Ricerc@Sapienza

The plant cell wall (CW) is a complex structure that acts as a mechanical barrier, restricting
the access to most microbes. Phytopathogenic microorganisms can deploy an arsenal of CWdegrading
enzymes (CWDEs) that are required for virulence. In turn, plants have evolved proteins
able to inhibit the activity of specific microbial CWDEs, reducing CW damage and favoring the
accumulation of CW-derived fragments that act as damage-associated molecular patterns (DAMPs)
and trigger an immune response in the host. CW-derived DAMPs might be a component of the

The plant cell wall is the barrier that pathogens must overcome to cause a disease and to this purpose they secrete degrading enzymes of the various cell wall components. Due to the complexity of these components, several types of oligosaccharide fragments may be released during pathogenesis and some of these can act as Damage-Associated Molecular Pattern (DAMPs). Well-known DAMPs are the oligogalacturonides (OGs) released upon degradation of homogalacturonan and the products of the cellulose breakdown, i.e. the cellodextrins (CDs).

Oligogalacturonides (OGs) are pectic fragments derived from the partial degradation of homogalacturonan in the plant cell wall and able to elicit plant defence responses. Recent methodological advances in the isolation of OGs from plant tissues and their characterization have confirmed their role as bona fide plant Damage-Associated Molecular Patterns. Here, we describe the methods for the isolation of OGs from Arabidopsis leaf tissues and for the characterization of OG structure and biological activity.