Upon wounding of plant tissues, pectic fragments from oligogalacturonides in the cell wall induce the accumulation of reactive oxygen species (ROS) and pathogenesis-related proteins (PRPs) to protect plant tissues against pathogen infection (Ferrari et al., 2013). Chitosan triggers similar responses when applied to plant tissues (Malerba and Cerana, 2015, Mejía-Teniente et al., 2013 and Pastor et al., 2013).