Premium
Arabinogalactan proteins have deep roots in eukaryotes: identification of genes and epitopes in brown algae and their role in Fucus serratus embryo development
Author(s) -
Hervé Cécile,
Siméon Amandine,
Jam Murielle,
Cassin Andrew,
Johnson Kim L.,
Salmeán Armando A.,
Willats William G. T.,
Doblin Monika S.,
Bacic Antony,
Kloareg Bernard
Publication year - 2016
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13786
Subject(s) - biology , brown algae , arabinogalactan , multicellular organism , algae , cell wall , botany , red algae , green algae , gene , glycome , glycan , genetics , glycoprotein
Summary Arabinogalactan proteins ( AGP s) are highly glycosylated, hydroxyproline‐rich proteins found at the cell surface of plants, where they play key roles in developmental processes. Brown algae are marine, multicellular, photosynthetic eukaryotes. They belong to the phylum Stramenopiles, which is unrelated to land plants and green algae (Chloroplastida). Brown algae share common evolutionary features with other multicellular organisms, including a carbohydrate‐rich cell wall. They differ markedly from plants in their cell wall composition, and AGP s have not been reported in brown algae. Here we investigated the presence of chimeric AGP ‐like core proteins in this lineage. We report that the genome sequence of the brown algal model Ectocarpus siliculosus encodes AGP protein backbone motifs, in a gene context that differs considerably from what is known in land plants. We showed the occurrence of AGP glycan epitopes in a range of brown algal cell wall extracts. We demonstrated that these chimeric AGP ‐like core proteins are developmentally regulated in embryos of the order Fucales and showed that AGP loss of function seriously impairs the course of early embryogenesis. Our findings shine a new light on the role of AGP s in cell wall sensing and raise questions about the origin and evolution of AGP s in eukaryotes.