A Repetitive DNA Sequence DifferentiatesXanthomonas campestrispv.oryzaefrom Other Pathovars ofX. campestris

Abstract

Two repetitive DNA sequences were detected in the genome of Xanthomonas campestris pv. oryzae. An EcoRI-HindIII restriction fragment (2.4 kilobases) containing one highly repetitive sequence was cloned (pJEL101). Approximately 81 copies of the repetitive sequence in pJEL101 were dispersed throughout the genome as determined by quantitative filter hybridizations. Repetitive sequences related to pJEL101 were detected in all strains of X. c. pv. oryzae from different geographic areas. Strains representing five of 25 other X. campestris pathovars appeared to contain multiple copies of a related element. Only X. c. pv. oryzicola, another rice pathogen, contained a relatively high copy number of pJEL101 sequences compared to X. c. pv. oryzae, although the hybridization banding pattern was different. The pJEL101 sequence is a useful probe for pathovar identification as well as strain and population analyses.