AMPLIFIED DNA POLYMORPHISMS OF PUTATIVE 2-COMPONENT REGULATORY GENES OF SEVERAL XANTHOMONAS-CAMPESTRIS PATHOVARS

Oligonucleotide primers were generated based on conserved sequences of two-component regulatory genes of Xanthomonas campestris pv. campestr is. Amplification products from DNA of X. campestris pathovars alfalfa e, phaseoli, phaseoli var. fuscans, pisi, cucurbitae, campestris, caro tae, and vesicatoria revealed that there were multiple copies of putat ive regulator and sensor genes in their genomes. The most strongly amp lified fragments were 610-660 bp and 380 bp, and were present in all t ested pathovars of X. campestris. Amplified DNA polymorphisms correspo nded to the traditional pathovar classification scheme except for X. c . pv. phaseoli var. fuscans and X. c. pv. phaseoli which were distinct . The results indicate that although the fuscans variant is included i n the pathovar phaseoli, it is as genetically different from nonfuscan s strains as it is from some pathovars. In addition, the polymorphisms with these primers may be a quick and simple means of determining at least some pathovars of X. campestris.