May be involved in plant defense against cyst nematode pathogens. Hydrolysis of (1->3)-beta-D-glucosidic linkages in (1->3)-beta-D-glucans. (Microbial infection) Interacts with the 30C02 effector protein (AC G3GD54) of the beet cyst nematode Heterodera schachtii. Interaction with the 30C02 effector protein may potentially suppress beta-1,3-glucanase activity and plant defense. Induced by infection with the Cucumber mosaic virus (CMV). (Microbial infection) Specifically down-regulated by Heterodera schachtii (cyst nematodes) in nematode-induced syncytia. Belongs to the glycosyl hydrolase 17 family.