article published yes Han Tang author 19BDF720-25A0-11EA-AC6E-928F3DDC885E0000-0001-6152-6637 KJ Lu author Y Zhang author YL Cheng author SL Tu author Jiří Friml author 4159519E-F248-11E8-B48F-1D18A9856A870000-0002-8302-7596 JiFr department Tracing Evolution of Auxin Transport and Polarity in Plants project The phytohormone auxin and its directional transport through tissues play a fundamental role in development of higher plants. This polar auxin transport predominantly relies on PIN-FORMED (PIN) auxin exporters. Hence, PIN polarization is crucial for development, but its evolution during the rise of morphological complexity in land plants remains unclear. Here, we performed a cross-species investigation by observing the trafficking and localization of endogenous and exogenous PINs in two bryophytes, Physcomitrium patens and Marchantia polymorpha, and in the flowering plant Arabidopsis thaliana. We confirmed that the GFP fusion did not compromise the auxin export function of all examined PINs by using radioactive auxin export assay and by observing the phenotypic changes in transgenic bryophytes. Endogenous PINs polarize to filamentous apices, while exogenous Arabidopsis PINs distribute symmetrically on the membrane in both bryophytes. In Arabidopsis root epidermis, bryophytic PINs show no defined polarity. Pharmacological interference revealed a strong cytoskeleton dependence of bryophytic but not Arabidopsis PIN polarization. The divergence of PIN polarization and trafficking is also observed within the bryophyte clade and between tissues of individual species. These results collectively reveal a divergence of PIN trafficking and polarity mechanisms throughout land plant evolution and a co-evolution of PIN sequence-based and cell-based polarity mechanisms. https://research-explorer.ista.ac.at/download/14251/14911/2023_PlantCommunications_Tang.pdf application/pdfno Elsevier2024 eng 2590-3462 37528584 00115805450000110.1016/j.xplc.2023.100669 51 Tang, H., Lu, K., Zhang, Y., Cheng, Y., Tu, S., &#38; Friml, J. (2024). Divergence of trafficking and polarization mechanisms for PIN auxin transporters during land plant evolution. <i>Plant Communications</i>. Elsevier. <a href="https://doi.org/10.1016/j.xplc.2023.100669">https://doi.org/10.1016/j.xplc.2023.100669</a> H. Tang, K. Lu, Y. Zhang, Y. Cheng, S. Tu, J. Friml, Plant Communications 5 (2024). Tang H, Lu K, Zhang Y, Cheng Y, Tu S, Friml J. Divergence of trafficking and polarization mechanisms for PIN auxin transporters during land plant evolution. <i>Plant Communications</i>. 2024;5(1). doi:<a href="https://doi.org/10.1016/j.xplc.2023.100669">10.1016/j.xplc.2023.100669</a> Tang H, Lu K, Zhang Y, Cheng Y, Tu S, Friml J. 2024. Divergence of trafficking and polarization mechanisms for PIN auxin transporters during land plant evolution. Plant Communications. 5(1), 100669. Tang, Han, et al. “Divergence of Trafficking and Polarization Mechanisms for PIN Auxin Transporters during Land Plant Evolution.” <i>Plant Communications</i>, vol. 5, no. 1, 100669, Elsevier, 2024, doi:<a href="https://doi.org/10.1016/j.xplc.2023.100669">10.1016/j.xplc.2023.100669</a>. Tang, Han, KJ Lu, Y Zhang, YL Cheng, SL Tu, and Jiří Friml. “Divergence of Trafficking and Polarization Mechanisms for PIN Auxin Transporters during Land Plant Evolution.” <i>Plant Communications</i>. Elsevier, 2024. <a href="https://doi.org/10.1016/j.xplc.2023.100669">https://doi.org/10.1016/j.xplc.2023.100669</a>. H. Tang, K. Lu, Y. Zhang, Y. Cheng, S. Tu, and J. Friml, “Divergence of trafficking and polarization mechanisms for PIN auxin transporters during land plant evolution,” <i>Plant Communications</i>, vol. 5, no. 1. Elsevier, 2024. 142512023-09-01T11:32:02Z2025-08-05T13:27:26Z