Endoplasmic reticulum calnexins participate in the primary root growth response to phosphate deficiency.
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State: Public
Version: Author's accepted manuscript
License: Not specified
Serval ID
serval:BIB_03BEF9A16860
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Endoplasmic reticulum calnexins participate in the primary root growth response to phosphate deficiency.
Journal
Plant physiology
ISSN
1532-2548 (Electronic)
ISSN-L
0032-0889
Publication state
Published
Issued date
17/03/2023
Peer-reviewed
Oui
Volume
191
Number
3
Pages
1719-1733
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Publication Status: ppublish
Abstract
Accumulation of incompletely folded proteins in the endoplasmic reticulum (ER) leads to ER stress, activates ER protein degradation pathways, and upregulates genes involved in protein folding. This process is known as the unfolded protein response (UPR). The role of ER protein folding in plant responses to nutrient deficiencies is unclear. We analyzed Arabidopsis (Arabidopsis thaliana) mutants affected in ER protein quality control and established that both CALNEXIN (CNX) genes function in the primary root response to phosphate (Pi) deficiency. CNX1 and CNX2 are homologous ER lectins promoting protein folding of N-glycosylated proteins via the recognition of the GlcMan9GlcNAc2 glycan. Growth of cnx1-1 and cnx2-2 single mutants was similar to that of the wild type under high and low Pi conditions, but the cnx1-1 cnx2-2 double mutant showed decreased primary root growth under low Pi conditions due to reduced meristematic cell division. This phenotype was specific to Pi deficiency; the double mutant responded normally to osmotic and salt stress. Expression of CNX2 mutated in amino acids involved in binding the GlcMan9GlcNAc2 glycan failed to complement the cnx1-1 cnx2-2 mutant. The root growth phenotype was Fe-dependent and was associated with root apoplastic Fe accumulation. Two genes involved in Fe-dependent inhibition of primary root growth under Pi deficiency, the ferroxidase LOW PHOSPHATE 1 (LPR1) and P5-type ATPase PLEIOTROPIC DRUG RESISTANCE 2 (PDR2) were epistatic to CNX1/CNX2. Overexpressing PDR2 failed to complement the cnx1-1 cnx2-2 root phenotype. The cnx1-1 cnx2-2 mutant showed no evidence of UPR activation, indicating a limited effect on ER protein folding. CNX might process a set of N-glycosylated proteins specifically involved in the response to Pi deficiency.
Keywords
Calnexin/genetics, Calnexin/metabolism, Arabidopsis Proteins/genetics, Arabidopsis Proteins/metabolism, Arabidopsis/metabolism, Molecular Chaperones/metabolism, Endoplasmic Reticulum/metabolism, Endoplasmic Reticulum Stress/genetics, Phosphates/metabolism, Glycoproteins/metabolism, Adenosine Triphosphatases/metabolism
Pubmed
Web of science
Create date
03/01/2023 16:33
Last modification date
06/08/2023 7:08