| Leaf spot is a new disease of Polyscias guifoylei in Ghuangzhou, resulting in seriously economic
loss of P. guifoylei. It’s occurrance rate was 10%-50%. In this study, the pathogen isolate FLT4 was obtained from
diseased P. guifoylei samples from Guangzhou. Identification of the isolate was carried out through physiological and
biochemical identification and phylogeny analysis of 16S rRNA sequences, the results showed that FLT4 was clustered
in the same branch with Xanthomonas campestris pv. vesicatoria、X. axonopodis and X. citri. According to Bergey’s
Manual of Systematic Bacteriology (Second Edition), Xanthomonas campestris pv. vesicatoria and X. citri are classified
in X. axonopodis. Then, the results of physiological and biochemical characteristics indicated that the similarity
of pathogenic isolate FLT4 and X. axonopodis was 55.56%. Therefore, the pathogen of leaf spot of P. guifoylei was
preliminarily identified as a Xanthomonas axonopodis. |
