---
OA_type: closed access
_id: '22366'
abstract:
- lang: eng
text: Gravitropism is a fundamental adaptive response in plants that enables directional
growth to optimize resource acquisition. In this study, we employed forward genetic
screening to identify Arabidopsis mutants with defective hypocotyl gravitropism
and isolated the short and agravitropic hypocotyl in dark1 (sad1) mutant, which
carries a point mutation (G110E) in the SAC1 gene encoding a phosphoinositide
phosphatase. Deficiency of SAC1 disrupted gravity-induced polar localization of
PIN3 in endodermal cells, impairing auxin redistribution and leading to hypocotyl
gravitropism defects. Subcellular localization analysis revealed that SAC1 is
partially localized to the PVC/tonoplast and participates in late endosomal trafficking.
The sac1 mutation leads to abnormal vacuolar morphology, which is associated with
defects in amyloplast sedimentation during the gravitropic response in Arabidopsis
shoots. We further revealed that SAC1 interacts with GRV2, a key regulator of
the late endocytic pathway, and that both proteins cooperatively regulate shoot
gravitropism. In summary, this study identified SAC1 as a regulator of shoot gravitropism,
revealing its important role in modulating vacuolar homeostasis, amyloplast sedimentation,
PIN3 trafficking, and auxin distribution. These findings provide insights into
the molecular mechanisms linking membrane transport to environmental adaptation
in plants.
acknowledgement: We acknowledge Prof. Dolf Weijers (Wageningen University), Prof.Karin
Schumacher (Heidelberg University), Prof. Yohann Boutt ´e(Universit ´e de Bordeaux),
and Prof. Jinbo Shen (Zhejiang A&FUniversity) for providing published plasmids and
Arabidopsislines. We thank Dr. Gergely Moln ´ar (ISTA) for help with NGS dataanalysis,
and Prof. Jianru Zuo (IGDB, CAS), Prof. Chengbin Xiang(USTC), and Prof. Zhong Zhao
(USTC) for critical comments onthe manuscript. We thank the staff members of the
Mass Spec-trometry System at the National Facility for Protein Science inShanghai
(NFPS), Zhangjiang Lab, China for providing technicalsupport and assistance in data
collection and analysis. This workwas supported by grants from the National Natural
Science Foun-dation of China (32570366, and 32321001 to ST), the Natural Sci-ence
Foundation of Anhui Province (2508085QC070 to MK), theFundamental Research Funds
for the Central Universities(WK9100250095 to MK, and WK9100000021 to ST), the ForestryBureau
of Anhui Province (AHLYJBGS-2024-01 to ST), the Centerfor Advanced Interdisciplinary
Science and Biomedicine of IHM,Division of Life Sciences and Medicine, University
of Science andTechnology of China (QYPY20220012 to ST), the USTC ResearchFunds of
the Double First-Class Initiative (YD9100002016 to ST),and start-up funding from
the University of Science and Technol-ogy of China and the Chinese Academy of Sciences(GG9100007007,
KY9100000026, KY9100000051, XKTS-202591014,XKTS-2026910122, and KJ2070000079 to
ST).
article_number: e71042
article_processing_charge: No
article_type: original
author:
- first_name: Lianghanxiao
full_name: Sun, Lianghanxiao
last_name: Sun
- first_name: Wenxin
full_name: Jia, Wenxin
last_name: Jia
- first_name: Yanbo
full_name: Mao, Yanbo
last_name: Mao
- first_name: Xin
full_name: Li, Xin
last_name: Li
- first_name: Mengjuan
full_name: Kong, Mengjuan
last_name: Kong
- first_name: Ji
full_name: She, Ji
last_name: She
- first_name: Jiří
full_name: Friml, Jiří
id: 4159519E-F248-11E8-B48F-1D18A9856A87
last_name: Friml
orcid: 0000-0002-8302-7596
- first_name: Shutang
full_name: Tan, Shutang
id: 2DE75584-F248-11E8-B48F-1D18A9856A87
last_name: Tan
orcid: 0000-0002-0471-8285
citation:
ama: Sun L, Jia W, Mao Y, et al. Regulation of shoot gravitropism and branching
angle by the GRV2-SAC1 axis in Arabidopsis. The Plant Journal. 2026;127(1).
doi:10.1111/tpj.71042
apa: Sun, L., Jia, W., Mao, Y., Li, X., Kong, M., She, J., … Tan, S. (2026). Regulation
of shoot gravitropism and branching angle by the GRV2-SAC1 axis in Arabidopsis.
The Plant Journal. Wiley. https://doi.org/10.1111/tpj.71042
chicago: Sun, Lianghanxiao, Wenxin Jia, Yanbo Mao, Xin Li, Mengjuan Kong, Ji She,
Jiří Friml, and Shutang Tan. “Regulation of Shoot Gravitropism and Branching Angle
by the GRV2-SAC1 Axis in Arabidopsis.” The Plant Journal. Wiley, 2026.
https://doi.org/10.1111/tpj.71042.
ieee: L. Sun et al., “Regulation of shoot gravitropism and branching angle
by the GRV2-SAC1 axis in Arabidopsis,” The Plant Journal, vol. 127, no.
1. Wiley, 2026.
ista: Sun L, Jia W, Mao Y, Li X, Kong M, She J, Friml J, Tan S. 2026. Regulation
of shoot gravitropism and branching angle by the GRV2-SAC1 axis in Arabidopsis.
The Plant Journal. 127(1), e71042.
mla: Sun, Lianghanxiao, et al. “Regulation of Shoot Gravitropism and Branching Angle
by the GRV2-SAC1 Axis in Arabidopsis.” The Plant Journal, vol. 127, no.
1, e71042, Wiley, 2026, doi:10.1111/tpj.71042.
short: L. Sun, W. Jia, Y. Mao, X. Li, M. Kong, J. She, J. Friml, S. Tan, The Plant
Journal 127 (2026).
das_tickbox: '1'
dataavailabilitystatement: Biological materials (seeds, plasmids) are available upon
request from ST (sttan@ustc.edu.cn). The data that support the findings of this study
are available on request from the corresponding author. The data are not publicly
available due to privacy or ethical restrictions.
date_created: 2026-07-19T22:01:47Z
date_published: 2026-07-01T00:00:00Z
date_updated: 2026-07-20T13:53:44Z
day: '01'
department:
- _id: JiFr
doi: 10.1111/tpj.71042
external_id:
pmid:
- '42438075'
intvolume: ' 127'
issue: '1'
keyword:
- auxin
- SAC1
- GRV2
- PIN3
- vacuole
- gravitropism
- Arabidopsis
language:
- iso: eng
month: '07'
oa_version: None
pmid: 1
publication: The Plant Journal
publication_identifier:
eissn:
- 1365-313X
issn:
- 0960-7412
publication_status: published
publisher: Wiley
quality_controlled: '1'
researchdata_availability: upon request
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Regulation of shoot gravitropism and branching angle by the GRV2-SAC1 axis
in Arabidopsis
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 127
year: '2026'
...
---
_id: '9986'
abstract:
- lang: eng
text: Size control is a fundamental question in biology, showing incremental complexity
in plants, whose cells possess a rigid cell wall. The phytohormone auxin is a
vital growth regulator with central importance for differential growth control.
Our results indicate that auxin-reliant growth programs affect the molecular complexity
of xyloglucans, the major type of cell wall hemicellulose in eudicots. Auxin-dependent
induction and repression of growth coincide with reduced and enhanced molecular
complexity of xyloglucans, respectively. In agreement with a proposed function
in growth control, genetic interference with xyloglucan side decorations distinctly
modulates auxin-dependent differential growth rates. Our work proposes that auxin-dependent
growth programs have a spatially defined effect on xyloglucan’s molecular structure,
which in turn affects cell wall mechanics and specifies differential, gravitropic
hypocotyl growth.
acknowledgement: "We are grateful to Paul Knox, Markus Pauly, Malcom O’Neill, and
Ignacio Zarra for providing published material; the BOKU-VIBT Imaging Center for
access and M. Debreczeny for expertise; J.I. Thaker and Georg Seifert for critical
reading.\r\n"
article_number: '9222'
article_processing_charge: Yes
article_type: original
author:
- first_name: Silvia Melina
full_name: Velasquez, Silvia Melina
last_name: Velasquez
- first_name: Xiaoyuan
full_name: Guo, Xiaoyuan
last_name: Guo
- first_name: Marçal
full_name: Gallemi, Marçal
id: 460C6802-F248-11E8-B48F-1D18A9856A87
last_name: Gallemi
orcid: 0000-0003-4675-6893
- first_name: Bibek
full_name: Aryal, Bibek
last_name: Aryal
- first_name: Peter
full_name: Venhuizen, Peter
last_name: Venhuizen
- first_name: Elke
full_name: Barbez, Elke
last_name: Barbez
- first_name: Kai Alexander
full_name: Dünser, Kai Alexander
last_name: Dünser
- first_name: Martin
full_name: Darino, Martin
last_name: Darino
- first_name: Aleš
full_name: Pӗnčík, Aleš
last_name: Pӗnčík
- first_name: Ondřej
full_name: Novák, Ondřej
last_name: Novák
- first_name: Maria
full_name: Kalyna, Maria
last_name: Kalyna
- first_name: Gregory
full_name: Mouille, Gregory
last_name: Mouille
- first_name: Eva
full_name: Benková, Eva
id: 38F4F166-F248-11E8-B48F-1D18A9856A87
last_name: Benková
orcid: 0000-0002-8510-9739
- first_name: Rishikesh P.
full_name: Bhalerao, Rishikesh P.
last_name: Bhalerao
- first_name: Jozef
full_name: Mravec, Jozef
last_name: Mravec
- first_name: Jürgen
full_name: Kleine-Vehn, Jürgen
last_name: Kleine-Vehn
citation:
ama: Velasquez SM, Guo X, Gallemi M, et al. Xyloglucan remodeling defines auxin-dependent
differential tissue expansion in plants. International Journal of Molecular
Sciences. 2021;22(17). doi:10.3390/ijms22179222
apa: Velasquez, S. M., Guo, X., Gallemi, M., Aryal, B., Venhuizen, P., Barbez, E.,
… Kleine-Vehn, J. (2021). Xyloglucan remodeling defines auxin-dependent differential
tissue expansion in plants. International Journal of Molecular Sciences.
MDPI. https://doi.org/10.3390/ijms22179222
chicago: Velasquez, Silvia Melina, Xiaoyuan Guo, Marçal Gallemi, Bibek Aryal, Peter
Venhuizen, Elke Barbez, Kai Alexander Dünser, et al. “Xyloglucan Remodeling Defines
Auxin-Dependent Differential Tissue Expansion in Plants.” International Journal
of Molecular Sciences. MDPI, 2021. https://doi.org/10.3390/ijms22179222.
ieee: S. M. Velasquez et al., “Xyloglucan remodeling defines auxin-dependent
differential tissue expansion in plants,” International Journal of Molecular
Sciences, vol. 22, no. 17. MDPI, 2021.
ista: Velasquez SM, Guo X, Gallemi M, Aryal B, Venhuizen P, Barbez E, Dünser KA,
Darino M, Pӗnčík A, Novák O, Kalyna M, Mouille G, Benková E, Bhalerao RP, Mravec
J, Kleine-Vehn J. 2021. Xyloglucan remodeling defines auxin-dependent differential
tissue expansion in plants. International Journal of Molecular Sciences. 22(17),
9222.
mla: Velasquez, Silvia Melina, et al. “Xyloglucan Remodeling Defines Auxin-Dependent
Differential Tissue Expansion in Plants.” International Journal of Molecular
Sciences, vol. 22, no. 17, 9222, MDPI, 2021, doi:10.3390/ijms22179222.
short: S.M. Velasquez, X. Guo, M. Gallemi, B. Aryal, P. Venhuizen, E. Barbez, K.A.
Dünser, M. Darino, A. Pӗnčík, O. Novák, M. Kalyna, G. Mouille, E. Benková, R.P.
Bhalerao, J. Mravec, J. Kleine-Vehn, International Journal of Molecular Sciences
22 (2021).
corr_author: '1'
date_created: 2021-09-05T22:01:24Z
date_published: 2021-08-26T00:00:00Z
date_updated: 2024-10-09T21:00:50Z
day: '26'
ddc:
- '575'
department:
- _id: EvBe
doi: 10.3390/ijms22179222
external_id:
isi:
- '000694347100001'
pmid:
- '34502129'
file:
- access_level: open_access
checksum: 6b7055cf89f1b7ed8594c3fdf56f000b
content_type: application/pdf
creator: cchlebak
date_created: 2021-09-06T12:50:19Z
date_updated: 2021-09-07T09:04:53Z
file_id: '9988'
file_name: 2021_IntJMolecularSciences_Velasquez.pdf
file_size: 2162247
relation: main_file
file_date_updated: 2021-09-07T09:04:53Z
has_accepted_license: '1'
intvolume: ' 22'
isi: 1
issue: '17'
keyword:
- auxin
- growth
- cell wall
- xyloglucans
- hypocotyls
- gravitropism
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
pmid: 1
publication: International Journal of Molecular Sciences
publication_identifier:
eissn:
- 1422-0067
issn:
- 1661-6596
publication_status: published
publisher: MDPI
quality_controlled: '1'
scopus_import: '1'
status: public
title: Xyloglucan remodeling defines auxin-dependent differential tissue expansion
in plants
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
volume: 22
year: '2021'
...