Pathotypic variation of Xanthomonas oryzae pv. oryzae in Bangladesh

Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo), a destructive disease of rice. Altogether, 96 isolates of Xoo were collected from 19 rice growing districts of Bangladesh in irrigated and rainfed seasons during 2014 to assess pathotypic variation. Pathotypic analyses on a set of 12 Near Isogenic Lines (NILs) of rice containing resistance genes viz. Xa1, Xa2, Xa3, Xa4, Xa5, Xa7, Xa8, Xa10, Xa11, Xa13, Xa14 and Xa21 and two check varieties IR24 and TN1 by leaf clip-inoculation technique. A total of 24 pathotypes were identified based on their virulence patterns on NILs tested. Among these, pathotypes VII, XII, and XIV considered as major, containing maximum number of isolates, (9.38% each) frequently distributed in North to Mid-Eastern districts of Bangladesh. Most virulent pathotype I recorded from Habiganj and Brahmanbaria. This pathotypic variation explained the pathogenic relatedness of X. oryzae pv. oryzae populations from diverse geographic areas in Bangladesh.