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Craterostigma plantagineum cell wall composition is remodelled during desiccation and the glycine‐rich protein CpGRP1 interacts with pectins through clustered arginines
Author(s) -
Jung Niklas U.,
Giarola Valentino,
Chen Peilei,
Knox John Paul,
Bartels Dorothea
Publication year - 2019
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14479
Subject(s) - pectin , cell wall , chemistry , biochemistry , apoplast , dehydration , biophysics , biology
Summary Craterostigma plantagineum belongs to the desiccation‐tolerant angiosperm plants. Upon dehydration, leaves fold and the cells shrink which is reversed during rehydration. To understand this process changes in cell wall pectin composition, and the role of the apoplastic glycine‐rich protein 1 (CpGRP1) were analysed. Cellular microstructural changes in hydrated, desiccated and rehydrated leaf sections were analysed using scanning electron microscopy. Pectin composition in different cell wall fractions was analysed with monoclonal antibodies against homogalacturonan, rhamnogalacturonan I, rhamnogalacturonan II and hemicellulose epitopes. Our data demonstrate changes in pectin composition during dehydration/rehydration which is suggested to affect cell wall properties. Homogalacturonan was less methylesterified upon desiccation and changes were also demonstrated in the detection of rhamnogalacturonan I, rhamnogalacturonan II and hemicelluloses. CpGRP1 seems to have a central role in cell adaptations to water deficit, as it interacts with pectin through a cluster of arginine residues and de‐methylesterified pectin presents more binding sites for the protein−pectin interaction than to pectin from hydrated leaves. CpGRP1 can also bind phosphatidic acid (PA) and cardiolipin. The binding of CpGRP1 to pectin appears to be dependent on the pectin methylesterification status and it has a higher affinity to pectin than its binding partner CpWAK1. It is hypothesised that changes in pectin composition are sensed by the CpGRP1−CpWAK1 complex therefore leading to the activation of dehydration‐related responses and leaf folding. PA might participate in the modulation of CpGRP1 activity.