Arabinosylation of cell wall extensin is required for the directional response to salinity in roots.
Plant Cell
; 36(9): 3328-3343, 2024 Sep 03.
Article
in En
| MEDLINE
| ID: mdl-38691576
ABSTRACT
Soil salinity is a major contributor to crop yield losses. To improve our understanding of root responses to salinity, we developed and exploited a real-time salt-induced tilting assay. This assay follows root growth upon both gravitropic and salt challenges, revealing that root bending upon tilting is modulated by Na+ ions, but not by osmotic stress. Next, we measured this salt-specific response in 345 natural Arabidopsis (Arabidopsis thaliana) accessions and discovered a genetic locus, encoding the cell wall-modifying enzyme EXTENSIN ARABINOSE DEFICIENT TRANSFERASE (ExAD) that is associated with root bending in the presence of NaCl (hereafter salt). Extensins are a class of structural cell wall glycoproteins known as hydroxyproline (Hyp)-rich glycoproteins, which are posttranslationally modified by O-glycosylation, mostly involving Hyp-arabinosylation. We show that salt-induced ExAD-dependent Hyp-arabinosylation influences root bending responses and cell wall thickness. Roots of exad1 mutant seedlings, which lack Hyp-arabinosylation of extensin, displayed increased thickness of root epidermal cell walls and greater cell wall porosity. They also showed altered gravitropic root bending in salt conditions and a reduced salt-avoidance response. Our results suggest that extensin modification via Hyp-arabinosylation is a unique salt-specific cellular process required for the directional response of roots exposed to salinity.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Cell Wall
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Arabidopsis
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Plant Roots
/
Arabidopsis Proteins
/
Salinity
Language:
En
Journal:
Plant Cell
Journal subject:
BOTANICA
Year:
2024
Document type:
Article
Affiliation country:
Country of publication: