Chitosan nanoparticle induced defense responses in fingermillet plants against blast disease caused by Pyricularia grisea (Cke.) Sacc

•Chitosan nanoparticle inhibit the growth of Pyricularia grisea under in vitro condition.•Application of chitosan nanoparticle delayed the blast symptom appearance.•Treated plants exhibited reduced disease incidence.•Treatment resulted in accumulation of ROS, peroxidase in the leaves. The in vitro antifungal properties of chitosan nanoparticle and its role in protection of fingermillet plants from blast disease were evaluated. Chitosan nanoparticle inhibited the radial growth of Pyricularia grisea indicating the antifungal property. Application of chitosan nanoparticle delayed blast symptom expression on fingermillet leaves for 25days while it was on 15day in control plants. Chitosan naoparticle was able to induce the reactive oxygen species and the level of peroxidase actvitiy in leaves of fingermillet, which might be the reason for delayed symptom. The treated plants showed reduced disease incidence when compared to untreated control plants. These results suggested the role of chitosan nanoparticle in protecting fingermillet plants from P. grisea infection.