Oligogalacturonide oxidases (OGOXs) play a role in plant immunity and development

Plant immunity can be activated by endogenous elicitors referred to as damage-associated molecular patterns (DAMPs). Typical DAMPs are the oligogalacturonides (OGs), released from the cell wall pectin upon pathogen infection or mechanical injury or during the physiological cell wall remodeling. Four OG oxidases, named OGOX1-4, that belong to the Berberine Bridge Enzyme-like (BBE-like) family have been identified in Arabidopsis. BBE-l enzymes play a role in immunity, likely preventing over-accumulation of DAMPs and consequent deleterious effects on plant health (hyper-immunity). The oxidation reaction produces hydrogen peroxide (H2O2) as a secondary product. To study the role of OGOXs, transgenic plants over-expressing OGOX1 and CRISPR-Cas9 edited single and double ogox1 and ogox2 mutants have been generated. The characterization of these mutants shows that OGOXs play a role in the homeostasis of OGs and in the growth-defense trade-off.