Valorization of biowastes from olive oil mill as inducers of plant defence responses

Olive oil production generates significant amounts of biowaste with harmful effects on the environment. These agro-industrial biowastes can be enriched in cell wall polysaccharides and oligosaccharides (Sciubba et al., 2020). The industrial process could produce molecules like the self-harm signals generated upon pathogen infection, referred as damage-associated molecular patterns (DAMPs) (Coculo et al., 2022; Swaminathan et al., 2022). With a view to circular economy, we aim to unravel the potential of biowastes from olive mill as source of plant bioprotectants and biostimulants. Pectic and hemicellulosic oligosaccharides were isolated from different biowastes and their chemical structure characterized. The isolated oligosaccharides induced the expression of defence genes in Arabidopsis and improved Arabidopsis tolerance to the fungus Botrytis cinerea without affecting growth. Further biochemical and physiological characterizations of these elicitors are in progress. Investigations into early defense responses and resistance of important crops against different pathogens are ongoing.