• Home
  • Search Results
  • Calcium Binding by Arabinogalactan Polysaccharides Is Important for Normal Plant Development.

Calcium Binding by Arabinogalactan Polysaccharides Is Important for Normal Plant Development.

The Plant cell (2020-08-10)
Federico Lopez-Hernandez, Theodora Tryfona, Annalisa Rizza, Xiaolan L Yu, Matthew O B Harris, Alex A R Webb, Toshihisa Kotake, Paul Dupree
ABSTRACT

Arabinogalactan proteins (AGPs) are a family of plant extracellular proteoglycans involved in many physiological events. AGPs are often anchored to the extracellular side of the plasma membrane and are highly glycosylated with arabinogalactan (AG) polysaccharides, but the molecular function of this glycosylation remains largely unknown. The β-linked glucuronic acid (GlcA) residues in AG polysaccharides have been shown in vitro to bind to calcium in a pH-dependent manner. Here, we used Arabidopsis (Arabidopsis thaliana) mutants in four AG β-glucuronyltransferases (GlcAT14A, -B, -D, and -E) to understand the role of glucuronidation of AG. AG isolated from glcat14 triple mutants had a strong reduction in glucuronidation. AG from a glcat14a/b/d triple mutant had lower calcium binding capacity in vitro than AG from wild-type plants. Some mutants had multiple developmental defects such as reduced trichome branching. glcat14a/b/e triple mutant plants had severely limited seedling growth and were sterile, and the propagation of calcium waves was perturbed in roots. Several of the developmental phenotypes were suppressed by increasing the calcium concentration in the growth medium. Our results show that AG glucuronidation is crucial for multiple developmental processes in plants and suggest that a function of AGPs might be to bind and release cell-surface apoplastic calcium.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Calcium chloride, anhydrous, granular, ≤7.0 mm, ≥93.0%
Sigma-Aldrich
Murashige and Skoog Basal Medium, powder, suitable for plant cell culture