Leucine rich repeat-malectin receptor kinases IGP1/CORK1, IGP3 and IGP4 are required for arabidopsis immune responses triggered by β-1,4-D-Xylo-oligosaccharides from plant cell walls

The reducing end of cell wall oligosaccharides is critical for DAMP activity inArabidopsis thalianaand can be exploited by oligosaccharide oxidases in the scavenging of phenolic radicals

“…It is likely that the open-chain acid residue at the C1-end may impair binding with plant recognition receptors (PRRs), highlighting the reducing end as critical for oligosaccharide-receptor interactions. (Brutus et al, 2010;Fernández-Calvo et al, 2024). It is also possible that, in addition to PRR-mediated recognition, the signal transduction cascade triggered by a cell wall DAMP may require its oxidation.…”

“…Subsequently, the purified FHS-CELLOX1 and H-GOOX were separately used to oxidize CD4 whereas H-XOOX was used to oxidize Xyl4. Cello-and xylo-tetramers served as reference cell wall oligomers with a proven elicitor activity in A. thaliana (Fernández-Calvo et al, 2024;Locci et al, 2019). The enzymatic reactions also occurred in the presence of a mammalian catalase, here used to recycle the hydrogen peroxide generated from oligosaccharide oxidation into H2O and O2, molecules both required for the oxidative reaction catalyzed by OSOXs (Pontiggia et al, 2020;Scortica et al, 2022).…”

“…Recently, 3-α-L-arabinofuranosyl-xylo-tetraose (XA3XX) and xylo-tetraose (Xyl4) have been reported to act as DAMPs in A. thaliana (Fernández-Calvo et al, 2024;Mélida et al, 2020). By using OSOXs of both fungal and plant origin, we demonstrate here that oxidized Xyl4 (xylo-tetraonic acid, ox-Xyl4) and oxidized CD4 (cello-tetraonic acid, ox-CD4) have a weaker elicitor activity than their non-oxidized counterparts, reinforcing the view that DAMP action of cell wall oligosaccharides is dependent on the oxidation state of their reducing end, regardless whether the OSOX employed for their oxidation originates from fungi or plants.…”