Hair In the Middle- A Unique Tool For Planar Polarity Disruption In Arabidopsis Root Cells

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In the plant root or stem, cells orient themselves along the basal and apical axis. This polarity determines incorporation of important proteins such as plant hormone transporters or structures such as root hairs, which always emerge at the basal pole of the root hair cell. What mechanism governs this polarity is unknown. The source of polarity signal, referred to as the Unknown Polarity Cue (UPC), has stumped the scientific community for decades, largely attributed to the failure to reliably and significantly disrupt the planar polarity of the plants. The host laboratory pioneered the method to interfere with the UPC by ectopically expressing polarity cues from the root columella - NGR proteins. Resulting plant lines exhibit a previously unachievable root hair displacement to the middle of the trichoblast- HIM phenotype and other phenotypes consistent with full loss of the planar polarity. I will use targeted NGR expression and subcellular targeting as a tool to understand how plant planar polarity is established. By investigating and functionally characterising the NGR family proteins and how they interrupt the UPC, I will unravel the origin and character of the UPC, as well as mechanisms driving its manifestation. Successful delivery of the project will equip the scientific community with fundamental knowledge on plant planar polarity establishment and generate innovative tools for directional membrane targeting, complemented by optogenetic control over membrane domain assembly. Furthermore, experience, skills and networking opportunities gained through the implementation of the MSCA Action will elevate my postdoctoral experience and build a strong career foundation, positioning me as an expert in the field of cell polarity.