Brown stripe, incited by Acidovorax oryzae is one of the most important and widespread diseases in rice (Oryza sativa) nurseries in Iran. Rice seedlings showing brown stripes were collected from suburb areas in southern Sari. Bacteria were isolated on plates of sorbitol neutral red agar. Species-specific PCR using trpB1/trpB2 and SEQID1/SEQID2 primer pairs resulted in amplification of the expected 478 bp and 514 bp long fragments, respectively. The 32 isolates subjected to REP-PCR analysis displayed 15 different banding profiles, with just one being shared by 10 isolates and 10 profiles were solitary and not shared by any isolates. Nonetheless, the isolates could not be different phenotypically. They appeared to be biochemically and nutritionally rather homogeneous while the genetic diversity as depicted in REP-PCR analysis was remarkable among the strains isolated from the closely located and even neighboring rice seedbeds. The implication of the findings in breeding programs is briefly discussed.
Keywords: Acidovorax oryzae; Bacterial brown stripe of rice; REP-PCR; Species-specific PCR.