The isolation and characterization of polyclonal and monoclonal antibodies to anastomosis group 8 of Rhizoctonia solani

Abstract

Polyclonal and monoclonal antibodies were raised against secreted proteins from an anastomosis group 8 isolate of Rhizoctonia solani and tested for reactivity to field isolates from anastomosis groups 2‐1, 3,4 and 8. Polyclonal antibodies raised against total secreted proteins cross‐reacted in immunoblotting experiments with all R. solani isolates. However, immunoreactive proteins specific to Ag‐8 isolates were evident. Monoclonal antibodies to secreted proteins were raised which reacted with fewer proteins and showed a greater degree of specificity for AG‐8 isolates. Two monoclonals were selected for further study. One, an IgM monoclonal antibody, reacted with all R. solani isolates, recognizing a 40‐kDa protein specific to AG‐8 isolates and proteins of lower molecular weight in isolates from other anastomosis groups. The other, an IgG monoclonal antibody, was more specific, reacting with 38, 40 and 55‐kDa proteins from AG‐8 isolates and cross‐reacting with few isolates from other anastomosis groups. Preliminary results on the induction of antigens recognized by the monoclonal antibodies are presented. The monoclonal antibodies characterized here are useful for the identification of isolates of R. solani and may also be used as probes to clarify the relationships between anastomosis groups.