Tropisms, growth responses to environmental stimuli such as light or gravity, are spectacular examples of adaptive plant development. The plant hormone auxin serves as a major coordinative signal. The PIN auxin exporters, through their dynamic polar subcellular localizations, redirect auxin fluxes in response to environmental stimuli and the resulting auxin gradients across organs underly differential cell elongation and bending. In this review, we discuss recent advances concerning regulations of PIN polarity during tropisms, focusing on PIN phosphorylation and trafficking. We also cover how environmental cues regulate PIN actions during tropisms, and a crucial role of auxin feedback on PIN polarity during bending termination. Finally, the interactions between different tropisms are reviewed to understand plant adaptive growth in the natural environment.
We are grateful to Lukas Fiedler, Alexandra Mally (IST Austria) and Dr. Bartel Vanholme (VIB, Ghent) for their critical comments on the manuscript. We apologize to those researchers whose great work was not cited. This work is supported by the European Research Council under the European Union’s Horizon 2020 research and innovation Programme (ERC grant agreement number 742985), and the Austrian Science Fund (FWF, grant number I 3630-B25) to JF. HH is supported by the China Scholarship Council (CSC scholarship, 201506870018) and a starting grant from Jiangxi Agriculture University (9232308314).
Han H, Adamowski M, Qi L, Alotaibi S, Friml J. PIN-mediated polar auxin transport regulations in plant tropic responses. New Phytologist. 2021. doi:10.1111/nph.17617
Han, H., Adamowski, M., Qi, L., Alotaibi, S., & Friml, J. (2021). PIN-mediated polar auxin transport regulations in plant tropic responses. New Phytologist. Wiley. https://doi.org/10.1111/nph.17617
Han, Huibin, Maciek Adamowski, Linlin Qi, SS Alotaibi, and Jiří Friml. “PIN-Mediated Polar Auxin Transport Regulations in Plant Tropic Responses.” New Phytologist. Wiley, 2021. https://doi.org/10.1111/nph.17617.
H. Han, M. Adamowski, L. Qi, S. Alotaibi, and J. Friml, “PIN-mediated polar auxin transport regulations in plant tropic responses,” New Phytologist. Wiley, 2021.
Han H, Adamowski M, Qi L, Alotaibi S, Friml J. 2021. PIN-mediated polar auxin transport regulations in plant tropic responses. New Phytologist.
Han, Huibin, et al. “PIN-Mediated Polar Auxin Transport Regulations in Plant Tropic Responses.” New Phytologist, Wiley, 2021, doi:10.1111/nph.17617.