Ricerc@Sapienza

Plants defense responses can be triggered by endogenous elicitors, which are released upon pathogen infection or mechanical injury, indicated as damage-associated molecular patterns (DAMPs). Among DAMPs, there are fragments originating from cell wall polysaccharides, such as the oligogalacturonides (OGs). The activity of OGs as DAMPs is well documented(Ferrari et al. 2013). Benedetti et al. 2018 have recently identified a possible mechanism by which the homeostasis of OGs may be maintained by specific oxidases named OGOXs. These enzymes belong to the so-called berberine-bridge enzyme-like (BBEl) family. A role of OGOXs in immunity has been demonstrated. Besides OGs, other oligosaccharides released from the cell wall have been recently shown to be involved in signaling, for example, cellodextrins (CDs) derived from the degradation of cellulose have been shown to act as DAMPs. In the laboratory where I perform my thesis, one member of the Arabidopsis BBEl family has been recently identified as a specific oxidase of CDs: CELLOX1. The aim of my project is to characterize part of the BBE-like family oxidases and to identify their substrates and the respective products. In general my research will address the problem of controlling immunity triggered by DAMPs and preventing their deleterious effects. Whether cell wall-derived DAMPs act in concert and their oxidation merely dampens the immune response or modulates it for a finely tuned output will be defined. Moreover, my work may elucidate the role of cell-wall derived signals in development. This knowledge may be exploited to improve resistance of crops to biotic stresses, and to optimize plant development and growth.