--- _id: '8589' abstract: - lang: eng text: The plant hormone auxin plays indispensable roles in plant growth and development. An essential level of regulation in auxin action is the directional auxin transport within cells. The establishment of auxin gradient in plant tissue has been attributed to local auxin biosynthesis and directional intercellular auxin transport, which both are controlled by various environmental and developmental signals. It is well established that asymmetric auxin distribution in cells is achieved by polarly localized PIN-FORMED (PIN) auxin efflux transporters. Despite the initial insights into cellular mechanisms of PIN polarization obtained from the last decades, the molecular mechanism and specific regulators mediating PIN polarization remains elusive. In this thesis, we aim to find novel players in PIN subcellular polarity regulation during Arabidopsis development. We first characterize the physiological effect of piperonylic acid (PA) on Arabidopsis hypocotyl gravitropic bending and PIN polarization. Secondly, we reveal the importance of SCFTIR1/AFB auxin signaling pathway in shoot gravitropism bending termination. In addition, we also explore the role of myosin XI complex, and actin cytoskeleton in auxin feedback regulation on PIN polarity. In Chapter 1, we give an overview of the current knowledge about PIN-mediated auxin fluxes in various plant tropic responses. In Chapter 2, we study the physiological effect of PA on shoot gravitropic bending. Our results show that PA treatment inhibits auxin-mediated PIN3 repolarization by interfering with PINOID and PIN3 phosphorylation status, ultimately leading to hyperbending hypocotyls. In Chapter 3, we provide evidence to show that the SCFTIR1/AFB nuclear auxin signaling pathway is crucial and required for auxin-mediated PIN3 repolarization and shoot gravitropic bending termination. In Chapter 4, we perform a phosphoproteomics approach and identify the motor protein Myosin XI and its binding protein, the MadB2 family, as an essential regulator of PIN polarity for auxin-canalization related developmental processes. In Chapter 5, we demonstrate the vital role of actin cytoskeleton in auxin feedback on PIN polarity by regulating PIN subcellular trafficking. Overall, the data presented in this PhD thesis brings novel insights into the PIN polar localization regulation that resulted in the (re)establishment of the polar auxin flow and gradient in response to environmental stimuli during plant development. acknowledged_ssus: - _id: Bio - _id: LifeSc acknowledgement: I also want to thank the China Scholarship Council for supporting my study during the year from 2015 to 2019. I also want to thank IST facilities – the Bioimaging facility, the media kitchen, the plant facility and all of the campus services, for their support. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Huibin full_name: Han, Huibin id: 31435098-F248-11E8-B48F-1D18A9856A87 last_name: Han citation: ama: Han H. Novel insights into PIN polarity regulation during Arabidopsis development. 2020. doi:10.15479/AT:ISTA:8589 apa: Han, H. (2020). Novel insights into PIN polarity regulation during Arabidopsis development. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:8589 chicago: Han, Huibin. “Novel Insights into PIN Polarity Regulation during Arabidopsis Development.” Institute of Science and Technology Austria, 2020. https://doi.org/10.15479/AT:ISTA:8589. ieee: H. Han, “Novel insights into PIN polarity regulation during Arabidopsis development,” Institute of Science and Technology Austria, 2020. ista: Han H. 2020. Novel insights into PIN polarity regulation during Arabidopsis development. Institute of Science and Technology Austria. mla: Han, Huibin. Novel Insights into PIN Polarity Regulation during Arabidopsis Development. Institute of Science and Technology Austria, 2020, doi:10.15479/AT:ISTA:8589. short: H. Han, Novel Insights into PIN Polarity Regulation during Arabidopsis Development, Institute of Science and Technology Austria, 2020. date_created: 2020-09-30T14:50:51Z date_published: 2020-09-30T00:00:00Z date_updated: 2023-09-07T13:13:05Z day: '30' ddc: - '580' degree_awarded: PhD department: - _id: JiFr doi: 10.15479/AT:ISTA:8589 file: - access_level: closed checksum: c4bda1947d4c09c428ac9ce667b02327 content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2020-09-30T14:50:20Z date_updated: 2020-09-30T14:50:20Z file_id: '8590' file_name: 2020_Han_Thesis.docx file_size: 49198118 relation: source_file - access_level: open_access checksum: 3f4f5d1718c2230adf30639ecaf8a00b content_type: application/pdf creator: dernst date_created: 2020-09-30T14:49:59Z date_updated: 2021-10-01T13:33:02Z file_id: '8591' file_name: 2020_Han_Thesis.pdf file_size: 15513963 relation: main_file file_date_updated: 2021-10-01T13:33:02Z has_accepted_license: '1' language: - iso: eng month: '09' oa: 1 oa_version: Published Version page: '164' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '7643' relation: part_of_dissertation status: public status: public supervisor: - first_name: Jiří full_name: Friml, Jiří id: 4159519E-F248-11E8-B48F-1D18A9856A87 last_name: Friml orcid: 0000-0002-8302-7596 title: Novel insights into PIN polarity regulation during Arabidopsis development type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2020' ...