Experiments were conducted to investigate the presence, number of copies and integration site of pAN7-1 in the genome of mutants of Magnaporthe grisea impaired in pathogenicity to rice. The mutants T41, T93, T251 (obtained by REMI) and T108 (obtained by conventional mutagenesis) exhibiting different alterations in pathogenicity were analyzed. Polymerase chain reaction (PCR) and Southern blot analyses were conducted with total DNA of mutants. The presence of pAN7-1 in genome of mutants was confirmed by PCR. Based in Southern blot analyses, two single-copy integration of vector were detected in T41. Two insertion sites of pAN7-1 were detected in the genome of T93, including an event of tandem integration. The results indicated the presence of a single-copy vector in single location in T108 and T251 genomes. Only T251 showed integration pattern of pAN7-1 suggesting the occurrence of REMI event. The difference in size of hybridizing band indicated the possible randomness of integration events in M. grisea genome. The potential of REMI to mutagenesis in M. grisea, using pAN7-1 and HindIII, was evidenced.
Rice blast; pathogenicity genes; insertional mutagenesis; Oryza sativa; Pyricularia grisea; REMI
