SURFACE-COAT OF MELOIDOGYNE-INCOGNITA

The nematode surface coat is defined as an extracuticular component on the outermost layer of the nematode body wall, visualized only by ele ctron microscopy. Surface coat proteins of Meloidogyne incognita race 3 infective juveniles were characterized by electrophoresis and Wester n blotting of extracts from radioiodine and biotin-labeled nematodes. Extraction of labeled nematodes with cetyltrimethylammonium bromide yi elded a principal protein band larger than 250 kDa and, with water sol uble biotin, several faint bands ranging from 31 kDa to 179 kDa. The p attern of labeling was similar for both labeling methods. Western blot s of unlabeled proteins were probed with a panel of biotin-lectin conj ugates, but only Concanavalin A bound to the principal band. Nematodes labeled with radioiodine and biotin released I-125 and biotin-labeled molecules into water after 20 hours incubation, indicating that surfa ce coat proteins may be loosely attached to the nematode. Antiserum to the partially purified principal protein bound to the surface of live nematodes and to several proteins on Western blots. Differential patt erns of antibody labeling were obtained on immune-blots of extracts fr om M. incognita race 1, 2, and 3; Meloidogyne hapla race 2; and Meloid ogyne arenaria cytological race B.