities of the AUXIN RESPONSE FACTOR family of transcription factors. ARF19 (AT1G19220) is critical in the auxin signaling pathway and has previously been shown to undergo protein condensation to tune auxin responses in the root. However, ARF19 condensation dynamics in other organs has not yet been described. In the Arabidopsis stomatal lineage, we found that ARF19 cytoplasmic condensates are enriched in guard cells and pavement cells, terminally differentiated cells in the leaf epidermis. This result is consistent with previous studies showing ARF19 condensation in mature root tissues. Our data reveal that the sequestration of ARF19 into cytoplasmic condensation in differentiated leaf epidermal cells is similar to root-specific condensation patterns.