SEPARATION OF TILLETIA-INDICA CHROMOSOMES USING CHEF GEL-ELECTROPHORESIS

Electrophoretic karyotypes were determined for single teliospore isolates and monosporidial lines of Tilletia indica, causal agent of Karnal bunt disease of wheat. Good separation of chromosomes of T. indica was achieved using 0.7% chromosomal grade agarose and a 3-15 minute ramped switching interval for 168 hours at 60 volts. At least 11 chromosomes were observed in T. indica, ranging in size from ca 1 to over 3.3 megabases. Many isolates contained unique karyotypes. Substantial variation in banding intensity was observed within many isolates, indicating the possible presence of multiple chromosomes within single bands. Electrophoretic karyotypes of single teliospore isolates from infected wheat seeds were compared with those of monosporidial isolates derived therefrom. Some differences were observed in karyotypes of teliospore and monosporidial lines, indicating that alterations in karyotype may occur through meiosis in T. indica. Southern blot hybridization revealed that the large subunit ribosomal DNA gene is located on the largest chromosome in T. indica.