Genetic screen for factors mediating PIN polarization in gravistimulated Arabidopsis thaliana hypocotyls

article Genetic screen for factors mediating PIN polarization in gravistimulated Arabidopsis thaliana hypocotyls published yes Hana Rakusová author Huibin Han author 31435098-F248-11E8-B48F-1D18A9856A87 Petr Valošek author 3CDB6F94-F248-11E8-B48F-1D18A9856A87 Jiří Friml author 4159519E-F248-11E8-B48F-1D18A9856A870000-0002-8302-7596 JiFr department Polarity and subcellular dynamics in plants project Gravitropism is an adaptive response that orients plant growth parallel to the gravity vector. Asymmetric distribution of the phytohormone auxin is a necessary prerequisite to the tropic bending both in roots and shoots. During hypocotyl gravitropic response, the PIN3 auxin transporter polarizes within gravity-sensing cells to redirect intercellular auxin fluxes. First gravity-induced PIN3 polarization to the bottom cell mem- branes leads to the auxin accumulation at the lower side of the organ, initiating bending and, later, auxin feedback-mediated repolarization restores symmetric auxin distribution to terminate bending. Here, we per- formed a forward genetic screen to identify regulators of both PIN3 polarization events during gravitropic response. We searched for mutants with defective PIN3 polarizations based on easy-to-score morphological outputs of decreased or increased gravity-induced hypocotyl bending. We identified the number of hypocotyl reduced bending (hrb) and hypocotyl hyperbending (hhb) mutants, revealing that reduced bending corre- lated typically with defective gravity-induced PIN3 relocation whereas all analyzed hhb mutants showed defects in the second, auxin-mediated PIN3 relocation. Next-generation sequencing-aided mutation map- ping identified several candidate genes, including SCARECROW and ACTIN2, revealing roles of endodermis specification and actin cytoskeleton in the respective gravity- and auxin-induced PIN polarization events. The hypocotyl gravitropism screen thus promises to provide novel insights into mechanisms underlying cell polarity and plant adaptive development. https://research-explorer.ista.ac.at/download/6262/6304/2019_PlantJournal_Rakusov.pdf application/pdfno Wiley2019 eng The Plant Journal 0960-7412 1365-313x 30821050 00047364410000810.1111/tpj.14301 9861048-1059 H. Rakusová, H. Han, P. Valošek, and J. Friml, “Genetic screen for factors mediating PIN polarization in gravistimulated Arabidopsis thaliana hypocotyls,” The Plant Journal, vol. 98, no. 6. Wiley, pp. 1048–1059, 2019. Rakusová H, Han H, Valošek P, Friml J. Genetic screen for factors mediating PIN polarization in gravistimulated Arabidopsis thaliana hypocotyls. The Plant Journal. 2019;98(6):1048-1059. doi:<a href="https://doi.org/10.1111/tpj.14301">10.1111/tpj.14301</a> Rakusová, H., Han, H., Valošek, P., & Friml, J. (2019). Genetic screen for factors mediating PIN polarization in gravistimulated Arabidopsis thaliana hypocotyls. The Plant Journal. Wiley. <a href="https://doi.org/10.1111/tpj.14301">https://doi.org/10.1111/tpj.14301</a> H. Rakusová, H. Han, P. Valošek, J. Friml, The Plant Journal 98 (2019) 1048–1059. Rakusová H, Han H, Valošek P, Friml J. 2019. Genetic screen for factors mediating PIN polarization in gravistimulated Arabidopsis thaliana hypocotyls. The Plant Journal. 98(6), 1048–1059. Rakusová, Hana, et al. “Genetic Screen for Factors Mediating PIN Polarization in Gravistimulated Arabidopsis Thaliana Hypocotyls.” The Plant Journal, vol. 98, no. 6, Wiley, 2019, pp. 1048–59, doi:<a href="https://doi.org/10.1111/tpj.14301">10.1111/tpj.14301</a>. Rakusová, Hana, Huibin Han, Petr Valošek, and Jiří Friml. “Genetic Screen for Factors Mediating PIN Polarization in Gravistimulated Arabidopsis Thaliana Hypocotyls.” The Plant Journal. Wiley, 2019. <a href="https://doi.org/10.1111/tpj.14301">https://doi.org/10.1111/tpj.14301</a>. 62622019-04-09T08:46:44Z2025-04-15T07:48:04Z