New Approach to Detect and Isolate Rhamnogalacturonan-II in <em>Arabidopsis thaliana</em> Seed Mucilage

Rhamnogalacturonan-II (RG-II) is one of the least studied domains of pectin, primarily due to its low abundance, the lack of reliable antibodies, and the complexity of its structure. The present study builds upon existing protocols and procedures used to analyse RG-II in tissues where it is more abundant, combining and adapting them for the isolation of RG-II from <i>Arabidopsis</i> seed mucilage-a structure previously thought to lack RG-II. By applying these adapted methods, we first confirmed the presence of RG-II in seed mucilage and subsequently succeeded in isolating it from a tissue where it is typically present in low abundance, thereby enabling future studies on this previously overlooked component. Key features • An efficient RG-II isolation protocol offers the opportunity to simplify and deepen the study of RG-II. • It provides reliable yields. • The protocol allows analysis of RG-II synthesis or structural changes affecting dimerisation in mutant lines using <i>Arabidopsis</i> seed mucilage.