Isolation and Preliminary Identification on Pathogen of Black Rot Disease on Non-heading Chinese Cabbages in Fuzhou

Pathogen that caused the black rot disease on non-heading Chinese cabbages in Fuzhou was investigated. Microbial samples were collected from the diseased plants for isolation. Based on the morphology and inoculation test, selected microorganisms were tested further. Their 16S rDNA were amplified by PCR with the universal primer 16S. The positive fragment was sequenced and analyzed against NCBI database. A 99.8% homology was found between an isolated bacterium and Xanthomonas campestris pv. campestris (Genbank:CP017308.1). Subsequently, the 16S rDNA sequence of the strain from the infected cabbage was confirmed to be identical to that of the pathogen for the inoculation. It was, therefore, concluded that the isolated strain was indeed the pathogen that caused the black rot disease on the non-heading cabbages, and was preliminary identified as Xanthomonas campestris pv. campestris.