Secreted chitinase involved in the degradation of chitin, a component of the cell walls of fungi and exoskeletal elements of some animals (including worms and arthropods) (By similarity). Plays a morphogenetic role during apical growth, cell division and differentiation (cell wall morphogenesis) (By similarity). Random endo-hydrolysis of N-acetyl-beta-D-glucosaminide (1->4)-beta-linkages in chitin and chitodextrins. Monomer. Belongs to the glycosyl hydrolase 18 family. Chitinase class III subfamily.