Xanthomonas oryzae pv.oryzae (Xoo) causes bacterial leaf blight (BLB), a devastating disease of rice in Asia countries.Xoo utilizes repertoires of transcriptional activator-like effectors (TALEs) to manipulate host resistance or susceptibility;thus TALEs can determine the outcome of BLB.In this report, we studies genetic diversity in putative tale genes of 50 Xoo strains that originated from six provinces of China.Genomic DNAs from 50 strains were digested with BamHI and hybridized with an internal fragment of pthXo1, a tale gene originating from the related pathogen, X.oryzae pv.oryzae (Xoo) that causes bacterial leaf blight (BLB).Southern blot analysis indicated that a variable number of pthXo1-hybridized fragments (e.g.putative tale genes) were contained in the tested strain.Based on the number and size of hybridizing bands, strains were classified into ten genotypes (designated 1 to 10).There are three genotypes in the strains from Liaoning and Guangxi, respectively;two genotypes from Jiangsu, Guangdong and Yunnan provinces, respectively;only one genotype is tested from Hunan province.And great interesting finding is that there are two genotypes distributed commonly: one in Jiangsu, Hunan and Guangxi;and another in Guangxi and Guangdong.These results suggest that investigation on diversities of tale-genotypes in Chinese Xoo strains may help planting resistant rice in a rice-growing region or predicting what would be the dominant virulent genotypes.