--- _id: '203' abstract: - lang: eng text: Asymmetric auxin distribution is instrumental for the differential growth that causes organ bending on tropic stimuli and curvatures during plant development. Local differences in auxin concentrations are achieved mainly by polarized cellular distribution of PIN auxin transporters, but whether other mechanisms involving auxin homeostasis are also relevant for the formation of auxin gradients is not clear. Here we show that auxin methylation is required for asymmetric auxin distribution across the hypocotyl, particularly during its response to gravity. We found that loss-of-function mutants in Arabidopsis IAA CARBOXYL METHYLTRANSFERASE1 (IAMT1) prematurely unfold the apical hook, and that their hypocotyls are impaired in gravitropic reorientation. This defect is linked to an auxin-dependent increase in PIN gene expression, leading to an increased polar auxin transport and lack of asymmetric distribution of PIN3 in the iamt1 mutant. Gravitropic reorientation in the iamt1 mutant could be restored with either endodermis-specific expression of IAMT1 or partial inhibition of polar auxin transport, which also results in normal PIN gene expression levels. We propose that IAA methylation is necessary in gravity-sensing cells to restrict polar auxin transport within the range of auxin levels that allow for differential responses. article_processing_charge: No author: - first_name: Mohamad full_name: Abbas, Mohamad id: 47E8FC1C-F248-11E8-B48F-1D18A9856A87 last_name: Abbas - first_name: García J full_name: Hernández, García J last_name: Hernández - first_name: Stephan full_name: Pollmann, Stephan last_name: Pollmann - first_name: Sophia L full_name: Samodelov, Sophia L last_name: Samodelov - first_name: Martina full_name: Kolb, Martina last_name: Kolb - first_name: Jirí full_name: Friml, Jirí id: 4159519E-F248-11E8-B48F-1D18A9856A87 last_name: Friml orcid: 0000-0002-8302-7596 - first_name: Ulrich Z full_name: Hammes, Ulrich Z last_name: Hammes - first_name: Matias D full_name: Zurbriggen, Matias D last_name: Zurbriggen - first_name: Miguel full_name: Blázquez, Miguel last_name: Blázquez - first_name: David full_name: Alabadí, David last_name: Alabadí citation: ama: Abbas M, Hernández GJ, Pollmann S, et al. Auxin methylation is required for differential growth in Arabidopsis. PNAS. 2018;115(26):6864-6869. doi:10.1073/pnas.1806565115 apa: Abbas, M., Hernández, G. J., Pollmann, S., Samodelov, S. L., Kolb, M., Friml, J., … Alabadí, D. (2018). Auxin methylation is required for differential growth in Arabidopsis. PNAS. National Academy of Sciences. https://doi.org/10.1073/pnas.1806565115 chicago: Abbas, Mohamad, García J Hernández, Stephan Pollmann, Sophia L Samodelov, Martina Kolb, Jiří Friml, Ulrich Z Hammes, Matias D Zurbriggen, Miguel Blázquez, and David Alabadí. “Auxin Methylation Is Required for Differential Growth in Arabidopsis.” PNAS. National Academy of Sciences, 2018. https://doi.org/10.1073/pnas.1806565115. ieee: M. Abbas et al., “Auxin methylation is required for differential growth in Arabidopsis,” PNAS, vol. 115, no. 26. National Academy of Sciences, pp. 6864–6869, 2018. ista: Abbas M, Hernández GJ, Pollmann S, Samodelov SL, Kolb M, Friml J, Hammes UZ, Zurbriggen MD, Blázquez M, Alabadí D. 2018. Auxin methylation is required for differential growth in Arabidopsis. PNAS. 115(26), 6864–6869. mla: Abbas, Mohamad, et al. “Auxin Methylation Is Required for Differential Growth in Arabidopsis.” PNAS, vol. 115, no. 26, National Academy of Sciences, 2018, pp. 6864–69, doi:10.1073/pnas.1806565115. short: M. Abbas, G.J. Hernández, S. Pollmann, S.L. Samodelov, M. Kolb, J. Friml, U.Z. Hammes, M.D. Zurbriggen, M. Blázquez, D. Alabadí, PNAS 115 (2018) 6864–6869. date_created: 2018-12-11T11:45:11Z date_published: 2018-06-26T00:00:00Z date_updated: 2023-09-08T13:24:40Z day: '26' department: - _id: JiFr doi: 10.1073/pnas.1806565115 ec_funded: 1 external_id: isi: - '000436245000096' intvolume: ' 115' isi: 1 issue: '26' language: - iso: eng main_file_link: - open_access: '1' url: http://eprints.nottingham.ac.uk/52388/ month: '06' oa: 1 oa_version: None page: 6864-6869 project: - _id: 25716A02-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '282300' name: Polarity and subcellular dynamics in plants publication: PNAS publication_status: published publisher: National Academy of Sciences publist_id: '7710' quality_controlled: '1' scopus_import: '1' status: public title: Auxin methylation is required for differential growth in Arabidopsis type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 115 year: '2018' ... --- _id: '1212' abstract: - lang: eng text: 'Plants adjust their growth according to gravity. Gravitropism involves gravity perception, signal transduction, and asymmetric growth response, with organ bending as a consequence [1]. Asymmetric growth results from the asymmetric distribution of the plant-specific signaling molecule auxin [2] that is generated by lateral transport, mediated in the hypocotyl predominantly by the auxin transporter PIN-FORMED3 (PIN3) [3–5]. Gravity stimulation polarizes PIN3 to the bottom sides of endodermal cells, correlating with increased auxin accumulation in adjacent tissues at the lower side of the stimulated organ, where auxin induces cell elongation and, hence, organ bending. A curvature response allows the hypocotyl to resume straight growth at a defined angle [6], implying that at some point auxin symmetry is restored to prevent overbending. Here, we present initial insights into cellular and molecular mechanisms that lead to the termination of the tropic response. We identified an auxin feedback on PIN3 polarization as underlying mechanism that restores symmetry of the PIN3-dependent auxin flow. Thus, two mechanistically distinct PIN3 polarization events redirect auxin fluxes at different time points of the gravity response: first, gravity-mediated redirection of PIN3-mediated auxin flow toward the lower hypocotyl side, where auxin gradually accumulates and promotes growth, and later PIN3 polarization to the opposite cell side, depleting this auxin maximum to end the bending. Accordingly, genetic or pharmacological interference with the late PIN3 polarization prevents termination of the response and leads to hypocotyl overbending. This observation reveals a role of auxin feedback on PIN polarity in the termination of the tropic response. © 2016 Elsevier Ltd' acknowledgement: "We thank Dr. Jie Li (Key Laboratory of Plant Molecular Physiology, Chinese Academy of Science, China) for the pPIN3::PIN3-GFP/DII::VENUS line and Martine De Cock for help in preparing the manuscript. This work was supported by the European Research Council (project ERC-2011-StG-20101109-PSDP), by the Czech Science Foundation GAČR (GA13-40637S) to J.F., and by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601) to H.S.R. H.R. is indebted to the Agency for Innovation by Science and Technology (IWT) for a predoctoral fellowship.\r\n" author: - first_name: Hana full_name: Rakusová, Hana last_name: Rakusová - first_name: Mohamad full_name: Abbas, Mohamad id: 47E8FC1C-F248-11E8-B48F-1D18A9856A87 last_name: Abbas - first_name: Huibin full_name: Han, Huibin id: 31435098-F248-11E8-B48F-1D18A9856A87 last_name: Han - first_name: Siyuan full_name: Song, Siyuan last_name: Song - first_name: Hélène full_name: Robert, Hélène last_name: Robert - first_name: Jirí full_name: Friml, Jirí id: 4159519E-F248-11E8-B48F-1D18A9856A87 last_name: Friml orcid: 0000-0002-8302-7596 citation: ama: Rakusová H, Abbas M, Han H, Song S, Robert H, Friml J. Termination of shoot gravitropic responses by auxin feedback on PIN3 polarity. Current Biology. 2016;26(22):3026-3032. doi:10.1016/j.cub.2016.08.067 apa: Rakusová, H., Abbas, M., Han, H., Song, S., Robert, H., & Friml, J. (2016). Termination of shoot gravitropic responses by auxin feedback on PIN3 polarity. Current Biology. Cell Press. https://doi.org/10.1016/j.cub.2016.08.067 chicago: Rakusová, Hana, Mohamad Abbas, Huibin Han, Siyuan Song, Hélène Robert, and Jiří Friml. “Termination of Shoot Gravitropic Responses by Auxin Feedback on PIN3 Polarity.” Current Biology. Cell Press, 2016. https://doi.org/10.1016/j.cub.2016.08.067. ieee: H. Rakusová, M. Abbas, H. Han, S. Song, H. Robert, and J. Friml, “Termination of shoot gravitropic responses by auxin feedback on PIN3 polarity,” Current Biology, vol. 26, no. 22. Cell Press, pp. 3026–3032, 2016. ista: Rakusová H, Abbas M, Han H, Song S, Robert H, Friml J. 2016. Termination of shoot gravitropic responses by auxin feedback on PIN3 polarity. Current Biology. 26(22), 3026–3032. mla: Rakusová, Hana, et al. “Termination of Shoot Gravitropic Responses by Auxin Feedback on PIN3 Polarity.” Current Biology, vol. 26, no. 22, Cell Press, 2016, pp. 3026–32, doi:10.1016/j.cub.2016.08.067. short: H. Rakusová, M. Abbas, H. Han, S. Song, H. Robert, J. Friml, Current Biology 26 (2016) 3026–3032. date_created: 2018-12-11T11:50:44Z date_published: 2016-11-21T00:00:00Z date_updated: 2021-01-12T06:49:08Z day: '21' ddc: - '581' department: - _id: JiFr doi: 10.1016/j.cub.2016.08.067 ec_funded: 1 file: - access_level: open_access checksum: 79ed2498185a027cf51a8f88100379e6 content_type: application/pdf creator: system date_created: 2018-12-12T10:09:33Z date_updated: 2020-07-14T12:44:39Z file_id: '4757' file_name: IST-2018-1008-v1+1_Rakusova_CurrBiol_2016_proof.pdf file_size: 5391923 relation: main_file file_date_updated: 2020-07-14T12:44:39Z has_accepted_license: '1' intvolume: ' 26' issue: '22' language: - iso: eng month: '11' oa: 1 oa_version: Submitted Version page: 3026 - 3032 project: - _id: 25716A02-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '282300' name: Polarity and subcellular dynamics in plants publication: Current Biology publication_status: published publisher: Cell Press publist_id: '6138' pubrep_id: '1008' quality_controlled: '1' scopus_import: 1 status: public title: Termination of shoot gravitropic responses by auxin feedback on PIN3 polarity type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 26 year: '2016' ...