THE CLONING AND PCR DETECTION OF GENOMIC DNAFRAGMENT OF POLYMYXA BETAE
甜菜多粘菌基因组片段的克隆及PCR检测

According to reports, primers were designed to amplify the genomic DNA fragment of P. betae,which was cloned to pGEM--3Zf( ). By restriction endonuclease digestion, PCR amplification and sequenceanalysis, the cloned DNA fragment is identificated as gemomic fragment of P. betae. NO any DNA product wasobtained in detection of P. graminis or O. brassicae from infected roots of wheat or string bean respectively,which further proved that the primers used for DNA fragment amplification of P. betae is specific to P. betaeonly. Posttransplant in infected soil for two or thee and half a days, cruds DNA was extracted from single rootof sugar beet seedlings and used for PCR test which showed that P. betae DNA could be identified specificallyin the sugar beet seedlings with easy infection period.