Composition and physicochemical properties of outer mucilage from seeds of Arabidopsis natural accessions

Seed mucilage is a hydrogel formed of polysaccharides released from the epidermal cells of the seed coat on imbibition. This characteristic is found in many plant species, including Arabidopsis thaliana where mucilage is formed of two layers. Many roles have been proposed for seed mucilage, but to date no clear function has emerged in A. thaliana, and as the two layers have different compositions and structure it is likely that they fulfil distinct functions. Large numbers of natural A. thaliana accessions have been collected from the wild. The study of natural variation in mucilage across these accessions could provide useful information about its physiological roles.

Poulain et al. recently published an Editor’s Choice dataset in AoBP describing six traits for polysaccharides extracted from the outer layer of mucilage for a panel of 306 natural A. thaliana accessions. Staining with ruthenium red facilitates the observation of the two mucilage layers released from Arabidopsis seeds. The outer layer can then be easily extracted with water. This data set provides a starting point for future analyses describing the genetic variation for these traits and the identification of accessions harbouring gene variants with strong effects. While the latter can be used to identify genes that contribute to the adaptive function of the traits through genetic linkage analysis using co-segregation, the data set as a whole could also provide valuable insights through association studies with other available data sets for genome sequence, phenotypes or geolocalization. The latter could highlight potential adaptations of mucilage traits to specific ecological or geographical environments.