Galactosylation of rhamnogalacturonan-II for cell wall pectin biosynthesis is critical for root apoplastic iron reallocation in Arabidopsis.
Mol Plant
; 14(10): 1640-1651, 2021 10 04.
Article
em En
| MEDLINE
| ID: mdl-34171482
ABSTRACT
Apoplastic iron (Fe) in roots represents an essential Fe storage pool. Reallocation of apoplastic Fe is of great importance to plants experiencing Fe deprivation, but how this reallocation process is regulated remains elusive, likely because of the highly complex cell wall structure and the limited knowledge about cell wall biosynthesis and modulation. Here, we present genetic and biochemical evidence to demonstrate that the Cdi-mediated galactosylation of rhamnogalacturonan-II (RG-II) is required for apoplastic Fe reallocation. Cdi is expressed in roots and up-regulated in response to Fe deficiency. It encodes a putative glycosyltransferase localized to the Golgi apparatus. Biochemical and mass spectrometry assays showed that Cdi catalyzes the transfer of GDP-L-galactose to the terminus of side chain A on RG-II. Disruption of Cdi essentially decreased RG-II dimerization and hence disrupted cell wall formation, as well as the reallocation of apoplastic Fe from roots to shoots. Further transcriptomic, Fourier transform infrared spectroscopy, and Fe desorption kinetic analyses coincidently suggested that Cdi mediates apoplastic Fe reallocation through extensive modulation of cell wall components and consequently the Fe adsorption capacity of the cell wall. Our study provides direct evidence demonstrating a link between cell wall biosynthesis and apoplastic Fe reallocation, thus indicating that the structure of the cell wall is important for efficient usage of the cell wall Fe pool.
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Base de dados:
MEDLINE
Assunto principal:
Parede Celular
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Pectinas
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Arabidopsis
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Proteínas de Arabidopsis
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Ferro
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Nucleotidiltransferases
Idioma:
En
Revista:
Mol Plant
Assunto da revista:
BIOLOGIA MOLECULAR
/
BOTANICA
Ano de publicação:
2021
Tipo de documento:
Article