---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '22301'
abstract:
- lang: eng
  text: Auxin, primarily indole-3-acetic acid (IAA), is a central regulator of growth
    and development in land plants, but its physiological role in chlorophyte algae
    remains unclear. Here, we show that exogenous IAA modulates growth in Chlorella
    sorokiniana, Chlorella variabilis, and Chlamydomonas reinhardtii in a concentration-dependent
    manner. Low IAA concentrations promoted growth by accelerating the onset of cell
    division without affecting cell size, whereas higher concentrations inhibited
    proliferation. Radiotracer assays showed that all three species take up and release
    IAA across the plasma membrane through a combination of passive diffusion and
    energy-dependent, saturable processes. Competition by excess unlabeled natural
    and synthetic auxins further supported the presence of carrier-mediated transport
    with broad substrate recognition. Phylogenetic analyses identified potential PIN-like
    auxin exporters in chlorophytes and other non-plant eukaryotes, and structural
    modeling supported conservation of the overall PIN fold and predicted auxin-binding
    residues. However, functional assays in Xenopus laevis oocytes, tobacco BY-2 cultured
    cells, and Arabidopsis thaliana did not support a role for these proteins in directional
    auxin export. Instead, non-plant PIN homologs localized predominantly to the endoplasmic
    reticulum and showed limited or no transport activity in heterologous systems.
    Together, these findings indicate that auxin responsiveness and basic cellular
    auxin transport predate canonical PIN-mediated directional auxin export, which
    appears to be a later innovation of the streptophyte lineage.
acknowledged_ssus:
- _id: Bio
- _id: NanoFab
acknowledgement: Research in the Friml group was supported by the European Research
  Council (ERC) under grant agreement No. 101142681 (CYNIPS), and by the Austrian
  Science Fund (FWF) through projects I 6123-B and P 37051-B. A DOC Fellowship from
  the Austrian Academy of Sciences (ÖAW; PR.C0102.1.F.1023.A.2) provided additional
  support. Work was partly supported by the Deutsche Forschungsgemeinschaft (DFG,
  German Research Foundation) under grant HA 3468/8-1. We thank the Imaging and Optics
  Facility (IOF) at the Institute of Science and Technology Austria (ISTA) for support
  with confocal imaging, and the Nanofabrication Facility at ISTA for assistance with
  microfluidic device fabrication. We also acknowledge the microscopy service of IFIEB
  CAS, supported by MEYS CR (LM2023050 Czech-BioImaging). Open Access funding provided
  by Institute of Science and Technology Austria.
article_number: jipb.70309
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Adrijana
  full_name: Smoljan, Adrijana
  id: cced8a85-223e-11ed-af04-b0596c55053b
  last_name: Smoljan
- first_name: Sarah
  full_name: Koutnik‐Abele, Sarah
  last_name: Koutnik‐Abele
- first_name: Dmitrii
  full_name: Vladimirtsev, Dmitrii
  id: 60466724-5355-11ee-ae5a-fa55e8f99c3d
  last_name: Vladimirtsev
- first_name: Petr
  full_name: Klíma, Petr
  last_name: Klíma
- first_name: Anita
  full_name: Bírošíková, Anita
  last_name: Bírošíková
- first_name: Yuzhou
  full_name: Zhang, Yuzhou
  id: 3B6137F2-F248-11E8-B48F-1D18A9856A87
  last_name: Zhang
  orcid: 0000-0003-2627-6956
- first_name: Jack
  full_name: Merrin, Jack
  id: 4515C308-F248-11E8-B48F-1D18A9856A87
  last_name: Merrin
  orcid: 0000-0001-5145-4609
- first_name: Maximilian
  full_name: Schuster, Maximilian
  id: 37e65def-d415-11eb-ae59-a7b67be103db
  last_name: Schuster
- first_name: Katarina
  full_name: Kurtović, Katarina
  last_name: Kurtović
- first_name: Ulrich Z.
  full_name: Hammes, Ulrich Z.
  last_name: Hammes
- first_name: Jan
  full_name: Petrášek, Jan
  last_name: Petrášek
- first_name: Jiří
  full_name: Friml, Jiří
  id: 4159519E-F248-11E8-B48F-1D18A9856A87
  last_name: Friml
  orcid: 0000-0002-8302-7596
citation:
  ama: Smoljan A, Koutnik‐Abele S, Vladimirtsev D, et al. Auxin response and PIN‐mediated
    transport in chlorophyte algae. <i>Journal of Integrative Plant Biology</i>. 2026.
    doi:<a href="https://doi.org/10.1111/jipb.70309">10.1111/jipb.70309</a>
  apa: Smoljan, A., Koutnik‐Abele, S., Vladimirtsev, D., Klíma, P., Bírošíková, A.,
    Zhang, Y., … Friml, J. (2026). Auxin response and PIN‐mediated transport in chlorophyte
    algae. <i>Journal of Integrative Plant Biology</i>. Wiley. <a href="https://doi.org/10.1111/jipb.70309">https://doi.org/10.1111/jipb.70309</a>
  chicago: Smoljan, Adrijana, Sarah Koutnik‐Abele, Dmitrii Vladimirtsev, Petr Klíma,
    Anita Bírošíková, Yuzhou Zhang, Jack Merrin, et al. “Auxin Response and PIN‐mediated
    Transport in Chlorophyte Algae.” <i>Journal of Integrative Plant Biology</i>.
    Wiley, 2026. <a href="https://doi.org/10.1111/jipb.70309">https://doi.org/10.1111/jipb.70309</a>.
  ieee: A. Smoljan <i>et al.</i>, “Auxin response and PIN‐mediated transport in chlorophyte
    algae,” <i>Journal of Integrative Plant Biology</i>. Wiley, 2026.
  ista: Smoljan A, Koutnik‐Abele S, Vladimirtsev D, Klíma P, Bírošíková A, Zhang Y,
    Merrin J, Schuster M, Kurtović K, Hammes UZ, Petrášek J, Friml J. 2026. Auxin
    response and PIN‐mediated transport in chlorophyte algae. Journal of Integrative
    Plant Biology., jipb. 70309.
  mla: Smoljan, Adrijana, et al. “Auxin Response and PIN‐mediated Transport in Chlorophyte
    Algae.” <i>Journal of Integrative Plant Biology</i>, jipb. 70309, Wiley, 2026,
    doi:<a href="https://doi.org/10.1111/jipb.70309">10.1111/jipb.70309</a>.
  short: A. Smoljan, S. Koutnik‐Abele, D. Vladimirtsev, P. Klíma, A. Bírošíková, Y.
    Zhang, J. Merrin, M. Schuster, K. Kurtović, U.Z. Hammes, J. Petrášek, J. Friml,
    Journal of Integrative Plant Biology (2026).
corr_author: '1'
das_tickbox: '0'
date_created: 2026-07-13T10:44:55Z
date_published: 2026-06-10T00:00:00Z
date_updated: 2026-07-13T14:26:31Z
day: '10'
ddc:
- '580'
department:
- _id: JiFr
- _id: GradSch
- _id: NanoFab
- _id: Bio
doi: 10.1111/jipb.70309
external_id:
  pmid:
  - '42271607'
has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1111/jipb.70309
month: '06'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 8f347782-16d5-11f0-9cad-8c19706ee739
  grant_number: '101142681'
  name: Cyclic nucleotides as second messengers in plants
- _id: bd76d395-d553-11ed-ba76-f678c14f9033
  grant_number: I06123
  name: Peptide receptors for auxin canalization in Arabidopsis
- _id: 7bcece63-9f16-11ee-852c-ae94e099eeb6
  grant_number: P37051
  name: Guanylate cyclase activity of TIR1/AFBs auxin receptors
publication: Journal of Integrative Plant Biology
publication_identifier:
  eissn:
  - 1744-7909
  issn:
  - 1672-9072
publication_status: epub_ahead
publisher: Wiley
quality_controlled: '1'
researchdata_availability: no
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Auxin response and PIN‐mediated transport in chlorophyte algae
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...